WO2017161204A1

WO2017161204A1 - Device and method of thrombus retrieval

Info

Publication number: WO2017161204A1
Application number: PCT/US2017/022837
Authority: WO
Inventors: Richard E. FULTON III; Aaron CALL; Kelvin Ning
Original assignee: Calture Vascular Inc
Current assignee: Calture Vascular Inc
Priority date: 2016-03-16
Filing date: 2017-03-16
Publication date: 2017-09-21
Anticipated expiration: 2018-09-16
Also published as: WO2017161204A8

Abstract

Disclosed herein are devices, systems and methods for removal of a thrombus or embolus from a vascular channel of the body. A device comprising at least one actively expandable scaffold is inserted into the vascular channel and positioned at the thrombus or embolus in a collapsed configuration. A lytic agent is delivered by a delivery member fluidly coupled to a source of lytic agent and an infusion pump to the thrombus or embolus. The scaffold is expanded through the thrombus or embolus to an expanded configuration while the lytic agent is being infused in order to urge the thrombus or embolus into the scaffold. The scaffold is then collapsed around the thrombus or embolus and removed from the patient with the thrombus or embolus captured therein.

Description

DEVICE AND METHOD OF THROMBUS RETRIEVAL

CROSS-REFERENCE

[0001] This application claims the benefit of U.S. Provisional Application No. 62/309,056, filed March 16, 2016, which application is incorporated herein by reference.

BACKGROUND

[0002] It is estimate that over 2 million cases of deep venous thrombosis (DVT) occur in the U.S. each year. Of those, only about 700,000 are actually diagnosed. One complication of DVT, pulmonary embolism, causes approximately 200,000 deaths each year - more than breast cancer and AIDS combined - making it the third leading cause of death in the U.S. Roughly 60-70% of patients with DVT will eventually experience post thrombotic syndrome (PTS) and chronic venous insufficiency, primarily as a result of damage to the venous valves by the thrombus. The overall interventional venous market is $700 million and expected to double in five years. Unfortunately, however, the current standard of care is anticoagulation which may have less than favorable long-term results in patients.

[0003] Venous thrombus usually begins from some combination of hypercoagulability, endothelial injury/dysfunction, and hemodynamic changes/stasis (i.e. the classic Virchow's triad). Typically, the thrombus initially forms behind the valvular leaflets and extends along the wall of the vein as it propagates. The thrombus may enlarge from the vessel wall inward until it occludes the vein. Most thrombolytic efforts begin in a central region of the thrombus as the catheters usually seek the path of least resistance and, since it was the last to form, the center of the thrombus is often the softest and easiest to penetrate. Tissue plasminogen activator, or tPA, and its analogues are frequently utilized as a lytic agent to perform thrombolysis.

[0004] Commonly used lytic agents such as tPA often require at least 30 minutes to begin dissolving the clot and may be limited in their penetration into clots. Thick clots often take several hours to dissolve as the tPA penetration, or lack thereof, may result in dissolution of the clot in a layer-like fashion, with the area exposed to tPA dissolving in order to expose older clot below it to the tPA to allow it to dissolve, and so on. The clot adjacent to the vessel wall is the oldest, firmest, and most difficult part of the clot to dissolve and remove. In some cases, methods for fragmenting the clots, including rotating baskets, water jets, and the like, have been used to increase the contact of the tPA with the clot material with varying degrees of success. Such procedures, however, frequently take hours and may not remove the entire clot. In some instances, the central clot can be removed to restore flow within the vessel while the wall-adherent clot remains. Residual clot after treatment may increase the likelihood of recurrent DVT, subsequent pulmonary embolism, and PTS. Thus, additional efforts may be necessary using such procedures in order to remove the entire clot, thereby prolonging the procedure, in order to reduce the risk of subsequent recurrence and other complications. This may also result in inefficiencies in patient care as the physician must focus more time on removing the clot, for example using additional maceration techniques, which may prevent the physician from performing other procedures on the patient at the same time or within a reasonable time frame.

[0005] The current interventional methods of treating venous diseases (including DVT and its complications including pulmonary embolism and PTS) may be less than satisfactory for several reasons. Previous thrombolytic and thrombectomy devices are typically designed to treat the thrombus but may not remove the entire thrombus. It is well-known and accepted in the medical field that such prior art devices only remove or dissolve acute thrombus.

Organized, firm, and fibrous subacute or chronic thrombus, which is frequently present in patients, is more resistant to current methods of thrombolysis and thrombectomy and thrombus removal using such devices may less than complete.

[0006] It is important to note that the efficacy of thrombolytic drugs often depends on the age of the clot. Older clots have more fibrin cross-linking and are more compacted than younger clots. Older clots are therefore more difficult to dissolve than younger, more acute clots. When treating acute myocardial infarction, for example, thrombolytic agents should ideally be given within the first 2 hours after the incident. Beyond that time, the efficacy of the lytic agents can diminish and higher doses are generally required to achieve desired lysis. The thrombus of a patient with DVT or peripheral arterial disease may be days or weeks old. Fibrin cross-linking and compaction may therefore be much more advanced than in the acute scenario. Strands of fibrin form cross-linked mesh or web-like structures as the thrombus ages. These mesh structures attach to one another and the vessel wall, and are consequently resistant to dissolution by lytic agents (including tPA). Currently available methods and devices often do not effectively remove chronic, compacted, fibrous thrombi which are attached to vessel walls. It would therefore be desirable to provide a device which is able physically and/or chemically dissociate the thrombus. It would also be desirable to provide a device capable of fragmenting the thrombus into smaller pieces or fragments, detaching the thrombus from the vessel wall, encapsulating the thrombus or thrombus fragments, and/or removing the thrombus or thrombus fragments from the vessel. [0007] DVT is classified into one of three categories based on the age of the thrombus - acute (14 days or less), subacute (15-28 days), or chronic (more than 28 days). DVT typically develops in a slow, progressive process without the knowledge of the patient (asymptomatic) for much of its development. It may, however, develop more rapidly. When the DVT began, and thus how old the thrombus is and how to classify it, can therefore be difficult to determine with any degree of certainty. Physicians may thus be unable to accurately determine whether the thrombolytic and thrombectomy devices currently available to them are likely to be effective in treating the thrombus. Given that such devices require an invasive procedure and can be very expensive, this inability to determine the likelihood of success can be a deterrent for their use. Other intervention techniques, such as percutaneous intervention, may have similar drawbacks. While intended to be a straightforward and quick procedure, percutaneous delivery of lytic therapy frequently requires several days of treatment and can cost as much as $30,000-$50,000 if the thrombus is not acute and readily lysed. Most primary care physicians are cost-profiled by their insurers which may make them reluctant to embark on a potentially costly therapy with an unknown result as it may negatively affect their relationship with their insurer. This unknown can prevent many patients from receiving aggressive therapy that may be beneficial to them. The market penetration is therefore very modest as a result of these factors. It is expected that such factors will continue to negatively affect market penetration unless there is an improvement in the reliability and/or

predictability of results. Both the lack of success of the prior art devices and the fact that many patients are not treated because of the unknown outcomes may lead to leaving a patient with residual thrombus which can require costly treatment (such as prolonged lytic therapy), and may increase the risk of valvular damage (which predisposes patients to developing chronic venous insufficiency and PTS) as time goes on.

[0008] Given that residual clot after interventions can be a strong predictor of DVT recurrence, PTS, and future PE, a patient with residual clot following initial treatment may be placed on an overnight drip of the lytic agent and observed in an intensive care unit (ICU). The lytic drip may subject the patient to additional risks, including gastrointestinal bleeds or intracranial hemorrhage, as well as significant additional costs related to an overnight stay in the ICU. A patient may then be returned to the laboratory the following day and additional attempts to remove the clot may occur, thus further extending treatment time and increasing treatment costs.

[0009] Furthermore, the position in which the patient is kept during treatment may be less than ideal. In many instances, the patient is prone on a bed or gurney with their chest facing downwards. Such a position may be uncomfortable or induce fear in the patient. Additionally, many of the current treatment procedures are performed under fluoroscopy which, given the possible length of such procedures for a non-acute thrombus, the patient as well as the physician and other laboratory personnel may be exposed to higher doses of ionizing radiation than could be achieved with a shorter procedure duration.

[0010] A device(s) that can successfully remove the entire thrombus quickly and efficiently in a majority of patients would likely result in decreased treatment and overall healthcare costs and would be expected to be widely adopted such that more patients would receive the appropriate thrombus-removing therapy compared to the case with the currently available devices. A procedure which works most of the time, or all of the time, could reduce or remove the question of failure which plagues the currently available procedures and weighs heavily in the clinical decision-making process, thereby reducing or eliminating a major deterrent to transcatheter thrombolysis/thrombectomy. It would therefore be desirable to provide a device which would allow a majority of patients to receive treatment quickly, efficiently, and with reliable expected outcomes. It is expected that such a device would allow the majority of patients with femoral and iliolfemoral DVT, for example, to receive definitive therapy and prevent downstream complications at later dates. Further, treating more patients with a successful thrombectomy device could increase the number of patients that would be available for stenting and other ancillary interventional procedures that might otherwise be unavailable to them due to the presence of a thrombus.

SUMMARY

[0011] One objective of the present disclosure is to provide a device and methods that remove the entire thrombus in a timely and cost-efficient manner in order to increase the number of patients that receive aggressive percutaneous treatment for DVT (instead of receiving only anti-coagulation therapy). It would be desirable to provide a device capable of removing a thrombus within about 3 to about 6 hours. This may for example entail a quick, 20 minute session in a catheter lab to insert and deploy a device as described herein and about 3 to about 5 hours in a separate observation area during which time a lytic agent and intermittent mechanical action of the device is at work. This may be followed by a 30 to 40 minute session in the catheter lab to complete the procedure and remove the device. Such a work flow may provide a same-day complete thrombectomy with improved results and reduced costs compared to currently available devices. [0012] One objective of the current invention is to provide a system which allows for efficient removal of thrombus or other materials from tubular channels of the body (including veins, arteries, and grafts) in a successful and predictable manner. Alternatively or in combination, it would be desirable to provide systems, devices, and methods which reduce procedure duration, reduce exposure to radiation, reduce total treatment time, reduce patient risk, or any combination thereof. In some instances, for example in treating DVT, one or all of these objectives may be accomplished by utilizing a device comprising a scaffold which is configured to expand over time towards the vessel wall as a result of gradual outward radial pressure on the scaffold. The scaffold may comprise scaffold filaments or members.

Expansion of the scaffold may insinuate and/or encapsulate the thrombus with the scaffold filaments or members due to radial outward pressure of the scaffold during expansion. This may be accomplished with or without concurrent delivery of a lytic agent to the clot. In some embodiments, the system is not configured to deliver a lytic agent. When combined with delivery of a lytic agent, however, the outward expansion of the scaffold and the lytic agent may work in concert with each other to improve the efficacy and speed of dissolution of the clot. The lytic agent may dissolve the clot adjacent to the scaffold as the scaffold

progressively expands into the dissolve areas of the clot, eventually reaching the vessel wall where the lytic agent may act on the wall-adherent (i.e. oldest) clot. In some embodiments, the lytic agent may be delivered through one or more of the members or filaments of the scaffold. Alternatively or in combination, the scaffold may be configured to vibrate in order to further enhance to the expansion of the scaffold into the clot, by encouraging the clot to break up, and/or the action of the lytic agent, by exposing additional surface area to the lytic agent as the clot is vibrated. Vibration may be particular effective after the scaffold has expanded (or begun expanding) into the clot but may also be utilized when the scaffold is in a collapse configuration in order to facilitate penetration of the scaffold, guide wire, or other device into the clot so as to pierce the clot and position the distal end of the scaffold, guide wire, or other device downstream of the clot. The vibration may be operably coupled to a timer and/or controller in order to control the time during which the vibration occurs and/or the frequency (or frequencies) at which the scaffold vibrates. A tensioning mechanism, for example a spring, may be used to provide additional outward radial force to the scaffold to encourage expansion and/or prevent collapse of the scaffold.

[0013] Another objective is to provide a system, device, or methods for recovering a blood clot from various vessels using a similar technique to insinuate or encapsulate the clot prior to removal. Such a technique may be modified to account for the anatomy of the location of the clot as well as the urgency of removal. For example, the removal of a blood clot from a cerebral, pulmonary, or coronary artery may need to occur as soon as possible in patients with stroke, pulmonary embolism, or myocardial infarction, respectively. In the peripheral arteries, near- immediate removal of a clot may be less critical, though there is often still some urgency in removal. In DVT and graft thrombosis, the rapid removal of clot is even less critical. In DVT, for example, a slower, more methodical removal may be practical so as to ensure that all of the clot is removed. The methods provided herein may be modified to address the specific needs of the specific situation and location.

