HK40059080A - Embolic retrieval catheter - Google Patents

Description

Thrombus retrieval catheter

Cross Reference to Related Applications

This application is a partial continuation of U.S. patent application No. 16/589,563 filed on 1/10/2019, and further claims the benefit of U.S. provisional application No. 63/026,898 filed on 1/5/2020, in accordance with 35u.s.c. § 119(e), the entire contents of which are incorporated herein by reference. Further, International patent application No. PCT/US2019/029709, filed on 29/4/2019, incorporated herein by reference.

Background

Stroke (stroke) is the third most common cause of death in the united states and is also the most disabling neurological disease. Approximately 700,000 patients suffer from a stroke annually. Cerebral stroke is a syndrome characterized by an acute episode of neurologic deficit that lasts at least 24 hours, reflecting a focal involvement of the central nervous system, and is the result of a cerebral circulatory disorder. Its incidence increases with age. Risk factors for cerebral stroke include systolic or diastolic hypertension, hypercholesterolemia, smoking, alcohol abuse, and oral contraceptives.

Hemorrhagic stroke accounts for 20% of the annual stroke population. Hemorrhagic stroke often occurs due to rupture of an aneurysm or arteriovenous malformation bleeding into the brain tissue, resulting in cerebral infarction. The remaining 80% of stroke populations are ischemic strokes, which are caused by vascular occlusion depriving the brain of oxygenated blood. Ischemic cerebral stroke is often caused by emboli or pieces of thrombotic tissue that fall off other body parts or from the cerebral blood vessels themselves, leading more distally to occlusion in stenotic cerebral arteries. The term Transient Ischemic Attack (TIA) is used when patients present with neurological symptoms and signs that resolve completely within 1 hour. Etiologically, TIA and stroke share the same pathophysiological mechanisms and therefore represent a continuum based on symptom persistence and the extent of ischemic injury.

During arrhythmia, emboli occasionally form around the heart valves or in the left atrial appendage, which then slough off and follow the blood flow into the distal region of the body. These emboli can be transmitted to the brain and cause embolic stroke. As will be discussed below, many such occlusions occur in the Middle Cerebral Artery (MCA), although this is not the only site at which an embolism lands.

When a patient develops neurological deficit, a diagnostic hypothesis for the cause of a stroke can be generated based on the patient's medical history, brain stroke risk factor review, and neurological examination. If an ischemic event is suspected, the clinician can heuristically assess whether the patient has a cardiac embolus, a cranial or intracranial disease in the aorta, an intraparenchymal disease in the arterioles, or a disease in the blood system or other systemic disease. Head CT scans are often performed to determine whether a patient has ischemic or hemorrhagic damage. Blood is found on CT scans in cases of subarachnoid hemorrhage, intraparenchymal hematoma, or intracerebroventricular hemorrhage.

Traditionally, emergency management of acute ischemic brain stroke has primarily involved general supportive care such as hydration, monitoring of neurological status, blood pressure control, and/or antiplatelet or anticoagulant therapy. In 1996, (USA) food and drug administration approved the use of the thrombolytic drug, tissue plasminogen activator (t-PA) or tissue plasminogen activator (tPA) from GenentechCan be used for treating acute cerebral apoplexy. A randomized double-blind trial at the national institute for neurological diseases and t-PA stroke has shown that ischemic stroke episodesIn the group of patients receiving intravenous t-PA within 3 hours, the stroke scale score at 24 hours improved statistically significantly. Since the approval of t-PA, emergency room physicians were the first to provide effective treatment for stroke patients in addition to supportive care.

However, systemic t-PA treatment is associated with an increased risk of intracranial hemorrhage and other bleeding complications. Patients receiving t-PA treatment are more prone to symptomatic intracranial bleeding within the first 36 hours of treatment. The frequency of symptomatic bleeding increases when t-PA is administered over 3 hours of stroke onset. In addition to the time constraints of using t-PA in acute ischemic cerebral stroke, the following other contraindications are included: whether a patient has had a stroke or severe head trauma within the last 3 months, whether the patient has a systolic pressure above 185mmHg or a diastolic pressure above 110mmHg, whether the patient needs active treatment to reduce blood pressure to a prescribed limit, whether the patient is taking anticoagulants or has a bleeding tendency, and/or whether the patient has recently undergone invasive surgery. Therefore, only a small fraction of selected stroke patients will receive t-PA.

Infarcted emboli have also been mechanically removed from various sites in the vascular (vascular) system for many years. Mechanical therapy includes capturing and removing clots, dissolving clots, breaking up and suctioning (sucking) clots, and/or forming flow channels through clots. One of the earliest mechanical devices developed for the treatment of stroke was the MERCI Retriever system (central Medical, Redwood City, ca). A balloon-tipped guide catheter is used to access the Internal Carotid Artery (ICA) from the femoral artery. A microcatheter is placed through the guide catheter and used to deliver a retriever with a coil at the end through the clot and then the microcatheter is pulled back to place the retriever around the clot. The microcatheter and retriever are then pulled back into the balloon guide catheter in order to pull the clot while the balloon is inflated (inflated), and a syringe is connected to the balloon guide catheter to aspirate the guide catheter during clot retrieval. The device has an initial positive beneficial effect compared to thrombolytic (thrombolytic) therapy alone.

Other thrombectomy devices utilize expandable cages, baskets, or snares to capture and retrieve clots. Temporary stents (sometimes referred to as stent retrievers/retrieval devices/embolextractors or revascularization devices) are used to remove or retrieve clots and restore flow to the vessel. A series of devices that use active laser or ultrasonic energy to break up the clot have also been employed. Other active energy devices have been used in conjunction with intra-arterial thrombolytic infusion to accelerate the dissolution of the thrombus. Many of these devices are used in conjunction with aspiration to help remove clots and reduce the risk of embolism. Aspiration of clots has also been used in conjunction with single lumen catheters and syringes or aspiration pumps, with or without concomitant disruption of clots. Devices that apply a dynamic fluid vortex in conjunction with aspiration have been utilized to improve the efficacy of this thrombectomy method. Finally, balloons or stents have been used to create open lumens through the clot when clot removal or dissolution is not possible.

Nevertheless, there remains a need for new devices and methods for treating vascular occlusions in the body, including acute ischemic stroke and occlusive cerebrovascular disease.

Disclosure of Invention

According to one aspect of the present invention, a system for removing embolic material from an intravascular site is provided. The system includes an elongated flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one central lumen extending axially therethrough. An axial restraint carried by the sidewall and exposed to the lumen; a rotatable core wire can extend through the lumen, the core wire having a proximal end and a distal end. A restraint is carried by the core wire, the restraint having a bearing surface for rotatably engaging the restraint, and a clot gripping tip is disposed on a distal end of the core wire. The constraining member and the constraining member are configured to allow rotation of the core wire but limit distal travel of the tip to a distance no greater than about 6mm beyond the distal end of the tubular body.

The constraining member and the constraining member can be configured to allow rotation of the core wire but limit distal travel of the tip to a distance no greater than about 3mm beyond the distal end of the tubular body. The clot gripping tip may include a helical thread. The constraining member and the constraining member may be configured to allow rotation of the core wire but limit distal travel of the tip to expose about one to three full turns of the thread beyond the distal end of the tubular body.

The axial restraint may include a proximally facing bearing surface. The axial restraint includes a radially inwardly extending protrusion. The axial restraint may include an annular flange. The restraint may include a distally facing bearing surface. The restricting member may include a radially outwardly extending protrusion. The radially outwardly extending protrusion may be configured to be in sliding contact with the restraint.

The proximal bearing surface on the axial restraint can be in a range of about 30cm from the distal end of the tubular body. The proximal bearing surface may be in a range of about 4cm to about 12cm from the distal end of the tubular body. The restraint can be located within about the distal most 25% of the length of the core wire.

The helical thread may have a maximum major diameter that is no greater than about 90% of the inner diameter of the lumen, leaving an annular flow path between the tip and the inner surface of the sidewall. The helical thread may have a blunt outer edge.

The core wire may be removably positioned within the tubular body. The system may also include a manipulation member configured to manually rotate the core-wire.

The helical thread may extend entirely no more than about eight full turns. The helical thread may have a major diameter that increases proximally from a first diameter near the distal tip to a second maximum major diameter, and then decreases proximally to a third diameter at the maximum major diameter. The inner diameter of the tubular body adjacent the clot gripping tip is at least about 0.015 inches greater than the maximum outer diameter of the tip.

According to one aspect of the present invention, a torque transfer system for rotationally orienting a distal end of a catheter is provided. The system includes an elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. The first engagement surface is carried by the sidewall and exposed to the internal cavity. A torque wire may extend through the lumen, the torque wire having a proximal end and a distal end. The torque wire carries the second engagement surface. Outward lateral travel of the torque wire brings the second engagement surface into rotationally coupled engagement with the first engagement surface such that rotation of the torque wire in at least a first direction causes rotation of the distal end of the catheter.

The first engagement surface may include at least one inclined surface and may be carried by a radially inwardly extending projection. The protrusion may comprise a ring located in the lumen. The second engagement surface may comprise a distal facing surface, which may be inclined relative to the longitudinal axis of the catheter.

According to another aspect of the invention, a system for dislodging embolic material from within a blood vessel is provided. The system includes an elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. The first engagement surface is carried by the sidewall and exposed to the internal cavity. A tap/branch/suction line (tap wire) may extend through the lumen, the tap wire having a proximal end and a distal end. The tap line carries the second engagement surface. Distal advancement of the tap line brings the second engagement surface into contact with the first engagement surface and transfers momentum from the tap line to the distal end of the tubular body.

The first engagement surface may comprise a proximally facing surface and may be carried by a radially inwardly extending protrusion. The first engagement surface may comprise an annular flange. The second engagement surface may comprise a distally facing surface that may be carried by the distal end of the tap line. The distally facing surface may be on a hammer head carried by the wire.

According to another aspect of the present invention, a torque transfer system for rotationally orienting a distal end of a catheter is provided. The system includes an elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. The first connector is disposed on the sidewall and exposed to the internal cavity. A torque wire may extend through the lumen, the torque wire having a proximal end and a distal end. The second complementary connector is carried by the torque line. Coupling the first and second connectors enables the distal end of the catheter to rotate in response to rotation of the torque wire.

The first connector may comprise at least one angled/beveled tooth or radially inwardly extending protrusion. The protrusion may comprise a ring located in the lumen. The ring may include at least two angled/beveled teeth extending in a proximal direction. The second connector may include a distally facing surface carried by the torque wire. The distal facing surface may comprise at least one inclined surface. The second connector may be movable radially outward and may include an inflatable bladder, and the first connector may include an inner surface on the sidewall. The first connector may include a sidewall of an axially extending slot configured to receive a protrusion on the torque wire.

A method of rotationally orienting a catheter is also provided. The method includes the step of advancing a catheter to a location in a body lumen, the catheter having a central lumen and a distal end. The torque wire is advanced into the lumen. The first connector on the torque wire engages the second connector on the catheter and rotating the torque wire causes rotation of the distal end of the catheter.

Any feature, structure, or step disclosed herein may be substituted for or combined with any other feature, structure, or step disclosed herein or may be omitted. Moreover, for purposes of summarizing the disclosure, certain aspects, advantages, and features of the embodiments have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment disclosed herein. No individual aspect of the disclosure is required or essential. Other features and advantages of various embodiments will be apparent to those skilled in the art from the following detailed description, when considered in conjunction with the accompanying drawings and claims.

Drawings

FIG. 1A is a side view of a catheter with an internal stop ring.

FIG. 1B is a longitudinal cross-sectional view through the catheter of FIG. 1A, and a detail view of the stop ring.

Fig. 1C is a side view of an agitator having complementary limiting members for engaging the stop rings of fig. 1A and 1B.

Fig. 1D is a side view of a distal section of the agitator of fig. 24C.

Fig. 1E is a longitudinal section through the agitator of fig. 1D.

Fig. 1F is a perspective cut-away view of a distal section of the agitator of fig. 24C.

Fig. 1G is a cross-sectional view of a distal stop carried by the agitator.

Fig. 1H is a cross-sectional view through an alternative distal stop.

Fig. 2A is a side view of a torque wire used to rotate the distal end of the aspiration catheter.

Fig. 2B and 2C show torsion lines associated with a distal stop configured as a torsion ring.

FIG. 3A is a side view of an axially unconstrained occlusion junction line within an access catheter.

Fig. 3B and 3C are side views of an occlusion junction line having a limited distal range of motion beyond the distal end of the catheter.

Fig. 4 is a side view of a drive wire for use with the catheter of fig. 1A and 1B.

Figures 5A and 5B are side views of a blood flow assist wire for use with a catheter having a stop collar.

Fig. 5C shows a steerable wire used with a catheter having a stop collar.

Fig. 5D is a detailed view of the distal end of the steerable wire of fig. 5C.

Fig. 5E is a side view of the line of fig. 5C in a deflected/turned configuration.

6A-6B illustrate various distal cover embodiments for coupling a wick to an annular flange of an agitator tip.

Fig. 7A shows a cross-sectional view of a conduit wall according to one embodiment.

