Balloon catheter and balloon catheter system

Abstract

The present invention allows for stably bringing the balloon of a balloon catheter into contact with a target site. A balloon catheter according to the present invention has a cylinder part having a cylindrical shape in a state in which the balloon is inflated to atmospheric pressure.

Description

Balloon catheter and balloon catheter system

[0001] The present invention relates to a balloon catheter and a balloon catheter system.

[0002] Catheter ablation therapy is a treatment method that uses a catheter inserted into the body to ablate a target site within the body. For example, by destroying the target site through ablation, diseases such as arrhythmia due to atrial fibrillation, endometriosis, and cancer are treated. As disclosed in Patent Document 1, Patent Document 2, and Non-Patent Document 1, balloon catheters having a balloon at their distal end are known as catheters used in catheter ablation therapy.

[0003] Patent Document 1: Patent No. 3607231 Patent Document 2: WO2021 / 201078 Publication

[0004] Non-Patent Document 1: Takahiro Hayashi, "Research on a non-clinical evaluation model for cryoballoon ablation based on anatomical features of the left atrium and pulmonary veins," Doctoral dissertation, Graduate School of Advanced Science and Engineering, Waseda University, 2022

[0005] When the balloon catheter is inserted into the body, the balloon is deflated and stretched in the longitudinal direction of the balloon catheter. Once the balloon catheter is inserted into the body, a liquid is supplied to the balloon catheter. The balloon is inflated by the supplied liquid. The surface temperature of the balloon is controlled by adjusting the temperature of the liquid inside the balloon. By contacting the balloon, which has been adjusted to a predetermined surface temperature, with a circumferential target region, for example, a connection region of a vein to the atrium, the circumferential target region can be ablated in one go.

[0006] In ablation treatment using a balloon catheter, it is important to control the surface temperature of the balloon, the contact of the balloon with the target site, and the ablation time. In Patent Document 2, the temperature of the liquid inside the balloon is controlled by a temperature sensor placed in the liquid path of the balloon catheter. The contact of the balloon with the target site is confirmed by X-ray images during ablation treatment.

[0007] Even when ablation treatment is performed by monitoring the balloon surface temperature and the contact of the balloon with the target site using the above-described method, and by managing the ablation time, there are cases where ablation treatment needs to be repeated. The present inventors investigated this phenomenon and found that it is difficult to accurately determine the presence or absence of contact between the catheter and the target site using X-ray images. After further investigation, the present inventors discovered that a balloon with a different shape than conventional balloons can stably ensure contact between the catheter and the target site.

[0008] The present invention is based on this finding of the present inventors, and has an object to bring the balloon of a balloon catheter into more stable contact with the target site.