[0014] Another objective is to provide a system comprising a plurality of expandable scaffolds. The plurality of expandable scaffolds may be mounted on the same structure. Alternatively or in combination, the plurality of expandable scaffolds may be mounted on different structures. For example, two expandable scaffolds may be coupled to one or more catheters or members in series as described herein. In some embodiments, three of more expandable scaffolds may be provided on the same catheter or member structure. In some embodiments, each of the plurality of scaffolds may comprise the same density of filaments and/or the same size interstices between filaments. In some embodiments, each of the plurality of scaffolds may comprise different filament densities and/or interstices sizes. For example the plurality of scaffolds may comprise progressively smaller interstices from the most proximal scaffold to the most distal scaffold in order to provide a system in which the most proximal scaffold (or first scaffold) cuts through or fragments the clot and the subsequent scaffolds with smaller interstices act to further fragment the clot and/or provide traction on the clot (and act as a netting) for removal.

[0015] Another objective is to provide a method of delivering a lytic agent while an expandable scaffold is expanding to the vessel wall. This may be accomplished by delivering the lytic agent to the clot via the scaffold or a separate delivery mechanism. The lytic agent may optionally be delivered with other agents (for example the patient's blood) in order to enhance the activity of the lytic agent. The lytic agent and the scaffold may work together to break down and remove the clot. The lytic agent may facilitate expansion of the scaffold towards the vessel wall and through the clot by chemically cleaving the fibrin bonds.

Expansion of the scaffold may physically generate increased surface area on which the lytic agent may act by cutting into the thrombus with the scaffold members (also referred to herein as struts or filaments). When the scaffold members are expanded to the vessel wall, the lytic agent may be delivered to the space adjacent to the vessel wall and the fibrin strands which hold the clot to the vessel wall may be cleaved by the synergistic action of the scaffold and the lytic agent. This may free the thrombus (as a single mass or as fragments of thrombus) from attachment to the vessel wall. The thrombus may be captured by the scaffold as the scaffold is collapsed and removed when the scaffold is removed.

[0016] Another objective is to provide a device for removal of thrombus or embolus from a vascular channel of the body. The device comprises at least one actively expandable scaffold comprising a proximal end, a distal end, and a longitudinal axis therebetween, and a delivery member configured to deliver a lytic agent to the thrombus or embolus. The at least one actively expandable scaffold comprises a collapsed configuration and an expanded configuration. The at least one actively expandable scaffold may be configured to deliver the lytic agent. In some embodiments, the delivery member may be in fluid communication with the at least one actively expandable scaffold. Alternatively or in combination, the at least one actively expandable scaffold may comprise a plurality of filaments. One or more of the filaments may comprise a hollow tube with one or more hole disposed along a length thereof through which the lytic agent may be delivered. The delivery member may comprise an infusion pump. Alternatively or in combination, the delivery member may comprise a hollow tube operably coupled to the at last one actively expandable scaffold. The hollow tube may expand outward towards the thrombus or embolus when the at least one actively expandable scaffold is in the expanded configuration. The lytic agent may comprise tissue plasminogen activator. The device may further comprise a support structure operably coupled to the at least one actively expandable scaffold at a distal end of the support structure. The support structure may comprise a guidewire, a catheter shaft, or an inner activation member. The device may further comprise a tension element coupled to the at least one actively expandable scaffold. The tensioning element may be configured to provide continuous tension to the at least one actively expandable scaffold when the at least one actively expandable scaffold is in the expanded configuration. The at least one actively expandable scaffold may comprise a mesh braid. The at least one actively expandable scaffold may be actuated from the collapsed configuration to the expanded configuration by compression along the longitudinal axis of the at least one actively expandable scaffold. The at least one actively expandable scaffold may further comprise a plurality of scaffold members with a plurality of interstices therebetween. The plurality of interstices may be larger in a proximal region of the at least one actively expandable scaffold than in a distal region of the at least one actively expandable scaffold. The device may further comprise a steering mechanism configured to move the at least one actively expandable scaffold in a direction parallel to the longitudinal axis, in a direction oblique to the longitudinal axis, in a direction transverse to the longitudinal axis, and/or rotationally about the longitudinal axis. The steering mechanism may be configured to move the at least one actively expandable scaffold intermittently. The intermittent movement may optionally comprise a quiescent time that is greater than an activation time. The at least one actively expandable scaffold may comprise a proximal scaffold and a distal scaffold. The proximal scaffold may comprise a first plurality of filaments with a first plurality of interstices therebetween. The distal scaffold may comprise a second plurality of filaments with a second plurality of interstices therebetween. The first plurality of interstices may be larger than the second plurality of interstices. The second plurality of interstices may comprise a proximal region of larger interstices and a distal region of smaller interstices. The at least one actively expandable scaffold may comprise an inner scaffold and an outer scaffold. The inner scaffold may be disposed within the outer scaffold. Both the inner scaffold and the outer scaffold may be configured to expand from the collapsed configuration to the expanded configuration. The inner scaffold may be configured to support the outer scaffold when in the expanded configuration. The outer scaffold may be configured to expand through the thrombus or embolus when in the expanded configuration. The inner scaffold may be positioned within the outer scaffold at a longitudinally central portion of the outer scaffold in order to provide radial support to the outer scaffold when both the inner scaffold and the outer scaffold are in the expanded configuration. The proximal end of the at least one actively expandable scaffold may be configured to provide traction to the thrombus or embolus. The proximal end may have an acute angle or convex shape in order to provide traction on the thrombus or embolus. The proximal end of the at least one actively expandable scaffold may be configured to fragment the thrombus or embolus. The proximal end may have a substantially flat or concave shape in order to facilitate fragmentation of the thrombus or embolus.

[0017] Another objective is to provide a method of removing a thrombus or embolus from a vascular channel of a body. The method comprises inserting a device comprising at least one actively expandable scaffold into the vascular channel; wherein the at least one actively expandable scaffold comprises a collapsed configuration and an expanded configuration, and wherein the device is inserted with the at least one actively expandable scaffold in the collapsed configuration; positioning the at least one actively expandable scaffold at the thrombus or embolus; delivering a lytic agent to the thrombus or embolus; expanding the at least one actively expandable scaffold from the collapsed configuration to the expanded configuration through the thrombus or embolus while the lytic agent is being delivered, wherein expanding the at least one actively expandable scaffold urges the thrombus or embolus into the at least one actively expandable scaffold; collapsing the at least one actively expandable scaffold with the thrombus or embolus within the at least one actively expandable scaffold; and removing the at least one actively expandable scaffold from the vascular channel, wherein the at least one actively expandable scaffold contains the thrombus or embolus therein. The lytic agent may be delivered by a fluid delivery member coupled to the at least one actively expandable scaffold. The delivery member may optionally be in fluid communication with the at least one actively expandable scaffold. The delivery member may comprise an infusion pump. The lytic agent may be delivered by the at least one actively expandable scaffold. The at least one actively expandable scaffold may comprise a plurality of filaments. One or more of the filaments may comprise a hollow tube with at least one hole disposed along a length thereof through which the lytic agent is delivered. The lytic agent may comprise tissue plasminogen activator. The lytic agent may be delivered about a perimeter of the at least one actively expandable scaffold in the expanded configuration.

[0018] Another objective is to provide a system for removal of a thrombus or embolus from a vascular channel of a body. The system comprises a thrombectomy device having a delivery member configured to deliver a lytic agent to the thrombus or embolus, a source of the lytic agent, and an infusion pump fluidly coupled to the delivery member and the lytic agent source to provide lytic agent from the source to the delivery member. The thrombectomy device further comprises at least one actively expandable scaffold comprising a collapsed configuration and an expanded configuration, and an inner activation member disposed within an outer activation member. The at least one actively expandable scaffold may be configured to deliver the lytic agent. The delivery member may be in fluid communication with the at least one actively expandable scaffold. The at least one actively expandable scaffold may optionally comprise a plurality of filaments. One or more of the filaments may comprise a hollow tube with at least one hole disposed along a length thereof through which the lytic agent is delivered. The delivery member may comprise an infusion pump. The lytic agent may comprise tissue plasminogen activator. The system may optionally comprise a support structure operably coupled to the at least one actively expandable scaffold at the distal end of the support structure. The support structure may comprise a guidewire, a catheter shaft, or an inner activation member. Alternatively or in combination, the system may further comprise a tension element coupled to, and configured to provide continuous tension to, the at least one actively expandable scaffold when the at least one actively expandable scaffold is in the expanded configuration. The at least one actively expandable scaffold may comprise a mesh braid. Alternatively or in combination, the system may further comprise a vibration mechanism operably coupled to the at least one actively expandable scaffold. The system may optionally comprise a controller operably coupled vibration mechanism and configured to control the frequency or timing of the vibration applied to the at least one actively expandable scaffold.

[0019] Another objective is to provide a device for removal of a thrombus or embolus from a vascular channel of a body. The device comprises at least one actively expandable scaffold comprising a proximal end, a distal end, and a longitudinal axis therebetween, wherein the at least one actively expandable scaffold comprises a collapsed configuration and an expanded configuration, wherein the at least one actively expandable scaffold comprises a plurality of filaments or tines, wherein the plurality of filaments or tines are configured to expand outward toward a wall of the vascular channel when the at least one expandable scaffold is actuated from the collapsed configuration to the expanded configuration; an outer activation member; and an inner activation member slidably disposed within the outer activation member, wherein translation of the inner activation member relative to the outer activation member actuates the at least one actively expandable scaffold between the collapsed configuration and the expanded configuration. The at least one expandable scaffold may comprise a plurality of tines configured to fragment the thrombus or embolus. Alternatively or in combination, the at least one expandable scaffold may comprise a plurality of filaments configured to fragment the thrombus or embolus. The device may optionally further comprise a lytic delivery member configured to deliver a lytic agent to the thrombus or embolus. A proximal portion of the at least one expandable scaffold may be coupled to the inner activation member. A distal portion of the at least one expandable scaffold may be coupled to the outer activation member.

[0020] Another objective is to provide a method of removing of a thrombus or embolus from a vascular channel of a body. The method comprises inserting a device comprising at least one actively expandable scaffold into the vascular channel, wherein the at least one actively expandable scaffold comprises a collapsed configuration and an expanded configuration, and wherein the device is inserted with the at least one actively expandable scaffold in the collapsed configuration; positioning the at least one actively expandable scaffold distal to the thrombus or embolus; expanding the at least one actively expandable scaffold from the collapsed configuration to the expanded configuration to contact a wall of the vascular channel; moving the at least one actively expandable scaffold proximally towards the thrombus or embolus; fragmenting the thrombus or embolus with the at least one actively expandable scaffold; capturing the thrombus or embolus within the at least one actively expandable scaffold; collapsing the at least one actively expandable scaffold with the thrombus or embolus therein; and removing the at least one actively expandable scaffold from the vascular channel, wherein the at least one actively expandable scaffold contains the thrombus or embolus therein when removed. The at least one expandable scaffold may comprise a plurality of tines configured to fragment the thrombus or embolus. The at least one expandable scaffold may comprise a plurality of filaments configured to fragment the thrombus or embolus. Moving the at least one expandable scaffold may comprise providing traction to the at least one expandable scaffold. The method may further comprise delivering a lytic agent to the thrombus or embolus to facilitate fragmentation of the thrombus or embolus. The lytic agent may be delivered by a fluid delivery member coupled to the at least one actively expandable scaffold. The delivery member may be in fluid communication with the at least one actively expandable scaffold. The at least one actively expandable scaffold may be configured to deliver the lytic agent. The at least one actively expandable scaffold may comprise a plurality of filaments. One or more of the filaments may comprise a hollow tube with at least one hole disposed along a length thereof through which the lytic agent is delivered. The delivery member may comprise an infusion pump. The lytic agent may comprise tissue plasminogen activator.

INCORPORATION BY REFERENCE

[0021] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

[0023] FIG. 1 shows a side view of an actively expandable scaffold device in a collapsed configuration, according to embodiments of the present disclosure.

[0024] FIG. 2 shows a side view of the actively expandable scaffold device of FIG. 1 in an expanded configuration, according to embodiments of the present disclosure. [0025] FIG. 3 shows a magnified view of the hollow tubing elements of the scaffold device of FIGS. 1 and 2, according to embodiments of the present disclosure.