FIG. 7B shows a cross-sectional view of a catheter wall showing one or more axially extending wires, according to another embodiment.

Fig. 7C depicts a side view of the catheter.

Fig. 7D shows a cross-sectional view along a conduit having a sidewall with. One or more axially extending filaments.

Fig. 7E is a side cross-sectional view through an angled distal catheter or extension tube tip.

Fig. 8A depicts a side view of a catheter according to an embodiment.

Fig. 8B depicts a cross-sectional view taken along line a-a of fig. 8A.

Fig. 8C shows a cross-sectional view taken along line B-B of fig. 8A.

Fig. 9A depicts a side view of a catheter according to another embodiment.

FIG. 9B depicts a cross-sectional view taken along line A-A of FIG. 9A showing one or more axially extending filaments.

FIG. 9C shows a cross-sectional view taken along line B-B of FIG. 9A, showing one or more axially extending filaments.

10A-10B are side cross-sectional views along a blunt, angled distal catheter or extension tube tip.

FIG. 11A is a side cross-sectional view of a sinusoidally shaped distal catheter or extension tube tip.

FIG. 11B is a perspective view of a sinusoidal distal catheter or extension tube tip.

FIG. 12 shows a schematic diagram of a Computational Fluid Dynamics (CFD) velocity field model.

Fig. 13A shows an image of a numerical simulation of clot aspiration/suction using the model of fig. 12, showing the initial state after some aspiration has occurred.

Fig. 13B shows an image of a numerical simulation of clot aspiration using the model of fig. 12, showing active aspiration.

Fig. 14 shows a graphical representation of the percent increase in inhaled mass for the catheter distal tip shape shown in fig. 7E and 10A-11B as a percent improvement over the flattened or planar catheter distal tip shape shown in fig. 3A.

Fig. 15A depicts the CFD velocity field distribution of the distal tip of a flat or planar catheter.

Fig. 15B depicts the CFD velocity field distribution of the distal tip of the catheter with a 30 ° angle.

Fig. 15C depicts the CFD velocity field distribution of the distal tip of the catheter with a 60 ° angle.

Fig. 16A shows the uptake length of the angled distal catheter tip.

Fig. 16B shows the uptake length (ingestion length) of the blunt, angled distal catheter tip.

Fig. 17 shows a graphical representation of the percent increase in inhaled mass for the distal tip shape of the catheter shown in fig. 7E and 10A-11B as a percent improvement over the flat vertical catheter distal tip shape shown in fig. 3A.

Figure 18A illustrates a side view of a catheter having increased flexibility according to one embodiment.

FIG. 18B is a proximal end view of the enhanced flexibility catheter of FIG. 18A.

Fig. 19 shows the supportive nature of a catheter according to the present invention.

Fig. 20 depicts a graph of the modulus or stiffness of a catheter along the length of the catheter from the proximal end to the distal end.

Fig. 21 depicts a deflection test plot for a catheter according to the present invention compared to a conventional catheter.

Detailed Description

Referring to fig. 1A, a catheter 10 according to one aspect of the present invention is disclosed. Although described primarily in the context of an elongated flexible catheter having a single central lumen, such as an embolic clot/thrombus retrieval catheter, the catheter of the present invention can be readily modified to incorporate additional structures, such as a permanent or removable radial support force (column struts) reinforcing mandrel, two or more lumens, for example to allow for perfusion of drugs, contrast or irrigation agents, or to supply an inflation medium to an inflatable balloon carried by the catheter, or a combination of these features, as will be readily apparent to those skilled in the art in view of the disclosure herein. Furthermore, the invention will be described primarily in the context of removing occlusive material from the remote vasculature in the brain, but also has applicability as an access catheter for the delivery and removal of any of a variety of diagnostic or therapeutic devices with or without aspiration.

The catheter disclosed herein may be readily adapted for use throughout the body wherever it may be desirable to locate a catheter configured to accurately limit distal advancement of other internal catheter components or tools axially therethrough. For example, catheter shafts according to the present invention may be sized for use throughout the venous or arterial side of the neurovasculature, coronary and peripheral vasculature, gastrointestinal tract, urethra, ureters, fallopian tubes, as well as other lumens and potential lumens. Specific applications include clot removal in the case of ischemic stroke, deep vein thrombosis, and pulmonary embolism. The catheter structures of the present invention may also be used to provide minimally invasive percutaneous tissue access, for example for diagnostic or therapeutic access to a solid tissue target (e.g., breast or liver or brain diagnostic or therapy), the delivery of laparoscopic tools or access to bone such as the spine for delivery of devices benefiting from precise axial control.

The catheter 10 generally includes an elongated tubular body 16 extending between the proximal end 12 and the distal functional end 14. The length of the tubular body 16 depends on the desired application. For example, lengths in the region of about 120cm to about 150cm or more are commonly used in percutaneous transluminal (intraluminal) coronary applications for femoral access. Intracranial or other applications may require different catheter shaft lengths depending on the vascular access site, as will be understood in the art.

Referring to fig. 1B, any of the catheters disclosed herein may be provided with an axial restraint 2402 to cooperate with a complementary stop of an inner member, such as a rotation device, to allow rotation of the device but limit the distal axial range of travel of the inner device. This allows for accurate positioning of the distal tip of the inner device relative to the distal end of the catheter unaffected by bending of the catheter shaft and prevents the distal tip of the inner device from extending beyond a preset position such as the distal end of the catheter.

In the illustrated embodiment, the distal restraining member or element 2402 includes at least one protrusion extending radially inward from the inner surface of the tubular body configured to limit the inner diameter of the suction lumen and provide an interference bearing surface to engage the distal face presented by the agitator. The restraint may comprise one or two or three or four or more protrusions, such as tabs, or, as shown in fig. 1B, may comprise a continuous or open annular ring providing a substantially continuous, annular, proximally facing restraining surface. The proximal bearing surface 2405 of the axial restraint 2402 can be located within about 50cm or 30cm or 15cm of the distal end of the tubular body, such as within a range of about 4cm to about 12cm of the distal end.

Alternatively, bearing surface 2405 may be disposed at the proximal end of catheter 10, depending on the desired performance and the intended vasculature. For example, the proximal hub 15 may be provided with an internal bearing surface 11 to slidably engage a complementary distal bearing surface carried by the core wire. An outer surface 13 carried by the hub 15, such as an annular surface surrounding a central lumen, may alternatively be in sliding engagement with a complementary distal surface carried by the control wire manipulation member, as described below.

To optimize the alignment of the distal rotatable tip of the inner device with the distal port of the catheter and to make this axial alignment unaffected by the curvature of the vascular pathway that would otherwise alter the relative axial position of the catheter outlet port and tip, the proximal bearing surface of the axial restraint is typically at a position in the range of about 3mm to about 50mm, in some embodiments about 5mm to about 20mm, and in one embodiment about 6mm to about 14mm from the distal port on the catheter.

The distal restraining element may be a circular band or ring or protrusion 2402 of metal (e.g., nitinol, stainless steel, aluminum, etc.) or polymer that is mounted on or built into the inner surface of the sidewall 2403 of the catheter near the distal tip, with the distal restraining element 2402 extending into the inner diameter of the catheter. Further, distal constraining element 2402 may be radiopaque to be visible under fluoroscopy. The distal restraining element 2402 has a proximally facing surface 2405, such as an annular circumferential bearing surface, that extends into the inner diameter of the catheter to engage/interact with a distal stop 2414 on the rotating assembly. Referring to fig. 1C, for example, distal stop 2414 may be a rounded feature on the rotation assembly that interacts with the distal restraining element 2402 of the catheter to stop distal advancement and prevent the distal tip from being displaced beyond the distal tip of the catheter.

In one embodiment, in the relaxed form of the ring 2402 prior to fixation within the catheter lumen, the ring 2402 is C-shaped or cylindrical with an axially extending slit to form an open ring. The loop 2402 is compressed using a clamp that contracts the loop into a closed circular shape, thereby enabling the loop to slide within a (e.g., 0.071 inch) catheter. When the ring is released from the clamp, the ring expands radially to the maximum diameter permitted by the inner diameter of the catheter. The radial force of the ring engages the inner surface of the conduit and resists axial displacement under the applied force of the intended use. In another embodiment, the ring is a fully closed, continuous annular structure (as is typical of marker bands) and its distal end is slightly flared in a radially outward direction to form a locking edge. The ring is inserted into the catheter from the distal end. The flared section with locking edge secures the ring in place/holds in place when an axial force is applied proximally.

Alternatively, the distal restraint may be formed by: by forming a radially inwardly directed restriction in the catheter body, or by introducing the bearing surface through the catheter wall and communicating with the central lumen, for example by directing at least one or two or more protrusions through the wall and into the lumen. The restraint may take the form of a concentric inner tube having an axial length of at least about 1mm or 2mm or more, but typically less than about 5cm or 3cm or 2 cm. Depending on the nature of the distal restraint, it may be secured by a mechanical interference fit, a friction fit, or a bond formed by any of a variety of bonding techniques, including adhesive bonding and thermal bonding.

Referring to fig. 1C and 1D, the inner member is in the form of a clot retrieval device 2401. The distal section 2407 of the rotatable core wire includes a torque coil 2412 surrounding the core wire 2410. The torque coil 2412 includes an outer coil 2413 concentrically surrounding an inner coil 2415, the inner and outer coils having opposite winding directions. Although coil 2412 is shown as having a constant diameter, this leaves an internal embedded space between the coil and core due to the tapered core. The diameter of the coil 2412 may taper in the distal direction to follow the taper of the core wire when the area of the aspiration lumen between the coil and the inner wall of the respective catheter is optimally maximized. This may be accomplished by winding a coil onto a core wire that acts as a tapered mandrel, or using other techniques known in the art. In this implementation, the Outer Diameter (OD) of the core-wire is tapered in the distal direction, while the area of the aspiration lumen is tapered in the distal direction.

The proximal end of the core wire 2410 is provided with a manipulation member configured for manually rotating the core wire. The manipulation member may be a molded part, such as a knob, having axially oriented surface features, such as ribs, flats or grooves, to enhance gripping. The operating member may have two opposing tabs extending in opposite directions from the axis of the core wire and may be rotated using two or three fingers.

As further shown in fig. 1E and 1F, a torque coil 2412 extends between the proximal end 430 and the distal end 432. The proximal end 430 is secured to a tapered portion of the core wire 2410. As shown in fig. 1E, the core wire 2410 tapers from a larger diameter in the proximal region to a smaller diameter in the distal region 434, the core wire having a distal transition 436 between the tapered section and the distal region 434, which may have a substantially constant diameter throughout. The inner diameter of the inner coil 2415 is complementary (about the same) to the outer diameter at the proximal end 430 of the core wire 2410. The tapered section of the core wire 2410 extends in a proximal direction from the distal transition 436 to a proximal transition (not shown), the core wire 2410 having a constant diameter proximal to the proximal transition.

The torque coil 2412 may also be provided with proximal radiopaque markers and/or connections such as braze joints 438. In the illustrated embodiment, the proximal connector 438 is in the form of an annular band of silver solder material that surrounds the inner coil 415 and abuts the proximal end of the outer coil 2413.

The axial length of the torque coil 2412 is in the range of about 10mm to about 50mm, and in some embodiments, in the range of about 20mm to about 40 mm. The distal transition 436 and distal stop 2414 may be positioned at a location in a range of about 5mm to about 20mm, and in some embodiments, in a range of about 8mm to about 12mm from the proximal end of the distal cap 2420.

Referring to fig. 1E-1I, distal stop 2414 may be provided with one or two or three or more spoke portions 440 extending radially outward from outer coil 413 and optionally supported by an annular hub 442 carried by torque coil 2412. The spoke portion 440 supports a slide 441 having a peripheral surface 442 that is configured to be a sliding fit within the inner diameter of the delivery catheter lumen. Preferably, at least three or at least four or at least five or more spokes 440 are provided, which are equally spaced to provide rotational balance. In the illustrated embodiment, three spoke portions 440 are provided that are spaced apart at about 120 ° intervals around the circumference of the torque coil 2412.

In the illustrated embodiment, the axial length of the spokes or struts 440 is greater than their width measured in the circumferential direction and extends parallel to the longitudinal axis of the conduit. Alternatively, the spokes 440 may be oriented in a helical configuration to form a propeller that may assist in transporting material in a proximal direction during rotation. The leading edge may be sharp to sever thrombus engaged by rotation of the core wire while applying a vacuum to the central lumen.

The distal stop 2414 carries a plurality of distal surfaces 446, for example on the slider 441. The distal surface 446 is configured to slidably engage a proximal surface of a stop on the inner diameter of the delivery catheter, such as a proximally facing surface 2405 on a radially inwardly extending annular flange or ring 2402. See FIG. 1B, previously discussed. This creates a sliding interference fit with the bearing surface such that when the distal surface 446 is slidably engaged with the proximal surface 2405 on the stop ring 2402, the distal stop 2414 can rotate within the delivery catheter and cannot travel further in the axially distal direction.

