JP2023095576A - Balloon catheter and balloon catheter system - Google Patents

Abstract

To suppress deviation between an actual surface temperature of a balloon and an estimated surface temperature based on a temperature actually measured by a temperature sensor.SOLUTION: A balloon catheter includes a balloon, a catheter shaft, a temperature sensor, a heating member, and a relative movement restriction member. The catheter shaft includes an outer cylinder shaft connected to a proximal end of the balloon, and an inner cylinder shaft projecting into the balloon and connected to a distal end of the balloon. The inner cylinder shaft extends through the inside of the outer cylinder shaft. A gap between the inner cylinder shaft and the outer cylinder shaft forms a liquid transmission path communicating with an internal space of the balloon. The temperature sensor is arranged between the outer cylinder shaft and the inner cylinder shaft. The heating member is arranged on an outer circumference of the inner cylinder shaft in the balloon and heats liquid in the balloon. The relative movement restriction member restricts relative movement of the outer cylinder shaft to the inner cylinder shaft in a direction in which the distal end of the outer cylinder shaft approaches the heating member.SELECTED DRAWING: Figure 15A

Description

The present invention relates to balloon catheters and balloon catheter systems.

Ablation therapy is a treatment method in which an ablation catheter is inserted into the body to ablate a target site in the body. As an example, diseases such as arrhythmia due to atrial fibrillation, endometriosis, and cancer are treated by destroying the target site by ablation. A catheter used for ablation treatment has a catheter shaft forming a lumen, a balloon attached to the distal end of the catheter shaft and having an inner space communicating with the lumen, and a high-frequency electrode installed in the balloon. A balloon catheter is disclosed in US Pat.

When the balloon catheter is inserted into the body, the balloon is deflated and stretched longitudinally of the catheter shaft. Fluid is then supplied to the lumen of the catheter shaft inserted into the body and the balloon is inflated. The temperature of the liquid in the balloon is controlled by applying high-frequency current between the high-frequency electrode installed inside the balloon and the high-frequency external electrode (hereinafter referred to as the counter electrode) installed outside the patient's body. This allows the surface temperature of the balloon to be controlled. By bringing a balloon adjusted to a predetermined surface temperature into contact with a circumferential target site, for example, a connection site of a vein to the atrium, the circumferential target site can be ablated at once.

Japanese Patent No. 3611799 Japanese Patent No. 4747141 WO2021/201078

In ablation therapy using a balloon catheter, it is important to accurately grasp the surface temperature of the balloon. In this regard, in the balloon catheters disclosed in Patent Documents 1 and 2, a temperature sensor for measuring the surface temperature of the balloon is provided on the surface of the balloon. US Pat. No. 5,300,002 uses a temperature sensor attached to the inner surface of the balloon.

However, it is not easy to accurately place the temperature sensor on the surface of the balloon that expands from the contracted state. In this respect, Patent Document 2 proposes that the balloon has a two-layer structure and a temperature sensor is arranged between the two layers. However, it is difficult to actually manufacture the two-layered balloon, to install the heat-sensitive part of the temperature sensor between the two-layered balloons, and to handle the lead wire of the temperature sensor. not reached. That is, in the conventional balloon catheter, it was difficult to specify the surface temperature of the balloon with high accuracy.

Patent Literature 3 proposes a catheter that measures the surface temperature of a balloon with high precision by arranging a temperature sensor in the liquid feeding channel of the balloon catheter. However, in such a balloon catheter, if the catheter shaft is pushed in and the heating member and the outer cylinder shaft are extremely close when the catheter is strongly pressed, the temperature measured inside the shaft may become higher than the actual surface temperature. can be considered.

SUMMARY OF THE INVENTION An object of the present invention is to suppress the deviation between the actual surface temperature of the balloon and the estimated surface temperature based on the temperature actually measured by the temperature sensor.

A balloon catheter of the present invention comprises a balloon, a catheter shaft, a temperature sensor, a heating member, and a relative movement restricting member, the catheter shaft being an outer sleeve shaft connected to a proximal end of the balloon; an inner barrel shaft extending into the balloon and connected to the distal end of the balloon, the inner barrel shaft passing through the outer barrel shaft and connecting the inner barrel shaft and the outer barrel shaft; The gap forms a liquid feeding path leading to the internal space of the balloon, the temperature sensor is arranged between the outer cylinder shaft and the inner cylinder shaft, and the heating member is disposed inside the balloon. The relative movement restricting member is disposed on the outer peripheral surface of the barrel shaft to heat the liquid in the balloon, and the relative movement limiting member moves the barrel shaft within the barrel shaft in a direction in which the distal end of the barrel shaft approaches the heating member. It is characterized by limiting relative movement with respect to the cylinder shaft.

In the balloon catheter of the present invention, the relative movement restricting member is arranged such that the distance between the distal end of the outer shaft and the proximal end of the heating member is 3 mm or more. may restrict relative movement to

In the balloon catheter of the present invention, the relative movement restricting member may be fixed to the outer cylinder shaft and extend into the balloon, and the relative movement of the outer cylinder shaft with respect to the inner cylinder shaft is equal to the relative movement of the outer cylinder shaft. A restriction member may be restricted by contact with the heating member.

In the balloon catheter of the present invention, the relative movement restricting member is configured such that the outer peripheral surface of the inner cylinder shaft and the inner peripheral surface of the outer cylinder shaft at the connecting portion between the liquid feeding path and the inner space of the balloon are the outer peripheral surface and the inner peripheral surface of the outer cylinder shaft. It may have portions extending toward the outer peripheral surface of the inner cylindrical shaft so as to be spaced apart from each other over the entire circumference of the inner peripheral surface.

In the balloon catheter of the present invention, the relative movement restricting member may be fixed to the outer peripheral surface of the inner cylinder shaft inside the balloon, and the relative movement of the outer cylinder shaft with respect to the inner cylinder shaft is controlled by the outer cylinder shaft. The distal end of the barrel shaft may be restricted by contacting the relative movement restriction member.

In the balloon catheter of the present invention, the relative movement restricting member includes a first restricting member fixed to the inner peripheral surface of the outer cylindrical shaft and a second restricting member fixed to the outer peripheral surface of the inner cylindrical shaft. Alternatively, relative movement of the outer cylinder shaft with respect to the inner cylinder shaft may be restricted by contact of the first restriction member with the second restriction member.

In the balloon catheter of the present invention, the heating member may be arranged within a range obtained by projecting the internal volume of the outer cylindrical shaft from the central axis direction of the inner cylindrical shaft.

In the balloon catheter of the present invention, the distance between the distal end of the outer tube shaft and the temperature sensor may be 5-150 mm.

The balloon catheter system of the present invention comprises the balloon catheter, a supply device that supplies liquid to the liquid feed channel, and the liquid in the balloon by repeatedly supplying the liquid to the liquid feed channel and discharging the liquid from the liquid feed channel. A stirring device for stirring a liquid and a control device electrically connected to the heating member for applying electrical energy to the heating member are provided.

According to the present invention, it is possible to suppress the deviation between the actual surface temperature of the balloon and the estimated surface temperature based on the temperature actually measured by the temperature sensor.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram for explaining an embodiment, showing a balloon catheter system and a balloon catheter; Figure 2 shows the distal end portion of the balloon catheter of Figure 1 with the balloon inflated; Figure 2 shows the distal end portion of the balloon catheter of Figure 1 with the balloon deflated and extended; FIG. 3 is a cross-sectional view taken along line II of FIG. 2; Sectional drawing along the II-II line of FIG. FIG. 4 is a view showing the distal end portion of the balloon catheter, and is a view for explaining the flow of liquid when the liquid is discharged into the balloon from the liquid feeding path. FIG. 4 is a view showing the distal end portion of the balloon catheter, and is a view for explaining the flow of liquid when liquid is sucked from the inside of the balloon into the liquid feed channel. FIG. 10 is a view showing the distal end portion of the balloon catheter, and is a view for explaining the flow of liquid when liquid is sucked from the inside of the balloon into the liquid feed channel while the catheter is strongly pressed against the treatment site. 4 is a graph showing the temperature difference between the estimated surface temperature of the balloon and the actual surface temperature for each distance between the heating member and the outer cylinder shaft. A graph showing the relationship between the liquid temperature detected by the temperature sensor in the liquid feed path and the surface temperature of the balloon obtained by CAE analysis (liquid volume: 15 ml, distance between the proximal end of the heating member and the distal end of the outer cylinder shaft : 13 mm). A graph showing the relationship between the liquid temperature detected by the temperature sensor in the liquid feed path and the surface temperature of the balloon obtained by CAE analysis (liquid volume: 15 ml, distance between the proximal end of the heating member and the distal end of the outer cylinder shaft : 7 mm). A graph showing the relationship between the liquid temperature detected by the temperature sensor in the liquid feed path and the surface temperature of the balloon obtained by CAE analysis (liquid volume: 15 ml, distance between the proximal end of the heating member and the distal end of the outer cylinder shaft : 1 mm). FIG. 4 is a diagram showing the temperature distribution of the liquid at the distal end portion of the coaxial balloon catheter obtained by thermal fluid analysis using CAE. FIG. 4 is a diagram showing the temperature distribution of the liquid at the distal end portion of the non-coaxial balloon catheter obtained by thermal fluid analysis using CAE. FIG. 3 is a partially enlarged view of FIG. 2; FIG. 15B is a cross-sectional view of the relative movement restricting member taken along line III-III in FIG. 15A; FIG. 15C is a view corresponding to FIG. 15B and showing a modification of the relative movement restricting member; FIG. 15B is a view corresponding to FIG. 15A and showing another modification of the relative movement restricting member; FIG. 16B is a cross-sectional view of the relative movement restricting member taken along line IV-IV of FIG. 16A; FIG. 16C is a view corresponding to FIG. 16B and showing still another modification of the relative movement restricting member; FIG. 3 is a view corresponding to FIG. 2 and showing still another modification of the relative movement restricting member; FIG. 17B is a cross-sectional view of the relative movement restricting member taken along line VV of FIG. 17A; FIG. 17B is a cross-sectional view of the relative movement restricting member taken along line VI-VI of FIG. 17A; FIG. 17C is a view corresponding to FIG. 17B and showing still another modification of the relative movement restricting member; FIG. 17C is a view corresponding to FIG. 17C and showing still another modification of the relative movement restricting member;

An embodiment of the present invention will now be described with reference to specific examples shown in the drawings. In addition, in the drawings attached to this specification, for the convenience of illustration and ease of understanding, the scale and the ratio of vertical and horizontal dimensions are appropriately changed and exaggerated from those of the real thing. In addition, the terms such as "parallel", "perpendicular", "same" and the like, length and angle values, etc. that specify shapes and geometric conditions and their degrees used in this specification are strictly It shall be interpreted to include the extent to which similar functions can be expected without being bound by the meaning.