[0026] FIG. 4 shows a side, schematic view of a thrombectomy system employing the actively expanding scaffold device of FIGS. 1 and 2, according to embodiments of the present disclosure.

[0027] FIG. 5 shows a side view of the actively expandable scaffold device of FIGS. 1 and 2 as positioned within a vessel with thrombus, according to embodiments of the present disclosure.

[0028] FIG. 6 shows a side view of the actively expandable scaffold device of FIGS. 1 and 2 as positioned and expanded within a vessel with thrombus, according to embodiments of the present disclosure.

[0029] FIG. 7 shows a side view of another actively expandable scaffold device in a collapsed configuration, according to embodiments of the present disclosure.

[0030] FIG. 8 shows a side view of the actively expandable scaffold device of FIG. 7 in an expanded configuration, according to embodiments of the present disclosure.

[0031] FIG. 9 shows a side view of another actively expandable scaffold device in an expanded configuration, according to embodiments of the present disclosure; the FIG. 9 scaffold device is collapsed and expanded by translating multiple, coaxial inner members relative to one another.

[0032] FIG. 10 shows a side view of another actively expandable scaffold device in a collapsed configuration, according to embodiments of the present disclosure.

[0033] FIG. 11 shows a side view of the actively expandable scaffold device of FIG. 10 in an expanded configuration, according to embodiments of the present disclosure.

[0034] FIG. 12 shows a side view of still another actively expandable scaffold device in a collapsed configuration, according to embodiments of the present disclosure.

[0035] FIG. 13 shows a side view of the actively expandable scaffold device of FIG. 12 in an expanded configuration, according to embodiments of the present disclosure.

[0036] FIG. 14 shows a side view of still another actively expandable scaffold device in a collapsed configuration, according to embodiments of the present disclosure.

[0037] FIG. 15 shows a side view of the actively expandable scaffold device of FIG. 14 in an expanded configuration, according to embodiments of the present disclosure.

[0038] FIG. 16 shows a side view of an actively expandable scaffold device in an expanded configuration positioned in a vessel, according to embodiments of the present disclosure. [0039] FIG. 17 shows a side view of the actively expandable scaffold device of FIG. 16 in a collapsed configuration positioned in a vessel, according to embodiments of the present disclosure.

[0040] FIGS. 18A-18C show exemplary end views of the actively expandable scaffold device of FIG. 16 in an expanded configuration, according to embodiments of the present disclosure.

[0041] FIG. 19A shows a side view of another actively expandable scaffold device in a collapsed configuration positioned in a vessel, according to embodiments of the present disclosure.

[0042] FIG. 19B shows a side view of the actively expandable scaffold device of FIG. 19A in an expanded configuration positioned in a vessel, according to embodiments of the present disclosure.

[0043] FIG. 19C shows a side view of the actively expandable scaffold device of FIG. 19A with a captured thrombus therein, according to embodiments of the present disclosure.

[0044] FIG. 20 shows a side view of the actively expandable scaffold device of FIG. 19A in the expanded configuration positioned in an iliac vein, according to embodiments of the present disclosure.

DETAILED DESCRIPTION

[0045] Various configurations of a scaffold-like thrombecotomy, emolectomy, and embolic protection device are provided herein. The device may comprise a scaffold. The scaffold may expand from a collapsed configuration to an expanded configuration. The scaffold may be gradually expanded over time through a plurality of intermediate configurations between the collapsed configuration and the expanded configuration. The scaffold may be self-expandable upon withdrawal of a delivery catheter. The scaffold may be actively expanded and contracted, for example using a push-pull mechanism as described herein.

[0046] The scaffold may comprise a plurality of scaffold members (also referred to herein as filaments, struts, or tines). The scaffold members may comprise hollow, tubular members Alternatively or in combination, the scaffold members may be solid (without a lumen or hollow inside). For example, the scaffold may comprise a plurality of hollow, tubular members and a plurality of solid members. Hollow, tubular members may be used to deliver a variety of medicaments. For example, such medicaments may include lytic agents such as tPA or analogues thereof, non-pro liferative agents, anti-coagulants, vascular endothelial growth factor and other growth-promoting agents, anti- vascular agents, gene therapies, factors, anti-platelet agents, or the like. The medicaments may be infused into the hollow members by a dedicated pump using techniques known to one of ordinary skill in the art. The hollow members or filaments may comprise holes in order to allow the therapeutic medicament to the clot. Alternatively or in combination, medicaments such as lytic agents like tPA may be delivered to the clot by a delivery mechanism other than the scaffold members as described herein.

[0047] The scaffold may comprise a tubular scaffold. The scaffold may comprise a mesh braid configuration, stent-like configuration, or other scaffold configuration as desired by one of ordinary skill in the art. The scaffold may be self-expanding or actively expandable by other mechanisms as described herein. For example, the scaffold may preferably comprise a tubular braid-like structure coupled to inner and outer activation members. The outer activation member may comprise a lumen in which the inner activation member may be disposed. The inner activation member may be coupled to a distal aspect or end of the scaffold. The outer activation member may be coupled to a proximal aspect or end of the scaffold. Retraction of the inner activation member relative to the outer activation member proximally in a direction parallel to a longitudinal axis of the scaffold may compress the scaffold and cause it to expand from a collapsed configuration to an expanded configuration. The scaffold may comprise a plurality of partially expanded intermediate configurations between the collapsed configuration and a fully expanded configuration (which would allow the scaffold to contact the vessel wall). The scaffold may be configured to gradually expand from the collapsed configuration, through the intermediate configurations, to the fully expanded configuration as the thrombus is fragmented and/or dissolved during treatment.

[0048] The inner activation member may be about 20 centimeters (cm) to about 200 cm in length, for example about 60 cm to about 120 cm. The inner activation member may be about 0.003 inches to about 0.54 inches in diameters, for example about 0.008 inches to about 0.035 inches. The outer activation member may be about 20 centimeters (cm) to about 200 cm in length, for example about 60 cm to about 120 cm. The outer activation member may be about 0.003 inches to about 0.54 inches in diameters, for example about 0.008 inches to about 0.035 inches. The outer activation member may have a larger diameter than the inner activation member. The inner activation member may be coaxially disposed within the lumen of the outer activation member such that the longitudinal axis of the inner activation member is coaxial with the longitudinal axis of the outer activation member.

[0049] Tension on the inner and/or outer activation members may be provided to generate outward radial force on the scaffold. Tension may be used to provide radially outward force to a self-expanding scaffold. Tension may be used to provide radially outward force to an actively expandable scaffold. A tension element or spring may be operably, for example directly or indirectly, coupled to one or more of the inner activation member, the outer activation member, the scaffold, or any combination thereof. The tension element may provide continuous tension so as to continually expand the scaffold with minimal or without manual manipulation.

[0050] FIG. 1 shows a side view of an actively expandable scaffold device in a collapsed configuration. The scaffold 10 may be delivered to the site of the thrombus in the collapsed configuration, positioned near or within the thrombus, and then expanded into an expanded configuration with the thrombus therearound. The scaffold 10 may comprise a scaffold members or filaments 11 in a tubular, braid-like configuration. The scaffold members may be solid or a hollow tube-like element as described herein. The proximal end of the scaffold 10 may be coupled or attached to an outer activation member 12. The distal end of the scaffold 10 may be coupled or attached to an inner activation member 13. The inner activation member 13 may be slidably disposed coaxially within a lumen of the outer activation member 12.

[0051] FIG. 2 shows a side view of the actively expandable scaffold device of FIG. 1 in the expanded configuration. Translation of the inner activation member 13 relative to the outer activation member 12 may compress the ends of the scaffold 10 towards one another and cause the scaffold 10 to expand. Expansion of the scaffold 10 may provide outward radial tension on structures, such as a thrombus, in contact with the scaffold members 11 in order to compress and expand those structures and/or surrounding tissue which would otherwise tend to constrain the scaffold 10 and resist expansion of the scaffold 10.

[0052] FIG. 3 shows a magnified view of the scaffold members 11 of the scaffold device 10 of FIGS. 1 and 2. The scaffold 10 may comprise interstices 26 between the scaffold members 10 as described herein. The scaffold members 11 may comprise hollow tubular elements as described herein. Any of the scaffolds 10 described herein may comprise one or more hollow scaffold members 11. The hollow scaffold members 11 may comprise one or more holes or apertures 14 along the length thereof. The holes 14 may be fluidly coupled to a source of a medicament, such as a lytic agent, via the hollow lumens of the scaffold members 11 in order to deliver the medicament to the thrombus. The holes 14 may be mechanically-generated (for example by manual or automatic piercing or stamping) or laser-cut at predetermined locations along the scaffold members 11. The holes 14 may be on the exterior or outside of the scaffold in order to provide improved contact of the delivered lytic agent with the surrounding thrombus. The lytic agent may be delivered into the thrombus via the holes 14 so as to dissolve at least a portion of the thrombus adjacent to the scaffold members 11 of the scaffold 10. While the holes 14 are shown at the crossing points or intersection of the filaments 11, it will be understood by one of ordinary skill in the art that the holes 14 may be created at any location on or along the filaments 11 as desired.

[0053] FIG. 4 shows a side, schematic view of a thrombectomy system employing the actively expanding scaffold device of FIGS. 1 and 2. Any of the scaffolds 10 described herein may be used with the system shown in FIG. 4. The system may comprise a scaffold device 10 and a receiving catheter 8. The scaffold 10 may be coupled to inner and outer activation members (not shown) as described herein. The inner and outer activation members may be coaxial tubular members as described herein which may be translated, for example pushed/pulled, relative to one another. For example, a distal end of the inner member may be coupled to a distal end of the scaffold while a distal end of the outer member may be coupled to a proximal end of the scaffold such that changing a distance between the inner and outer member distal ends may shorten the scaffold and cause it to radially expand as described herein.

[0054] The scaffold 10 may comprise hollow scaffold members as shown in FIG. 3 or another lytic agent delivery member as described herein. The hollow scaffold members may be fluidly coupled to a source 24 of lytic agent and optionally to an infusion pump 22.

[0055] The scaffold apparatus 10 may optionally be connected to a tensioning element 23 that may provide a force on the scaffold 10 in order to continuously expand the scaffold 10. The tensioning element 23 may for example comprise a spring disposed over and coupled to inner activation member 13, catheter, or other connector coupled to the inner activation member 13 such that tension is translated from the tensioning element 23 to the scaffold 10 via the inner activation member 13 (not shown). The tensioning element 23 may comprise any tensioning element known to one of ordinary skill in the art and may be operably coupled to the inner activation member 13 as described herein.

[0056] The receiving catheter 8 may comprise a funnel catheter 8. The funnel catheter 8 may be a generic funnel catheter which is not operably coupled to the inner and outer members 13, 12. Alternatively, the funnel catheter 8 may be a braided member which expands to form a funnel and is operably coupled or attached to the inner and outer members 13, 12 of any of the devices described herein. The braided member 8 may expand to from an unexpanded state to an expanded state as the inner and outer members 13, 12 are translated relative to one another or the braided member 8 as described herein. In the expanded state, the braided member 8 may form a funnel with a tubular channel of the body (e.g. vessel) thereby enlarging the mouth of the delivery catheter to act as a funnel catheter.

[0057] A vibration mechanism or vibrator 19 may optionally be operably coupled to the scaffold 10 as described herein. The vibration mechanism 19 may be external to the body as shown and removably or fixedly connected to a proximal portion of the scaffold 10 via a rigid connector 9 in order to efficiently transmit vibrations to the scaffold structure 10. The vibration mechanism 19 may alternatively be within the scaffold apparatus (not shown). Vibration of the scaffold 10 may accelerate outward expansion of the scaffold 10 and/or the action of the lytic agent. Vibration may help loosen or lyse fibrin bonds within the clot, physically agitate the clot, enhance outward expansion of the scaffold 10, or any combination thereof. Vibration may also improve insinuation of the clot into the inner aspect of the scaffold 10. The vibration mechanism 19 may be coupled to a controller 20 which may control the vibratory frequency and/or activation times of the vibration generated by the vibration mechanism 19. The controller 20 may be directly connected to the vibration mechanism 19, for example via wiring 21. The controller 20 may be indirectly or wirelessly connected to the vibration mechanism 19, for example via Wi-Fi or Bluetooth (not shown).