[0009] <1> A balloon catheter comprising a balloon, an outer cylindrical shaft connected to the proximal end of the balloon, and an inner cylindrical shaft passing through the outer cylindrical shaft, extending into the balloon, and connected to the distal end of the balloon, wherein the balloon includes a cylinder portion having a length of 15 mm or more, the cylinder portion having a cylindrical shape when the balloon is inflated to atmospheric pressure. <2> The balloon catheter according to <1>, wherein the length of the cylinder portion is 15 mm or more and 40 mm or less. <3> The balloon catheter according to <1> or <2>, wherein the maximum width of the cylinder portion is 15 mm or more and 40 mm or less. <4> The balloon catheter according to any of <1> to <3>, wherein the ratio of the length of the cylinder portion to the maximum width of the cylinder portion is 0.50 or more and 1.4 or less. <5> The balloon catheter according to any of <1> to <4>, wherein the length of the balloon from the distal end of the balloon to the cylinder portion is 0.5 mm or more and 30 mm or less. <6> The balloon catheter according to any one of <1> to <5>, wherein the length of the balloon is 20 mm or more and 50 mm or less. <7> The balloon catheter according to any one of <1> to <6>, wherein the width of the cylinder portion gradually decreases from the distal side to the proximal side. <8> The balloon catheter according to any one of <1> to <7>, wherein the cylinder portion has a minimum width at a middle portion and the width of the cylinder portion gradually increases from the middle portion to the proximal side, and the width of the cylinder portion gradually increases from the middle portion to the distal side. <9> The balloon catheter according to any one of <1> to <8>, wherein the balloon comprises a tip portion connected to the cylinder portion from the distal side and constituting the distal end, and a base portion connected to the cylinder portion from the proximal side and constituting the proximal end, wherein the tip portion tapers toward the distal end and the base portion tapers toward the proximal end. <10> The balloon catheter according to any one of <1> to <9>, further comprising a temperature adjustment member disposed within the balloon for heating or cooling a fluid within the balloon. <11> The balloon catheter according to any one of <1> to <10>, further comprising a temperature sensor within the balloon.<12> The balloon catheter according to any one of <1> to <11>, further comprising a temperature sensor disposed in a flow path formed between the outer tubular shaft and the inner tubular shaft and leading to the inside of the balloon. <13> A balloon catheter system comprising the balloon catheter according to any one of <1> to <12>, a supply device that supplies fluid to a flow path formed between the outer tubular shaft and the inner tubular shaft and leading to the inside of the balloon, and a stirring device that repeatedly supplies fluid to and discharges fluid from the flow path. <14> The balloon catheter system according to <13>, further comprising a temperature adjustment member for heating or cooling the fluid in the balloon, and a temperature sensor that acquires information about the temperature of the fluid, and wherein the amount of energy supplied to the temperature adjustment member is adjusted based on the information about the temperature acquired by the temperature sensor.

[0010] According to the present invention, the balloon of the balloon catheter can be brought into more stable contact with the target site.

[0011] 1 is a diagram for explaining an embodiment, showing an example of a balloon catheter system and a balloon catheter. 1 is a diagram showing the distal end portion of the balloon catheter of FIG. 1 with the balloon in an inflated state. 2 is a diagram showing the distal end portion of the balloon catheter of FIG. 1 with the balloon in a deflated and extended state. 3 is a cross-sectional view taken along line IV-IV of FIG. 2. 4 is a diagram showing an example of a balloon. 5 is a diagram showing another example of a balloon. 6 is a diagram showing yet another example of a balloon. 7 is a diagram showing yet another example of a balloon. 8 is a diagram showing yet another example of a balloon. 9 is a diagram showing yet another example of a balloon. 10 is a diagram showing yet another example of a balloon. 11 is a diagram showing yet another example of a balloon. 12 is a diagram showing yet another example of a balloon. 13 is a diagram showing yet another example of a balloon. 14 is a diagram showing yet another example of a balloon. 15 is a diagram showing yet another example of a balloon. Graph showing test results using pulmonary vein model B. Graph showing test results using pulmonary vein model B. Graph showing test results using pulmonary vein model B. Graph showing test results using pulmonary vein model B. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C. Graph showing test results using pulmonary vein model C.

[0012] An embodiment of the present disclosure will be described below with reference to the drawings. In the drawings accompanying this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for ease of understanding. Configurations shown in some drawings may be omitted in other drawings. The scale and aspect ratios may differ between the drawings.

[0013] In this specification, terms that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," and "identical," as well as values ​​of lengths and angles, are not limited to their strict meanings, but are interpreted to include a range within which similar functions can be expected.

[0014] 1 includes a balloon catheter 15, a feeding device 74, and an agitation device 75 connected to the balloon catheter 15. In the illustrated example, the balloon catheter 15 includes a catheter body 20 having a longitudinal direction LD, and a handle 50 connected to the proximal end of the catheter body 20.