Referring to fig. 1E, the distal end 432 of the torque coil 2412 is provided with a distal cap 2420. The distal cap 2420 may include an annular band, such as a radiopaque marker band, bonded to the outer surface of the inner coil 2415 and axially distally abutting or overlapping the distal end of the outer coil 2413. A proximally extending appendage, such as an annular flange 2417, may be provided on agitator end 2416 for coupling to distal cap 2420 and, in the illustrated embodiment, to outer coil 2413. The distal cap 2420 can also be coupled directly or indirectly to the distal end of the core wire 2410.

The agitator tip 2416 is provided with a distal end 450 and a proximally extending helical flange 452 that increases in diameter in a proximal direction to a maximum diameter and then decreases in diameter in a proximal direction to a minimum diameter, which may be greater than the diameter at the distal end. The flange may extend at least about one full turn, and typically less than about five or four or three turns, about the direction of extension of the longitudinal axis of the core-wire 2410. The helical flange is provided with a rounded blunt edge 454 configured to slidably rotate within the tubular delivery catheter.

The maximum outer diameter of the tip 2416 is typically at least about 0.005 inches, and preferably at least about 0.01 inches or 0.015 inches or more, as measured at the axial operative position of the tip 2416 when the stop 2414 is engaged with the stop ring, less than the inner diameter of a catheter aspiration lumen through which the embolic treatment system 2401 is intended to be advanced. For example, a tip having a maximum outer diameter in the range of about 0.050 inches to 0.056 inches would be positioned in a catheter having a distal inner diameter in the range of about 0.068 inches to about 0.073 inches, and in one embodiment about 0.071 inches. With the tip centrally located in the lumen of the delivery (aspiration) catheter, the tip is spaced from the inner wall of the catheter in all directions by a distance of at least about 0.005 inches, and in some embodiments at least about 0.007 inches or 0.010 inches or more.

Thus, an unobstructed flow path is formed in the annular space between the maximum outer diameter of the tip and the inner diameter of the catheter lumen. The annular flow path cooperates with the vacuum and the helical tip to grasp and pull the occlusive material into the catheter under rotation and vacuum. The annular flow path is significantly larger than any flow path created by manufacturing tolerances configured to shear the tip of embolic material between the tip and the catheter wall.

An additional suction volume is obtained, since a helical channel is defined between each two adjacent threads of the tip. The cross-sectional area of the spiral flow path of the tip having a maximum outer diameter in the range of about 0.050 inches to about 0.056 inches will typically be at least about 0.0003 square inches, and in some embodiments at least about 0.00035 or at least about 0.000375 inches. Thus, the total suction flow path along the helical tip is the sum of the helical flow path through the tip and the annular flow path defined between the outer diameter of the tip and the inner diameter of the catheter lumen.

The combination of the rounded edges 454 on the threads 452, the slow manual rotation of the tip by less than about 20 or 10 or 5 or less turns, and the space between the threads 452 and the inner wall of the catheter allows aspiration to occur both through the helical channel formed between adjacent helical threads and around the outside of the tip 2416, such that the assembly is configured to engage and capture embolic material without shearing it between the sharp edges and the inner wall of the catheter. Once engaged, additional rotation draws the aspiration catheter distally onto the clot to conceal/grip a proximal portion of the clot (ensconce) to facilitate proximal retraction and removal. The axial length of the end 2416, including the attachment sleeve 2417, is typically less than about 6mm, and preferably less than about 4mm or 3mm or 2.5mm or less, depending on the desired performance.

The pitch/profile angle of threads 452 may generally vary from about 35 degrees to about 80 degrees, depending on the desired performance. Thread pitch angles in the range of about 40-50 degrees may be most suitable for hard clots, while thread pitch angles in the range of about 50-70 degrees may be most suitable for soft clots. For certain embodiments, the pitch angle will be in the range of about 40-65 degrees or about 40-50 degrees.

The tip 2416 can also be provided with features to attract and/or enhance the adhesion of the clot to the tip. For example, a texture such as a micro-pore, micro-particle, nano-pore or nano-particle surface may be provided on the tip by treating the material of the tip or by applying a coating. A clot-attracting moiety such as a coating of a polymer or drug may be applied to the surface of the tip. For example, a roughened polyurethane (Tecothane, Tecoflex) coating may be applied to at least the surface of the threads and optionally to the entire tip. Desirably, the polyurethane may be roughened, for example, by solvent treatment after coating, and the adhesion of the coating to the tip may be enhanced by roughening the surface of the tip prior to coating.

Alternatively, the core wire 2410 may be provided with an insulating coating to allow propagation of negative charges to be transferred to the tip to attract thrombus. The two conductors may extend over the entire length of the body, for example in a coaxial arrangement. Energy parameters and considerations are described in U.S. patent No. 10,028,782 to Orion and U.S. patent publication No. 2018/0116717 to Taff et al, each of which is expressly incorporated herein by reference in its entirety. As another alternative, the tip 2416 can be cooled to a low temperature to create a small cryoadhesion between the tip and the thrombus. Considerations for forming a small cryogenic tip for an intravascular catheter are disclosed in U.S. patent publication No. 2015/0112195 to Berger et al and in U.S. patent publication No. 2018/0116704 to Ryba et al, the respective disclosures of which are expressly incorporated herein in their entirety by reference.

Referring to fig. 1G, a cross-section through distal stop 2414 is shown, wherein slider 441 is a continuous circumferential wall having a continuous outer peripheral bearing surface 442. The three struts 440 are spaced apart to define three flow channels 443 extending axially therethrough. The percentage of the sum of the surface areas of the leading edges of the struts 440 to the sum of the surface areas of the open flow channels 443 is preferably minimized. This allows for maximizing the suction area while still providing sufficient axial support for the distal surface 446 (see fig. 1F) to engage a complementary stop surface on the inner wall of the catheter and prevent the tip 2416 from advancing distally beyond a preset relationship with the catheter. The sum of the forward (distally facing) surface areas of the struts is typically less than about 45% of the total area of the flow channel 443, and typically less than about 30% or 25% or 20% of the total area of the flow channel 443.

In the embodiment having the torque coil 2412, the outer diameter of the coil is about 0.028 inches and the outer diameter of the stop 2414 is about 0.068 inches. The wall thickness of the struts is typically less than about 0.015 inches, and typically less than about 0.010 inches, and in some embodiments, less than about 0.008 inches or less than about 0.005 inches or less. The length of post 440 in the catheter axial direction is sufficient to support the assembly to prevent distal travel beyond the catheter stop ring, and may be at least about 50% of the outer diameter of stop 2414. In a stop 2414 having an outer diameter of about 0.68 inches, the strut 2440 has an axial length of at least about 0.75mm or 0.95 mm.

Referring to fig. 1H, a stop 2414 is shown with three different slides 441, each slide 441 being supported by a unique post 440. The sum of the perimeters of these three peripheral surfaces preferably does not exceed about 75% of the entire perimeter of the continuous peripheral surface 442 shown in fig. 1G and in some embodiments does not exceed about 50% or 40% of the entire perimeter of the continuous peripheral surface 442. This further increases the cross-sectional area of the flow path 443. In a catheter having an inner diameter of no greater than about 0.07 inch, the hub 443 has an outer diameter of at least about 0.026 or 0.028 or 0.030 or greater, and the sum of the flow paths 443 is at least about 0.0015 inch, preferably at least about 0.020 or 0.022 inch or greater. The area of the front edges of the post 440 and slider 441 are preferably less than about 0.003 inches, and preferably less than about 0.001 inches or 0.0008 inches or less. The length of the struts 440 is at least about 0.50mm or 0.75mm in the catheter axial direction, and in one embodiment, the length of the struts 440 and the sliding members 441 is about 1 mm.

One method of using the above system is described below. A 0.088LDP guide catheter was introduced and advanced, if possible, until the catheter tip was slightly proximal to the occlusion site. The 0.071 aspiration catheter of fig. 1A and 1B was introduced through 088LDP and advanced until the catheter tip reached the clot surface. All intermediate catheters or guidewires (if applicable) are removed. The rotatable core wire was introduced so that its distal end was flush with the distal end of the 0.071 aspiration catheter. The proximal RHV was sealed and vacuum was applied to the 0.071 aspiration catheter using a suction pump. The core-wire is manually rotated about 2 to 10 times, typically no more than 20 times, to engage the clot without cutting and to pull the catheter partially over the clot distally and interrupt rotation of the core-wire.

The suction catheter is anchored to the clot at this point using vacuum and mechanical engagement. The 0.088LDP catheter was then advanced over an aspiration catheter that functions similar to a guidewire until the 0.088 catheter reached the surface of the clot. Vacuum is applied to the 088LDP guide catheter using a vacuum source (e.g., VacLok syringe). The suction catheter, with the clot anchored at its end, is retracted proximally through the 088LDP guide catheter while maintaining the 088LDP in position at the occlusion site.

If the flow has not been restored by 088LDP, the core wire may be removed from the aspiration catheter. If necessary, the helical end of the core wire may be wiped to remove residual clot, then the core wire and aspiration catheter are returned to the occlusion site, and the clot retrieval procedure is repeated until flow is restored. After the flow was restored, the 0.088LDP catheter was removed.

According to another aspect of the present invention, a torque transfer system for changing a direction of rotation of a distal end of a highly flexible catheter shaft is provided. Some highly flexible conduits have angled cuts and elliptical openings at the distal end, such as discussed further in connection with fig. 7E. One feature of the beveled tip is to aid in the introduction and aspiration of the clot. Ideally, such an angled incision would be oriented such that the resulting large oval opening is oriented to face the clot as directly as possible, even in vasculature with bends and branches. In general, neurovascular catheters, and in particular the distal wall structures disclosed herein, exhibit poor torque transmission, and thus, due to the flexible structure and thin walls, it is unpredictable whether rotation of the proximal end of the catheter will provide an equivalent degree of rotation at the distal end. Thus, it is not practical to orient the angled tip by attempting to directly twist the catheter from the proximal end.

Referring to fig. 2A, a torque wire is provided for transmitting torque directly to the distal region of the catheter. A distal stop 2414, such as a circular ring/annular ring, is attached to the core wire in a manner similar to that described in connection with fig. 1C. The portion of the core wire 2410 extending beyond about the distal transition 436 (see fig. 1E) may be omitted, leaving a distal stop 2414 at the distal end of the torque wire. Alternatively, a short head section of the core-wire may extend through and distally beyond the distal stop 2414 as a centering guide. A distal stop 2414 carries a distal end face that carries at least one and typically at least two or at least three or more engagement elements 2415 for rotationally engaging complementary engagement structures within the catheter lumen.

Referring to fig. 2B and 2C, as previously described, the catheter tubular body 16 carries a distal limiter 2402. The proximal surface includes at least a second engagement structure 2417 for at least rotationally engaging the first engagement structure 2415 on the distal surface of the distal stop. In fig. 2A and 2B, the engagement features are complementary interlocking ramp teeth to allow a distal end face 2415 formed in the distal end of the twistable guidewire and a proximal end face of the distal limiter 2402 to engage and key together. This provides a mechanical connection to transmit torque to rotate the catheter in response to rotation of the wire.

In the embodiment of fig. 2A and 2B, the engagement element includes an axially distally extending protrusion having a first surface 2419 extending substantially parallel to the longitudinal axis of the wire and an opposing angled surface 2421 extending at an angle of inclination of at least about 15 degrees or 20 degrees or more relative to the longitudinal axis. When the wire is rotated in a first direction to responsively rotate the stop ring, the complementary protrusion engages with the insertion recess on the stop ring, but when the wire is rotated in an opposite second direction, the complementary protrusion and the insertion recess may jump over each other so that the catheter does not rotate in response to the rotation of the wire.

The configuration of FIG. 2B may be integrated into any of the systems of FIGS. 1A-1H. This allows rotation of the wire in a first direction to rotate the catheter to a desired rotational position within the vessel and adjacent the obstruction. The wire may then be rotated in a second, opposite direction to rotate the end 2416 and engage the occlusion for removal, as previously described.

Alternatively, the complementary engagement surfaces may be bidirectional to engage in either rotational direction, such as at least one protrusion on the guidewire for engaging at least one recess on the catheter. In the illustrated embodiment, the engagement structure 2415 includes at least one rectangular edge tooth for rotationally engaging a corresponding recess, such as an axially extending slot. (see, e.g., fig. 3B). This allows the catheter to be coupled and rotated in either direction.

Optionally, either or both of the complementary engagement surfaces carried by the distal stop 2414 and the distal limiter 2402 may be provided with friction enhancing features, such as textured surfaces or a material or coating with sufficiently high static friction to transmit sufficient torque from the core wire to the catheter body to rotationally redirect the catheter tip, such as into or out of a side branch, or to assume a different relationship between the catheter and embolic material.

When the angular orientation of the clot and catheter (see fig. 7E) is not conducive to orienting the maximum opening of the catheter directly toward the clot, the wire is advanced against the inner stop ring of the catheter and the complementary engagement surfaces engage so that the wire can be used to provide torque to rotationally reorient the catheter tip to more facilitate clot aspiration.

Further, during distal advancement of the catheter through tortuous vasculature, the catheter tip may be rotated to optimize the angular orientation of the angled tip to facilitate distal advancement of the catheter. Thus, the angled tip of the catheter can be rotated precisely to avoid being stuck by arterial branches or calcification.