[0058] The vibration may be generated at any frequency desired by one of ordinary skill in the art. The vibration may for example be at a frequency within a range of about 1 hertz (Hz) to about 100 kilo hertz (100 kHz), for example within a range of about 100 to about 1000 Hz. Lower vibrational frequencies have longer wavelengths and thus may create less heat and more disruptive force than shorter wavelengths in the ultrasonic frequency range, particularly when a limited duty cycle is utilized. The vibrations may be translational, rotational, or side to side, for example at a frequency within a range of about 1 Hz to about 10 kHz. The frequency of vibration may be within a range of about 1 megahertz (MHz) to about 150 MHz. The vibrations may be applied to the scaffold 10 continuously or intermittently. Intermittent vibration may be rhythmic or arrhythmic. Intermittent vibration may occur with periods of vibration follow by periods of quiescence of equal duration (50% duty cycle). Intermittent vibration may occur with short periods of vibration followed by longer periods of quiescence (<50% duty cycle). Intermittent vibration may occur with long periods of vibration followed by shorter periods of quiescence (>50% duty cycle).

[0059] The device may comprise a mechanism (not shown) for actively steering the scaffold (which may comprise any of the scaffolds described herein) in a direction to the longitudinal access of the scaffold in a longitudinal motion, in a direction oblique or transverse to the longitudinal access in a side-to-side motion, or rotationally about the longitudinal axis in a rotation motion. The steering mechanism may comprise any steering mechanism desired by one of ordinary skill in the art. The steering mechanism may for example comprise a steerable catheter shaft which may be disposed in the inner activation member or outer activation member. In some instances, the inner activation member or outer activation member may be a steerable catheter shaft. The steering mechanism may be configured to move the scaffold continuously or intermittently. Intermittent movement may be rhythmic or arrhythmic. Intermittent movement may occur with periods of activation movement follow by periods of quiescence of equal duration (50% duty cycle). Intermittent movement may occur with short periods of movement followed by longer periods of quiescence (<50% duty cycle). Intermittent movement may occur with long periods of movement followed by shorter periods of quiescence (>50% duty cycle).

[0060] FIG. 5 shows a side view of the actively expandable scaffold device 10 of FIGS. 1 and 2 as positioned within a vessel and partially expanded into the thrombus 15. The scaffold members 11 of the scaffold 10 may expand radially outward towards, and into, the thrombus 15 as the scaffold 10 is actuated, for example by compression of the scaffold 10 by movement of the inner and outer activation members (not shown). Optional infusion of a lytic agent via the scaffold elements 11 or other delivery member may facilitate dissolution of the thrombus 15 and allow the scaffold 10 to further expand into the thrombus 15. A continual lytic infusion may be used to dissolve the thrombus 15 as the scaffold 10 expands radially outward to reach the vessel wall 16 as shown in FIG. 6. As the scaffold 10 nears or reaches the vessel wall 16, the continued infusion may provide lytic agent near the vessel wall 16 where it may act to dissolve the older, firmer clot 15 which may otherwise be resistant to dissolution and removal (especially in instances where the lytic agent is primarily delivered to the center of the thrombus 15). Expansion of the scaffold 10 and dissolution of the thrombus 15 adjacent to the scaffold may result in the thrombus being "diced" into fragments 17 by the filaments 11. The fragments 17 may be removed from the body via aspiration, for example through a receiving catheter 8 as shown in FIG. 4. Alternatively or in combination, the scaffold 10 may be collapsed, thereby insinuating or encapsulating the clot fragments 17 in the interior of the scaffold 10, and then withdrawn through the catheter 8 taking the fragments 17 along therewith. Alternatively or in combination, other techniques or mechanisms may be used to remove the thrombus fragments 17 from the body. For example, a smaller version of the scaffold 10 may be provided to withdraw the fragments 17 from the interior of the scaffold 10 and into the receiving catheter 8 while the scaffold 10 is in the expanded configuration. [0061] In clinical use, a patient diagnosed with DVT may be placed in a prone position and the popliteal vein on the affected side may be accessed and entered. The device described herein, for examples the device of shown in FIGS. 1-6 (though one of ordinary skill in the art will understand that the device may comprise any of the scaffolds 10 described herein as desired), may be inserted through a sheath, catheter, or funnel catheter 8 and the scaffold 10 may be positioned at least partially within the clot 15 with the scaffold 10 in the collapsed configuration. The scaffold 10 may be positioned such that it traverses the entire length of the clot 15. The scaffold 10 may then be partially expanded until such time as the clot 15 prevents further expansion (as shown in FIG. 5). A lytic agent, such as tPa, may be pulsed into the clot 15 from a source 24 by a standard infusion pump 22 for a predetermined period of time, for example 1 to 30 minutes, in order to begin the lysis process. The lytic agent may then be delivered as a continuous drip or with intermittent pulsing. Alternatively, the lytic agent may be delivered continuously for the duration of the procedure. In some instances, a lytic agent may not be delivered to the clot 15 at all. Continuous tension may be provided to the scaffold 10 by an optional tensioning element 23 in order to provide a force to

continuously expand the scaffold 10 into the thrombus 15. The scaffold 10 may optionally be coupled to a vibrator 19 which may vibrate the scaffold 10 at a desired frequency and/or for a desired duty cycle (made up of a desired activation time and a desired inactivation time) as described herein. The system may comprise a pump 22, tensioning element 23, a vibrator 19, or any combination thereof. The system may for example comprise a pump 22 configured to continuously infuse tPA at a rate of about 2 milliliters per minute or intermittently infuse tPA with bolus injections at a rate of 3 pulses per minute. A tensioning element 23 may for example provide about one pound per square foot of tension to the scaffold 10. The vibration mechanism 19 may for example be set to vibrate at 1000 cycles per second with five seconds of activation followed by three minutes of quiescence or de-activation. The patient may then be transferred to an observational area and observed for several hours while the lytic agent dissolves the clot 15, the scaffold 10 gradually expands to contact the vessel wall 16 (as in FIG. 6), and the vibrator 19 gently accelerates the thrombolectomy process with intermittent vibrations. The patient may or may not be examined by ultrasound or fluoroscopy in the observation area to monitor the clot dissolution. The patient may be returned to the laboratory and re-assessed after a predetermined amount of time. The fragments 17 of clot 15, if any, may be aspirated, retracted into the sheath or catheter 8 with an expandable device (not shown) from within the scaffold 10, and/or the scaffold 10 may be collapsed over the clot fragments 17 and removed with the entrapped clot fragments 17 trapped therein. The device may be removed from the patient to complete the procedure.

[0062] Although the steps above and described through the disclosure show methods of removing a thrombus or embolus using an expandable scaffold device in accordance with embodiments, a person of ordinary skill in the art will recognize many variations based on the teaching described herein. The steps may be completed in a different order. Steps may be added or deleted. Some of the steps may comprise sub-steps. Many of the steps may be repeated to completely remove the thrombus or embolus.

[0063] Methods of the current disclosure may comprise accessing a vessel in a patient diagnosed with thrombus in a vascular channel or graft using standard techniques as will be known to one of ordinary skill in the art, placing an expandable scaffold comprising filaments (which may be capable of delivering a lytic agent) through and/or within a clot, expanding the scaffold to contact the clot, optionally delivering the lytic agent to the clot while the scaffold is expanding towards the vessel wall in order to fragments the clot, collapsing the scaffold with the clot fragments inside the scaffold and removing the scaffold and clot fragments from the body. Alternatively or in combination, the method may comprise one or more of: continuously vibrating the scaffold, intermittently vibrating the scaffold, dissolving the clot while the patient is not in the catheter lab, placing tension on the scaffold to promote expansion of the scaffold, retrieving the scaffold through a funnel catheter, delivering the lytic agent through a delivery element that is distinct from the scaffold filaments, retracting clot fragments from within the scaffold while it is in an expanded configuration, utilizing a rigid connection to transmit the vibrations from a vibrator to the scaffold, or any combination thereof.

[0064] Deep venous thrombosis frequently leads to pulmonary embolism, which results in over 200,000 deaths in the U.S. each year. Blockage of the pulmonary arteries can result in right heart strain and eventually right heart failure along with diminished oxygenation of the blood from diminished pulmonary blood flow. This combination can create a situation in which deoxygenated blood is supplied to the coronary arteries which may cause further myocardial dysfunction. The right heart failure, due to back-pressure on the right ventricle secondary to the occluded pulmonary vascular tree, is usually a critical factor. Removing the clots from the pulmonary arteries quickly and efficiently to restore blood flow to the lungs and alleviate the right heart strain and right heart failure is of utmost importance in treating patients with pulmonary embolism. Thrombolysis and thrombectomy currently available may take a long time to remove the clot and may be insufficient in such situations when more urgent treatment is needed. The embolic clot or thrombus may have some characteristics that make it difficult to retrieve into an end-hole catheter given that at least part of the thrombus may have been present in recognized or unrecognized DVT for several weeks and may therefore be very fibrous and organized compared to a fresh clot. The embolus may not be adherent to the walls of the pulmonary arteries, as is frequently the case in DVT, having embolized from the legs or pelvis just prior to the diagnosis of pulmonary embolism. In many cases, the embolic clot fragments are large. Removing large, tough clot fragments through a catheter may therefore be particularly challenging and may be one reason why the prior art pulmonary embolectomy devices have been only partly successful or largely unsuccessful at complete removal of the embolus. The device described herein may be used to insinuate, encapsulate, or engulf the clot within the scaffold before removal. This may allow for rapid and efficient clot removal, which may of particular importance when removing clots from the pulmonary arteries.

[0065] Removal of a pulmonary embolism or vascular thrombus by the scaffold 10 may comprise encapsulating, insinuating, or engulfing the embolic thrombus into the inner portion of the scaffold or braid 10 prior to removal of the scaffold 10. To accomplish this, at least a portion of the scaffold "basket" may pass through or around the clot while the scaffold 10 is in the collapsed configuration, prior to the expansion of the scaffold 10. In some cases it may be difficult to pass a guidewire and/or the device through the clot due to the fibrous, organized nature of clots typically lodged at the origin of lobar branches of the pulmonary arteries. Hence, the guidewire or device may be placed between the wall of the vessel and the clot fragment, rather than through the central portion of the clot fragment. Upon expanding the scaffold, the clot may be compressed by the radial outward force generated by the expanding scaffold. The filaments of the scaffold may be configured to cut through portions of the clot, thereby insinuating at least part of the clot into the inner portion of the scaffold and/or attaching the scaffold to the clot for subsequent removal. The clot may then be retracted into a receiving catheter, for example a funnel catheter, as described herein. Simple retraction of the clot by pulling the clot into the mouth of the receiving catheter may be possible at times, but given the large variation in clot fragment sizes and consistency, as well as the flow dynamics and size of the pulmonary artery, a clot insinuator may be more effective than a simple clot retractor at removing the clot.

[0066] In some cases, an actively expandable scaffold may be preferred to a self-expandable scaffold for the simple reason that a self-expanding scaffold may not possess enough radial force to at least partly cut through a tough, organized clot in order to insinuate the clot within the scaffold. The actively expandable scaffold may resemble a stent-like structure or may be a tubular mesh-like braid as described herein. The scaffold may be actively expanded via a push-pull mechanism as described herein. The members or filaments of the scaffold may be round, triangular, square, pentagonal, hexagonal, heptagonal, octagonal, polygonal, irregular/asymmetrical, or any other shape configured to cut into the clot rather than displace it as the currently available stents typically do.

[0067] The interstices between the members or filaments may be large enough for the clot to protrude through the interstices into the interior of the scaffold when outward radial pressure is applied to the clot by the scaffold. The interstices may have a maximum dimension across within a range of about 1 mm to about 50 mm, for example within a range of about 5 mm to about 20 mm. The filaments may comprise a diameter within a range of about 0.003 inches to 0.035 inches, for example within a range of about 0.005 inches and about 0.015 inches. The scaffold filaments may be constructed from heat-set nitinol or any other suitable material. In the case of a braid-like structure, the density of the crosses (measured as pics per inch) may be within a range of about 0.5 to about 24 pics per inch, for example about 2 to about 16 pics per inch. The filaments may vary in size and/or shape. Some of the filaments may be utilized for support while other filament may be used to cut through the clot. Scaffold filaments or members may be removed to create openings within the scaffold (or a lower density of crosses). Openings or reduced pics per inch in a proximal portion of the scaffold may allow the scaffold to engulf clot fragments as it is retracted to the receiving catheter. The active expansion construction of the scaffold may allow the transverse diameter of the scaffold to be adjusted for variably sized pulmonary arteries and branch arteries.