[0015] Figure 2 shows the distal end portion of the balloon catheter of Figure 1. Figure 2 shows the balloon 25 in an inflated state. The catheter body 20 includes the balloon 25, an outer cylindrical shaft 30 connected to the proximal end 25b of the balloon 25, and an inner cylindrical shaft 35 connected to the distal end 25a of the balloon 25. The inner cylindrical shaft 35 passes through the outer cylindrical shaft 30 and extends into the balloon 25. A flow path LP is formed between the outer cylindrical shaft 30 and the inner cylindrical shaft 35. The flow path LP communicates with the interior space of the balloon 25. The flow path LP functions as a fluid flow path. Fluid is supplied into the balloon 25 through the flow path LP.

[0016] In the illustrated example, the catheter body 20 further includes a temperature adjustment member 40 and a temperature sensor 45. The temperature adjustment member 40 heats or cools the fluid. The temperature sensor 45 obtains information about the temperature of the fluid.

[0017] The fluid may be either a liquid or a gas as long as it functions as a heat exchange medium, and is preferably a liquid.

[0018] The longitudinal direction LD of the catheter main body 20 is specified as the direction in which the central axis of the inner cylindrical shaft 35 extends. Furthermore, in this specification, the "distal" side used with respect to each component of the balloon catheter 15 and the catheter main body 20 means the side away from the operator (surgeon) of the handle 50 and the balloon catheter 15 along the longitudinal direction LD of the catheter main body 20, or in other words, the tip side. Furthermore, the "proximal" side used with respect to each component of the balloon catheter 15 and the catheter main body 20 means the side close to the operator (surgeon) of the handle 50 and the balloon catheter 15 along the longitudinal direction LD of the catheter main body 20, or in other words, the base end side.

[0019] The balloon catheter system 10 and the balloon catheter 15 will be described in further detail 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 illustrated balloon catheter 15 includes the balloon 25, the outer cylindrical shaft 30, the inner cylindrical shaft 35, the temperature adjustment member 40, and the temperature sensor 45.

[0020] The outer cylindrical shaft 30 and the inner cylindrical shaft 35 are both tubular, typically cylindrical. The outer cylindrical shaft 30 and the inner cylindrical shaft 35 each include a lumen as an internal space. A guide wire (not shown), for example, is inserted through the lumen formed by the inner cylindrical shaft 35. The inner cylindrical shaft 35 is inserted through the lumen formed by the outer cylindrical shaft 30. That is, the outer cylindrical shaft 30 and the inner cylindrical shaft 35 form a double-tube shaft. The inner diameter of the outer cylindrical shaft 30 is larger than the outer diameter of the inner cylindrical shaft 35. Therefore, a lumen exists between the outer cylindrical shaft 30 and the inner cylindrical shaft 35. This lumen between the outer cylindrical shaft 30 and the inner cylindrical shaft 35 forms a flow path LP. As shown in FIG. 2 , the flow path LP communicates with the balloon 25. The flow path LP also extends into the handle 50.

[0021] The materials used for the outer cylindrical shaft 30 and the inner cylindrical shaft 35 are not particularly limited. The outer cylindrical shaft 30 and the inner cylindrical shaft 35 may be made of a flexible material with excellent antithrombogenicity. Examples of flexible materials with excellent antithrombogenicity include fluoropolymers, polyamides, polyurethane polymers, and polyimides. The outer cylindrical shaft 30 may be made by laminating layers of different flexible materials to achieve both slidability with the inner cylindrical shaft 35 and adhesive or heat-weldability with the balloon 25.

[0022] The lengths of the outer cylindrical shaft 30 and the inner cylindrical shaft 35 may each be 500 mm or more and 1700 mm or less, or 600 mm or more and 1200 mm or less. The outer diameter of the outer cylindrical shaft 30 may be 3.0 mm or more and 4.0 mm or less. The inner diameter of the outer cylindrical shaft 30 may be 2.5 mm or more and 3.5 mm or less. The outer diameter of the inner cylindrical shaft 35 may be 1.4 mm or more and 2.0 mm or less. The inner diameter of the inner cylindrical shaft 35 may be 1.1 mm or more and 1.5 mm or less.