In the embodiment shown in fig. 3A, a torque wire, such as clot retrieval device 2401, is similar to the torque wire shown in fig. 1C, except that there is no distal stop 2414. In such embodiments, the clot retrieval device may be free to advance axially through the lumen of the outer catheter 2403 and beyond the distal end of the outer catheter 2403. The clot retrieval device 2401 may be advanced distally to engage the clot and the outer catheter 2403 advanced distally over the wire by traction on the clot retrieval device and optionally adding vacuum through the catheter 2403 to grasp and remove the clot.

Optionally, the helical tip 450 may be rotated into and optionally through the occlusion clot to act as an anchor on the wire. The catheter 2403 may be withdrawn proximally, leaving the anchored core wire 2410 in place. The core wire 2410 may then be used as a guide wire to guide other interventional devices over or along the wire to the occlusion to perform additional functions. The core wire 2410 may be provided with an elongated central lumen extending between a proximal port at the proximal end and a distal port at the distal tip 450. After the distal tip is placed, if the distal tip 450 has been rotated distally that far, the guidewire may be advanced through the central lumen and through the occlusion. The tip 450 and core wire 2410 may then be counter-rotated to disengage the occlusion and withdrawn proximally from the patient, leaving the guidewire in place for subsequent surgery.

In another configuration, the catheter 2403 may be provided with a second lumen, for example for irrigation, aspiration, or receiving a guidewire therethrough, extending axially from the proximal port to a distal opening at or near the distal end 14. At a desired point during the procedure, the helix and catheter 2403 may be withdrawn proximally, leaving the guidewire in place for further access.

In the embodiment shown in fig. 3B and 3C, the torque wire and complementary catheter are configured in a manner similar to fig. 1A-1H, except that the distal tip 450 is allowed to extend a small controlled distance beyond the distal end 14 of the catheter 10. In fig. 3B, the distal tip 450 is generally axially aligned with the distal end 14 of the catheter 10 (or the distal tip 3132 in fig. 6E). This leaves an axial gap 18 between the complementary stop surface on the axial limiter 2404 and the distal stop 2414. As shown in fig. 3C, contact with the complementary stop surface allows the distal tip 450 to extend outside the catheter a maximum distance 18. The distance 18 may be at least about 0.5mm or at least about 1mm or at least 2mm, but typically is not more than about 1.5 cm or 1cm or 0.5cm, depending on the desired function. In some embodiments, the distance 18 is in the range of about 0.5-3 millimeters.

Alternatively, the maximum distal extension distance 18 may be related to the pitch of the helical thread. For example, the distance 18 may be a distance equal to the axial length of about one turn to about five turns of the thread, and preferably in the range of about one turn to about three turns of the thread.

In use, the distal tip 450 of the system of fig. 3B and 3C can be extended out of the catheter and rotated to engage the occlusion. As the helix rotates, it pulls the catheter forward (distally) and allows the helix to advance further distally over the core wire.

Fig. 4 illustrates a further application of the distal stop to a wire structure. The core wire 2410 extends only as far as about the transition 436 (fig. 1E), so the distal stop is at/away from the distal end of the wire. A distal end face 2411 on the distal stop 2414 may be used to tap a proximal surface 2405 on the distal limiter 2402 (see fig. 1B) to provide a hammer effect to pull the catheter distally rather than pushing it proximally. The tapping may be low frequency, done manually by the clinician, or higher frequency, such as at least about 10Hz or 100Hz or ultrasound, depending on the catheter configuration and desired clinical results.

Such a configuration may reduce column strength requirements along the length of the catheter body, at least from a pushability perspective. Maintaining hoop strength is still desirable in catheters that are intended to be placed under vacuum. In a non-vacuum device, however, the side walls of the catheter may be reduced if the target site can be reached by "pulling" the catheter distally from the distal limiter 2402 rather than pushing from the proximal manifold.

Referring to fig. 5A and 5B, side views of a blood flow assisted access line for use with a catheter having a baffle ring are shown. As described above, the wire 2410 carries a stop 2414 for limiting the distal travel of the wire relative to the catheter by interference engagement with the stop ring 2402. Force transmitting element 2440 is carried by wire 2410 and is configured to move between a radially collapsed configuration (fig. 5A) for positioning within the catheter and a radially expanded configuration (fig. 5B) when advanced distally out of the catheter. The force transmitting element 2440 is adapted to at least partially obstruct blood flow and transmit a distally directed force to the wire 2410. The responsive downstream distal advancement of force transfer element 2440 causes stop 2414 to engage stop ring 2402 and pull the catheter in an antegrade direction.

In the illustrated embodiment, the force transfer element 2440 comprises a conical membrane, such as a filter having an open proximal end 2442 and a closed distal end 2444. The proximal opening 2442 may be supported by a nitinol wire loop that is connected to the wire 2410 by an angled strut 2446. As the wire 2410 is withdrawn proximally, the angled struts 2446 facilitate the force transfer element 2440 to re-enter the distal end of the catheter.

In alternative embodiments of the invention, force transfer element 2440 may comprise alternative structures for capturing force from the blood stream, including an inflatable balloon. The thread 2410 may be provided with a central lumen extending throughout its length and which communicates with the balloon to effect inflation and deflation as understood in the art.

Referring to fig. 5C-5E, a wire 2410 with a steerable distal region 2450 is shown. The turning region 2450 can include a tubular body having a first side 2452 that is relatively axially non-collapsible. The second, generally opposite side is provided with a plurality of transverse slots 2454 that allow axial contraction/collapse. Pull wire 2456 is attached to the distal end of steering zone 2450. As shown in fig. 5E, proximal retraction of the pull wire 2456 relative to the tubular body results in axial contraction/collapse of the transverse slot 2454 and the resulting bending.

Any catheter shaft or various segments of a catheter shaft according to the present invention may comprise a multi-layered structure having a high degree of flexibility and sufficient pushability to penetrate deep into the cerebral vasculature, for example at least as deep as a core segment of the Internal Carotid Artery (ICA), a cavernous sinus segment, or a brain segment.

In one example, referring to fig. 7A, catheter 3000 can have an effective length from the manifold to the distal tip of about 70cm to about 150cm, about 80cm to about 140cm, about 90cm to about 130cm, about 100cm to about 120cm, or about 105cm to about 115 cm. The outer diameter of the catheter 3000 may be about 0.07 inches to about 0.15 inches, about 0.08 inches to about 0.14 inches, about 0.09 inches to about 0.13 inches, about 0.1 inches to about 0.12 inches, or about 0.105 inches to about 0.115 inches, and may be smaller in the distal section than in the proximal section. The inner diameter 3108 of the catheter 3000 in a single central lumen embodiment may be greater than or equal to about 0.11 inches, greater than or equal to about 0.1 inches, greater than or equal to about 0.09 inches, greater than or equal to about 0.088 inches, greater than or equal to about 0.08 inches, greater than or equal to about 0.07 inches, greater than or equal to about 0.06 inches, or greater than or equal to about 0.05 inches. The inner diameter 3108 of the catheter 3000 in a single central lumen embodiment may be less than or equal to about 0.11 inches, less than or equal to about 0.1 inches, less than or equal to about 0.09 inches, less than or equal to about 0.088 inches, less than or equal to about 0.08 inches, less than or equal to about 0.07 inches, less than or equal to about 0.06 inches, or less than or equal to about 0.05 inches.

Referring to fig. 7A, liner 3014 may be formed by dip coating a mandrel (not shown) to provide a thin-walled tubular inner layer of catheter body 3000. The dip coating may be produced by coating a wire, such as a silver coated copper wire, in PTFE. The mandrel may thereafter be axially elongated to reduce the diameter and removed to leave a tubular liner.

The outer surface of the tubular inner liner 3014 may then be coated with a soft tie layer 3012, such as polyurethane (e.g., Tecoflex)^TM) To produce a layer having a thickness of no more than about 0.005 inches and in some embodiments about 0.001 inches. The tie layer 3012 typically extends at least about 10cm or 20cm, typically less than about 50cm, along the distal most side of the catheter shaft 3000, and in one embodiment may extend about 30cm distal of the catheter shaft 3000, 3100.

A braid (e.g., 75ppi stainless steel braid 3010) may then be wrapped around the inner liner 3014, through the proximal region, and to the distal transition 3011. A coil 3024 comprising a shape memory material such as nitinol may then be wrapped around the inner liner 3014 from the distal transition 3011 to the distal end of the catheter 3000. In one embodiment, the nitinol coil has a transition temperature below body temperature such that the nitinol remains in an austenitic (elastic) state at body temperature. Adjacent loops or filaments of the coil 3024 may be tightly wound in the proximal region, while the distal section has a looser spacing between adjacent loops. In embodiments having a coil section 3024 with an axial length of between at least about 20% and 30% of the total catheter length (e.g., a coil length of 28cm in a 110cm catheter shaft 3000), at least the distal 1 or 2 or 3 or 4cm of the coil will have a spacing that is at least about 130% and in some embodiments at least about 150% or more of the spacing in the proximal coil section. In a 110cm catheter shaft 3000 with a nitinol coil, the spacing in the proximal coil may be about 0.004 inches, and in the distal section may be at least about 0.006 inches or 0.007 inches or more.

In embodiments including an extension catheter, the distal extendable portion of the catheter may be configured in accordance with the foregoing. The length of coil 3024 may be proportional to the length of the extendable catheter segment or the overall (e.g., extended) length of catheter 3000. The coil 3024 may extend at least about 50%, 60%, 70%, 80%, or 90% of the length of the extendable segment from the distal end of the extendable segment. In some embodiments, catheter 3000 or the extendable section may not include a braid, and coil 3024 may extend to the proximal end (100% of the length) of the extendable section.

The distal end of the coil 3024 may be spaced proximally from the distal end of the liner 3014, e.g., to provide space for the annular radiopaque marker 3400. In some embodiments, the coil 3024 may be retracted proximally from the distal end by no more than about 1cm, 2cm, or 3 cm. In one embodiment, the distal end of the catheter 3000 is provided with an inclined distal surface 3006 that lies on a plane that is at an angle of at least about 10 ° or 20 ° and in one embodiment about 30 ° to the longitudinal axis of the catheter 3000. The radiopaque marker 3040 may be in a plane transverse to the longitudinal axis. Alternatively, at least the distal facing edge of the annular radiopaque marker 3040 can be an ellipse that lies on a plane that is inclined relative to the longitudinal axis to complement the oblique angle of the distal surface 3006. Additional details are described below in association with fig. 7E.

After the proximal braid 3010, distal coil 3024, and RO marker 3040 are applied, an outer sheath 3020, such as a shrink-wrap tube, may be applied to enclose the catheter body 3000. The outer shrink wrap sleeve 3020 may comprise any of a variety of materials, such as polyethylene, polyurethane, polyether block amide (e.g., PEBAXTM), nylon, or other materials known in the art. Sufficient heat is applied to cause the polymer to flow into and embed the proximal braid and distal coil.

In one embodiment, the outer shrink wrap sheath 3020 is formed by advancing a plurality of short tubular segments 3022, 3026, 3028, 3030, 3032, 3034, 3036, 3038 concentrically in sequence on a catheter shaft subassembly and applying heat to shrink the segments onto the catheter 3000 and provide a smooth continuous outer tubular body. The structure described above may extend along at least the most distal 10cm of the catheter body 3000 and preferably at least about the most distal 20cm, 25cm, 30cm, 35cm, 40cm or more than 40 cm. The entire length of the outer shrink wrap sheath 3020 may be formed from multiple tubular sections, and the distal tubular section (e.g., 3022, 3026, 3028, 3030, 3032, 3034, 3036, 3038) may be shorter in length than the one or more tubular sections forming the proximal portion of the outer shrink wrap sheath 3020 in order to provide a more abrupt transition in flexibility to the distal end of the catheter 3000.

The stiffness of each outer wall section may decrease in the distal direction. For example, the proximal segments, such as 3022 and 3026, may have a durometer of at least about 60 or 70D, while the durometer of successive segments in the distal direction gradually decreases to a durometer of no more than about 35D or 25D or less. A 25cm section may have at least about 3 or 5 or 7 or more sections and the catheter 3000 as a whole may have at least about 6 or 8 or 10 or more different flex zones. The outer diameter of the distal 1 or 2 or 4 or more segments 3036, 3038 after retraction may be smaller than the more proximal segments 3022-3034, resulting in a stepped reduction in outer diameter at the final catheter body 3000. The smaller outer diameter section 3004 may have a length in the range of about 3cm to about 15cm, in some embodiments in the range of about 5cm to about 10cm, such as about 7 or 8cm, and may be achieved by providing a smaller wall thickness for the distal sections 3036, 3038.

Referring to fig. 7B and 7D, the catheter may further include a tensile support for increasing the resistance to tension in the distal region. The tensile support may comprise a filament, and more particularly, may comprise one or more axially extending filaments 3042. The one or more axially extending wires 3042 can be axially disposed in the catheter wall near the distal end of the catheter. The one or more axially extending wires 3042 serve as tensile supports and prevent the catheter wall from elongating under tension (e.g., as the catheter is retracted proximally through the tortuous vasculature).