Balloon catheter system 10 shown in FIG. The balloon catheter 15 also has a catheter body 20 having a longitudinal direction LD and a handle 50 connected to the proximal end of the catheter body 20 .

As shown in FIG. 2 , the catheter body 20 of this embodiment has a balloon 25 , a catheter shaft 28 to which the balloon 25 is attached, and a heating member 40 arranged inside the balloon 25 . The catheter shaft 28 has an outer barrel shaft 30 connected to the proximal end 25 b of the balloon 25 and an inner barrel shaft 35 connected to the distal end 25 a of the balloon 25 . The inner cylinder shaft 35 passes through the outer cylinder shaft 30 and extends into the balloon 25 . A liquid feed path LP leading to the inside of the balloon 25 is formed between the outer tube shaft 30 and the inner tube shaft 35 . Heating member 40 heats the liquid within balloon 25 .

The longitudinal direction LD of the catheter main body 20 is specified as the direction in which the central axes 30X and 35X of the outer cylinder shaft 30 and the inner cylinder shaft 35 extending from the outer cylinder shaft 30 extend. Further, in this specification, the “distal” side used for each configuration of the balloon catheter 15 and the catheter main body 20 means that the operator (operator) of the handle 50 and the balloon catheter 15 along the longitudinal direction LD of the catheter main body 20. means the side away from the , or in other words the distal side. In addition, the “proximal” side used for each configuration of the balloon catheter 15 and the catheter main body 20 is the side that is close to the operator (operator) of the handle 50 and the balloon catheter 15 along the longitudinal direction LD of the catheter main body 20. In other words, it means the proximal side.

The balloon catheter system 10 and the balloon catheter 15 are further detailed below. First, the catheter body 20 of the balloon catheter 15 will be described in detail. As described above, the catheter body 20 of the balloon catheter 15 according to this embodiment has the balloon 25 , the outer cylinder shaft 30 , the inner cylinder shaft 35 , the heating member 40 and the temperature sensor 45 .

Outer cylinder shaft 30 and inner cylinder shaft 35 are both cylindrical, typically cylindrical. Therefore, the outer cylinder shaft 30 and the inner cylinder shaft 35 each form a lumen as an internal space. For example, a guide wire (not shown) is inserted into the lumen formed by the inner cylinder shaft 35 . The inner cylinder shaft 35 is inserted through the lumen formed by the outer cylinder shaft 30 . That is, the outer cylinder shaft 30 and the inner cylinder shaft 35 have a structure of a double pipe shaft. The inner diameter of the outer cylinder shaft 30 is larger than the outer diameter of the inner cylinder shaft 35 . Therefore, a lumen remains between the outer barrel shaft 30 and the inner barrel shaft 35 . A lumen between the outer tube shaft 30 and the inner tube shaft 35 forms a liquid feeding path LP. As shown in FIG. 2, the liquid feed path LP communicates with the inside of the balloon 25 . Also, the liquid feed path LP extends into the handle 50 .

The lengths of the outer cylinder shaft 30 and the inner cylinder shaft 35 are preferably 500 mm or more and 1700 mm or less, and more preferably 600 mm or more and 1200 mm or less. The outer cylinder shaft 30 and the inner cylinder shaft 35 are preferably made of a flexible material with excellent antithrombotic properties. Flexible materials with excellent antithrombotic properties include, but are not limited to, fluoropolymers, polyamides, polyurethane-based polymers, polyimides, and the like. In addition, the outer cylinder shaft 30 is manufactured by laminating layers of different flexible materials in order to achieve both slidability with respect to the inner cylinder shaft 35 and adhesiveness or heat-weldability with the balloon 25. is preferred.

The outer diameter of the outer cylinder shaft 30 is preferably 3.0 mm or more and 4.0 mm or less. The inner diameter of the outer cylinder shaft 30 is preferably 2.5 mm or more and 3.5 mm or less. Moreover, the outer diameter of the inner cylinder shaft 35 is preferably 1.4 mm or more and 1.7 mm or less. The inner diameter of the inner cylinder shaft 35 is preferably 1.1 mm or more and 1.3 mm or less.

A balloon 25 is connected to the outer cylinder shaft 30 and the inner cylinder shaft 35 . The balloon 25 is formed so as to be inflatable by being filled with liquid and to be contracted by being discharged from the liquid. The balloon 25 preferably has a shape that can fit the target site (eg, blood vessel) to be treated. As an example, a spherical shape with a diameter of 15 mm or more and 40 mm or less can be adopted as the shape of the balloon 25 that fits the pulmonary vein junction of the left atrium. Here, the spherical shape includes true spheres, oblate spheroids, prolate spheres, and further includes substantially spherical shapes.

The film thickness of the balloon 25 is preferably 10 μm or more and 200 μm or less. As the material of the balloon 25, a stretchable material having excellent antithrombotic properties is preferable, and specifically, a polyurethane-based polymer material or the like can be used. Examples of the polyurethane-based polymer material applied to the balloon 25 include thermoplastic polyether urethane, polyether polyurethane urea, fluorine polyether urethane urea, polyether polyurethane urea resin, and polyether polyurethane ureaamide.

In the illustrated catheter body 20, the distal end (tip) 25a of the balloon 25 is fixed to the distal end (tip) 35a of the inner barrel shaft 35, as shown in FIGS. A proximal end (proximal end) 25b of the balloon 25 is fixed to a distal end (tip) 30a of the outer cylinder shaft 30 . Adhesion or heat welding can be used to connect the balloon 25 to the outer cylinder shaft 30 and the inner cylinder shaft 35 .

The balloon 25 connected to the outer cylinder shaft 30 and the inner cylinder shaft 35 is deformed by relative movement of the outer cylinder shaft 30 and the inner cylinder shaft 35 in the longitudinal direction LD. In the illustrated example, relative movement of the outer barrel shaft 30 and the inner barrel shaft 35 allows adjustment of the dimension of the balloon 25 in the longitudinal direction LD. As shown in FIG. 3, the inner cylinder shaft 35 moves distally in the longitudinal direction LD relative to the outer cylinder shaft 30, so that the balloon 25 is stretched in the longitudinal direction LD and is further tightened. In the illustrated example, the range of movement of the inner cylinder shaft 35 to the distal side in the longitudinal direction LD with respect to the outer cylinder shaft 30 is restricted by the balloon 25 . As the inner cylinder shaft 35 moves relative to the outer cylinder shaft 30 in the longitudinal direction LD from the state shown in FIG. 3, the balloon 25 becomes relaxed. By introducing a liquid into the relaxed balloon 25, the balloon 25 can be inflated, as shown in FIG. That is, the relative movement of the outer cylinder shaft 30 and the inner cylinder shaft 35 allows adjustment of the dimension of the balloon 25 in the longitudinal direction LD.

Next, the heating member 40 will be explained. A heating element 40 is positioned within the balloon 25 . The heating member 40 is a member for heating the liquid filled in the balloon 25 . As the heating member 40, for example, a nichrome wire that generates heat by electric resistance can be used. As another example of the heating member 40, a coil electrode 41 can be employed as shown in FIGS. By applying a high-frequency current to the heating member 40 as the coil electrode 41, a high-frequency current flows between the opposing electrode 77 (FIG. 1) arranged outside, and the coil electrode 41 and the opposing electrode 77 are positioned between the coil electrode 41 and the opposing electrode 77. The liquid generates Joule heat. The counter electrode 77 is placed, for example, on the back of the patient.

In the example shown in FIGS. 2 and 3, the coil electrode 41 is provided on an inner tubular shaft 35 that extends within the balloon 25 . The coil electrode 41 may be constructed by a wire wound on the inner cylindrical shaft 35 . The coil electrode 41 is electrically connected to the wiring 42 for high-frequency energization. The wiring 42 extends to the handle 50 inside the liquid feed path LP as a lumen between the outer cylinder shaft 30 and the inner cylinder shaft 35 . As a specific example of the coil electrode 41 forming the heating member 40, a coil electrode obtained by stripping off the coating of a lead wire with an insulating coating used for the wiring 42 and winding it on the inner cylinder shaft 35 can be adopted. Since the coil electrode 41 is integrally formed with the wiring 42, problems such as disconnection can be effectively suppressed.

The diameters of the coil electrode 41 and the wiring 42 are preferably 0.1 mm or more and 1 mm or less, more preferably 0.1 mm or more and 0.4 mm or less. Examples of the conductive material forming the coil electrode 41 and the wiring 42 include copper, silver, gold, platinum, and alloys thereof. In order to prevent a short circuit, the wiring 42 preferably has a structure in which the conductive linear portion is covered with an insulating film such as a fluoropolymer (see FIGS. 4 and 5).

Next, the temperature sensor 45 will be explained. A temperature sensor 45 obtains information regarding the temperature of the liquid flowing between the outer cylinder shaft 30 and the inner cylinder shaft 35 . In this embodiment, the temperature sensor 45 has a heat sensitive portion 46 arranged between the outer cylinder shaft 30 and the inner cylinder shaft 35 . According to this temperature sensor 45, it is possible to acquire information about the liquid temperature in the liquid feed path LP. Information acquired by the temperature sensor 45 is used to estimate the surface temperature of the balloon 25, which is important in ablation treatment using the balloon catheter system 10. FIG.