[0068] With respect to FIGS. 4 to 6, the expandable scaffold may be configured to have a length extending along a longitudinal axis of the scaffold of about 20 to about 50 cm, or more than 50 cm. Additional support may be need in order to provide support for the mid-portion of the expanded scaffold and to provide outward radial force on the thrombus in order to urge the scaffold toward the vessel wall. In some embodiments, the device may be constructed such that smaller expandable scaffold structure, like those in illustrated in FIGS. 1, 2, 7, 8, and 9, comprising at least one expandable scaffold may be placed in the interior of a larger expandable scaffold, such as those illustrated in FIGS. 4, 5, and 6, in order to provide support to the larger expandable scaffold and increased outward radial pressure. The interior scaffold(s) may be placed coaxially over a central inner activation member of the larger scaffold and expanded by a push-pull mechanism during or after expansion of the larger outer expandable scaffold. A preferred configuration may place inner scaffolds every 5 to 20 cm within the larger outer scaffold. Alternatively or in combination, other structures may be employed to support the larger outer scaffold. Such structures may include but are not limited to struts originating at the inner activation member or other components of the larger expandable outer scaffold, rings that are part of the larger outer scaffold, springs, or the like, or any combination thereof. The added support may aid in the expansion of the outer scaffold, particularly through a chronic dense clot, toward the vessel wall. Any of the scaffolds described herein may comprise a support structure as described herein.

[0069] FIG. 7 shows a side view of an actively expandable scaffold device comprising two distinct scaffolds 10a, 10b in a collapsed configuration. FIG. 8 shows a side view of the actively expandable scaffold device of FIG. 7 in an expanded configuration. A proximal scaffold 10a and a distal scaffold 10b may be operably coupled to an outer activation member 12 and an inner activation member 13. The scaffolds 10a, 10b may comprise any of the scaffolds described herein. The scaffolds 10a, 10b may comprise scaffold members which may be substantially similar to any of the scaffold members described herein. In some instances, the proximal scaffold 10a may comprise a sparse braid- or stent-like structure with a low density of scaffold filaments or members 11. The distal scaffold 10b may comprise a tight braid- or stent-like structure with a higher density of filaments or members 11, particularly in a more distal aspect 27 of the scaffold 10b. A proximal aspect 28 of the scaffold 10b may comprise a lower density of scaffold filaments 11 compared to the density of filaments 11 at the distal aspect 27. The scaffolds 10a, 10b may be coupled to the inner activation member 13 at their respective distal ends 31a, 31b in order to provide support for each scaffold 10a, 10b. The proximal end of the proximal scaffold 10a may be coupled to the inner activation member 13 as described herein. A section of material or collar 30 around the inner activation member 13 may be coupled to a proximal portion of the distal scaffold 10b and may act as the outer activation member for the distal scaffold 10b. The collar 30 may or may not be attached to the proximal scaffold 10a, the inner activation member 13, or the combination thereof.

[0070] The two or more actively expandable scaffolds 10a, 10b may comprise the same or different patterns of a braid- or a stent-like structure. In the case of a braid, the pattern of the proximal scaffold 10a may have only a few pics per inch with rather large interstices 26 which tend to cut through, rather than provide traction to, the clot or thrombus. At least a portion of the filaments 11 may be relatively thin and/or possess sharp edges in order to enhance the cutting action over a traction type or pulling actions in order to fragment the clot. The distal scaffold 10b may be comprised of a section 27 of a denser braid pattern with more pics per inch to provide traction on the fragments created by the first scaffold 10a and to pull the clot fragments into a receiving catheter, which may be a funnel catheter. The distal scaffold 10b may have a sparse braid density on its proximal aspect 28, which may allow clot fragments to be engulfed into the open scaffold 10b end 28 while the more distal portion 27 comprising a tighter braid density may prevent the fragments from exiting the scaffold 10b.

[0071] An elastomer (not shown) may partially or completely cover (or fill) the interstices 26 of the distal portion 27 of the distal scaffold 10b in addition to or instead of the tight braid density so as to trap clot fragments within the structure of the scaffold 10b. The elastomer may partly cover or fill the interstices 26 such that the openings on the trailing or distal aspect 27 of the scaffold 10b are smaller than the interstices 26 of the leading edge or proximal aspect 28 of the scaffold 10b, thereby allowing particles to pass through the leading or proximal aspect 28 but not the trailing or distal aspect 27 of the scaffold 10b. When the elastomer more or less completely covers the distal aspect 27 of the scaffold 10b, holes may be placed within the elastomer by laser or some other method in order to allow blood (but not clot fragments) to flow through the device 10b.

[0072] Because the scaffolds 10a, 10b are fixedly attached to the inner activation member 13, the proximal scaffold 10a may translate a distance X when the inner activation member is pulled proximally in order compress and expand the proximal scaffold 10a. The distal scaffold 10b may translate proximally the same distance X without compression, as the collar 30 may also translate a distance of X, and the distal scaffold 10b may not be put into compression. In some cases, it may be desirable to have both scaffolds expand. To expand the two scaffolds 10a, 10b by the same amount with similar degrees of outward radial force, the properties of the two scaffolds 10a, 10b may be varied. The two scaffolds 10a, 10b may have different properties in order to provide about the same amount of outward radial force from the when expanded. The variable properties may include lengths, pics per inch, filament number, filament size, heat treating, or other factors which may influence the expansivity of the scaffolds 10a, 10b, or any combination thereof. For example, the scaffolds 10a, 10b may be different lengths, i.e., scaffold 10a may be a length Y + X and scaffold 10b may be length Y.

[0073] Creating multiple scaffolds on the same device may be more challenging that than using a single scaffold. Constricting a single stent-like or braided segment in one or more locations to form multiple scaffolds may require that the compressive forces originate only at the two ends of the segment when the scaffold is placed under tension. Hence, the section of the scaffold closest to the distal end may exert more outward radial pressure when compressed than a more proximal section of scaffold, for example a middle scaffold in a series of scaffolds. This may be desirable in at least some instances, such as when the scaffold comprises a short length or has a large diameter relative to the length and the differences may not be very consequential for an indication or application using such a scaffold. In some instances, however, this may not be the case. For example, a treatment device configured to remove blood clots from the femoral and iliac veins should be at least about 20 cm in length and may often be about 50 cm or more in length. Simply constricting a continuous braid or stent-like segment to form several sequential scaffolds may not provide a desired outward radial force in the mid-portion of an elongated scaffold structure. This may be overcome by fixedly attaching the braid or stent-like structure to the inner activation member, which may cause more outward radial pressure to be exerted by each scaffold when traction is applied to the inner activation member in relation to the outer activation member. For example, if a clot removal device was about 40 cm in total length and comprised three sequential scaffolds of about 12 cm each in length that were attached to the inner activation member at their respective distal ends and separated by two outer activation members of about 2 cm each in length, more uniform outward radial pressure may be exerted by the middle scaffold compared to a device where only the distal end of the distal scaffold was attached to the inner activation member. Any of the embodiments described herein may comprise a plurality of scaffolds. The scaffolds may utilize the same or a different braid or stent-like pattern for each of two or more segments. The scaffolds may comprise distinct scaffolds with different properties of expansion, function, support, and other properties. The distal end of each expandable scaffold segment or individual scaffold may be attached to the inner activation member in order to provide improved control and more precise activation of each individual segment than may be achieved by simply attaching the distal aspect of the most distal scaffold to the inner activation member.

[0074] In instances, more than two scaffolds may be self-expandable or actively expandable. The scaffolds may be configured so that a first scaffold in the most proximal position on the device may comprise a very sparse braid or strut density, a second more distal scaffold may comprise an intermediate braid or strut density, and a third or subsequent even more distal scaffold may comprise a relatively dense braid or strut density such that the first scaffold may fragment the clot into large fragments, the second scaffold may fragment the clot into smaller fragments, and the third or most distal scaffold may place traction on the shredded clot fragments and pull them into a receiving catheter, which may be a funnel catheter. [0075] Alternatively or in combination, the device described herein may be supplied with separate self-expandable or actively expandable scaffolds that are utilized in sequence. For example, a scaffold with very sparse braid density may be utilized first to treat the clot. The fist scaffold may be passed through the clot while in a collapsed configuration then expanded and withdrawn through the clot in order to fragment the clot into large fragments. The first scaffold may then be removed and a second scaffold with a tighter braid or strut density may be inserted and positioned to pass distally to the clot while in a collapsed configuration. The second scaffold may be expanded and withdrawn through the clot in order to further fragment the clot and/or pull the fragments into the receiving catheter as the second scaffold is removed. A third or subsequent scaffold with tighter braid or strut density may be inserted thereafter to provide traction on the thrombus. Withdrawing and removing the third scaffold may also withdraw and remove the thrombus into and out of the receiving catheter. The exact configuration of scaffolds, braid densities, etc. may depend on the consistency and characteristics of the thrombus or clot. A scaffold may be provided which is "clot specific" with properties which suit the characteristics of the thrombus as described herein. For example, if the clot is acute and soft, the clot may be able to be removed with a single scaffold comprising a tight braid or strut density. If the clot or portions of the clot are chronic with firm, dense, consolidated portions, all three of the scaffold described may be utilized. A subacute with a mixture of soft and moderately firm clot may for example be treated with a device comprising two scaffolds as described herein.

[0076] FIG. 9 shows a side view of another actively expandable scaffold device in an expanded configuration. The scaffolds 10a, 10b may be collapsed and expanded by translating multiple, coaxial activation members relative to one another. The scaffolds 10a, 10b may be substantially similar to any of the scaffolds described herein. An inner activation member 13a may be coupled (e.g. fixedly attached) to the distal end of scaffold 10a at a point 31a. The inner activation member 13a may be coaxially contained within the outer activation member 12a. The outer activation member 12a may be coupled to the scaffold 10a at a point 36a. Translation of the inner activation member 13a relative to the outer activation member 12a along a longitudinal axis of the scaffold 10a may apply tension to the proximal scaffold 10a and cause it to radially expand toward the vessel wall (or contract if tension is removed by translation of the inner activation member 13a) as described herein. A second inner activation member 13b may be housed coaxially within a second "outer" activation member 12b, which may be housed coaxially within the first inner activation member 13a. The inner activation member 13b may be coupled to the scaffold 10b at a point 31b. The outer activation member 12b may be coupled to the scaffold 10b at a point 36b. Translation of the inner activation member 13b relative to the outer activation member 12b along a longitudinal axis of the scaffold 10b may apply tension to the distal scaffold 10b and cause it to radially expand toward the vessel wall (or contract if tension is removed by translation of the inner activation member 13b) as described herein. The scaffolds 10a, 10b may be expanded or contracted, or both, independently of one another. The scaffolds 10a, 10b may be expanded or contracted, or both, with different degrees of tension and outward radial force. If three or more scaffolds are desired for a particular indication, additional inner and outer activation members (not shown) may be utilized in a similar coaxial manner. Alternatively or in combination, a coaxial configuration may be used for some of the scaffolds while other scaffolds may be provided separately or expanded using other methods (such as is shown in FIGS. 7 and 8) as described herein. Active expansion and contraction of multiple scaffolds may utilize multiple inner members which are arranged side-to- side with each other, each inner activation member being attached to the distal end of a specific scaffold. Multiple mechanisms for expansion of the scaffolds may be employed within the same device.

[0077] FIG. 10 shows a side view of another actively expandable scaffold device in a collapsed configuration. FIG. 11 shows a side view of the actively expandable scaffold device of FIG. 10 in an expanded configuration. The scaffold filaments 11 may be substantially similar to any of the filaments described herein. The inner activation member 13 and outer activation member 12 may be substantially similar to those described herein. The scaffolds 10a, 10b may be substantially similar to other scaffolds described herein with the main distinction between them being the shape of the proximal ends 32a, 32b of the scaffolds 10a, 10b, respectively. The scaffolds shown in FIGS. 7 and 8 have tapered proximal ends which may allow them to at least partially plow through the thrombus and displace it rather than engage the thrombus and slice through the thrombus. The scaffolds 10a, 10b may comprise proximal ends 32a, 32b as shown which are configured to engage the thrombus at a less acute angle and may tend to cut through the thrombus rather than displace it. The configuration of the proximal ends 32a, 32b of the scaffolds 10a, 10b may be concave as shown. Concave proximal ends 32a, 32b may tend to engulf the thrombus in addition to slicing through it, especially if there were a proximal device or structure provided so as to prevent the thrombus from being pulled proximally (for example as shown in FIG. 16). A funnel catheter may provide such a structure. When the thrombus is pulled against the funnel catheter, the struts or members 11 of the scaffold 10a, 10b may slice or cut through the thrombus and fragment it into smaller pieces with a greater overall surface area that can then be better acted upon by a lytic agent and further dissolved, withdrawn more easily into the funnel or other catheter, or the combination thereof.