At least one of the one or more axially extending wires 3042 can extend proximally along the length of the catheter wall from a distance within about 1.0cm from the distal end of the catheter to less than about 5cm from the distal end of the catheter, less than about 10cm from the distal end of the catheter, less than about 15cm from the distal end of the catheter, less than about 20cm from the distal end of the catheter, less than about 25cm from the distal end of the catheter, less than about 30cm from the distal end of the catheter, less than about 35cm from the distal end of the catheter, less than about 40cm from the distal end of the catheter, or less than about 50cm from the distal end of the catheter.

The one or more axially extending filaments 3042 can have a length of greater than or equal to about 50cm, greater than or equal to about 40cm, greater than or equal to about 35cm, greater than or equal to about 30cm, greater than or equal to about 25cm, greater than or equal to about 20cm, greater than or equal to about 15cm, greater than or equal to about 10cm, or greater than or equal to about 5 cm.

At least one of the one or more axially extending filaments 3042 can have a length of less than or equal to about 50cm, less than or equal to about 40cm, less than or equal to about 35cm, less than or equal to about 30cm, less than or equal to about 25cm, less than or equal to about 20cm, less than or equal to about 15cm, less than or equal to about 10cm, or less than or equal to about 5 cm. At least one of the one or more axially extending wires 3042 can extend at least about the most distal 50cm of the catheter length, at least about the most distal 40cm of the catheter length, at least about the most distal 35cm of the catheter length, at least about the most distal 30cm of the catheter length, at least about the most distal 25cm of the catheter length, at least about the most distal 20cm of the catheter length, at least about the most distal 15cm of the catheter length, at least about the most distal 10cm of the catheter length, or at least about the most distal 5cm of the catheter length.

In some embodiments, the filaments extend proximally from the distal end of the catheter along the length of the coil 24 and terminate proximally within about 5cm or 2cm or less on either side of the transition 3011 between the coil 3024 and the braid 3010. The filaments may terminate at the transition 3011 without overlapping the braid 3010.

In another embodiment, the distal-most portion of the catheter 3000 can comprise a durometer of less than about 35D (e.g., 25D) to form a highly flexible distal portion of the catheter and the distal-most portion of the catheter 3000 can have a length of about 25cm to about 35 cm. The distal portion may include one or more tubular segments (e.g., segment 3038) of the same durometer. A series of proximally adjacent tubular segments may form a transition region between a proximal stiffer portion of the catheter 3000 and a distal highly flexible portion of the catheter. The series of tubular sections forming the transition region may have the same or substantially similar length, such as about 1 cm.

The relatively short length of the series of tubular sections may provide a sharp drop in stiffness over the transition region. For example, the transition region may have a proximal tubular section 3036 having a durometer of about 35D (proximally adjacent to the distal portion). The adjacent proximal segment 3034 may have a durometer of about 55D. The adjacent proximal segment 3032 may have a durometer of about 63D. The adjacent proximal segment 3030 may have a durometer of about 72D.

The more proximal section may comprise a durometer greater than about 72D and may extend to the proximal end of the extension catheter section or catheter. For example, the extension catheter segment can include a proximal portion of greater than about 72D between about 1cm to about 3 cm. In some embodiments, the proximal portion may be about 2cm long. In some embodiments, the distal-most section (e.g., 3038-3030) may comprise PEBAX^TMWhile the more proximal section may comprise a generally harder material such as

The inner diameter of the conduit 3000 or conduit extension section may be about 0.06 to 0.08 inches, about 0.065 to 0.075 inches, or about 0.068 to 0.073 inches. In some embodiments, the inner diameter is about 0.071 inches.

In some embodiments, the distal-most portion may taper to a reduced inner diameter, as described elsewhere herein. The tapering may occur approximately between the distal highly flexible portion and the transition region (e.g., on a proximal-most portion of the distal highly flexible portion). The taper may be relatively gradual (e.g., occurring above about 10 cm), or may be relatively sharp (e.g., occurring on the order of less than 5 cm). The inner diameter may taper to an inner diameter of between about 0.03 and 0.06 inches. For example, the inner diameter at the distal end of the conduit 3000 may be about 0.035 inches, about 0.045 inches, or about 0.055 inches. In some embodiments, the inner diameter may remain constant over at least the catheter extension segment.

In some embodiments, the coil 3024 may extend proximally from the distal end of the catheter 3000 along a highly flexible distal portion that terminates at the distal end of the transition region. In other embodiments, the coil 3024 may extend from the distal end of the catheter to the proximal end of the transition region, to a point along the transition region or proximally beyond the transition region. In other embodiments, the coil 3024 may extend the entire length of the catheter extension section or catheter 3000, as described elsewhere herein. When present, braid 3010 may extend from the proximal end of coil 3024 to the proximal end of catheter extension segment or catheter 3000.

The one or more axially extending wires 3042 may be positioned adjacent to or radially outward of tie layer 3012 or liner 3014. The one or more axially extending filaments 3042 can be disposed adjacent to or radially inward of the braid 3010 and/or coils 3024. The one or more axially extending wires 3042 may be carried between the inner liner 3014 and the helical coil 3024.

When more than one axially extending wire 3042 is disposed in the catheter wall, the axially extending wires 3042 can be disposed in a radially symmetric manner. For example, the angle between the two axially extending wires 3042 relative to the radial center of the catheter may be about 180 degrees. Alternatively, the axially extending wires 3042 can be positioned in a radially asymmetric manner depending on the desired clinical properties (e.g., flexibility, trackability). The angle between any two axially extending filaments 3042 relative to the radial center of the catheter can be less than about 180 degrees, less than or equal to about 165 degrees, less than or equal to about 150 degrees, less than or equal to about 135 degrees, less than or equal to about 120 degrees, less than or equal to about 105 degrees, less than or equal to about 90 degrees, less than or equal to about 75 degrees, less than or equal to about 60 degrees, less than or equal to about 45 degrees, less than or equal to about 30 degrees, less than or equal to about 15 degrees, less than or equal to about 10 degrees, or less than or equal to about 5 degrees.

The one or more axially extending filaments 3042 can be made of a material such as Kevlar, polyester, meta-para-aramid, or any combination thereof. At least one of the one or more axially extending filaments 3042 can include a single fiber or a multi-fiber bundle, and the fiber or bundle can have a circular or rectangular cross-section. The term fiber or filament does not denote a component, and they may include any of a variety of high tensile strength polymers, metals, or alloys, depending upon design considerations such as desired tensile break limit and wall thickness. The one or more axially extending filaments 3042 can have a cross-sectional dimension measured in the radial direction that is no more than about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 20%, 25%, or 30% of the cross-sectional dimension of the catheter 3000. The one or more axially extending wires 3042 can have a cross-sectional dimension, as measured in the radial direction, of no more than about 0.001 inch, about 0.002 inch, about 0.003 inch, about 0.004 inch, about 0.005 inch, about 0.006 inch, about 0.007 inch, about 0.008 inch, about 0.009 inch, about 0.010 inch, about 0.015 inch, about 0.020 inch, about 0.025 inch, or about 0.030 inch.

The one or more axially extending wires 3042 can increase the tensile strength of the distal region of the catheter to at least about 1 pound, at least about 2 pounds, at least about 3 pounds, at least about 4 pounds, at least about 5 pounds, at least about 6 pounds, at least about 7 pounds, at least about 8 pounds, or at least about 10 pounds or more.

Any of the aspiration catheters or tubular extension segments disclosed herein, whether comprising an axial wire or not, may be provided with an angled distal tip. Referring to fig. 7E, the distal tip 3110 of the catheter includes a tubular body 3112 including a pusher section 3114, a marker band 3116 and a proximal section 3118. The tubular liner 3120 may extend the entire length of the distal catheter tip 3110 and may comprise dip-coated PTFE.

A reinforcing element 3122, such as a braid or spring coil, is embedded in the outer casing 3124, and the outer casing 3124 may extend the entire length of the distal catheter tip 3110.

The pusher section 3114 terminates distally in an angled end surface 3126 to provide a front side wall portion 3128, the front side wall portion 3128 having a length measured between a distal end 3130 and a distal tip 3132 of the marker band 3116. In the illustrated embodiment, the rear side wall portion 3134 of the pusher section 3114 has an axial length approximately equal to the axial length of the front side wall portion 3128, measured at a position about 180 degrees around the catheter from the front side wall portion 3128. The axial length of the front side wall portion 3128 may be in the range of about 0.1mm to about 5mm, and typically in the range of about 1mm to 3 mm. Depending on the desired performance, the axial length of the rear side wall portion 3134 may be at least about 0.1mm or 0.5mm or 1mm or 2mm or more shorter than the axial length of the front side wall portion 3128.

The angled end surface 3126 is angled at an angle a with respect to the longitudinal axis of the conduit that is in the range of about 45 degrees to about 80 degrees. For certain embodiments, the angle is in a range of about 55 degrees to about 65 degrees or in a range of about 55 degrees to about 65 degrees relative to the longitudinal axis of the catheter. In one embodiment, angle a is about 60 degrees. The result of the angle a being less than 90 degrees is an elongation of the major axis of the region of the distal port, which increases the surface area of the port and may enhance aspiration or retention of clots. The area of the angled ports compared to the surface area of the circular ports (angle a is 90 degrees) is typically at least about 105%, and no more than about 130%, and in certain embodiments, in the range of about 110% to about 125%, and in one example about 115%.

In the illustrated embodiment, the axial length of the pusher section is substantially constant along the circumference of the catheter such that the angled end surface 3126 is substantially parallel to the distal surface 3136 of the marker band 3116. The marker band 3116 has a proximal surface that is generally transverse to the longitudinal axis of the catheter, forming a marker band 3116 having a right angle trapezoidal configuration in side view. The short side walls 3138 are rotationally aligned with the rear side wall portion 3134 and have an axial length in the range of about 0.2mm to about 4mm, and typically in the range of about 0.5mm to about 2 mm. The opposing long side walls 3140 are rotationally aligned with the front side wall portion 3128. Depending on the desired performance, the long side walls 3140 of the tag tape 3116 are typically at least about 10% or 20% longer than the short side walls 3138, and may be at least about 50% or 70% or 90% or more longer than the short side walls 3138. Typically, the long sidewalls 3140 will have a length of at least about 0.5mm or 1mm and less than about 5mm or 4 mm.

The marker band may have at least one and optionally two or three or more axially extending slits over its entire length to enable radial expansion. The slits may be located on the short side wall 3138 or the long side wall 3140 or between the two, depending on the desired bending properties. The marker band may comprise any of a variety of radiopaque materials, such as a platinum/iridium alloy, with a wall thickness preferably no greater than about 0.003 inches, and in one embodiment about 0.001 inches.

The marker band region of the assembled catheter will have a relatively high bending stiffness and a high compressive strength, e.g., at least about 50% less or at least about 100% less than the proximal section 18, but typically no greater than about 200% of the proximal section 3118. The high compressive strength may provide radial support to adjacent pusher sections 3114, particularly front side wall portion 3128, to facilitate the function of distal tip 3132 as an atraumatic bumper during transluminal advancement and to resist collapsing under vacuum. The proximal section 3118 preferably has a lower bending stiffness than the marker band regions, and the pusher section 3114 preferably has an even lower bending stiffness and compressive strength than the proximal section 3118.

The pusher section 3114 may include a distal extension of the outer casing 3124 and optional inner lining 3120 without other internal support structure distal to the marker band 3116. The outer shell may include extruded Tecothane. The pusher section 3114 may have a bending stiffness and a radial crush stiffness that are no greater than about 50% of the respective values for the proximal section 3118, and in some embodiments, no greater than about 25% or 15% or 5% or less of the respective values.

As already described elsewhere herein, the support fibers 3142 extend through at least a distal portion of the length of the proximal segment 3118. As shown, the support fibers 3142 may terminate distally at the proximal surface of the marker band 3116 and extend axially radially outward of the tubular liner 3120 and radially inward of the support coil 3122. The fibers 3142 may extend substantially parallel to the longitudinal axis or may be inclined in a slight helical configuration having no more than 10 or 7 or 3 or 1 or less complete turns around the catheter along the length of the helical configuration. The fibers may comprise a high tensile strength material such as multifilament yarn spun from a liquid crystal polymer, e.g. Vectran multifilament LCP fibers.

An intraluminal extension catheter (e.g., a tubular telescoping extension section with a proximally extending control wire) may be inserted through the catheter 3000 from the proximal end of the catheter 3000, depending on whether the catheter 3000 is capable of being sufficiently guided distally to reach the target site. The extension segment is inserted and advanced distally such that the distal end of the extension segment is further distally beyond the distal end of the catheter 3000. The outer diameter of the extension section is smaller than the inner diameter of the conduit 3000. In this way, the extension segment can slide within the lumen of the catheter 3000.

The extension section has the features of the sidewall structure of the conduit 3000 described herein. The axial length of the tubular extension section may be less than about 50% of the length of the catheter 3000 and typically less than about 25% of that length. The axial length of the tubular extension section will typically be at least about 10cm or 15cm or 20cm or 25cm or more, but typically not more than about 70cm or 50cm or 30 cm.