[0023] A balloon 25 is connected to the outer cylindrical shaft 30 and the inner cylindrical shaft 35. The balloon 25 can be expanded by filling it with a fluid and can be contracted by discharging the fluid. The balloon 25 preferably comes into contact with and fits the target site to be treated (e.g., a blood vessel). In this embodiment, the balloon 25 includes a cylinder portion 26. The shape of the balloon 25 including the cylinder portion 26 will be described later.

[0024] The thickness of the balloon 25 may be 10 μm or more and 200 μm or less. The material constituting the balloon 25 may be a stretchable material with excellent antithrombotic properties. The material constituting the balloon 25 may be a polyurethane-based polymer material or the like. Examples of polyurethane-based polymer materials that can be used for the balloon 25 include thermoplastic polyether urethane, polyether polyurethane urea, fluorine polyether urethane urea, polyether polyurethane urea resin, and polyether polyurethane urea amide.

[0025] 2 and 3 , in the illustrated catheter main body 20, the distal end (tip) 25a of the balloon 25 is fixed to the distal end (tip) 35a of the inner cylindrical shaft 35. The proximal end (base end) 25b of the balloon 25 is fixed to the distal end (tip) 30a of the outer cylindrical shaft 30. The balloon 25 may be connected to the outer cylindrical shaft 30 and the inner cylindrical shaft 35 by adhesive or thermal welding.

[0026] The balloon 25 connected to the outer cylindrical shaft 30 and the inner cylindrical shaft 35 is deformed by the relative movement of the outer cylindrical shaft 30 and the inner cylindrical shaft 35 in the longitudinal direction LD. The relative movement of the outer cylindrical shaft 30 and the inner cylindrical shaft 35 allows the size of the balloon 25 in the longitudinal direction LD to be adjusted.

[0027] Fig. 3 shows a state in which the inner cylindrical shaft 35 has moved distally relative to the outer cylindrical shaft 30 in the longitudinal direction LD. In the state shown in Fig. 3, the balloon 25 is stretched in the longitudinal direction LD. In the state shown in Fig. 3, the balloon 25 is further tensioned. In the illustrated example, the range of distal movement of the inner cylindrical shaft 35 relative to the outer cylindrical shaft 30 in the longitudinal direction LD is restricted by the balloon 25.

[0028] The balloon 25 is brought into a relaxed state by moving the inner cylindrical shaft 35 relative to the outer cylindrical shaft 30 proximally in the longitudinal direction LD from the state shown in Fig. 3. By introducing a fluid into the relaxed balloon 25, the balloon 25 can be inflated as shown in Fig. 2. In other words, the size of the balloon 25 in the longitudinal direction LD can be adjusted by moving the outer cylindrical shaft 30 and the inner cylindrical shaft 35 relative to each other.

[0029] The temperature adjustment member 40 heats or cools the fluid. As best shown in FIG. 2 , the temperature adjustment member 40 may be disposed within the balloon 25. The temperature adjustment member 40 may heat or cool the fluid within the balloon 25. The surface temperature of the balloon 25 may be adjusted by the output of the temperature adjustment member 40.

[0030] The temperature control member 40 may be, for example, a nichrome wire that generates heat through electrical resistance. Alternatively, a Peltier element may be used for cooling. As a variant, the temperature control member 40 may not be provided inside the balloon, and a cooled fluid may be transported from outside the balloon using the flow path LP.

[0031] When the balloon does not have a temperature adjustment member 40 inside and a cooled fluid is transported from outside the balloon using the flow path LP, the temperature may be adjusted by adjusting the amount of cooled gas.