For the purpose of specifying the surface temperature of the balloon 25 with high accuracy, the preferred distance DX along the longitudinal direction LD from the distal end 30a of the outer tube shaft 30 to the heat-sensitive portion 46 of the temperature sensor 45 is strictly described later. It depends on how much liquid the agitator 75 supplies and discharges. However, considering the dimensions of the balloon catheter 15 and the amount of liquid supplied and discharged from the stirrer 75, which are usually applied to cardiac ablation therapy, the distance DX from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 2) is preferably 5 mm or more and 150 mm or less, more preferably 10 mm or more and 20 mm or less.

Unless otherwise specified, the distance DX from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 is the distance specified when the balloon 25 shown in FIG. 2 is inflated with liquid. . Similarly, unless otherwise specified, the temperature sensor 45 is located inside the liquid feed path LP, the temperature sensor 45 is located inside the outer cylinder shaft 30, and the temperature sensor 45 is located between the outer cylinder shaft 30 and the inner cylinder shaft 35. Expressions such as being between and assume that the balloon 25 shown in FIG. 2 is inflated with a liquid.

A thermocouple or a thermistor can be used as the temperature sensor 45 . A T-type thermocouple is particularly suitable as the temperature sensor 45 . A T-type thermocouple can reduce the heat capacity of the heat sensitive portion 46 . Moreover, by adopting a T-type thermocouple as the temperature sensor 45, the thermoelectromotive force is stabilized. Furthermore, the T-type thermocouple can detect temperatures in the range of 50° C. to 80° C. with high accuracy, and is particularly suitable for cardiac ablation therapy. The temperature-related information acquired by the temperature sensor 45 is, for example, a potential acquired from a thermocouple or a resistance value acquired from a thermistor.

As shown in FIGS. 2 and 3, the temperature sensor 45 typically has a heat sensitive portion 46 and lead wires 47 electrically connected to the heat sensitive portion 46 . In the temperature sensor 45 as a thermocouple, a heat-sensitive portion 46 is formed by connecting dissimilar metals. In the temperature sensor 45 as a thermistor, a ceramic element forms a heat sensitive portion 46 . The lead wire 47 extends to the handle 50 inside the liquid feed path LP as a lumen between the outer cylinder shaft 30 and the inner cylinder shaft 35 .

The diameter of the lead wire 47 is preferably 0.05 mm or more and 0.5 mm or less, more preferably 0.05 mm or more and 0.3 mm or less. In the temperature sensor 45 as a thermocouple, for example, copper can be used for one lead wire 47 and constantan can be used for the other lead wire 47 . In this example, the heat sensitive portion 46 formed by joining a pair of lead wires 47 can function as a T-type thermocouple. In order to prevent the pair of lead wires 47 from short-circuiting, as shown in FIGS. 4 and 5, it is preferable that an electrically insulating film such as fluoropolymer or enamel is provided.

In the illustrated example, the temperature sensor 45 is attached to the inner cylinder shaft 35 . Specifically, as shown in FIGS. 2 to 4, the temperature sensor 45 is attached to the inner cylinder shaft 35 by fixing the lead wire 47 of the temperature sensor 45 . However, the heat sensitive portion 46 is separated from both the outer cylinder shaft 30 and the inner cylinder shaft 35 . In other words, the heat sensitive portion 46 is out of contact with the outer cylinder shaft 30 and the inner cylinder shaft 35 . As a result, it is possible to avoid the possibility that the heat sensing portion 46 detects the temperature of the outer cylinder shaft 30 or the inner cylinder shaft 35 having a large heat capacity and the responsiveness of the temperature sensor 45 deteriorates. As a result, the responsiveness of the temperature sensor 45 to the liquid temperature in the liquid feed path LP can be enhanced. As the fixing means 48 for fixing the lead wire 47 to the inner cylinder shaft 35, various means can be used without particular limitation. In the illustrated example, a heat-shrinkable tube that shrinks when heated is used as the fixing means 48 . However, it is not limited to this example, and various shrinkable tubes, adhesive tapes, adhesives, etc. can be used as the fixing means 48 .

On the other hand, in the illustrated example, the wiring 42 is not attached to either the outer cylinder shaft 30 or the inner cylinder shaft 35 . However, the wiring 42 may be attached to either the outer cylinder shaft 30 or the inner cylinder shaft 35 without being limited to this example. In this case, both the wiring 42 and the lead wire 47 of the temperature sensor 45 are preferably attached to the outer cylinder shaft 30 . Alternatively, both the wiring 42 and the lead wire 47 of the temperature sensor 45 are preferably attached to the inner cylinder shaft 35 . Since the wiring 42 and the temperature sensor 45 are both attached to one of the outer cylinder shaft 30 and the inner cylinder shaft 35, the wiring 42 and the lead wire 47 are connected when the outer cylinder shaft 30 and the inner cylinder shaft 35 move relative to each other. It is possible to effectively prevent entanglement in the liquid feed path LP. This contributes to stably obtaining temperature information of the liquid flowing through the liquid feed path LP using the temperature sensor 45 , which in turn contributes to stably estimating the surface temperature of the balloon 25 .

Further, as shown in FIG. 3, even in a state in which the inner cylinder shaft 35 has moved relative to the outer cylinder shaft 30 to the maximum in the longitudinal direction LD so that the balloon 25 expands, the temperature sensor 45 is still in contact with the outer cylinder. Located within shaft 30 . According to this embodiment, the temperature sensor 45 can be positioned within the outer cylinder shaft 30 regardless of the relative position of the inner cylinder shaft 35 with respect to the outer cylinder shaft 30 . Therefore, the temperature sensor 45 can be stably protected by the outer cylinder shaft 30 without depending on the relative position of the inner cylinder shaft 35 with respect to the outer cylinder shaft 30 .

Note that, unlike the illustrated example, the temperature sensor 45 may be attached to the outer cylinder shaft 30 . For example, the lead wire 47 of the temperature sensor 45 may be fixed to the inner surface of the outer cylinder shaft 30 . In this case, the temperature sensor 45 is positioned inside the outer cylinder shaft 30 regardless of the relative position of the inner cylinder shaft 35 with respect to the outer cylinder shaft 30 . Therefore, the temperature sensor 45 can be stably protected by the outer cylinder shaft 30 without depending on the relative position of the inner cylinder shaft 35 with respect to the outer cylinder shaft 30 .

Next, the handle 50 connected to the catheter main body 20 described above from the approximate side will be described. The handle 50 is a part held by an operator (surgeon) while using the balloon catheter system 10 . Therefore, it is preferable that the handle 50 has a design that allows the operator to easily grip and operate it. The material constituting the handle 50 is preferably a material with high chemical resistance, and for example polycarbonate or ABS resin can be used.

The handle 50 shown in FIG. 1 has a first handle portion 51 and a second handle portion 52 that are slidable relative to each other. A first handle portion (front handle portion) 51 is connected to the outer tube shaft 30 of the catheter body 20 . A second handle portion (rear side handle portion) 52 is connected to the inner cylinder shaft 35 of the catheter body 20 . By moving the second handle portion 52 relative to the first handle portion 51 , the inner cylinder shaft 35 can be moved relative to the outer cylinder shaft 30 .

As shown in FIG. 1, the handle 50 also serves as a connection site between the balloon catheter 15 and other devices included in the balloon catheter system 10 .

First, a connector 56 extends from the second handle portion 52 . This connector 56 electrically connects the wiring 42 of the catheter body 20 and the lead wire 47 of the temperature sensor 45 to a control device 70 which will be described later.

Also, as shown in FIG. 1 , an extension tube 57 extends from the first handle portion 51 . This extension tube 57 allows the liquid feed path LP of the catheter body 20 to communicate with a supply device 74 or a stirring device 75, which will be described later. Extension tube 57 is connected via valve 58 to feeder 74 and agitator 75 . In the illustrated example, by operating the valve 58, it is possible to select whether the feeding device 74 or the agitating device 75 is communicated with the liquid path LP. A three-way stopcock can be used as the valve 58 .

Next, the devices constituting the balloon catheter system 10 together with the balloon catheter 15 described above, specifically, the control device 70, the supply device 74 and the stirring device 75 will be described.

The illustrated controller 70 is electrically connected to the coil electrode 41 via the wiring 42 . The control device 70 has a high-frequency energization control section 70 a that controls high-frequency energization (supply of electrical energy) to the coil electrode 41 . In the illustrated example, the output from the heating member 40 is adjusted by controlling the high-frequency energization to the coil electrode 41 by the high-frequency energization control section 70a. Based on the surface temperature of the balloon 25 estimated by the temperature calculation unit 70b (hereinafter also referred to as "estimated surface temperature"), the high-frequency power supply control unit 70a follows preset processing, or follows an operator's request. By following the input, high-frequency energization to the coil electrode 41 can be controlled.

Also, the control device 70 is electrically connected to the lead wire 47 of the temperature sensor 45 . The control device 70 has a temperature calculator 70b that performs calculations based on the temperature information acquired by the temperature sensor 45 . The temperature calculator 70b calculates the temperature of the liquid in the liquid feed path LP based on the temperature information acquired by the temperature sensor 45, and further estimates the estimated surface temperature of the balloon 25 based on the calculated liquid temperature. The temperature calculation unit 70 b may display the estimated surface temperature of the balloon 25 on the display unit 71 .

Further, the control device 70 has a stirring device control section 70 c that controls the stirring device 75 . The stirring device control section 70 c may display the control conditions of the stirring device 75 on the display section 71 .

The control device 70 is configured by hardware such as a CPU, for example. One or more of the high-frequency power supply control section 70a, the temperature calculation section 70b, the stirring device control section 70c, and the display section 71 included in the control device 70 may be configured as separate hardware, or may share a part. can be At least part of the control device 70 may be configured by software. Portions of controller 70 may be physically spaced apart. Also, the control device 70 may be capable of cooperating with other components through communication through a network, with some components thereof. In addition, the control device 70 may have a part of its constituent parts on a device capable of communicating with other constituent parts through an external network, for example, on a cloud server or database.