Referring to fig. 8A-8C, any of the catheters described herein may have one or more axially extending wires 3242.

Referring to fig. 10A-10B, the angled end surface 3126 of the catheter of fig. 7E is further modified to a blunt angled end surface 4000 such that the leading edge tip (as shown in fig. 7E) is removed. As shown in fig. 10B, the catheter distal end face 4000 includes a first section 4012 lying on a first plane that intersects the longitudinal axis of the tubular body at a first angle 4020 in the range of about 35 degrees to about 55 degrees and a second section 4014 lying on a second plane that intersects the longitudinal axis of the tubular body at a second angle 4010 in the range of about 55 degrees to about 90 degrees. The section 4016 shown in fig. 10A of the distal end face 4000 shown in fig. 7E is removed. One result of the angle 4020 being less than 90 degrees and the blunted length 4014 is that the major axis of the distal port region is elongated, which increases the surface area of the port and may enhance clot aspiration or retention while also minimizing the likelihood of vessel wall damage.

The area of the angled/sloped passivated (blunted) port is typically at least about 105% and no more than about 150%, in some embodiments in the range of about 110% to about 125%, and in one example about 115%, as compared to the surface area of a circular port (both angle 4020 and angle 4010 are 90 degrees). The degree of passivation may be defined by the ratio of the unpassivated axial length 4022 measured from the trailing edge 4024 to the leading edge 4026 to the passivated axial length as shown in cross-section 4018.

As shown in fig. 10A, a blunting ratio (blunting ratio) of 3/4 is shown. The blunted length 4016 of tip 4000 may be 1-5 millimeters, 1-4 millimeters, 1-3 millimeters, 1-2 millimeters, 0.1-0.2 millimeters, 0.2-0.3 millimeters, 0.3-0.4 millimeters, 0.4-0.5 millimeters, 0.5-0.6 millimeters, 0.6-0.7 millimeters, 0.7-0.8 millimeters, 0.8-0.9 millimeters, 0.9-1.0 millimeters, 0.1-0.5 millimeters, 0.5-1.0 millimeters, less than 1 millimeter, greater than 1 millimeter, at least 2 millimeters, at least 3 millimeters, at least 4 millimeters, at least 5 millimeters, or any range or any subrange therebetween of the total catheter distal end face 2. In some embodiments, length 4016 of distal end face 4000 is defined by a percentage of the outer diameter of the catheter, for example, length 4016 may be equal to a length of 10% -500%, 10% -20%, 20% -30%, 30% -40%, 40% -50%, 50% -60%, 60% -70%, 70% -80%, 80% -90%, 100% -200%, 200% -300%, 300% -400%, 400% -400%, or any range or any subrange therebetween of the outer diameter of the catheter.

Referring to fig. 10B, the angle 4020 of the first or angled/sloped segment of the distal end face 4000 may be 5-10 degrees, 10-15 degrees, 15-20 degrees, 20-25 degrees, 25-30 degrees, 30-35 degrees, 35-40 degrees, 40-45 degrees, 45-50 degrees, 50-55 degrees, 55-60 degrees, 60-65 degrees, 65-70 degrees, 70-75 degrees, 75-80 degrees, 80-85 degrees, 85-90 degrees, 90-95 degrees, or any range or subrange therebetween. The angle 4020 of the first or angled/sloped section of the distal end face 4000 may be at least 10 degrees, at least 15 degrees, at least 20 degrees, at least 25 degrees, at least 30 degrees, at least 35 degrees, at least 40 degrees, at least 45 degrees, at least 50 degrees, at least 55 degrees, at least 60 degrees, at least 65 degrees, at least 70 degrees, at least 75 degrees, at least 80 degrees, at least 85 degrees, at least 90 degrees, or at least 95 degrees. In some embodiments, the angle 4020 of the first or angled section of the distal end face is equal to 0-30 degrees, 30-60 degrees, 60-90 degrees, or any range or subrange therebetween. In some embodiments, angle 4020 is equal to 15-45 degrees, 45-75 degrees, 75-95 degrees, or any range or subrange therebetween. The angle 4010 of the second or blunted section of the distal end face 4000 may be 55-60 degrees, 60-65 degrees, 65-70 degrees, 70-75 degrees, 75-80 degrees, 80-85 degrees, 85-90 degrees, or any range or subrange therebetween. The angle 4010 of the second or blunted section of the distal end face 4000 may be at least 55 degrees, at least 60 degrees, at least 65 degrees, at least 70 degrees, at least 75 degrees, at least 80 degrees, at least 85 degrees, or at least 90 degrees. In some embodiments, the angle 4010 of the second or blunted section of the distal end face 4000 is equal to 55-65 degrees, 65-75 degrees, 75-90 degrees, or any range or subrange therebetween.

Referring to fig. 11A-11B, a sinusoidal distal end surface 4100 is shown to include a first segment or convex wave or shape or notch or curve 4110 defined by a first radius of curvature that transitions to a second segment or concave wave or shape or notch or curve 4120 defined by a second radius of curvature. Each curve 4110, 4120 may have a diameter ranging from 0.02 inches to 0.05 inches, for example, depending on the conduit size. As shown in fig. 41B, each curve 4110, 4120 is further defined by a radius of curvature 4112, 4114, respectively. In some embodiments, the first convex curve 4110 and the second concave curve 4120 have the same or similar or substantially similar (+/-5%) radii of curvature 4112, 4114, respectively. In other embodiments, the first convex curve 4110 and the second concave curve 4120 have different radii of curvature 4112, 4114, respectively. The 2D profile of distal end shape 4100 (e.g., when projected onto the radial plane shown in fig. 11A) is given by the following equation:

wherein Δ z is total end length 4130;

m is a slope factor;

r is the radial position; and is

r_cIs the catheter radius.

By varying the slope factor, the steepness of the waveform can be adjusted.

As shown in fig. 11A, the slope or angle of each curve 4110, 4120 may be defined by an angle 4140 and 4150, respectively. For example, for the calculation of each angle 4140, 4150, the axis may be located at a transition point along the longitudinal center of the catheter between the first curve 4110 and the second curve 4120, such that the angles 4140 and 4150 define the curve or shape of the distal end face 4100. In some embodiments, angle 4140 is 0-5 degrees, 5-10 degrees, 10-15 degrees, 15-20 degrees, 20-25 degrees, 25-30 degrees, 30-35 degrees, 35-40 degrees, 40-45 degrees, 45-50 degrees, 50-55 degrees, 55-60 degrees, 60-65 degrees, 65-70 degrees, 70-75 degrees, 75-80 degrees, 80-85 degrees, 85-90 degrees, or any range or subrange therebetween. In some embodiments, the angle 4140 is 30-60 degrees, 15-85 degrees, or any range or subrange therebetween. In some embodiments, angle 4150 is 0-5 degrees, 5-10 degrees, 10-15 degrees, 15-20 degrees, 20-25 degrees, 25-30 degrees, 30-35 degrees, 35-40 degrees, 40-45 degrees, 45-50 degrees, 50-55 degrees, 55-60 degrees, 60-65 degrees, 65-70 degrees, 70-75 degrees, 75-80 degrees, 80-85 degrees, 85-90 degrees, or any range or subrange therebetween. In some embodiments, the angle 4150 is 30-60 degrees, 15-85 degrees, or any range or subrange therebetween.

Referring to fig. 12, a schematic diagram of a numerical simulation model is shown. A Computational Fluid Dynamics (CFD) model was created to simulate aspiration of a soft clot 4120 (surrounded by blood 4130) in a blood vessel 4210 into a catheter 4140 having various distal end face shapes or angles 4150.

FIGS. 13A-13B illustrate exemplary computational fluid dynamics model data. Numerical simulation images of clot aspiration show the initial state 4300 in fig. 13A and the active aspiration state 4310 in fig. 13B. For various distal end face shapes or angles 4150, the amount of clot material aspirated in a given time is measured. The values of the circular (lateral) ports (e.g., as shown in fig. 3A) are used as a benchmark or comparison to benchmark the success of the proposed profile. A particular distal end shape or angle is considered more successful if it can aspirate more material than a circular port shape. Higher aspiration rates indicate less resistance to aspiration and a lower chance of aspiration thrombectomy complications.

Referring to fig. 14, the percent increase in aspiration volume is shown as a function of distal end face angle. For example, a distal end face exhibiting a 60 degree angle has the greatest increase in suction efficiency compared to an end face having a smaller angle (15 to 45 degrees). The increase in suction at the 60 degree inclined end surface is more than 60% compared to the circular end surface, 60-70% compared to the circular end surface, or 50-70% compared to the circular end surface. The increase in suction at the 45 degree distal end face compared to the circular end face is greater than 40%, between 40-50%, between 30-60%, or greater than 45%. The increase in suction at the 30 degree distal end face compared to the circular end face is greater than 20%, greater than 25%, between 20-30%, or between 15-40%. Even with a 15 degree distal end face, the aspiration is increased by 10% over a circular end face.

An exemplary reasoning for this improvement in pumping efficiency as a function of tip angle is (1) increasing the surface area of the catheter opening in contact with the clot, which increases the force (pressure force/area) on the clot and (2) increasing the distance length over which the clot is ingested (i.e., the intake length), thereby smoothing out the shape change of the clot as it flows from a larger diameter vessel into a smaller diameter catheter. The latter of these two design theories can be supported by flow profile/distribution studies during the aspiration experiment. For a more pronounced sinusoidal curve, the flow is more uniform and less disturbed when entering a smaller diameter conduit. As shown in fig. 14, the percentage of suction volume increases with increasing end face angle, collectively indicating that the larger end face opening due to the sloped end face profile increases suction efficiency.

Turning to fig. 15A-15C, computational fluid dynamic velocity field distributions for various end face angles (i.e., no angle or 0 degrees, 30 degrees, and 60 degrees) are shown. As shown in fig. 15A, the rounded end profile shows significant constriction of flow, thus increasing resistance to clot ingestion. In contrast, distal end faces with angles of 30 degrees (fig. 15B) or 60 degrees (fig. 15C) significantly increased clot uptake, as shown by the corresponding curves. As shown in fig. 15C, the 60 degree angled end face showed a greater distance between adjacent profiles than the leading edge 4510 of the 30 degree angled end face, and the leading edge 4500 of the velocity modulus extended further into the modeled catheter body.

Turning to fig. 16A-16B. Fig. 16A shows an intake length 4610 of the angled end face 4600 and fig. 16B shows an intake length 4620 of the blunt angled end face 4650. In some embodiments, length 4610 is equal or substantially equal to length 4620; in other embodiments, length 4610 is greater than length 4620, less than length 4620, or different than length 4620. The intake length 4610 is determined by calculating the difference between the leading edge end 4614 and the trailing edge end 4612, which have been described in connection with fig. 7E. Similarly, the intake length 4620 is determined by calculating the difference between the leading edge end 4624 and the trailing edge end 4622. In an exemplary non-limiting embodiment, the intake length ranges from 0.25 millimeters to 4.5 millimeters; 0.5mm to 4mm, 0.5mm to 2.5mm, 3.5 mm to 4mm, 2mm to 2.5mm, 1.5 mm to 2mm, 1mm to 1.5 mm, 0.5mm to 1mm, and the like. The intake length is directly related to the increased intake volume/percentage of intake volume based on the round end face comparative example.

Figure 17 shows the percent increase in inhaled mass as a function of intake length for catheters having different distal end face profiles (i.e., angled, blunt angled, sinusoidal). All the proposed profiles show an improvement to the profile of the rounded end face. The magnitude of improvement varied from about 10% to about 70%. Furthermore, blunt angled end faces and sinusoidal end faces are as successful as angled end faces, having the same intake length. This means that a blunt or smooth catheter can be as successful as a sharp catheter, as long as the intakes are of the same, similar or substantially similar length.

For example, with the intake length of the angled end face ranging from about 0.5mm to about 4mm, the percentage increase in the draw volume compared to the round end face comparative example is from about 10% to about 70%. With the intake length of the angled blunt end face ranging from about 1 millimeter to about 1.6 millimeters or about 1 millimeter to about 1.75 millimeters, the percent increase in suction volume compared to the round end face comparative example was about 18% to about 38%. For intake lengths of about 1.7 mm to about 1.7 mm, the sinusoidal end faces showed an increase in suction volume of about 35% compared to the round end face comparative example.