[0078] FIG. 12 shows a side view of still another actively expandable scaffold device in a collapsed configuration. FIG. 13 shows a side view of the actively expandable scaffold device of FIG. 12 in an expanded configuration. The scaffold filaments 11 may be

substantially similar to any of the filaments described herein. The inner activation member 13 and outer activation member 12 may be substantially similar to those described herein. The scaffolds 10a, 10b may be substantially similar to other scaffolds described herein with the main distinction between them being the shape of the proximal ends 32a, 32b of the scaffolds 10a, 10b, respectively. The scaffolds 10a, 10b may comprise proximal ends 32a, 32b as shown which are more or less perpendicular to the longitudinal axis of the catheter shaft, scaffolds, and the vessel lumen. The flat configuration of the proximal ends 32a, 32 may provide for cutting or slicing of the thrombus into smaller fragments that may increase the surface area for better action of the lytic agent, easier removal of the thrombus through a receiving catheter, or the combination thereof.

[0079] Any of the devices described herein may comprise one or more scaffolds, regardless of how many are illustrated. The device described herein may comprise a plurality of scaffolds. The device may for example comprise one, two, three, or more scaffolds. The scaffolds may comprise similar or different patterns of braiding, often with different size interstices between the filaments of the scaffold as described herein. In some cases, a plurality of the scaffold filaments or members may comprise cutting filaments. In some cases, a plurality of the scaffold filaments or members may comprise support filaments. The scaffold may comprise a mixture of cutting filaments and support filaments. The cutting filaments and support filaments may be uniformly braided together or braided such that the cutting filaments are positioned at predetermined locations in the clot. The number of cutting filaments may be fewer than the number of support filaments in order to direct the outward radial force of the expanding scaffold towards the cutting members which may concentrate the force at the cutting members and improve cutting or scoring of the clot where it contacts the cutting members.

[0080] The scaffold device (or devices) comprising multiple scaffolds (in series as a single device or as multiple devices) with varying cutting and/or pulling capabilities may be inserted through a delivery catheter(s) or sheath(s) into the target vessel via one of several access routes and passed distal to the clot in an unexpanded state. The scaffold may be expanded by withdrawing the delivery catheter, for example in the case of a self-expanding scaffold, or by a push-pull action, for example in the case of an actively expandable scaffold. After expansion, the scaffold device may be withdrawn towards a receiving catheter and removed proximally from that catheter along with some or all of the thrombus. The process may be repeated with another scaffold to either further fragment the clot or provide traction, or both, until the entire clot is removed.

[0081] The device may be introduced via a standard introduction procedure. The device may be guided toward the thrombus. In the case of a pulmonary embolism, the device may be guided toward the heart via the superior vena cava or the inferior vena cava, depending on the chosen access point, passed through the heart, and guided into the pulmonary artery. A wire and/or the scaffold may be passed beyond the clot and at least a portion of the device may be passed distal to the clot in a lobar branch of artery. Alternatively or in combination, vibration may be used to place the wire and/or the scaffold distal to the clot. The scaffold may then be expanded, thereby insinuating, encapsulating, or entrapping at least a portion of the clot within the scaffold. A potential benefit of expanding the scaffold may be displacing the clot to one side and enhancing flow around or through the clot thereby at least temporarily relieving some of the back pressure and strain on the right ventricle. The clot may be encapsulated with or without vibrations. The clot may then be withdrawn into the receiving catheter and removed. The procedure may be repeated for additional emboli as required until some, most, or all of the emboli have been removed. The catheter may then be removed from the patient. Such procedures may be used for any size of embolus. Insinuation of the clot may be particularly useful for larger or saddle-type embolie. Engulfing the clot, for example by applying vibration, may be particularly useful for moderately- sized emboli which may be lodged at the origins of lobar arteris.

[0082] Device for IVC Filter: In performing interventions in the venous space, whether in the legs, pelvis, or pulmonary circulation, it may be important to protect against pulmonary embolus (which may occur during the procedure or in the several days after the procedure). Current inferior vena cava (IVC) filters are retrievable, but often required separation from the catheter delivery mechanism in order to be deposited at a site within the IVC, typically just below the renal veins. The IVC filters are then left there for a period of time ranging from several days to several weeks or months. They are then removed by a second procedure. Deposition of the IVC filters often needs to be precise, which may be problematic in some cases as the filter may be partially or completely deposited incorrectly and then may need to be recaptured and repositioned. Repositioning the IVC filter may be inconvenient and time- consuming. The deposited filter may be separated from the delivery mechanism and left in place for several weeks or months. Because of tissue ingrowth, tilt of the filter, fracture of the filter, and/or other factors, the retrieval or removal process may be difficult since the device must be snared, guided into another catheter and then withdrawn. Even if there is no difficulty in the removal, a separate removal procedure is required which can entail tracking the patient during the period between deposition and removal so that they are not lost to contact, which can be problematic as many patients are lost to contact, scheduling the procedure, sedating the patient, puncturing the vein, guiding catheters to the site, engaging the IVC filter (which may involve "fishing" for the engagement element), securing the filter to the engagement element, manipulating the filter away from the IVC wall and into a receiving catheter, removing the filter, obtaining hemostasis, recovering the patient, observing the patient, and then finally discharging the patient. This second procedure may cost several thousand dollars and can take anywhere from one to several hours.

[0083] The device and methods describe herein may obviate the frequently tedious and risky removal process described. The inner and outer activation members may be permanently attached to the expandable scaffold structure, which may serve as an IVC filter, and to act to tether the scaffold structure. Any of the expandable scaffold structures described herein may be used as an IVC filter. For example, the scaffold shown in FIGS. 1 and 2 may be used as a filter. The scaffold may be expandable by the inner and outer activation members as described herein. In placing the IVC filter of the current invention, the collapsed expandable scaffold may be guided to the preferred site and expanded by a push-pull action of the inner and outer members in order to abut the edges of the expanded scaffold against the IVC wall. The expanded scaffold may be left in the patient attached to the proximal inner and outer activation members to act as an IVC filter. The expandable scaffold structure which serves as the filter may be removed simply by collapsing and withdrawing the scaffold from the patient along with the inner and outer members. In the case of a self-expandable scaffold structure, the scaffold may be delivered to the preferred site by a delivery catheter and then deposited by simply withdrawing the delivery catheter over on the scaffold and the attached support wire. The scaffold may be left in the patient attached to the proximal support wire which may later be used to remove the scaffold. In either case, the expandable scaffold filter structure may be left attached to the delivery wire for rapid, accurate, and adjustable placement as well as quick and efficient removal of the device. Hence, the device and method of the current invention may offer significant advantages over the current IVC filters.

[0084] An actively-expandable or a self-expandable scaffold structure, for example a braided structure as described herein, may be utilized as an IVC filter. The device may be inserted via the jugular, femoral, or other venous site and placed in the IVC below the level of the renal veins and expanded to wall of the IVC. The self-expandable structure may be delivered by a delivery catheter which contains the structure. The delivery catheter may be withdrawn once the structure is at the intended site, allowing the structure to expand to the vena cava walls. In the case of the actively expandable structure, it may be guided to the site of expansion by a delivery catheter or just by the attached outer and inner members and then expanded by a push-pull action of those two members. In either case, it may be utilized during the procedure of removing clot from the veins or for several days or weeks whether or not there is a procedure to remove clot. In other words, the scaffold may be utilized as a prophylaxis against pulmonary embolism and may or may not be used in association with a thrombectomy procedure. The scaffold filter may then be removed by utilizing a push-pull action on the inner and outer members to collapse the scaffold structure (in the case of the actively expandable scaffold), or by inserting a guide catheter over a proximal wire the scaffold (in the case of a self-expanding scaffold). The device may then be removed easily and quickly. The filter scaffold may comprise a sparse braid density (in the case of a braidlike scaffold) or a sparse strut density (in the case of a stent-like scaffold) about the caudal end of the scaffold and a tight braid or strut density about the cephalic end of the scaffold, similar to the scaffolds shown in FIGS. 7-15, in order to capture embolic clot fragments within the expanded scaffold structure but prevent them from passing through the scaffold structure. Since the embolic clot fragments travel from a caudal position in the legs or pelvis to a cephalic position in the lungs, the orientation of the relative porosity in the scaffold may change depending on whether the device is inserted via the femoral vein, in which case the sparse braids or struts would be proximal to the tight braid density on the device, or via the jugular or subclavian veins, in which case the sparse braids or struts may be distal to the tight braid density on the device.

[0085] In some instances the cephalic end of the most proximal scaffold in a system may comprise an elastomeric material instead of a tight braid or strut density as described herein. The elastomeric material may cover, partially cover, or fill the interstices of the braid- or stent-like scaffold structure. The elastomer may have perforations to allow blood to flow through the scaffold while large fragments remain trapped within the scaffold. Moreover, the IVC filter may be comprised of hollow filaments or members that may deliver a lytic or other agent as described herein so that a lytic or other agent may be infused to dissolve any embolus or embolus fragments which are trapped by the filter. [0086] In some cases, the filter scaffold may comprise small barbs or projections near its equator. These elements may be directed cephalad and may only be exposed when the filter structure is expanded. In use, the filter structure may be expanded so that the mid portion of the scaffold contacts the wall of the IVC or other vein. The filter structure may then be withdrawn cephalad a short distance in order to urge the barbs or projections into the vena cava wall and anchor the filter structure. Since there may be a tether wire extending from one end of the filter structure, the small barbs or projections may add additional stability to the filter structure. The actively expandable nature provided by the push-pull action of the device may expand the filter structure against the vena cava wall with some force which may anchor and secure it. The tether wire may provide stability as well. The small barbs or projections may further anchor the filter structure to the wall, which may prove necessary if a large amount of thrombus suddenly embolizes and becomes lodged in the filter structure. The relative venous hypertension distally may create flow dynamics and pressures that may displace the filter structure without these small barbs or projections.

[0087] Stoke Intervention: In the case of stroke intervention, the device and methods described herein may be utilized to remove an embolus or thrombus blocking a cerebral artery. An actively expandable scaffold utilizing a push-pull mechanism to expand the device into the clot may be used. The scaffold may insinuate or engulf the embolus or clot into the scaffold. The scaffold may then be withdrawn along with the captured embolus or clot into a receiving catheter, which may be a funnel catheter, and removed it from the body. The actively expandable scaffold may be delivered to the cerebral site by a guidewire or delivery catheter inserted via the femoral or other arteriotomy and guided into at least the common carotid artery if not the internal carotid artery. The device may be advanced to the occluded site and at least the tip of the device may be placed distal to the embolus or clot while in a collapsed configuration. Actively expanding the scaffold and thereby insinuating or entraining the embolus or clot within the expanded scaffold through the apertures of the scaffold may then be performed as described herein. The scaffold may then be actively collapsed or patially collapsed by translating the inner and outer activation members. The scaffold containing the embolus or clot may then be withdrawn into a receiving catheter. In some cases, the embolus or clot may be engulfed through large interstices of the scaffold by placing the scaffold distal to the clot and providing traction to the distal end of the clot as an alternative to, or in addition to, insinuating or entrapping it into the scaffold. The clot may be removed by pulling it towards and into the receiving catheter. In many cases, the clot may be removed by a combination of actions which may include insinuating, engulfing, encapsulating, entrapping, or applying traction to the embolus or clot.

[0088] Other Indications: The methods and device described herein for removing embolus or clot from different anatomic sites or in different clinical applications may be utilized in any, some, or all of the anatomical sites and clinical applications described herein, as well as other anatomical sites and clinical applications which have not been explicitly described but will be known to one of ordinary skill in the art. For example, the stroke intervention methods or the pulmonary embolectomy methods described herein may be employed in peripheral arterial disease, coronary arterial disease, and other applications and anatomic sites. Also, the method of delivery of a lytic agent through the expandable scaffold may be utilized or combined with any or all of the methods of removing thrombus or embolus described herein in any area of the body.

[0089] In some cases the actively expandable scaffold may serve as a distal embolic protection mechanism. The scaffold device may be guided to the preferred site and actively deployed and expanded by a translation of the inner and outer activation members as described herein. The device may be left in place, attached to the inner and outer members, while an intervention is performed proximally. Once the interventional procedure is completed, the scaffold may be collapsed, thereby capturing any embolic particles or debris which may have been liberated and trapped within the scaffold. The collapsed scaffold may be withdrawn into a receiving catheter, which may be a funnel catheter, and then removed. This method of embolic protection may be particularly useful when the interventional procedure is atherectomy, crossing or treating chronic total occlusions, thrombectomy, angioplasty, stent placement, or other interventions.