Next, the supply device 74 will be described. The supply device 74 supplies liquid into the liquid feed path LP. The balloon 25 can be inflated as shown in FIG. 2 by supplying the liquid from the supply device 74 to the balloon 25 through the liquid feed path LP. On the other hand, the balloon 25 can also be contracted by discharging the liquid from the balloon 25 from the supply device 74 via the liquid feed path LP. The liquid supplied into the liquid feed path LP can typically be physiological saline. The liquid supplied into the liquid feed path LP may be a contrast agent diluted with a physiological saline solution so that the balloon 25 inflated with the liquid can be confirmed with an X-ray fluoroscopic image. A syringe can be used as the delivery device 74, as shown. However, a pump or the like can also be used as the supply device 74 .

Next, the stirring device 75 will be described. A stirring device 75 is provided to stir the liquid in the balloon 25 . By agitating the liquid in the balloon 25, the heated liquid around the heating member 40 can be diffused and the surface temperature of the balloon 25 can be adjusted. The stirring device 75 repeatedly performs liquid supply to the liquid feed path LP and liquid discharge from the liquid feed path LP. When liquid is supplied from the stirring device 75 to the liquid feed path LP, the liquid is supplied from the liquid feed path LP into the balloon 25 (see FIG. 6). Further, when the liquid is discharged from the liquid feed path LP to the stirring device 75, the liquid is discharged from the inside of the balloon 25 to the liquid feed path LP (see FIG. 7). The liquid in the balloon 25 is agitated by repeatedly supplying the liquid to the balloon 25 and discharging the liquid from the balloon 25 . As the stirring device 75, a pump selected from the group consisting of a roller pump, a diaphragm pump, a bellows pump, a vane pump, a centrifugal pump, and a pump consisting of a combination of a piston and a cylinder can be employed. 6 and 7, as well as FIG. 8, which will be referred to later, the illustration of a relative movement restricting member 90, which will be described later, is omitted for clarity of illustration. 6 to 8, dotted arrows indicate the flow of the liquid.

The amount of liquid supplied to the liquid feed path LP and the amount of liquid discharged from the liquid feed path LP can be set to a constant amount (for example, 5 ml or more and 30 ml or less). Further, the liquid supply to the liquid feed path LP and the liquid discharge from the liquid feed path LP may be repeated at a constant cycle (for example, once or more and five times or less per second). The liquid supply amount to the liquid feeding path LP and the liquid discharge amount from the liquid feeding path LP may be adjusted by a control signal from the stirring device control section 70c or by direct input from the operator. Similarly, the period of liquid supply to the liquid feed path LP and liquid discharge from the liquid feed path LP may be adjusted by a control signal from the stirring device control section 70c or by direct input from the operator.

Next, an example of how to use the balloon catheter system 10 configured as described above will be described.

First, the valve 58 is operated to allow the supply device 74 to communicate with the liquid delivery path LP of the catheter body 20 via the handle 50 and the extension tube 57 . Thereafter, the supply device 74 is operated to flow the liquid into the liquid feed path LP, filling the inside of the balloon 25, the liquid feed path LP, and the extension tube 57 with the liquid. Next, the inner cylinder shaft 35 is moved relative to the outer cylinder shaft 30 toward the distal side (front end side) in the longitudinal direction LD to extend the balloon 25 as shown in FIG. At this time, by operating the first handle portion 51 and the second handle portion 52 of the handle 50, the outer cylinder shaft 30 and the inner cylinder shaft 35 can be relatively moved. Then, the catheter body 20 with the balloon 25 stretched is inserted into the body.

When the distal end of the catheter body 20 is guided to the vicinity of the target site (affected area), the inner cylinder shaft 35 is relatively moved to the proximal side (base end side) in the longitudinal direction LD with respect to the outer cylinder shaft 30, and the balloon is displaced. Relax 25. Next, the valve 58 is operated to allow the delivery device 74 to communicate with the liquid delivery path LP of the catheter body 20 via the handle 50 . After that, the supply device 74 is operated to flow the liquid into the liquid feed path LP, thereby inflating the balloon 25 with the liquid as shown in FIG.

Next, the valve 58 is operated to shut off the supply device 74 from the liquid feed path LP and connect the stirring device 75 to the liquid feed path LP. The stirrer 75 is controlled by a control signal from a stirrer controller 70 c of the controller 70 . The stirring device 75 repeatedly supplies a constant amount of liquid to the liquid feed path LP and discharges a constant amount of liquid from the liquid feed path LP at a constant cycle. As a result, a constant amount of liquid is discharged from the liquid feed path LP into the balloon 25 and a constant amount of liquid is sucked from the balloon 25 into the liquid feed path LP, which is repeated at a constant cycle. This agitates the liquid inside the balloon 25 .

Further, the heating member 40 is controlled by the high-frequency power supply control section 70 a of the control device 70 to adjust the temperature of the liquid inside the balloon 25 . Specifically, high-frequency current is applied from the control device 70 between the coil electrode 41 forming the heating member 40 and the counter electrode 77 arranged outside the patient's body. As a result, a high frequency current is generated between the coil electrode 41 and the counter electrode 77 . However, by making the size of the coil electrode 41 significantly smaller than the size of the counter electrode, the current density around the coil electrode 41 increases, and the liquid around the coil electrode 41 is heated by Joule heat. .

If the temperature sensor 45 is placed in the vicinity of the coil electrode 41 when a high-frequency current is applied between the coil electrode 41 and the counter electrode 77, a high-frequency current will also flow between the temperature sensor 45 and the counter electrode 77. The temperature sensor 45 may measure the temperature of the heated liquid and detect an abnormal value. However, in the illustrated example, the temperature sensor 45 is positioned within the barrel shaft 30 with the balloon 25 inflated, as described above. The thickness of the outer cylinder shaft 30 is significantly thicker than the thickness of the balloon 25 . Therefore, the temperature sensor 45 can be shielded from high frequency current by the outer cylinder shaft 30 . Therefore, it is possible to effectively prevent the liquid around the temperature sensor 45 from being locally heated.

As described above, the liquid in the balloon 25 is stirred while being heated. Then, the balloon 25 containing the heated liquid is pressed against the target site to ablate the target site. During the ablation, the temperature sensor 45 arranged in the liquid feed path LP acquires temperature information of the liquid flowing through the liquid feed path LP. Based on the obtained temperature information, the temperature calculation unit 70b of the control device 70 performs calculations to derive the estimated surface temperature of the balloon 25 . The estimated surface temperature of the balloon 25 obtained by the temperature calculation unit 70b is displayed on the display unit 71, for example.

When the target site has been ablated, the electrical energy supply to the heating member 40 is stopped. Also, the valve 58 is operated to allow the supply device 74 to communicate with the liquid feed path LP of the catheter body 20 via the handle 50, and the stirring device 75 is blocked from the liquid feed path LP. Then, the supply device 74 is used to discharge the liquid from the liquid feed path LP, and the balloon 25 is deflated. Next, the second handle portion 52 is operated to expand the deflated balloon 25 as shown in FIG. Then, the catheter body 20 with the balloon 25 stretched is pulled out from the body. Thus, the treatment using the balloon catheter system 10 is completed.

By the way, if the surface temperature of the balloon 25 can be accurately grasped all the time, the treatment can be performed while adjusting the surface temperature of the balloon 25 to an ideal temperature, and the effect of the ablation treatment can be dramatically improved. can. However, during ablation, the difference between the estimated surface temperature of the balloon 25 estimated by the temperature calculator 70b and the actual surface temperature of the balloon 25 may increase.

Regarding this point, the inventors of the present invention have obtained the following knowledge as a result of earnest research. That is, the balloon catheter 15 may be squeezed against the target site during ablation to ensure a tight fit of the balloon 25 to the target site. In such a case, the balloon 25 is so soft that the outer barrel shaft 30 advances distally in the longitudinal direction LD relative to the inner barrel shaft 35 (see FIG. 8). At this time, if the distal end 30a of the outer cylinder shaft 30 and the heating member 40 on the inner cylinder shaft 35 are too close, the difference between the estimated surface temperature of the balloon 25 and the actual surface temperature will increase. It is considered that this is due to the following reasons. That is, when the distance DY between the distal end 30a of the outer cylinder shaft 30 and the proximal end 40b of the heating member 40 is sufficiently large, when liquid is discharged from the balloon 25 by the stirrer 75, as shown in FIG. First, the liquid that has mainly flowed along the surface of the balloon 25 is drawn into the liquid feed path LP. Therefore, in this case the temperature sensor 45 can measure a liquid temperature close to the actual surface temperature of the balloon 25 . On the other hand, if the distance DY between the distal end 30a of the outer cylinder shaft 30 and the proximal end 40b of the heating member 40 is too small, as shown in FIG. At the same time, the heated liquid around the heating member 40 is more likely to be directly drawn into the liquid feed path LP. This results in the temperature sensor 45 measuring a liquid temperature significantly higher than the actual surface temperature of the balloon 25 in the case shown in FIG. As a result, the estimated surface temperature of balloon 25 is significantly higher than the actual surface temperature. Note that the distance DY is measured with the balloon 25 inflated with liquid (see FIG. 2).

In consideration of such points, the balloon catheter 15 of the present embodiment is devised to prevent the difference between the estimated surface temperature of the balloon 25 and the actual surface temperature of the balloon 25 from becoming too large during ablation. is done.

Specifically, the balloon catheter 15 of this embodiment includes a relative movement restricting member 90 that restricts relative movement of the outer tube shaft 30 with respect to the inner tube shaft 35 . The relative movement limiting member 90 limits relative movement of the outer barrel shaft 30 with respect to the inner barrel shaft 35 in the direction in which the distal end 30 a of the outer barrel shaft 30 approaches the heating member 40 . Such a relative movement restricting member 90 prevents the outer cylinder shaft 30 from coming too close to the heating member. As a result, when liquid is discharged from the balloon 25 by the stirrer 75, the liquid flowing along the surface of the balloon 25 is easily drawn into the liquid feed path LP, and the temperature sensor 45 detects the actual surface temperature of the balloon 25. can measure liquid temperatures close to . As a result, the surface temperature of the balloon 25 can be accurately estimated.