Referring to fig. 18A-18B, one example of an outside jacket segment stacking pattern for use in connection with a progressive flexible conduit of the type discussed, for example, in fig. 1A or 7A is shown. Distal segment 3038 may have a length in the range of about 1-3cm and a hardness of less than about 35D or 30D. The adjacent proximal segment 3036 may have a length in the range of about 4-6cm and a hardness of less than about 35D or 30D. The adjacent proximal segment 3034 may have a length in the range of about 4-6cm and a durometer of about 35D or less. The adjacent proximal segment 3032 can have a length in the range of about 1-3cm and a hardness in the range of about 35D to about 45D (e.g., 40D). The adjacent proximal segment 3030 can have a length in the range of about 1-3cm and a hardness in the range of about 50D to about 60D (e.g., about 55D). The adjacent proximal section 3028 may have a length in the range of about 1-3cm and a durometer in the range of about 35D to about 50D to about 60D (e.g., about 55D). The adjacent proximal section 3026 may have a length in the range of about 1-3cm and a durometer of at least about 60D and typically less than about 75D. The more proximal section may have a durometer of at least about 65D or 70D. The most distal two or three sections may comprise a material such as Tecothane, and the more proximal section may comprise PEBAX or other catheter sheath materials known in the art. At least three or five or seven or nine or more discrete segments may be employed so as to have a variation in hardness of at least about 10D, preferably at least about 20D, and in some embodiments at least about 30D or 40D or more between the highest and lowest hardness along the length of the catheter shaft.

The performance metrics of the catheter include support (back-up support), tracking, pushability, and kink resistance. Supportive refers to the ability of the catheter to remain in place within the anatomy and provide a stable platform for advancement of the endoluminal device. Referring to fig. 19, as the device is advanced through the catheter 3202, if there is insufficient support in the catheter 3202, the distal portion 3204 of the catheter 3202 may herniate, pull, or exit from a vessel 3206, wherein the vessel 3206 branches off of a main vessel (e.g., the brachiocephalic artery 82, common carotid artery 80, or subclavian artery 84). The support of the catheter 3202 may be improved by providing a high stiffness or modulus for the proximal region and a low stiffness or modulus for the distal region. The stiffness or modulus of the proximal region of the catheter 3202 may be increased by braid reinforcement. The region of increased stiffness or modulus of the catheter may be positioned near the branch point of the aortic arch 1114, 1214 branching into the brachiocephalic artery 82, common carotid artery 80, or subclavian artery 84, or other anatomical structures where the main vessel branches into one or more smaller vessels (i.e., branch points), thereby providing an opportunity for catheter prolapse with poor support. For example, the region of increased stiffness or modulus of the catheter may be positioned within about 0.5cm, about 1cm, about 2cm, about 3cm, about 4cm, about 5cm, or about 6cm from the branch point where the main vessel branches into one or more smaller vessels.

Trackability refers to the ability of a catheter to track further distally than other catheters (e.g., tracking forward to M1). For example, a catheter that can reach a cerebral segment of an Internal Carotid Artery (ICA) has better trackability than a catheter that can reach a cavernous sinus segment or a rock segment of the ICA. The tracking of the catheter may be improved by using a catheter wall with a low stiffness or modulus or by adding a coating (e.g., a hydrophilic coating) on at least a portion of the catheter wall. In one embodiment, a hydrophilic coating may be disposed along a distal-most region of the catheter. The hydrophilic coating on the catheter may extend to about 1cm, about 5cm, about 10cm, about 15cm, or about 20cm from the distal end of the catheter. The region of lower stiffness or modulus may be located at the most distal region of the catheter. The region of lower stiffness or modulus may extend to about 1cm, about 5cm, about 10cm, about 15cm, or about 20cm from the distal end of the catheter.

Pushability means that the catheter is rigid enough to be pushed through the anatomy without "buckling". The pushability of the catheter can be improved by increasing the stiffness or modulus of the catheter. The pushability of the catheter may also be improved by providing a high stiffness or modulus for the proximal region and a low stiffness or modulus for the distal region. The transition region of the catheter in which the stiffness or modulus varies along its longitudinal length (e.g., the stiffness or modulus decreases from the proximal end to the distal end) may begin at about 50%, 60%, 70%, 75%, 80% or more of the length of the catheter from its proximal end.

Kink resistance refers to the ability of a catheter to resist kinking. Furthermore, if the catheter does kink, the kink resistance of the catheter helps it return to its original shape. Kink resistance is important in distal sections of catheters that are more susceptible to kinking than proximal sections. The kink resistance of the catheter may be increased by adding one or more NiTi coils (or coils at least a portion of which is nitinol) to the catheter wall.

Fig. 20 depicts a graph of stiffness or modulus of a catheter according to the present invention from the proximal end (x-0) to the distal end (x-1) along the length of the catheter. A catheter according to one embodiment may have a stiffness or modulus (E) that decreases as it approaches its distal end. The proximal end of the catheter has a higher stiffness or modulus than the distal end of the catheter. The high stiffness or modulus near the proximal end provides excellent support for the catheter. The stiffness or modulus of the catheter is substantially constant along its length near the proximal end 3302 of the catheter. The stiffness or modulus of the catheter then decreases near the distal end 3304 of the catheter. The stiffness or modulus of the catheter may begin to decrease (i.e., the transition region) at about 50%, 70%, 75%, 80%, or 90% of the length of the catheter from its proximal end. The catheter may have a decreasing stiffness or modulus near its distal end by using a less stiff or modulus material near the distal end or having a thinner catheter wall. The reduced stiffness or modulus near the distal end provides excellent tracking of the catheter.

Fig. 21 depicts a graph of a flexibility test of a catheter according to the present invention compared to a conventional catheter. The flexibility of the catheter was measured by a three point deflection test with a span of one inch and a displacement of 2 mm. In other words, fig. 21 depicts the force (i.e., flexural load) required to vertically displace a one inch long catheter segment by 2mm with respect to the distance from the strain relief point (i.e., the proximal end of the catheter) to the force application point. The modulus of the catheter remains substantially constant along its length near the proximal end and then gradually decreases near the distal end.

A catheter according to the present invention has a substantially constant flexural load along the longitudinal length near the proximal end and a rapidly decreasing flexural load near the distal end. In a catheter having a length of about 125cm, the catheter may have a deflection load of greater than or equal to about 1.0lbF, about 1.5lbF, about 2.0lbF, about 2.5lbF, about 3.0lbF, or about 3.5lbF at about 85cm from the proximal end. The catheter may have a deflection load of less than or equal to about 2.5lbF, about 2.0lbF, about 1.5lbF, about 1.0lbF, or about 0.5lbF at about 95cm from the proximal end. The catheter may have a deflection load of less than or equal to about 1.5lbF, about 1.0lbF, about 0.75lbF, about 0.5lbF, about 0.25lbF, or about 0.1lbF at about 105cm from the proximal end. The catheter may have a flex load of less than or equal to about 1.0lbF, about 0.75lbF, about 0.5lbF, about 0.4lbF, about 0.3lbF, about 0.2lbF, or about 0.1lbF at about 115cm from the proximal end. For catheters having different lengths, the dimensions may be scaled from the distal end of the catheter as a percentage of the catheter length.

In certain embodiments constructed according to fig. 5, the flexural load is less than about 3.0 or 3.25lbF at 65cm from the proximal end and is greater than about 2.25 or 2.5lbF on average at 65cm to 85cm from the proximal end. The flexural load dropped to no more than about 1.0lbF and preferably no more than about 0.5lbF at about 95cm from the proximal end. This provides enhanced support while maintaining enhanced trackability into the distal vasculature.

In other embodiments, the catheter may have a deflection load of greater than or equal to about 1.0lbF, about 1.5lbF, about 2.0lbF, about 2.5lbF, about 3.0lbF, or about 3.5lbF at about 60cm from the proximal end. The catheter may have a flexural load of less than or equal to about 2.0lbF, about 1.5lbF, about 1.0lbF, or about 0.5lbF at about 70cm from the proximal end. The catheter may have a flex load of less than or equal to about 1.0lbF, about 0.75lbF, about 0.5lbF, about 0.4lbF, about 0.3lbF, about 0.2lbF, or about 0.1lbF at about 80cm from the proximal end. The catheter may have a flexural load of less than or equal to about 1.0lbF, about 0.75lbF, about 0.5lbF, about 0.4lbF, about 0.3lbF, about 0.2lbF, or about 0.1lbF at about 90cm from the proximal end.

The conduit may have a transition region wherein its deflection load change is greater than or equal to about 1.0lbF, about 1.5lbF, about 2.0lbF, about 2.5lbF, about 3.0lbF, or about 3.5 lbF. The longitudinal length of the transition region can be less than or equal to about 20cm, about 15cm, about 10cm, about 5cm, about 3cm, or about 1 cm.

Catheters according to the invention (e.g., 3404, 3406, 3408, 3410) have comparable modulus near their proximal ends as compared to Neuron Max (Penumbra corporation) 3402. Thus, the catheter according to the invention provides comparable support to Neuron Max. In addition, the catheter has a faster decreasing modulus near the transition region (between the proximal and distal ends) than Neuron Max.

Compared to Ace 68 catheter (Penumbra)3412, Ace 64 catheter (Penumbra)3414, Benchmark 71 catheter (Penumbra)3416 and Sofia Plus (MicroVention)3418, catheters according to the invention have a greater modulus near their proximal ends and a comparable modulus near their distal ends. In this way, the catheter according to the invention may provide comparable trackability and better support than conventional catheters. Catheters according to the invention can achieve this modulus profile even when their inner diameter (and hence lumen volume) is greater than or equal to the inner diameter of Ace 68, Ace 64, Benchmark 71, and Sofia Plus (in the range of 0.064 inches to 0.071 inches).

Access to the catheter for use in the present invention can be achieved using conventional techniques through an incision in a peripheral artery (e.g., the right femoral artery, the left femoral artery, the right radial artery, the left radial artery, the right brachial artery, the left brachial artery, the right axillary artery, the left axillary artery, the right subclavian artery, or the left subclavian artery). An incision may also be made in the right or left carotid artery in an emergency.

Avoiding a tight fit between the guidewire and the inner diameter of the guidewire lumen improves the slidability of the catheter over the guidewire. In ultra-small diameter catheter designs, it may be desirable to apply a lubricious coating to the outer surface of the guidewire and/or the inner surface of the wall defining the GW lumen to minimize friction as the catheter 10 moves axially relative to the guidewire. Various coatings may be used, such as Paralene, teflon, silicone, polyimide-polytetrafluoroethylene composites, or other materials known in the art and appropriate depending on the material of the guidewire or inner tubular wall.

Aspiration catheters of the present invention suitable for intracranial applications typically have a total length in the range of 60cm to 250cm, typically about 135cm to about 175 cm. The length of the proximal section 33 is typically 20cm to 220cm, more typically 100cm to about 120 cm. The length of the distal section 34 is typically in the range of 10cm to about 60cm, usually about 25cm to about 40 cm.

The catheter of the present invention may comprise any of a variety of biocompatible polymeric resins having suitable properties when formed into a tubular catheter body section. Exemplary materials include polyvinyl chloride, polyethers, polyamides, polyethylene, polyurethanes, copolymers thereof, and the like. Alternatively, the catheter body may be reinforced using a metal or polymer braid or other conventional reinforcement layer.

The catheter body may also include other components, such as radiopaque fillers; a colorant; a reinforcing material; a reinforcing layer, such as a braid or helical reinforcing element; and so on. In particular, the proximal body section may be reinforced in order to improve its radial support and torsion resistance (torque transmission) while preferably limiting its wall thickness and outer diameter.

In one aspect of the present disclosure, the system for aspirating a vascular occlusion further includes a controller for applying a pulsed vacuum cycle to the central lumen. In another aspect of the present disclosure, a system for aspirating a vascular occlusion further includes a rotary hemostasis valve coupled with the proximal end of the tubular body, the rotary hemostasis valve including: at least one main lumen along a longitudinal length thereof through which a proximal portion of the clot grip is configured to pass, and a suction lumen that diverges from the main lumen and is provided with a vacuum port.

According to another aspect, there is provided a method of extracting material from a site at least as far as a cavernous sinus segment of an internal carotid artery via a femoral access site, the method comprising the steps of: advancing a guidewire from a femoral access site at least as far as a cerebral segment of an internal carotid artery, the guidewire having a proximal section and a distal section, the proximal section having a diameter of at least about 0.030 inches, the distal section having a length of no more than about 25cm and a diameter of no more than about 0.020 inches; an aspiration catheter is tracked directly over the guidewire and to a site at least as far as the cavernous sinus segment, the aspiration catheter having a distal end with a diameter of at least about 0.080 inches and a beveled distal tip and a central lumen at the distal end. In one aspect of the disclosure, the proximal section of the guidewire is about 0.038 inches in diameter and the distal section is about 0.016 inches in diameter.

Applying a vacuum to the lumen to draw thrombus into the lumen with the distal end in place at least as far as a cavernous sinus segment of the middle cerebral artery; and the thrombus mechanically engaged to facilitate its attachment and possible entry into the lumen.

The mechanically engaging step can include advancing the clot gripping member to or beyond the distal end of the tubular body. A method of engaging a vascular occlusion may include manually rotating a clot gripping member within a tubular body to engage a clot.

In yet another aspect of the present disclosure, the method of aspirating a vascular occlusion further comprises providing sufficient stop support to the combined access and aspiration catheter to resist catheter pull-out into the aorta. The combined access and aspiration catheter may be provided with a stop support by advancing the combined access and aspiration catheter over a guidewire having a distal end positioned at least as distal as the cavernous sinus segment of the internal carotid artery, and having a diameter of at least about 0.030 inches at the point where the guidewire enters the brachiocephalic artery. The combined access and aspiration catheter may be provided with a stop support by advancing the combined access and aspiration catheter over a guidewire having a distal end positioned at least as distal as the cavernous sinus segment of the internal carotid artery, and having a diameter of at least about 0.030 inches, such as about 0.035 inches or about 0.038 inches, at the point where the guidewire enters the brachiocephalic artery.