[0032] 2 and 3, the temperature adjustment member 40 may be a coil electrode 41. By applying high-frequency current to the temperature adjustment member 40 serving as the coil electrode 41, a high-frequency current flows between the coil electrode 41 and an externally disposed counter electrode 77 (FIG. 1). At this time, the fluid located between the coil electrode 41 and the counter electrode 77 generates Joule heat. The counter electrode 77 is disposed, for example, on the back of the patient.

[0033] 2 and 3, the coil electrode 41 is provided on the inner cylindrical shaft 35 extending inside the balloon 25. The coil electrode 41 may be formed by a conductive wire wound around the inner cylindrical shaft 35. The coil electrode 41 is electrically connected to a wiring 42. High-frequency electricity is applied to the coil electrode 41 via the wiring 42. The wiring 42 extends to the handle 50 through a flow path LP serving as a lumen between the outer cylindrical shaft 30 and the inner cylindrical shaft 35.

[0034] A specific example of the coil electrode 41 constituting the temperature adjustment member 40 is a coil electrode formed by stripping the insulation-coated lead wire used for the wiring 42 and winding it around the inner cylindrical shaft 35. This coil electrode 41 is integrally formed with the wiring 42, and therefore can effectively prevent problems such as wire breakage.

[0035] The diameter of the coil electrode 41 and the wiring 42 may be 0.1 mm or more and 1 mm or less, or 0.1 mm or more and 0.4 mm or less. Examples of conductive materials constituting the coil electrode 41 and the wiring 42 include copper, silver, gold, platinum, and alloys thereof. As shown in FIG. 4 , the wiring 42 may include a conductive linear portion such as a metal wire and an insulating coating covering the conductive linear portion. The insulating coating can prevent short circuits of the wiring 42. Examples of materials constituting the insulating coating include fluoropolymers.

[0036] The temperature sensor 45 acquires information about the temperature of the fluid. The temperature sensor 45 may be located inside the balloon 25. Inside the balloon 25, the temperature sensor 45 may be fixed to the balloon 25, the inner cylindrical shaft 35, or the temperature adjustment member 40.

[0037] 2 , the temperature sensor 45 includes a heat-sensing element 46 disposed within the flow path LP. As described in Patent Document 2, the temperature sensor 45 can acquire information regarding the fluid temperature within the flow path LP. Based on the information acquired by the temperature sensor 45, the surface temperature of the balloon 25 can be determined with high accuracy. The surface temperature of the balloon 25 is important in ablation treatment using the balloon catheter system 10.

[0038] The length D46 along the longitudinal direction LD from the distal end 30a of the outer cylindrical shaft 30 to the heat-sensing portion 46 of the temperature sensor 45 may be determined from the viewpoint of determining the surface temperature of the balloon 25 with high accuracy. This length D46 may be determined based on the amount of fluid supplied and discharged by the agitator 75. Taking into consideration the dimensions of the balloon catheter 15 typically used in cardiac ablation treatment and the amount of fluid supplied and discharged from the agitator 75, this length D46 may be 5 mm or more and 150 mm or less, or 10 mm or more and 20 mm or less.

[0039] The temperature sensor 45 may be a thermocouple. The temperature sensor 45 may be a thermistor. The temperature sensor 45 may be a T-type thermocouple. Using a T-type thermocouple allows the heat capacity of the heat-sensing unit 46 to be reduced. Using a T-type thermocouple as the temperature sensor 45 allows the thermoelectromotive force to be stabilized. A T-type thermocouple can detect temperatures between 50°C and 80°C with high accuracy, making it suitable for cardiac ablation treatment. Information about the temperature acquired by the temperature sensor 45 is, for example, a potential acquired from a thermocouple or a resistance value acquired from a thermistor.

[0040] 2 and 3, the temperature sensor 45 may include a heat-sensing portion 46 and a lead wire 47 electrically connected to the heat-sensing portion 46. In the temperature sensor 45 as a thermocouple, the portion where the dissimilar metals are connected constitutes the heat-sensing portion 46. In the temperature sensor 45 as a thermistor, the ceramic element constitutes the heat-sensing portion 46. The lead wire 47 extends to the handle 50 through a flow path LP as a lumen between the outer cylindrical shaft 30 and the inner cylindrical shaft 35.