FIG. 9 shows the temperature difference between the estimated surface temperature and the actual surface temperature of balloon 25 due to variations in distance DY between heating member 40 and the distal end of barrel shaft 30 . The results shown in FIG. 9 were obtained by simulating the temperature distribution of the liquid inside the balloon 25 and inside the liquid feed path LP near the balloon 25 (near the distal end 30a of the outer cylinder shaft 30) by CAE (computer-aided engineering). was obtained by In the example shown in FIG. 9, the following simulation was performed following an actual clinical situation. That is, as models of the balloon catheter system 10, three models were used in which the amount of liquid injected into the balloon 25 was about 10 ml, about 15 ml, and about 20 ml. In the simulation, each model was controlled so that the temperature of the liquid around the heating member 40 was 70° C., and the driving power was 150 W.

In FIG. 9, the horizontal axis indicates the distance DY between the proximal end 40a of the heating member 40 and the distal end 30a of the outer cylinder shaft 30, and the vertical axis indicates the temperature difference between the estimated surface temperature of the balloon 25 and the actual surface temperature. is shown. The estimated surface temperature is the surface temperature of the balloon 25 estimated based on the temperature information acquired by the temperature sensor 45 . In FIG. 9, bar graphs A, B, and C show the above temperature differences for models in which the amount of liquid injected into balloon 25 is about 10 ml, about 15 ml, and about 20 ml, respectively. As can be seen from FIG. 9, the temperature difference was less than ±1.5° C. when the distance DY was 3 mm or more in any model. In particular, the temperature difference was less than ±1° C. when the distance DY was 9 mm or more, and less than ±0.5° C. when the distance DY was 13 mm or more. On the other hand, when the distance DY was 2 mm or less, the temperature difference was significantly larger than when the distance DY was 3 mm or more, and the temperature difference was about 2° C. or more. The reason why the temperature difference is significantly increased is that, as described with reference to FIG. is directly sucked, and the amount of fluid that has passed through the vicinity of the surface of the balloon 25 and flows into the liquid feed path LP is small. Here, the temperature difference between the estimated surface temperature of the balloon 25 and the actual surface temperature that is acceptable in actual clinical situations is generally less than ±2°C.

As a further representative example, FIGS. 10 to 12 show the distance between the proximal end 40b of the heating member 40 and the distal end 30a of the outer cylinder shaft 30 in a model in which the amount of liquid injected into the balloon 25 is about 15 ml. The temperature of the liquid measured by the temperature sensor 45 is shown when DY is 13 mm, 7 mm, and 1 mm. 10 to 12, the vertical axis is temperature (° C.) and the horizontal axis is time (s). FIGS. 10-12 show temperatures measured by the temperature sensor 45 at 10 millisecond intervals. 10 to 12 show the measurement results after the passage of time for the surface temperature of the balloon 25 to be sufficiently stabilized after the start of high-frequency electric power application, specifically, from 90 to 150 seconds after the start of electric power application. It is shown. 10-12 also show the actual surface temperature of the balloon 25 along with the temperature of the liquid measured by the temperature sensor 45. FIG. 10 to 12, the curves drawn with thin lines represent temperature measurements by the temperature sensor 45, and the straight lines drawn with thick lines represent the actual surface temperature of the balloon 25. FIG. More specifically, in FIGS. 10 to 12, the curves drawn with thin lines are temperature fluctuation lines connecting actual measurement values obtained by the temperature sensor 45. FIG. The minimum value of the temperature fluctuation line is the temperature sensor 45 is the liquid temperature measured in Further, the maximum value of the temperature variation line is detected by the temperature sensor when the liquid is discharged from the liquid feed path LP to the agitator 75 (that is, when the liquid is discharged from the balloon 25 to the liquid feed path LP) (see FIG. 7). is the liquid temperature measured at 45;

In the results shown in FIGS. 10 to 12, the temperature of the liquid inside the liquid feed path LP measured by the temperature sensor 45 fluctuates at intervals of about 0.5 seconds. 10 and 11, where the distance DY between the proximal end 40b of the heating member 40 and the distal end 30a of the barrel shaft 30 is 3 mm or more, the actual surface temperature of the balloon 25 is measured by the temperature sensor 45. , roughly agrees with the local maximum of the temperature variation line. From this point, when the distance DY is 3 mm or more, the temperature calculation unit 70b of the control device 70 calculates the maximum value (or the envelope connecting the maximum values) of the temperature variation line connecting the measured values by the temperature sensor 45. , can be specified as the actual surface temperature of the balloon 25 . Alternatively, in this case, the temperature calculation unit 70b of the control device 70 first specifies a triangular wave-like approximated curve from the actual measured values by the temperature sensor 45, and then finds the maximum value of the temperature fluctuation approximated curve (or the envelope connecting the maximum values). ) can be specified as the actual surface temperature of the balloon 25 .

On the other hand, the actual surface temperature of the balloon 25 in FIG. and the maximum value of the temperature variation line measured by the temperature sensor 45 . That is, in the example shown in FIG. 12, compared with the examples shown in FIGS. 10 and 11, the estimated surface temperature of the balloon 25 estimated from the temperature of the liquid inside the outer tube shaft 30 is different from the actual surface temperature of the balloon 25. remarkably high in comparison. This is because, as described with reference to FIG. 8, when the proximal end 25b of the balloon 25 is pushed in and the distance DY between the heating member 40 and the distal end 30a of the outer cylinder shaft 30 becomes extremely short, the balloon This is probably because the liquid that has flowed along the surface of 25 is less likely to be drawn into the liquid feed path LP, while the liquid heated by the heating member 40 is more likely to be directly drawn into the liquid feed path LP.

Note that when the balloon 25 is pressed against the target site, the outer cylinder shaft at the distal end 30a of the outer cylinder shaft 30 relative to the center axis 35X of the inner cylinder shaft 35 within the balloon 25 depends on the angle at which the balloon 25 is pressed against the target site. The angle of the central axis 30X of 30 changes. For example, as shown in FIG. 13, the balloon 25 may be pressed against the target site in a state in which the central axis 35X and the central axis 30X are aligned (hereinafter, this state is also referred to as a "coaxial state"). On the other hand, as shown in FIG. 14, the balloon 25 may be pressed against the target site in a state in which the central axis 30X is inclined with respect to the central axis 35X (hereinafter, this state is also referred to as a "non-coaxial state"). be. However, even if the pressing angle of the balloon 25 against the target site is different in this way, if the distance DY is sufficiently large, during the liquid discharge from the inside of the balloon 25 to the liquid feeding path LP, along the surface of the balloon 25 The flowing liquid can easily flow into the liquid feed path LP. As a result, the surface temperature of the balloon 25 can be specified with high accuracy based on the liquid temperature information acquired by the temperature sensor 45 . This point will be described with reference to FIGS. 13 and 14. FIG. 13 and 14 show the results of simulating the temperature distribution of the liquid inside the balloon 25 and inside the liquid feed path LP near the balloon 25 (near the distal end 30a of the outer cylinder shaft 30) by CAE. The simulations shown in FIGS. 13 and 14 were performed using a balloon catheter 15 with a distance DY of 3 mm or more.

FIG. 13 shows simulation results when the inner cylinder shaft 35 and the outer cylinder shaft 30 are coaxial and the balloon 25 is pressed against the target site. In the example shown in FIG. 13, distal end 30a of barrel shaft 30 and heating member 40 are aligned along central axis 30X of barrel shaft 30 at distal end 30a. In this case, as can be understood from the simulation results of FIG. 13, even if the liquid in the balloon 25 is stirred using the stirrer 75, a temperature gradient is generated in the liquid in the balloon 25 due to the arrangement of the heating member 40. end up When the coil electrode 41 is used as the heating member 40, this temperature gradient shows the same trend as the current density distribution. The temperature gradient within the balloon 25 is 5° C. or more in the example shown in FIG. However, the temperature of the liquid in the liquid passage LP near the distal end 30a of the outer cylinder shaft 30 is different from the temperature of the liquid around the heating member 40, but is approximately equal to the surface temperature of the balloon 25. Therefore, in the example shown in FIG. 13, it is understood that the surface temperature of the balloon 25 can be detected by measuring the liquid temperature in the liquid feed path LP near the distal end 30a of the outer cylinder shaft 30. FIG.

FIG. 14 shows a simulation result when the inner cylinder shaft 35 and the outer cylinder shaft 30 are non-coaxial and the balloon 25 is pressed against the target site. In the example shown in FIG. 14, the outer cylinder shaft 30 is greatly inclined with respect to the inner cylinder shaft 35 and the heating member 40 inside the balloon 25 . In this case, distal end 30a of barrel shaft 30 and heating member 40 are not aligned along central axis 30X of barrel shaft 30 at distal end 30a. As can be seen from the simulation results of FIG. 14, even in this case, even if the liquid in the balloon 25 is stirred using the stirrer 75, the temperature gradient caused by the arrangement of the heating member 40 will affect the liquid in the balloon 25. occur. The temperature gradient inside the balloon 25 is 5° C. or more even in the example shown in FIG. However, the temperature of the liquid inside the liquid feed path LP near the distal end 30 a of the outer cylinder shaft 30 is approximately equal to the surface temperature of the balloon 25 . Therefore, in the example shown in FIG. 14 as well, it is understood that the surface temperature of the balloon 25 can be detected by measuring the temperature of the liquid in the liquid feed path LP near the distal end 30a of the outer tube shaft 30.

As understood from the simulation results of FIGS. 13 and 14, the temperature distribution of the liquid in the balloon 25 differs when the angle at which the balloon 25 is pressed against the target site differs. However, in any case, the temperature of the liquid in the region near the distal end 30a of the outer cylinder shaft 30 and the surface temperature of the balloon 25 are approximately equal. Therefore, even if the angle at which the balloon 25 is pressed against the target site is different, the surface temperature of the balloon 25 can be detected by measuring the temperature of the liquid in the liquid feed path LP near the distal end 30a of the outer cylinder shaft 30. It is understood to obtain

In summary, if the distance DY between the proximal end 40b of the heating member 40 and the distal end 30a of the outer cylinder shaft 30 is sufficiently large, the surface of the balloon 25 will be heated regardless of the pressing angle of the balloon 25 against the target site. Temperature can be detected with high accuracy.