[0090] FIG. 14 shows a side view of still another actively expandable scaffold device in a collapsed configuration. FIG. 15 shows a side view of the actively expandable scaffold device of FIG. 14 in an expanded configuration. The scaffold 10 may be substantially similar to any of the scaffolds described herein. The scaffold filaments 11 may be substantially similar to any of the filaments described herein. While only a one scaffold 10 is illustrated, it will be understood by one of ordinary skill in the art that any number of scaffolds desired may be utilized as described herein. The inner activation member 13 and outer activation member 12 may be substantially similar to those described herein. The device may be configured to deliver a lytic agent to the periphery of the thrombus near or at the vessel wall. A fluid delivery member 50, for example a hollow tubular structure, may be used to deliver the lytic agent to the thrombus. One or more delivery members 50 may be disposed within the scaffold 10. The delivery members 50 may be compressed by the scaffold 10 when the scaffold 10 is in the collapsed configuration during insertion and removal of the device. The delivery member 50 may be in fluid communication with a source of medicament, such as a lytic agent, via the inner activation member 13, the outer activation member 12, or some combination thereof. Withdrawal of the inner member 13 relative to the outer member 12 may compress the scaffold 10 and cause at least a portion of the length of the delivery members 50 to protrude through the relatively large interstices 26 of the proximal aspect 28 of the scaffold 10. While two delivery members 50 are illustrated, it will be understood by one of ordinary skill in the art that any number of delivery members 50 may be employed as desired. For example, the device may comprise between one and 20 delivery members 50, for example about 4 to 8 delivery members 50. The scaffold members 11 may support the delivery member tubes 50.

[0091] A method of use may include inserting the device comprising one or more delivery members 50 into the thrombus and expanding the scaffold 10 so as expose the delivery member tube(s) 50 to the thrombus external to the scaffold 10. Providing proximal traction on the scaffold may encourage the delivery member tubes 50 to contact the thrombus urge the tubes 50 outward towards the vessel wall. A lytic agent and/or other substance as described herein may be injected while proximal traction is provided in order to deliver the lytic agent about the perimeter of the scaffold 10 or adjacent to the vessel wall. The action of the delivery member tubes 50 may be two-fold: 1) mechanical disruption of the compacted chronic thrombus adjacent to the vessel wall by outward expansion into the thrombus and/or 2) delivery of a lytic agent and/or other substances to the thrombus. Such actions may overcome the dilemma of the chronic, dense, compact thrombus with advanced fibrin cross- linking leading to resistance to thrombolysis by conventional methods.

[0092] FIG. 16 shows a side view of an actively expandable scaffold device in an expanded configuration positioned in a vessel. FIG. 17 shows a side view of the actively expandable scaffold device of FIG. 16 in a collapsed configuration positioned in a vessel. The scaffold 10 may be substantially similar to any of the scaffolds described herein. The scaffold filaments 11 may be substantially similar to any of the filaments described herein. While only a one scaffold 10 is illustrated, it will be understood by one of ordinary skill in the art that any number of scaffolds 10 desired may be utilized as described herein. The inner activation member 13 and outer activation member 12 may be substantially similar to those described herein. The scaffold 10 may be configured to shred or slice through the thrombus 15 as described herein. The scaffold 10 may be inserted into and urged through the thrombus 15 to be placed at a distal location as shown while in the collapsed configuration. The proximal or leading surface 32 of the scaffold 10 may be more or less flat or slightly concave when in the expanded configuration. The expanded scaffold 10 may be retracted proximally toward the thrombus 15 so as to engage the thrombus and pull a portion or all of the thrombus 15 toward a receiving catheter 8, for example a funnel catheter. Once the traction on the thrombus 15 by the expanded scaffold 10 begins to compress the thrombus 15 between the scaffold 10 and the receiving catheter 8, further traction on the scaffold 10 may cause the filaments or members 11 of the scaffold 10 to slice through the thrombus 15, even as the thrombus 15 is further retracted towards the mouth of the receiving catheter 8. The thrombus 15 may be forced through the open mesh of the scaffold 10, separated from the vessel wall 16, and/or cut into smaller pieces sufficiently small enough to be withdrawn through the receiving catheter 8. The receiving catheter 8 may extend to the vessel wall 16 and make full contact with the wall 16 in order to "seal" the vessel and prevent the thrombus 15 from being retracted more proximally than its distal end, which may occur if the receiving catheter 8 were an end-hole catheter. The compression between the expanded scaffold 10 and the distal end of a vessel occluding catheter 8 may be important to the slicing or cutting action of the expanded scaffold 10 through the thrombus 15 to create smaller fragments which may be subsequently aspirated through the receiving catheter 8. The receiving catheter 8 may prevent distal and/or proximal movement of thrombus 15 or thrombus pieces until aspiration occurs.

[0093] FIGS. 18A-18C show exemplary end views of the actively expandable scaffold device of FIGS. 16 and 17 in an expanded configuration. The scaffold filaments 11 and interstices 26 which make up the scaffold 10 may be configured with a variety of patterns. FIG. 18A shows an end view of the proximal end 32 of an exemplary scaffold with an overlapping circle pattern of scaffold members 11 and interstices 26. FIG. 18B shows an end view of the proximal end 32 of an exemplary scaffold with a wheel- like pattern of scaffold members 11 and interstices 26. FIG. 18C shows an end view of the proximal end 32 of an exemplary scaffold with a combination of a wheel- like pattern and a spiral pattern of scaffold member 11 and interstices 26. It will be understood by one of ordinary skill in the art that other patterns may be used as desired by one of ordinary skill in the art in order to promote cutting of the thrombus.

FIG. 19A shows a side view of another actively expandable scaffold device in a collapsed configuration positioned in a vessel distal to a clot 15. FIG. 19B shows a side view of the actively expandable scaffold device of FIG. 19A in an expanded configuration positioned in a vessel distal to the clot 15. FIG. 19C shows a side view of the actively expandable scaffold device of FIG. 19A with a captured thrombus therein. The scaffold 10 may be inserted near one or more valves 46 of the vessel. Depending on the direction of entry into vessel, the scaffold 10 may pull the clot 15 in the direction of or opposite to the valves 46. The scaffold 10 may comprise one or more tines or extending members 41. The scaffold tines 41 may be substantially similar to any of the scaffold filaments described herein with the exception that the proximal end of the tines 41 may be unattached to the support structure (such as a guidewire, catheter, or inner activation member). The tines 41 may be coupled to a guidewire 42 and/or a catheter 43 as shown or other support structure and may be self-expandable. Alternatively or in combination, the tines 41 may be actively expandable in a manner similar to that of other scaffolds utilizing a push-pull method of expansion as described herein. The tines 41 may be configured to cut through the thrombus 15. The tines 41 may have cross- section which is round, triangular, rectangular, or any other shape desired. The ends 45 of the tines 41 may be designed to easily pass through an organized clot 15 as the scaffold 10 expands towards the vessel wall 16. The ends 45 of the tines 41 may be shaped such that the tines 41 do not penetrate or damage the vessel wall 16. The ends 45 of the tines 41 may further be configured to collapse the scaffold 10 when pulled into a receiving catheter (as shown in FIG. 19C). Retraction of the catheter 10 toward the thrombus 15 may cause the tines 41 to contact and shred the thrombus 15. The tines 41 may be fixedly or movably (e.g. slidably) attached to optional support members 44 which may support the tines 41 against collapsing due to compression of the tines 41 as they engage the clot 15. The support members 44 may optionally act as cutting elements to help cut through the clot 15 as described herein.

[0094] The scaffold 10 may be delivered in a collapsed configuration by a delivery catheter (not shown) which encloses the scaffold 10 and compresses it. The scaffold 10 may pass through the thrombus 15 in a collapsed configuration to a position distal of the thrombus 15 before being expanded. Proximal traction may be provided and the tines 41 may be continuously expanded toward and to the vessel wall 16. Hence, the expanding tines 41 which comprise a cutting configuration may slice through fibrous and compacted thrombus 15 and separate the thrombus 15 from the vessel wall 16, thereby shredding the thrombus 15 into smaller fragments 17 and creating more surface area within the thrombus. The expandable scaffold 10 may be withdrawn into the funnel catheter mouth 8 for removal as illustrated in FIG. 19 C. The tines 41 may feed into the funnel catheter 8 and collapse around the thrombus 15. [0095] The scaffold 10 may be configured to separate or shred an organized clot 15 within a blood vessel of the body. The device may be configured so as to easily pass through the lesion in one direction and serve to separate or shred the lesion when pulled in the opposite direction. The tines 41 may collapse when pushed through the lesion 15 and passively or actively extend towards the vessel wall 16 when pulled back through the lesion 15. The tines 41 may be designed such that they can easily pass through clot, cross-links, fibrin, or the like within the organized clot 15. The tines 41 may comprise cutting members 44 configured to enhance the cutting ability of the scaffold 10 to sever the organized clot 15 into manageable pieces and to optionally promote lytic drug penetration deeper towards the vessel wall 16.

[0096] The scaffold device described herein may be used on its own or in conjunction with vessel occluding technologies such as the MegaVac™ funnel device which may prevent blood flow while the procedure is being performed. The tines 41 may be configured to collapsed back to its collapsed configuration feeding the tines 41 naturally back into the funnel 8 as the device is pulled towards the funnel 8.

[0097] In some instances, the scaffold 10 may be used to collect large embolus or foreign matter 15 in the distal tip region of the device. As the scaffold 10 is pulled back across the organized clot or lesion 15 the distal tip may gather up critically-sized matter, pulling them towards the receiving catheter and/or aspiration device (e.g. MegaVac™) or even fully out of the body.

[0098] FIG. 20 shows a side view of the actively expandable scaffold device of FIG. 19A in the expanded configuration positioned in an iliac vein 47. The scaffold 10 may retract a thrombus 15 in an iliac vein using a retrograde approach. The tines may be expanded to the vessel wall 16 may dislodge the thrombus 15 from the vessel wall 16. Delivery of a lytic agent or other substance may be incorporated into the tines 41 or elsewhere as described herein so that delivery of lytic agent to an area adjacent to the vessel wall may occur. For example, the tines 41 may comprise a hollow tubular component in fluid communication with a source of the desired substance as described herein.

[0099] The materials used to fabricate this or any of the scaffold devices described herein may be chosen from a wide range of materials known in the art including nitinol, and stainless steel, and the like. More than one material may be used to fabricate the scaffold device. The filaments or members may comprise one or more different shapes, one or more braid patterns, one or more stent constructions, one or more diameters, one or more lengths, or other configurations, or any combination thereof. [00100] The device and methods described herein may have one or more advantages over the currently available devices. Prior art devices typically employ a dwell time of about thirty minutes in order to give the lytic agent a chance to act upon the thrombus. This dwell time may be down time for the physician operator and the catheter lab personnel (frequently consisting of at least one nurse and two or three technologists). The device is then activated and attempts at maceration are begun. This method may be problematic as the tPA infused during the dwell time may begin to act on a small portion of the clot but will likely be unable to have an effect on the entire clot within that timeframe. Hence, the operator may be able to remove some of the clot, but the remaining clot may be resistant to fragmentation because of insufficient exposure to the lytic agent. This may be especially problematic with the older, firmer clot which is adjacent to and adherent to the vessel wall. The procedure may then become a prolonged event of chasing clot with a device unable to macerate or fully remove it. The device described herein may allow for the lytic agent to act over a prolonged period of time with intermittent agitation and clot fragmentation while the patient is in a remote location rather than in the laboratory suite. Mechanical agitation and clot fragmentation may occur in concert with the actions of the lytic agent to progressively dissolve and fragment the clot over a time frame that may be directly dependent on the length of time necessary for the tPA to act upon the clot. The methods described herein may therefore be much more efficient than the long-standing standard practice of waiting 30 minutes for the lytic agent to lyse the clot and then attacking the clot with mechanical means which, because much of the clot has not been acted upon by the lytic agent, may result in incomplete clot removal, a prolonged procedure, or the combination thereof.