[0041] The diameter of the lead wires 47 may be 0.05 mm or more and 0.5 mm or less, or 0.05 mm or more and 0.3 mm or less. In the temperature sensor 45 as a thermocouple, copper may be used for one of the lead wires 47, and constantan may be used for the other lead wire 47. In this example, the heat-sensing part 46 joining the pair of lead wires 47 can function as a T-type thermocouple. To prevent short-circuiting of the pair of lead wires 47, as shown in FIG. 4, the lead wires 47 may include an electrically insulating coating such as a fluoropolymer or enamel.

[0042] 2, the temperature sensor 45 may be attached to the inner cylindrical shaft 35. In the example shown in FIG. 2, the temperature sensor 45 is attached to the inner cylindrical shaft 35 by fixing a lead wire 47 to the inner cylindrical shaft 35.

[0043] In the example shown in FIG. 2 , the wiring 42 of the temperature adjustment member 40 is not attached to either the outer cylindrical shaft 30 or the inner cylindrical shaft 35. This example is not limited to this, and the wiring 42 may be attached to either the outer cylindrical shaft 30 or the inner cylindrical shaft 35. The wiring 42 of the temperature adjustment member 40 and the lead wire 47 of the temperature sensor 45 may both be attached to the same one of the outer cylindrical shaft 30 and the inner cylindrical shaft 35. This specific example effectively prevents the wiring 42 and the lead wire 47, which both extend through the flow path LP, from becoming entangled when the outer cylindrical shaft 30 and the inner cylindrical shaft 35 move relative to each other. This allows the temperature adjustment member 40 to stably adjust the temperature of the fluid in the balloon 25 and stably grasp the surface temperature of the balloon 25.

[0044] 3 , when the inner cylindrical shaft 35 has moved to the distal end in the longitudinal direction LD relative to the outer cylindrical shaft 30 to the maximum extent possible so that the balloon 25 is expanded, the temperature sensor 45 may be located inside the outer cylindrical shaft 30. According to this specific example, the temperature sensor 45 is located inside the outer cylindrical shaft 30, regardless of the relative position of the inner cylindrical shaft 35 with respect to the outer cylindrical shaft 30. Therefore, the temperature sensor 45 can be stably protected by the outer cylindrical shaft 30, regardless of the relative position of the inner cylindrical shaft 35 with respect to the outer cylindrical shaft 30.

[0045] On the other hand, unlike the illustrated example, the temperature sensor 45 may be attached to the outer cylindrical shaft 30. For example, the lead wires 47 of the temperature sensor 45 may be fixed to the inner surface of the outer cylindrical shaft 30. According to this specific example, the temperature sensor 45 is located inside the outer cylindrical shaft 30, regardless of the relative position of the inner cylindrical shaft 35 with respect to the outer cylindrical shaft 30. Therefore, the temperature sensor 45 can be stably protected by the outer cylindrical shaft 30, regardless of the relative position of the inner cylindrical shaft 35 with respect to the outer cylindrical shaft 30.

[0046] The handle 50 is connected to the catheter main body 20 described above from the proximal side. The handle 50 is the part that is grasped by the operator (surgeon) while using the balloon catheter system 10. Therefore, the handle 50 may have a design that makes it easy for the operator to grasp and operate it with their hands. The material that constitutes the handle 50 is preferably a material with high chemical resistance. Examples of materials that constitute the handle 50 include polycarbonate and ABS resin.

[0047] 1 , the handle 50 may include a first handle portion 51 and a second handle portion 52 that are slidable relative to each other. The first handle portion (front handle portion) 51 is connected to the outer cylindrical shaft 30 of the catheter main body 20. The second handle portion (rear handle portion) 52 is connected to the inner cylindrical shaft 35 of the catheter main body 20. By moving the second handle portion 52 relative to the first handle portion 51, the inner cylindrical shaft 35 can be moved relative to the outer cylindrical shaft 30.