It should be noted that the temperature gradient around the heating member 40 in the balloon 25 is not limited to the heating member expected to be resistively heated by the nichrome wire, but also the coil electrode 41 that is energized at high frequency, as demonstrated by the simulation results. The same problem can occur in the heating member 40 that has the same shape. When a high-frequency current is applied to the coil electrode 41 and the opposing electrode 77 outside the body, a high-frequency current flows between the coil electrode 41 and the opposing electrode 77 . Since the resistivity of the liquid near the coil electrode 41 is high in the high-frequency current, in this region (flowing current value) ² × (resistance value of the filling liquid)
Intensive generation of Joule heat expressed as This Joule heat rapidly decreases with distance from the coil electrode 41 . This is because the term “(flowing current value)” in “(flowing current value) ² ×(resistance value of filling liquid)” attenuates with the square of the distance. For example, when the liquid temperature near the heating member 40 is 70° C. in the simulation results of FIG. 13, the surface temperature of the balloon 25 is lowered to 65° C. or less.

As described above, in the illustrated example, the surface temperature of the balloon 25 is specified based on the temperature of the liquid discharged from the balloon 25 into the liquid feed path LP. Therefore, it is preferable that the heat-sensitive portion 46 of the temperature sensor 45 is positioned near the distal end 30 a of the outer cylinder shaft 30 . More specifically, in the liquid feed path LP in the vicinity of the distal end 30a of the outer cylinder shaft 30, the liquid inside the balloon 25 is drawn in when the stirring device 75 sucks the liquid (the liquid discharged from the balloon 25 reaches the area). It is preferably located within the area where the Thereby, the temperature of the liquid discharged from the balloon 25 can be detected by the temperature sensor 45 inside the outer cylinder shaft 30 . Specifically, the distance DX (see FIG. 2) from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 is defined as the liquid discharge amount [mm ³ ] from the liquid feed path LP by the stirring device 75, and the liquid feed path It is preferable to make it equal to or less than the value divided by the cross-sectional area [mm ² ] of the LP.

As described above, if the distance DY between the proximal end 40b of the heating member 40 and the distal end 30a of the barrel shaft 30 is sufficiently large, the surface of the balloon 25 will be heated regardless of the pressing angle of the balloon 25 against the target site. Temperature can be detected with high accuracy. In consideration of these points, the balloon catheter 15 of the present embodiment is designed so that the heating member 40 and the distal end 30a of the outer tube shaft 30 are kept in contact with each other even when the balloon 25 is pressed against the target site during ablation. is devised to keep the distance DY sufficiently large. Specifically, the balloon catheter 15 has a relative movement restricting member 90 that restricts relative movement of the outer tube shaft 30 with respect to the inner tube shaft 35 . The relative movement limiting member 90 limits relative movement of the outer barrel shaft 30 with respect to the inner barrel shaft 35 in the direction in which the distal end 30 a of the outer barrel shaft 30 approaches the heating member 40 .

The relative movement restricting member 90 will be described in detail below with reference to FIGS. 15A to 17E. In the example shown below, the relative movement restricting member 90 is arranged such that the distance between the distal end 30a of the outer cylindrical shaft 30 and the proximal end 40b of the heating member 40 is 3 mm or more. 35 to limit relative movement. As can be seen from the results shown in FIG. 9, this can effectively suppress the temperature difference between the estimated surface temperature of the balloon 25 and the actual surface temperature from becoming too large. can be estimated with high accuracy.

In the example shown in Figures 15A and 15B, the relative movement limiting member 90 is attached to the barrel shaft 30 and extends into the balloon 25 as shown in Figure 15A. Relative movement of the outer cylinder shaft 30 with respect to the inner cylinder shaft 35 is restricted by the contact of the relative movement restricting member 90 with the heating member 40 . In other words, the outer barrel shaft 30 is relatively movable along the longitudinal direction LD with respect to the inner barrel shaft 35 until the distal end 90a of the relative movement limiting member 90 contacts the proximal end 40b of the heating member 40. However, once the distal end 90 a of the relative movement limiting member 90 contacts the proximal end 40 b of the heating member 40 , it cannot move further distally relative to the inner barrel shaft 35 . According to such a relative movement restricting member 90, even if the balloon 25 is pressed against the target site during ablation, the distal end 30a of the outer cylinder shaft 30 and the proximal end 40b of the heating member 40 can be prevented from moving. Distance DY can be kept sufficiently large.

In the illustrated example, the relative movement limiting member 90 is fixed to the distal end 30 a of the barrel shaft 30 . The relative movement restricting member 90 extends along the longitudinal direction LD as a whole. The length of the relative movement restricting member 90 along the longitudinal direction LD is 3 mm or more. According to such a relative movement restricting member 90, even if the balloon 25 is pressed against the target site during ablation, the distal end 30a of the outer cylinder shaft 30 and the proximal end 40b of the heating member 40 can be prevented from moving. The distance DY can be maintained at 3 mm or more.

In the example shown in FIGS. 15A and 15B, the relative movement restricting member 90 includes two plate-shaped restricting elements 91 . The two limiting elements 91 each extend generally along the longitudinal direction LD. The two restrictive elements 91 are spaced apart from each other along the circumferential direction of the outer cylinder shaft 30 . Thereby, the relative movement limiting member 90 stably supports the outer cylinder shaft 30 with respect to the heating member 40 when the distal end 90a of the relative movement limiting member 90 contacts the proximal end 40b of the heating member 40. be able to. As shown in FIG. 15B , the restricting elements 91 of the relative movement restricting member 90 are preferably arranged at regular intervals along the circumferential direction of the outer cylinder shaft 30 . In this case, the relative movement limiting member 90 effectively stabilizes the barrel shaft 30 relative to the heating member 40 when the distal end 90a of the relative movement limiting member 90 contacts the proximal end 40b of the heating member 40. can be supported by

Note that the number of restricting elements 91 included in the relative movement restricting member 90 shown in FIG. 15B is not limited to two. Relative movement limiting member 90 may include any number of limiting elements 91 . For example, as shown in FIG. 15C, relative movement limiting member 90 may include three limiting elements 91 . When the relative movement restricting member 90 includes a plurality of restricting elements 91 , the restricting elements 91 are preferably spaced apart from each other along the circumferential direction of the outer cylinder shaft 30 . Thereby, the relative movement limiting member 90 stably supports the outer cylinder shaft 30 with respect to the heating member 40 when the distal end 90a of the relative movement limiting member 90 contacts the proximal end 40b of the heating member 40. be able to. Moreover, when the relative movement restricting member 90 includes a plurality of restricting elements 91 , the restricting elements 91 are preferably arranged at regular intervals along the circumferential direction of the outer cylinder shaft 30 . In this case, the relative movement limiting member 90 effectively stabilizes the barrel shaft 30 relative to the heating member 40 when the distal end 90a of the relative movement limiting member 90 contacts the proximal end 40b of the heating member 40. can be supported by Of course, the relative movement limiting member 90 may consist of a single limiting element 91 .

In the example shown in FIG. 15A , the relative movement restricting member 90 has a portion 92 extending toward the outer peripheral surface of the inner cylinder shaft 35 . In the illustrated example, the distance between the central axis 30X of the outer barrel shaft 30 at the proximal end 90b of the relative movement limiting member 90 and the relative movement limiting member 90 is the distance between the outer barrel shaft at the distal end 90a of the relative movement limiting member 90. 30 and the relative movement restricting member 90. According to such a relative movement restricting member 90, the portion 92 contacts the inner cylinder shaft 35, so that the outer peripheral surface of the inner cylinder shaft 35 and the outer surface of the inner cylinder shaft 35 at the connecting portion between the liquid feeding path LP and the inner space of the balloon 25 are displaced. The inner peripheral surfaces of the cylindrical shaft 30 can be spaced apart from each other over the entire circumference of the outer peripheral surface and the inner peripheral surface. As a result, the surface of the balloon 25 can be efficiently heated. Specifically, even if a force that bends the outer cylinder shaft 30 and the inner cylinder shaft 35 is applied to the balloon catheter 15 during the procedure, the outer cylinder shaft will not be able to bend at the connecting portion between the liquid feed path LP and the inner space of the balloon 25. A gap between 30 and the inner cylindrical shaft 35 is stably maintained over the entire circumference of the outer peripheral surface of the inner cylindrical shaft 35 and the inner peripheral surface 31 of the outer cylindrical shaft 30 . Then, the liquid from the liquid feed path LP is caused to flow into the inner space of the balloon 25 so as to surround the entire outer peripheral surface of the inner cylindrical shaft 35, and is directed toward the heating member 40 on the outer peripheral surface of the inner cylindrical shaft 35. can dodge. As a result, the liquid heated by the heating member 40 can be stably and efficiently diffused.

In the case where each of the restricting elements 91 of the relative movement restricting member 90 has the portion 92 described above, as shown in FIGS. When arranged, the outer cylinder shaft 30 and the inner cylinder shaft 35 can be maintained in the coaxial state shown in FIG. 13 even if a force that bends the catheter shaft 28 is applied to the balloon catheter 15 during the procedure. In this case, the surface of the balloon 25 can be heated more efficiently. That is, in this case, the liquid from the liquid feed path LP can flow into the balloon 25 so as to evenly surround the outer peripheral surface of the heating member 40 on the outer peripheral surface of the inner cylinder shaft 35 . As a result, the heated liquid surrounding the heating member 40 can be diffused more efficiently.