The guidewire is guidable to at least the cerebral segment of the internal carotid artery by having a distal segment with a diameter of no greater than about 0.020 inches. The guidewire can be directed to at least the cerebral segment of the internal carotid artery by having a distal segment with a diameter of about 0.016 inches. The proximal section of the guidewire may be about 0.038 inches in diameter and the distal section may be about 0.016 inches in diameter.

While the present invention has been described in terms of certain preferred embodiments, those skilled in the art, in light of the present disclosure, will be able to incorporate into other embodiments. Therefore, it is intended that the scope of the invention be limited not by the specific embodiments disclosed herein, but rather by the full scope of the appended claims.

Exemplary embodiments

A system for removing embolic material from an intravascular site, comprising one or more of:

an elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

an axial restraint carried by the sidewall and exposed to the lumen;

a rotatable core wire extendable through the lumen, the core wire having a proximal end and a distal end;

a restraint carried by the core wire, the restraint having a bearing surface for rotatably engaging the restraint; and

a clot gripping tip on a distal end of the core wire,

wherein the constraining member and the constraining member are configured to allow rotation of the core wire but limit distal travel of the tip to a distance no greater than about 6mm beyond the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the limiter and the constraint are configured to allow rotation of the core wire but limit distal travel of the tip to a distance no greater than about 3mm beyond the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the clot gripping tip comprises a helical thread.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the limiter and the constraint are configured to allow rotation of the core wire but limit distal advancement of the tip to expose about one to three complete turns of the thread beyond the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the axial restraint comprises a proximally facing bearing surface.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the axial restraint comprises a radially inwardly extending protrusion.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the axial restraint comprises an annular flange.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein wherein the restraint comprises a distally facing bearing surface.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein wherein the restraint comprises a radially outwardly extending protrusion.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the radially outwardly extending protrusion is configured for sliding contact with the constraint.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the proximal bearing surface on the axial constraint is within about 30cm of the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the proximal support surface is in the range of about 4cm to about 12cm from the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the helical thread has a maximum major diameter that is no greater than about 90% of the inner diameter of the lumen, thereby leaving an annular flow path between the tip and the inner surface of the sidewall.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the helical thread has a blunt outer edge.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the restriction is located within about the distal-most 25% of the length of the core wire.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the core wire is removably positioned within the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, further comprising a handle configured to manually rotate the core wire.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein wherein the helical thread extends entirely no more than about eight full turns.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the major diameter of the helical thread increases proximally from a first diameter near the distal tip to a second maximum major diameter and then decreases proximally at the maximum major diameter to a third diameter.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the inner diameter of the tubular body adjacent the clot gripping tip is at least about 0.015 inches greater than the maximum outer diameter of the tip.

A torque transfer system for rotationally orienting a distal end of a catheter, the system comprising one or more of:

an elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

a first engagement surface carried by the sidewall and exposed to the internal cavity;

a torque wire extendable through the lumen, the torque wire having a proximal end and a distal end;

a second engagement surface carried by the torque line,

wherein outward lateral travel of the torque wire brings the second engagement surface into rotationally coupled engagement with the first engagement surface such that rotation of the torque wire in at least a first direction causes rotation of the distal end of the catheter.

A torque transmitting system as disclosed in any one of the embodiments herein, wherein the first engagement surface comprises at least one inclined surface.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the first engagement surface is carried by a radially inwardly extending protrusion.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the protrusion comprises a ring located in the inner cavity.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the second engagement surface comprises a distally facing surface.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the distal facing surface comprises at least one ramped surface.

A torque transfer system for rotationally orienting a distal end of a catheter, comprising one or more of:

an elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

a first connector disposed on the sidewall and exposed to the internal cavity;

a torque wire extendable through the lumen, the torque wire having a proximal end and a distal end; and

a second complementary connector carried by the torque line;

wherein coupling the first and second connectors enables the distal end of the catheter to rotate in response to rotation of the torque wire.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the first connector comprises at least one angled tooth.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the first connector comprises a radially inwardly extending protrusion.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the protrusion comprises a ring located in the inner cavity.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the ring comprises at least two angled teeth extending in a proximal direction.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the second connector comprises a distally facing surface carried by the torque wire.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the distal facing surface comprises at least one ramped surface.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the second connector is movable radially outward.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the second connector comprises an inflatable bladder and the first connector may comprise a surface on the sidewall.

A torque transmitting system as disclosed in any of the embodiments herein, wherein the first connector comprises a sidewall of an axially extending slot configured to receive a protrusion on the torque wire.

A method of rotationally orienting a catheter, the method comprising one or more of the following steps:

advancing a catheter to a location in a body lumen, the catheter having a central lumen and a distal end;

advancing a torque wire into the lumen;

engaging a first connector on the torque wire with a second connector on the catheter; and

-rotating the torque wire to cause rotation of the distal end of the catheter.

A system for removing embolic material from an intravascular site, comprising:

an elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one central lumen extending axially therethrough;

a first engagement surface carried by the sidewall and exposed to the internal cavity;

a tap line/branch line/suction line (tap line) extendable through the lumen, the tap line having a proximal end and a distal end; and

the tap line carries the second engagement surface,

wherein distal advancement of the tap line brings the second engagement surface into contact with the first engagement surface and transfers momentum from the tap line to the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the first engagement surface comprises a proximally facing surface.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein wherein the first engagement surface is carried by a radially inwardly extending protrusion.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein wherein the first engagement surface comprises an annular flange.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the second engagement surface comprises a distal-facing surface.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the distal-facing surface is the distal end of a tapped line.

A system for removing embolic material from an intravascular site as disclosed in any of the embodiments herein, wherein the distal-facing surface is located on a hammer carried by a wire.

A system for facilitating distal advancement of a catheter, comprising one or more of:

an elongate flexible tubular body having a proximal end, a distal end, and a lumen extending therethrough;

a distal restraint within the lumen;

a tap/tap line axially movably positioned through the lumen and having a distal stop thereon;

wherein distal travel of the distal stop through the lumen is limited by the distal restraint.

A system for facilitating distal advancement of a catheter as disclosed in any of the embodiments herein, wherein the distal restraint comprises a loop.

A system for facilitating distal advancement of a catheter as disclosed in any of the embodiments herein, wherein the tubular body terminates in an angled end surface.

A neurovascular catheter with an atraumatic guiding tip comprising one or more of:

an elongate flexible tubular body having a proximal end, a distal end, and a sidewall defining a central lumen, a distal region of the tubular body comprising:

a tubular liner;

a helical coil surrounding the liner and having a distal end,

a tubular sheath surrounding the helical coil and extending distally beyond the distal end of the helical coil to terminate at a distal end face of the catheter, an

A tubular radiopaque marker embedded in the tubular sheath between the distal end and the distal end face of the coil,

wherein the catheter distal end face comprises a first segment lying on a first plane that intersects the longitudinal axis of the tubular body at a first angle in the range of about 35 degrees to about 55 degrees and a second segment lying on a second plane that intersects the longitudinal axis of the tubular body at a second angle in the range of about 55 degrees to about 90 degrees.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the marker has a proximal end face approximately perpendicular to the longitudinal axis and a marker distal end face lying on a plane intersecting the longitudinal axis at an angle in the range of about 55 degrees to about 65 degrees.

A neurovascular catheter having an atraumatic guiding tip as disclosed in any embodiment herein, wherein the distal end face defines a leading edge of the tubular body extending distally of a trailing edge of the tubular body, the leading edge and the trailing edge being spaced about 180 degrees from each other about the longitudinal axis.

A neurovascular catheter having an atraumatic guiding tip as disclosed in any embodiment herein, wherein the advancing section of the tubular body extends distally beyond the marker band.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the pusher section has an axial length on the leading edge of the tubular body in the range of about 0.1mm to about 5 mm.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any of the embodiments herein, wherein the axial length of the pusher section on the leading edge of the tubular body is greater than the length of the pusher section on the trailing edge of the tubular body.

A neurovascular catheter having an atraumatic guiding tip as disclosed in any embodiment herein, wherein the axial length of the marker band on the front edge of the tubular body is at least about 20% longer than the axial length of the marker band on the rear edge of the tubular body.

A neurovascular catheter having an atraumatic guiding tip as disclosed in any embodiment herein, wherein the axial length of the marker band on the anterior edge of the tubular body is in a range of about 1 millimeter to about 5 millimeters.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the marker band comprises at least one axial slit.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the tubular liner is formed by dip coating the removable mandrel.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the tubular liner comprises polytetrafluoroethylene.

A neurovascular catheter with an atraumatic leading tip as disclosed in any embodiment herein, further comprising a tie layer between the liner and the helical coil.

A neurovascular catheter having an atraumatic leading tip as disclosed in any embodiment herein, wherein the junction layer has a wall thickness of no more than about 0.005 inches.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any of the embodiments herein, wherein the tie layer extends at least 20cm along a distal-most side of the flexible body.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the coil comprises nitinol.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the nitinol comprises an austenitic state at body temperature.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the outer sheath is formed of at least five discrete axially-abutting tubular sections.

A neurovascular catheter with an atraumatic guiding tip as disclosed in any embodiment herein, wherein the outer sheath is formed of at least nine discrete axially-adjoined tubular segments.

A neurovascular catheter having an atraumatic guiding tip as disclosed in any embodiment herein, wherein the difference in stiffness between a proximal one of the tubular sections and a distal one of the tubular sections is at least about 20D.

A neurovascular catheter having an atraumatic guiding tip as disclosed in any embodiment herein, wherein the difference in stiffness between a proximal one of the tubular sections and a distal one of the tubular sections is at least about 30D.

A neurovascular catheter with an atraumatic leading tip as disclosed in any embodiment herein, further comprising a tensile support for increasing the resistance to tension in the distal region.

A neurovascular catheter having an atraumatic guiding tip as disclosed in any embodiment herein, wherein the tensile support comprises an axially extending filament.

A neurovascular catheter having an atraumatic guiding tip as disclosed in any embodiment herein, wherein the axially extending filament is carried between the liner and the helical coil.

A neurovascular catheter having an atraumatic leading tip as disclosed in any embodiment herein, wherein the axially extending filament increases the tensile strength of the tubular body to at least about 2 pounds.

Claims (20)

1. A system for removing embolic material from an intravascular site, comprising:

an elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

an axial restraint carried by the sidewall and exposed to the lumen;

a rotatable core wire extendable through the lumen, the core wire having a proximal end and a distal end;

a restraint carried by the core wire, the restraint having a bearing surface for rotatably engaging the restraint; and

a clot gripping tip on a distal end of the core wire,

wherein the constraining member and the constraining member are configured to allow rotation of the core wire but limit distal travel of the tip to a distance no greater than about 6mm beyond the distal end of the tubular body.

2. The system of claim 1, wherein the limiter and the constraint are configured to allow rotation of the core wire but limit distal travel of the tip to a distance no greater than about 3mm beyond the distal end of the tubular body.

3. The system of claim 1, wherein the clot gripping tip comprises a helical thread.

4. The system of claim 3, wherein the limiter and the constraint are configured to allow rotation of the core wire but limit distal travel of the tip to about one to three full turns of the thread exposed beyond the distal end of the tubular body.

5. The system of claim 1, wherein the axial restraint comprises a proximally facing bearing surface.

6. The system of claim 5, wherein the axial restraint comprises a radially inwardly extending protrusion.

7. The system of claim 6, wherein the axial restraint comprises an annular flange.

8. The system of claim 1, wherein the restraint includes a distally facing bearing surface.

9. The system of claim 8, wherein the restraint includes a radially outwardly extending protrusion.

10. The system of claim 9, wherein the radially outwardly extending protrusion is configured for sliding contact with the restraint.

11. The system of claim 1, wherein a proximal bearing surface on the axial restraint is within about 30cm of the distal end of the tubular body.

12. The system of claim 11, the proximal bearing surface being in a range of about 4cm to about 12cm from the distal end of the tubular body.

13. The system of claim 3, wherein the helical thread has a maximum major diameter that is no greater than about 90% of an inner diameter of the lumen, leaving an annular flow path between the tip and an inner surface of the sidewall.

14. The system of claim 3, wherein the helical thread has a blunt outer edge.

15. The system of claim 1, wherein the restraint is located within about the distal most 25% of the length of the core wire.

16. The system of claim 1, wherein the core wire is removably disposed within the tubular body.

17. The system of claim 1, further comprising a steering member configured to manually rotate the core-wire.

18. The system of claim 3, wherein the helical thread extends entirely no more than about eight full turns.

19. The system of claim 3, wherein the major diameter of the helical thread increases proximally from a first diameter near the distal tip to a second maximum major diameter and then decreases proximally from the maximum major diameter to a third diameter.

20. The system of claim 19, wherein an inner diameter of the tubular body adjacent the clot gripping tip is at least about 0.015 inches greater than a maximum outer diameter of the tip.