[0048] 1, the handle 50 also functions as a portion for connecting the balloon catheter 15 to other devices included in the balloon catheter system 10. As described above, in addition to the balloon catheter 15, the balloon catheter system 10 includes a supply device 74 and a stirring device 75. As shown in FIG. 1, the balloon catheter system 10 may further include a control device 70.

[0049] The supply device 74 supplies fluid to the flow path LP. The supply device 74 can supply fluid to the balloon 25 via the flow path LP. As shown in FIG. 2, the balloon 25 expands when fluid is supplied. The supply device 74 can also discharge fluid from the balloon 25 via the flow path LP. The balloon 25 contracts when fluid is discharged, as shown in FIG. 3. If the fluid supplied into the flow path LP is a liquid, it may be physiological saline. As shown in FIG. 1, an example of the supply device 74 is a syringe. However, the supply device 74 is not limited to a syringe and may be a pump or the like.

[0050] The agitator 75 agitates the fluid within the balloon 25. By agitating the fluid within the balloon 25, the heat supplied to the balloon 25 can be dispersed or uniformized, thereby adjusting the surface temperature of the balloon 25. The agitator 75 repeatedly supplies fluid to the flow path LP and discharges fluid from the flow path LP. Examples of the agitator 75 include a roller pump, a diaphragm pump, a bellows pump, a vane pump, a centrifugal pump, and a pump formed by a combination of a piston and a cylinder.

[0051] The amount of fluid supplied to the flow path LP and the amount of fluid discharged from the flow path LP may be constant. The amount of fluid supplied to the flow path LP and the amount of fluid discharged from the flow path LP may be 0.1 ml or more and 1.5 ml or less. The supply of fluid to the flow path LP and the discharge of fluid from the flow path LP may be repeated at a constant cycle. The supply of fluid to the flow path LP and the discharge of fluid from the flow path LP may be repeated once to five times per second. The amount of fluid supplied to the flow path LP and the amount of fluid discharged from the flow path LP may be adjusted by a control signal from the agitator control unit 70C described below or by direct input from the operator. The cycle of the supply of fluid to the flow path LP and the discharge of fluid from the flow path LP may be adjusted by a control signal from the agitator control unit 70C described below or by direct input from the operator.

[0052] The control device 70 may be electrically connected to the coil electrode 41 via wiring 42. In the illustrated example, the control device 70 includes a high-frequency current control unit 70A. The high-frequency current control unit 70A controls the application of high-frequency current to the coil electrode 41. The high-frequency current control unit 70A controls the application of high-frequency current to the coil electrode 41, and adjusts the output from the temperature adjustment member 40. The high-frequency current control unit 70A may control the application of high-frequency current to the coil electrode 41 based on the surface temperature of the balloon 25 determined by the temperature calculation unit 70B, or in accordance with preset processing, or in accordance with input from the operator.

[0053] The control device 70 may be electrically connected to the lead wire 47 of the temperature sensor 45. In the illustrated example, the control device 70 includes a temperature calculation unit 70B. The control device 70 includes the temperature calculation unit 70B that calculates information related to the temperature acquired by the inner cylindrical shaft 35. The temperature calculation unit 70B calculates the temperature of the fluid in the flow path LP based on the information related to the temperature acquired by the temperature sensor 45. The temperature calculation unit 70B may estimate the surface temperature of the balloon 25 based on the calculated fluid temperature. The temperature calculation unit 70B may display the identified surface temperature of the balloon 25 on the display unit 71.

[0054] The control device 70 may include an agitator control unit 70C that controls the agitator 75. The agitator control unit 70C may display the control conditions of the agitator 75 on the display unit 71.