Next, modifications of the relative movement restricting member 90 will be described with reference to FIGS. 16A to 16C. In the example shown in FIG. 16A , the relative movement restricting member 90 is fixed to the inner cylinder shaft 35 . More specifically, in this example, the relative movement limiting member 90 is fixed on the outer peripheral surface of the inner cylinder shaft 35 between the proximal end 40b of the heating member 40 and the distal end 30a of the outer cylinder shaft 30. ing. In this example, the relative movement restricting member 90 extends outward from the inner peripheral surface of the outer cylindrical shaft 30 in the radial direction. In the example shown in FIG. 16A , relative movement of outer barrel shaft 30 with respect to inner barrel shaft 35 is limited by contact of distal end 30 a of outer barrel shaft 30 with relative movement limiting member 90 . In other words, the outer barrel shaft 30 is relatively movable along the longitudinal direction LD with respect to the inner barrel shaft 35 until its distal end 30a contacts the proximal end 90b of the relative movement limiting member 90, Once distal end 30 a of outer barrel shaft 30 contacts proximal end 90 b of relative movement limiting member 90 , further distal movement relative to inner barrel shaft 35 is prevented. Such relative movement limiting member 90 also reduces the distance between distal end 30a of barrel shaft 30 and proximal end 40b of heating member 40, even when balloon 25 is pressed against the target site during ablation. DY can be kept sufficiently large.

In the illustrated example, the relative movement limiting member 90 is arranged such that the distance between its proximal end 90b and the proximal end 40b of the heating member 40 is 3 mm or more. According to the relative movement restricting member 90, even when the balloon 25 is pressed against the target site during ablation, the distance DY between the distal end of the outer tube shaft 30 and the heating member 40 is kept at 3 mm or more. can be maintained.

In the example shown in FIGS. 16A-16B, relative movement limiting member 90 includes two limiting elements 93 . The two restricting elements 93 each extend along the radial direction of a circle centered on the central axis 35X of the inner cylindrical shaft 35 as a whole. The two restricting elements 93 are spaced apart from each other along the circumferential direction of the inner cylinder shaft 35 . Thereby, the relative movement restricting member 90 can stably support the outer cylinder shaft 30 when the distal end 30 a of the outer cylinder shaft 30 contacts the proximal end 90 b of the relative movement restricting member 90 . As shown in FIG. 16B , the restricting elements 93 of the relative movement restricting member 90 are preferably arranged at regular intervals along the circumferential direction of the inner cylinder shaft 35 . In this case, relative movement limiting member 90 can effectively and stably support barrel shaft 30 when distal end 30a of barrel shaft 30 contacts proximal end 90b of relative movement limiting member 90. can.

Also in the example shown in FIG. 16A, the number of restricting elements 93 included in the relative movement restricting member 90 is not limited to two. Relative movement limiting member 90 may include any number of limiting elements 93 . For example, as shown in FIG. 16C, relative movement limiting member 90 may include three limiting elements 93 . When the relative movement restricting member 90 includes a plurality of restricting elements 93 , the restricting elements 93 are preferably spaced apart from each other along the circumferential direction of the inner cylinder shaft 35 . Thereby, the relative movement restricting member 90 can stably support the outer cylinder shaft 30 when the distal end 30 a of the outer cylinder shaft 30 contacts the proximal end 90 b of the relative movement restricting member 90 . Moreover, when the relative movement restricting member 90 includes a plurality of restricting elements 93 , the restricting elements 93 are preferably arranged at equal intervals along the circumferential direction of the inner cylinder shaft 35 . In this case, relative movement limiting member 90 can effectively and stably support barrel shaft 30 when distal end 30a of barrel shaft 30 contacts proximal end 90b of relative movement limiting member 90. can. Of course, in the example shown in FIG. 16A as well, the relative movement restricting member 90 may consist of a single restricting element 93 .

Next, another modification of the relative movement restricting member 90 will be described with reference to FIGS. 17A to 17E. 17A to 17C, the relative movement restricting member 90 includes a first restricting member 94 fixed to the inner peripheral surface of the outer cylindrical shaft 30 and a second restricting member 94 fixed to the outer peripheral surface of the inner cylindrical shaft 35. member 95; The first restricting member 94 extends radially inward of a circle centered on the central axis 30X of the outer cylindrical shaft 30 from the inner peripheral surface of the outer cylindrical shaft 30 . The second restricting member 95 extends radially outward of a circle centered on the central axis 35X of the inner cylindrical shaft 35 from the outer peripheral surface of the inner cylindrical shaft 35 . At least a portion of the first restricting member 94 overlaps at least a portion of the second restricting member 95 when viewed in the longitudinal direction LD. The first restricting member 94 is arranged closer to the proximal side than the second restricting member 95 . In the example shown in FIGS. 17A-17C, relative movement of the outer barrel shaft 30 with respect to the inner barrel shaft 35 is limited by the proximal contact of the first restricting member 94 with the second restricting member 95 . In other words, the outer barrel shaft 30 rotates longitudinally with respect to the inner barrel shaft 35 until the distal facing surface 94 a of the first restricting member 94 contacts the proximal facing surface 95 b of the second restricting member 95 . Although relatively movable along the LD, when the distally facing surface 94a of the first restricting member 94 contacts the proximally facing surface 95b of the second restricting member 95, the inner barrel shaft 35 is further displaced. Cannot move distally. The relative movement restricting member 90 also maintains a sufficiently large distance DY between the distal end of the outer cylinder shaft 30 and the heating member 40 even when the balloon 25 is pressed against the target site during ablation. can do.

In the illustrated example, the first and second restriction members 94 and 95 are positioned near the distal end 30a of the barrel shaft 30 and the heating member 40 when the first and second restriction members 94 and 95 are in contact. It is arranged so that the distance from the proximal end 40b is 3 mm or more. According to such a relative movement restricting member 90, even if the balloon 25 is pressed against the target site during ablation, the distal end 30a of the outer cylinder shaft 30 and the proximal end 40b of the heating member 40 can be prevented from moving. The distance DY can be maintained at 3 mm or more.

In the example shown in FIGS. 17A-17C, the first restricting member 94 and the second restricting member 95 are each composed of a single restricting element 96, 97, but the present invention is not limited to this. The first restricting member 94 and the second restricting member 95 may each include a plurality of restricting elements 96,97. In the example shown in Figures 17D-17E, the first restricting member 94 and the second restricting member 95 each include two restricting elements 96,97. The two limiting elements 96 of the first limiting member 94 are spaced apart from each other along the circumferential direction of the outer cylinder shaft 30 . Correspondingly, the two limiting elements 97 of the second limiting member 95 are spaced apart from each other along the circumferential direction of the inner cylindrical shaft 35 . Thereby, when the first restricting member 94 contacts the second restricting member 95 , the second restricting member 95 can stably support the outer tube shaft 30 . In addition, as shown in FIG. 17D , the restricting elements 96 of the first restricting member 94 are preferably arranged at equal intervals along the circumferential direction of the outer tube shaft 30 . Correspondingly, as shown in FIG. 17D , the restricting elements 97 of the second restricting member 95 are preferably arranged at equal intervals along the circumferential direction of the inner cylinder shaft 35 . In this case, when the first restricting member 94 contacts the second restricting member 95 , the second restricting member 95 can effectively and stably support the outer tube shaft 30 .

Of course, when the first restricting member 94 and the second restricting member 95 include a plurality of restricting elements 96, 97, the number of restricting elements 96, 97 of each restricting member 94, 95 is not limited to two. Each restriction member 94,95 may include three or more restriction elements 96,97. In this case, the plurality of restricting elements 96 of the first restricting member 94 are preferably spaced apart from each other along the circumferential direction of the outer cylinder shaft 30 . Correspondingly, the plurality of restricting elements 97 of the second restricting member 95 are preferably spaced apart from each other along the circumferential direction of the inner cylindrical shaft 35 . Thereby, when the first restricting member 94 contacts the second restricting member 95 , the second restricting member 95 can stably support the outer tube shaft 30 . Further, when each of the limiting members 94 and 95 includes three or more limiting elements 96 and 97, the plurality of limiting elements 97 of the first limiting member 94 are arranged at regular intervals along the circumferential direction of the outer cylindrical shaft 30. is preferably arranged. Correspondingly, the plurality of restricting elements 97 of the second restricting member 95 are preferably arranged at regular intervals along the circumferential direction of the inner cylinder shaft 35 . In this case, when the first restricting member 94 contacts the second restricting member 95 , the second restricting member 95 can effectively and stably support the outer tube shaft 30 .

Any method can be adopted as a method for fixing the relative movement restricting member 90 to the outer cylinder shaft 30 or the inner cylinder shaft 35 . For example, the relative movement restricting member 90 may be fixed to the outer cylinder shaft 30 or the inner cylinder shaft 35 by adhesion or heat welding.

Moreover, as the material of the relative movement restricting member 90, it is preferable to use a material having excellent antithrombotic properties. Examples of materials having excellent antithrombotic properties include fluoropolymers, polyamides, polyurethane-based polymers, polyimides, and the like, but are not limited to these.

Furthermore, in the example shown in FIG. 15A , the relative movement restricting member 90 contacts the inner cylinder shaft 35 and moves relative to the inner cylinder shaft 35 . In this case, the material of the relative movement restricting member 90 is selected in consideration of the frictional force acting between the relative movement restricting member 90 and the inner cylinder shaft 35 when the inner cylinder shaft 35 is moved relative to the outer cylinder shaft 30. preferably determined. That is, it is preferable to determine the material of the relative movement restricting member 90 so that smooth sliding between the inner cylindrical shaft 35 and the outer cylindrical shaft 30 is not hindered by the frictional force.

Further, in the illustrated example, further measures are taken to efficiently diffuse the heated liquid around the heating member 40. FIG. Specifically, as understood from FIGS. 15A, 16A, and 17A, the heating member 40 is arranged within a range obtained by projecting the inner volume of the outer cylinder shaft 30 from the central axis 35X direction of the inner cylinder shaft 35. ing. By arranging the heating member 40 within such a range, the liquid flow path LP, which is a region surrounded by the inner peripheral surface 31 of the outer cylindrical shaft 30 and the outer peripheral surface 36 of the inner cylindrical shaft 35, into the balloon 25. The supplied liquid can be promoted toward the heating member 40, and the diffusion efficiency of the liquid around the heating member 40 can be improved.