[00101] The patient, physician, lab personnel, facility, and/or health care system may benefit from the use of the device, system, and methods described herein. The patient may benefit as the procedure may obviate the need to have the patient maintain an uncomfortable prone position on a hard procedural table where they can't readily interact with nurses and personnel (as their face is down), which may impede adequate care. Using the methods described herein, the patient may spend most of the treatment time supine on a soft gurney while the device is expanding and/or the lytic is working. The patient may view television or be visited by their family while the thrombus is being dissolved. Additionally, overnight infusion of a lytic agent with monitoring in the ICU may be obviated, as is the potential for bleeding complications and even death. The patient may also experience less exposure to radiation. [00102] The physician and lab personnel may benefit by limiting their active involvement in the procedure to starting and terminating the procedure. Starting the procedure may involve placing the device and activating the device (by applying tension, infusing a lytic agent, and/or applying vibration, etc.) and may take about 20 minutes to set up. Terminating the procedure may involve removing the scaffold apparatus containing some clot fragments and is expected to take about 20 to about 30 minutes to complete. During the time between starting and terminating the procedure, the physician and lab personnel may be free to perform other procedures on the patient or on others while the patient is monitored in a remote location the clot dissolves. Furthermore, the physician and lab personnel may avoid prolonged exposure to radiation as imaging procedures may only be needed to start and terminate the procedure but not while the patient is monitored and the device is active.

[00103] The facility in which the procedure is performed may also benefit as there may be more efficient use of laboratory resources and personnel and physicians may be free to perform other procedures while the patient is being observed in a remote location.

Additionally, the device may be more patient- and physician-friendly, as well as more successful at complete removal of the clot, than previous devices and may therefore attract additional cases that may not have presented otherwise because of the potential costs, time, risks, awkwardness, and inefficiencies of the current methods of performing thrombectomy within the veins.

[00104] The healthcare system may benefit as the total cost of the device and methods described herein may be less than that of an overnight drip of lytic agent in the ICU.

Additionally, the procedure can be done on an outpatient basis. More complete clot removal may also translate into fewer re-interventions and subsequent complications.

[00105] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A device for removal of thrombus or embolus from a vascular channel of the body, the device comprising:

at least one actively expandable scaffold comprising a proximal end, a distal end, and a longitudinal axis therebetween,

wherein the at least one actively expandable scaffold comprises a collapsed configuration and an expanded configuration; and

a delivery member configured to deliver a lytic agent to the thrombus or embolus.

2. The device of Claim 1, wherein the at least one actively expandable scaffold is configured to deliver the lytic agent.

3. The device of Claim 2, wherein the delivery member is in fluid

communication with the at least one actively expandable scaffold.

4. The device of Claim 2, wherein the at least one actively expandable scaffold comprises a plurality of filaments, wherein one or more of the filaments comprise a hollow tube with one or more hole disposed along a length thereof through which the lytic agent is delivered.

5. The device of Claim 1, wherein the delivery member comprises an infusion pump.

6. The device of Claim 1, wherein the delivery member comprises a hollow tube operably coupled to the at last one actively expandable scaffold, wherein the hollow tube expands outward towards the thrombus or embolus when the at least one actively expandable scaffold is in the expanded configuration.

7. The device of Claim 1, wherein the lytic agent comprises tissue plasminogen activator.

8. The device of Claim 1, further comprising a support structure operably coupled to the at least one actively expandable scaffold at a distal end of the support structure.

9. The device of Claim 8, wherein the support structure comprises a guidewire, a catheter shaft, or an inner activation member.

10. The device of Claim 1, further comprising a tension element coupled to and configured to provide continuous tension to the at least one actively expandable scaffold when the at least one actively expandable scaffold is in the expanded configuration.

11. The device of Claim 1, wherein the at least one actively expandable scaffold comprises a mesh braid.

12. The device of Claim 1, wherein the at least one actively expandable scaffold is actuated from the collapsed configuration to the expanded configuration by compression along the longitudinal axis of the at least one actively expandable scaffold.

13. The device of Claim 1, wherein the at least one actively expandable scaffold further comprises a plurality of scaffold members with a plurality of interstices therebetween, wherein the plurality of interstices are larger in a proximal region of the at least one actively expandable scaffold than in a distal region of the at least one actively expandable scaffold.

14. The device of Claim 1, further comprising a steering mechanism configured to move the at least one actively expandable scaffold in a direction parallel to the longitudinal axis, in a direction oblique to the longitudinal axis, in a direction transverse to the

longitudinal axis, or rotationally about the longitudinal axis.

15. The device of Claim 14, wherein the steering mechanism is configured to move the at least one actively expandable scaffold intermittently.

16. The device of Claim 15, wherein the intermittent movement comprises a quiescent time that is greater than an activation time.

17. The device of Claim 1, wherein the at least one actively expandable scaffold comprises a proximal scaffold and a distal scaffold.

18. The device of Claim 17, wherein the proximal scaffold comprises a first plurality of filaments with a first plurality of interstices therebetween, wherein the distal scaffold comprises a second plurality of filaments with a second plurality of interstices therebetween.

19. The device of Claim 18, wherein the first plurality of interstices are larger than the second plurality of interstices.

20. The device of Claim 18, wherein the second plurality of interstices comprises a proximal region of larger interstices and a distal region of smaller interstices.

21. The device of Claim 1, wherein the at least one actively expandable scaffold comprises an inner scaffold and an outer scaffold, wherein the inner scaffold is disposed within the outer scaffold, and wherein both the inner scaffold and the outer scaffold are configured to expand from the collapsed configuration to the expanded configuration.

22. The device of Claim 21, wherein the inner scaffold is configured to support the outer scaffold when in the expanded configuration.

23. The device of Claim 21, wherein the outer scaffold is configured to expand through the thrombus or embolus when in the expanded configuration.

24. The device of Claim 21, wherein the inner scaffold is positioned within the outer scaffold at a longitudinally central portion of the outer scaffold in order to provide radial support to the outer scaffold when both the inner scaffold and the outer scaffold are in the expanded configuration.

25. The device of Claim 1, wherein the proximal end of the at least one actively expandable scaffold is configured to provide traction to the thrombus or embolus.

26. The device of Claim 25, wherein the proximal end has an acute angle or convex shape.

27. The device of Claim 1, wherein the proximal end of the at least one actively expandable scaffold is configured to fragment the thrombus or embolus.

28. The device of Claim 27, wherein the proximal end has a substantially flat or concave shape.

29. A method of removing of a thrombus or embolus from a vascular channel of a body, the method comprising:

inserting a device comprising at least one actively expandable scaffold into the vascular channel, wherein the at least one actively expandable scaffold comprises a collapsed configuration and an expanded configuration, and wherein the device is inserted with the at least one actively expandable scaffold in the collapsed configuration;

positioning the at least one actively expandable scaffold at the thrombus or embolus;

delivering a lytic agent to the thrombus or embolus;

expanding the at least one actively expandable scaffold from the collapsed configuration to the expanded configuration through the thrombus or embolus while the lytic agent is being delivered, wherein expanding the at least one actively expandable scaffold urges the thrombus or embolus into the at least one actively expandable scaffold;

collapsing the at least one actively expandable scaffold with the thrombus or embolus within the at least one actively expandable scaffold; and

removing the at least one actively expandable scaffold from the vascular channel, wherein the at least one actively expandable scaffold contains the thrombus or embolus therein.

30. The method of Claim 29, wherein the lytic agent is delivered by a fluid delivery member coupled to the at least one actively expandable scaffold.

31. The method of Claim 30, wherein the delivery member is in fluid communication with the at least one actively expandable scaffold.

32. The method of Claim 30, wherein the delivery member comprises an infusion pump.

33. The method of Claim 29, wherein the lytic agent is delivered by the at least one actively expandable scaffold.

34. The method of Claim 33, wherein the at least one actively expandable scaffold comprises a plurality of filaments, wherein one or more of the filaments comprise a hollow tube with at least one hole disposed along a length thereof through which the lytic agent is delivered.

35. The method of Claim 29, wherein the lytic agent comprises tissue

plasminogen activator.

36. The method of Claim 29, wherein the lytic agent is delivered about a perimeter of the at least one actively expandable scaffold in the expanded configuration.

37. A system for removal of a thrombus or embolus from a vascular channel of a body, the system comprising:

a thrombectomy device comprising at least one actively expandable scaffold comprising a collapsed configuration and an expanded configuration, an inner activation member disposed within an outer activation member, and a delivery member configured to deliver a lytic agent to the thrombus or embolus;

a source of the lytic agent; and

an infusion pump fluidly coupled to the delivery member and the lytic agent source to provide lytic agent from the source to the delivery member.

38. The system of claim 37, wherein the at least one actively expandable scaffold is configured to deliver the lytic agent.

39. The system of Claim 38, wherein the delivery member is in fluid

communication with the at least one actively expandable scaffold.

40. The system of Claim 39, wherein the at least one actively expandable scaffold comprises a plurality of filaments, wherein one or more of the filament comprise a hollow tube with at least one hole disposed along a length thereof through which the lytic agent is delivered.

41. The system of Claim 37, wherein the delivery member comprises an infusion pump.

42. The system of Claim 37, wherein the lytic agent comprises tissue plasminogen activator.

43. The system of Claim 37, further comprising a support structure operably coupled to the at least one actively expandable scaffold at the distal end of the support structure.

44. The system of Claim 43, wherein the support structure comprises a guidewire, a catheter shaft, or an inner activation member.

45. The system of Claim 37, further comprising a tension element coupled to, and configured to provide continuous tension to, the at least one actively expandable scaffold when the at least one actively expandable scaffold is in the expanded configuration.

46. The system of Claim 37, wherein the at least one actively expandable scaffold comprises a mesh braid.

47. The system of Claim 37, further comprising a vibration mechanism operably coupled to the at least one actively expandable scaffold.

48. The system of Claim 47, further comprising a controller operably coupled vibration mechanism and configured to control the frequency or timing of the vibration applied to the at least one actively expandable scaffold.

49. A device for removal of a thrombus or embolus from a vascular channel of a body, the device comprising:

wherein the at least one actively expandable scaffold comprises a collapsed configuration and an expanded configuration,

wherein the at least one actively expandable scaffold comprises a plurality of filaments or tines,

wherein the plurality of filaments or tines are configured to expand outward toward a wall of the vascular channel when the at least one expandable scaffold is actuated from the collapsed configuration to the expanded configuration;

an outer activation member; and

an inner activation member slidably disposed within the outer activation member,

wherein translation of the inner activation member relative to the outer activation member actuates the at least one actively expandable scaffold between the collapsed configuration and the expanded configuration.

50. The device of Claim 49, wherein the at least one expandable scaffold comprises a plurality of tines configured to fragment the thrombus or embolus.

51. The device of Claim 49, wherein the at least one expandable scaffold comprises a plurality of filaments configured to fragment the thrombus or embolus.

52. The device of Claim 49, further comprising a lytic delivery member configured to deliver a lytic agent to the thrombus or embolus.

53. The device of Claim 49, wherein a proximal portion of the at least one expandable scaffold is coupled to the inner activation member.

54. The device of Claim 53, wherein a distal portion of the at least one expandable scaffold is coupled to the outer activation member.

55. A method of removing of a thrombus or embolus from a vascular channel of a body, the method comprising:

positioning the at least one actively expandable scaffold distal to the thrombus or embolus;

expanding the at least one actively expandable scaffold from the collapsed configuration to the expanded configuration to contact a wall of the vascular channel;

moving the at least one actively expandable scaffold proximally towards the thrombus or embolus;

fragmenting the thrombus or embolus with the at least one actively expandable scaffold;

capturing the thrombus or embolus within the at least one actively expandable scaffold;

collapsing the at least one actively expandable scaffold with the thrombus or embolus therein; and

removing the at least one actively expandable scaffold from the vascular channel, wherein the at least one actively expandable scaffold contains the thrombus or embolus therein when removed.

56. The method of Claim 55, wherein the at least one expandable scaffold comprises a plurality of tines configured to fragment the thrombus or embolus.

57. The method of Claim 55, wherein the at least one expandable scaffold comprises a plurality of filaments configured to fragment the thrombus or embolus.

58. The method of Claim 55, wherein moving the at least one expandable scaffold comprises providing traction to the at least one expandable scaffold.

59. The method of Claim 55, further comprising delivering a lytic agent to the thrombus or embolus to facilitate fragmentation of the thrombus or embolus.

60. The method of Claim 59, wherein the lytic agent is delivered by a fluid delivery member coupled to the at least one actively expandable scaffold.

61. The method of Claim 60, wherein a delivery member is in fluid

communication with the at least one actively expandable scaffold.

62. The method of claim 59, wherein the at least one actively expandable scaffold is configured to deliver the lytic agent.

63. The method of Claim 62, wherein the at least one actively expandable scaffold comprises a plurality of filaments, wherein one or more of the filaments comprise a hollow tube with at least one hole disposed along a length thereof through which the lytic agent is delivered.

64. The method of Claim 61, wherein the delivery member comprises an infusion pump.

65. The method of Claim 59, wherein the lytic agent comprises tissue

plasminogen activator.