As described above, according to this embodiment, the balloon catheter 15 includes the balloon 25 , the catheter shaft 28 , the temperature sensor 45 , the heating member 40 and the relative movement restricting member 90 . The catheter shaft 28 has an outer tube shaft 30 connected to the proximal end 25 b of the balloon 25 and an inner tube shaft 35 extending into the balloon 25 and connected to the distal end 25 b of the balloon 25 . The inner cylinder shaft 35 passes through the outer cylinder shaft 30 . A gap between the inner cylinder shaft 35 and the outer cylinder shaft 30 forms a liquid feed path LP leading to the internal space of the balloon 25 . The temperature sensor 45 is arranged between the outer cylinder shaft 30 and the inner cylinder shaft 35 . The heating member 40 is arranged on the outer peripheral surface of the inner cylinder shaft 35 inside the balloon 25 and heats the liquid inside the balloon 25 . The relative movement limiting member 90 limits relative movement of the outer barrel shaft 30 with respect to the inner barrel shaft 35 in the direction in which the distal end 30 a of the outer barrel shaft 30 approaches the heating member 40 .

According to such a balloon catheter 15, even if the balloon 25 is pressed against the target site during ablation, the sheath shaft 30 is prevented from coming too close to the heating member. As a result, when liquid is discharged from the balloon 25 by the stirrer 75, the liquid flowing along the surface of the balloon 25 is easily drawn into the liquid feed path LP, and the temperature sensor 45 detects the actual surface temperature of the balloon 25. can measure liquid temperatures close to . As a result, the deviation between the actual surface temperature of the balloon 25 and the estimated surface temperature based on the temperature actually measured by the temperature sensor 45 can be suppressed. As a result, the surface temperature of the balloon 25 can be accurately estimated.

Moreover, in the balloon catheter 15 according to the present embodiment, the relative movement restricting member 90 is configured such that the distance between the distal end 30a of the outer tube shaft 30 and the proximal end 40b of the heating member 40 is 3 mm or more. It limits relative movement of the shaft 30 with respect to the inner cylinder shaft 35 . In this case, it is possible to effectively prevent the temperature difference between the estimated surface temperature of the balloon 25 and the actual surface temperature from becoming too large, and the surface temperature of the balloon 25 can be estimated with high accuracy.

Moreover, in the balloon catheter 15 according to the present embodiment, the relative movement restricting member 90 is fixed to the outer tube shaft 30 and extends into the balloon 25 . The relative movement of the outer cylinder shaft 30 and the inner cylinder shaft 35 is restricted by the relative movement restricting member 90 coming into contact with the heating member 40 . Such a relative movement restricting member 90 can prevent the outer tube shaft 30 from coming too close to the heating member 40 when the balloon 25 is pressed against the target site during ablation.

In addition, in the balloon catheter 15 according to the present embodiment, the relative movement restricting member 90 is provided on the outer peripheral surface of the inner cylindrical shaft 35 and the inner peripheral surface of the outer cylindrical shaft 30 at the connection portion between the liquid feeding path LP and the internal space of the balloon 25. has a portion 92 extending toward the outer peripheral surface of the inner cylindrical shaft 35 such that they are spaced apart from each other along the entire circumference of the outer peripheral surface and the inner peripheral surface. According to such a relative movement restricting member 90, the liquid heated by the heating member 40 can be stably and efficiently diffused, and the surface of the balloon 25 can be efficiently heated.

Moreover, in the balloon catheter 15 according to the present embodiment, the relative movement restricting member 90 is fixed to the outer peripheral surface of the inner cylinder shaft 35 inside the balloon 25 . Relative movement of the outer barrel shaft 30 with respect to the inner barrel shaft 35 is limited by the contact of the distal end 30 a of the outer barrel shaft 30 with the relative movement limiting member 90 . Such a relative movement restricting member 90 can also prevent the outer tube shaft 30 from coming too close to the heating member 40 when the balloon 25 is pressed against the target site during ablation.

Moreover, in the balloon catheter 15 according to the present embodiment, the relative movement restricting member 90 includes a first restricting member 94 fixed to the inner peripheral surface of the outer cylindrical shaft 30 and a first restricting member 94 fixed to the outer peripheral surface of the inner cylindrical shaft 35 . 2 limiting member 95 . Relative movement of the outer cylinder shaft 30 with respect to the inner cylinder shaft 35 is restricted by the contact of the first restricting member 94 with the second restricting member 95 . Such a relative movement restricting member 90 can also prevent the outer tube shaft 30 from coming too close to the heating member 40 when the balloon 25 is pressed against the target site during ablation.

Moreover, in the balloon catheter 15 according to the present embodiment, the heating member 40 is arranged within a range obtained by projecting the internal volume of the outer tube shaft 30 from the central axis 35X direction of the inner tube shaft 35 . According to such a balloon catheter 15, the liquid supplied into the balloon 25 from the region (liquid feed path LP) surrounded by the inner peripheral surface 31 of the outer cylindrical shaft 30 and the outer peripheral surface 36 of the inner cylindrical shaft 35 is It is possible to promote the movement toward the heating member 40 and improve the diffusion efficiency of the liquid around the heating member 40 .

Further, in the balloon catheter 15 according to the present embodiment, the distance DX from the distal end 30a of the outer tube shaft 30 to the temperature sensor 45 is 5 mm or more and 150 mm or less. In this case, the liquid flowing along the surface of the balloon 25 stably reaches the temperature sensor 45 when the stirring device 75 discharges the liquid from the inside of the balloon 25, and the temperature sensor 45 detects the actual surface temperature of the balloon 25. can stably measure liquid temperatures close to

In addition, the balloon catheter system 10 according to the present embodiment includes the balloon catheter 15, a supply device 74 that supplies liquid to the liquid feed path LP, a liquid supply to the liquid feed path LP and a liquid discharge from the liquid feed path LP. and a control device 70 that is electrically connected to the heating member 40 and applies electrical energy to the heating member 40 .

Such a balloon catheter system 10 prevents the sheath shaft 30 from getting too close to the heating element even if the balloon 25 is pressed against the target site during ablation. As a result, when liquid is discharged from the balloon 25 by the stirrer 75, the liquid flowing along the surface of the balloon 25 is easily drawn into the liquid feed path LP, and the temperature sensor 45 detects the actual surface temperature of the balloon 25. can measure the temperature of liquids close to As a result, the surface temperature of the balloon 25 can be accurately estimated.

In addition, in the balloon catheter system 10 according to the present embodiment, the control device 70 may control to apply electrical energy to the heating member 40 based on the temperature information acquired by the temperature sensor 45 .

The above-described embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof. Moreover, it is of course possible to partially appropriately combine the above-described embodiments and their modifications within the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be used for a balloon catheter system and a balloon catheter for treating arrhythmia such as atrial fibrillation, endometriosis, cancer, and the like.

DESCRIPTION OF SYMBOLS 10... Catheter system 15... Balloon catheter 25... Balloon 30... Outer cylinder shaft 30X... Central axis line of outer cylinder shaft 35... Inner cylinder shaft 35X... Axis of inner cylinder shaft 40 Heating member 45 Temperature sensor 50 Handle 70 Control device 75 Stirring device 90 Relative movement limiting member , 91...limiting element, 92...portion extending toward the outer peripheral surface of the inner cylindrical shaft 35, 93...limiting element, 94...first limiting member, 95...second limiting member, LP: liquid feed path

Claims (9)

a balloon, a catheter shaft, a temperature sensor, a heating member, and a relative movement limiting member;
The catheter shaft has an outer cylinder shaft connected to the proximal end of the balloon, and an inner cylinder shaft extending into the balloon and connected to the distal end of the balloon. A gap between the inner cylinder shaft and the outer cylinder shaft that passes through the outer cylinder shaft forms a liquid feeding path leading to the inner space of the balloon,
The temperature sensor is arranged between the outer cylinder shaft and the inner cylinder shaft,
The heating member is arranged on the outer peripheral surface of the inner cylinder shaft in the balloon and heats the liquid in the balloon,
The balloon catheter, wherein the relative movement limiting member limits relative movement of the outer barrel shaft with respect to the inner barrel shaft in a direction in which the distal end of the outer barrel shaft approaches the heating member. The relative movement restricting member restricts the relative movement of the outer cylinder shaft with respect to the inner cylinder shaft so that the distance between the distal end of the outer cylinder shaft and the proximal end of the heating member is 3 mm or more. The balloon catheter of claim 1. the relative movement restricting member is fixed to the outer tube shaft and extends into the balloon;
3. The balloon catheter according to claim 1 or 2, wherein relative movement of said outer barrel shaft with respect to said inner barrel shaft is limited by contact of said relative movement limiting member with said heating member. The relative movement restricting member is such that the outer peripheral surface of the inner cylinder shaft and the inner peripheral surface of the outer cylinder shaft are formed on the entire circumference of the outer peripheral surface and the inner peripheral surface at the connection portion between the liquid feeding path and the internal space of the balloon. 4. The balloon catheter of claim 3, having portions extending toward the outer peripheral surface of the inner shaft so as to be spaced apart from one another over the entire length of the catheter. The relative movement restricting member is fixed to the outer peripheral surface of the inner cylinder shaft inside the balloon,
3. The balloon catheter according to claim 1 or 2, wherein relative movement of said outer barrel shaft with respect to said inner barrel shaft is limited by contact of a distal end of said outer barrel shaft with said relative movement limiting member. The relative movement restricting member includes a first restricting member fixed to the inner peripheral surface of the outer cylinder shaft and a second restricting member fixed to the outer peripheral surface of the inner cylinder shaft,
3. The balloon catheter according to claim 1 or 2, wherein relative movement of said outer barrel shaft with respect to said inner barrel shaft is limited by contact of said first limitation member with said second limitation member. The balloon catheter according to any one of claims 1 to 6, wherein the heating member is arranged within a range obtained by projecting the internal volume of the outer cylindrical shaft from the central axis direction of the inner cylindrical shaft. The balloon catheter according to any one of claims 1 to 7, wherein the distance between the distal end of the outer barrel shaft and the temperature sensor is 5 to 150 mm. a balloon catheter according to any one of claims 1 to 8;
a supply device that supplies liquid to the liquid feed path;
a stirring device for stirring the liquid in the balloon by repeatedly supplying the liquid to the liquid feeding path and discharging the liquid from the liquid feeding path;
a controller electrically connected to the heating element for applying electrical energy to the heating element;
A balloon catheter system with

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