[0055] The control device 70 is configured with hardware such as a CPU, for example. One or more of the high-frequency current control unit 70A, the temperature calculation unit 70B, and the stirring device control unit 70C included in the control device 70 may be configured as separate hardware, or at least a portion of them may be shared. At least a portion of the control device 70 may be configured with software. A portion of the control device 70 may be physically located separately. Some of the components of the control device 70 may be able to cooperate with other components by communication through a network. Some of the components of the control device 70 may be a device that can communicate with other components through an external network, and may be, for example, a server or database on a cloud.

[0056] Next, an example of how to use the balloon catheter system 10 configured as above will be described.

[0057] First, the supply device 74 is connected to the flow path LP of the catheter main body 20 via the handle 50. The supply device 74 is then operated to introduce fluid into the flow path LP, filling the balloon and the flow path LP with fluid. Next, the inner cylindrical shaft 35 is moved distally (toward the tip) relative to the outer cylindrical shaft 30 in the longitudinal direction LD, thereby expanding the balloon 25 as shown in FIG. 3 . At this time, the outer cylindrical shaft 30 and the inner cylindrical shaft 35 can be moved relative to each other by operating the first handle portion 51 and the second handle portion 52 of the handle 50. The catheter main body 20 with the balloon 25 expanded is then inserted into the body.

[0058] Once the distal end of the catheter body 20 has been guided to the vicinity of the target site (affected area), the inner cylindrical shaft 35 is moved proximally (toward the base end) relative to the outer cylindrical shaft 30 in the longitudinal direction LD to relax the balloon 25. Next, the supply device 74 is operated to introduce fluid into the flow path LP, thereby inflating the balloon 25 with the fluid, as shown in FIG.

[0059] Thereafter, the supply device 74 is disconnected from the flow path LP, and the agitator 75 is connected to the flow path LP. The operation of the agitator 75 is controlled by a control signal from the agitator control unit 70C of the control device 70. The agitator 75 repeatedly supplies a fixed amount of fluid to the flow path LP and discharges a fixed amount of fluid from the flow path LP at a fixed cycle. As a result, the discharge of a fixed amount of fluid from the flow path LP into the balloon 25 and the suction of a fixed amount of fluid from the balloon 25 into the feed flow path LP are repeated at a fixed cycle. This causes the fluid inside the balloon 25 to be agitated.

[0060] Furthermore, the temperature adjustment member 40 is controlled by a high-frequency current control unit 70A of the control device 70 to adjust the temperature of the fluid in the balloon 25. Specifically, a voltage is applied from the control device 70 between the coil electrode 41 constituting the temperature adjustment member 40 and a counter electrode 77 disposed 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 fluid and contrast agent around the coil electrode 41 are heated by Joule heating.

[0061] Furthermore, in the illustrated example, the temperature sensor 45 is disposed not in the balloon 25 but in the outer cylindrical shaft 30. The thickness of the outer cylindrical shaft 30 is significantly greater than the thickness of the balloon 25. Therefore, the temperature sensor 45 can be effectively shielded from high-frequency current by the outer cylindrical shaft 30. This effectively prevents the temperature sensor 45 and the fluid around the temperature sensor 45 from being affected by the high-frequency current and experiencing a local temperature rise. In other words, the temperature sensor 45 can be prevented from detecting an abnormal value.

[0062] In this manner, the fluid in the balloon 25 is heated and stirred. The balloon 25 containing the heated fluid is then brought into contact with the target site to ablate the target site. During ablation, the temperature sensor 45 disposed in the flow path LP acquires information regarding the temperature of the fluid in the flow path LP. The acquired information is calculated by the temperature calculation unit 70B of the control device 70. The temperature calculation unit 70B may simply determine the temperature of the fluid in the region where the heat-sensing unit 46 of the temperature sensor 45 is disposed, and may also determine the surface temperature of the balloon 25. The surface temperature of the balloon 25 determined by the temperature calculation unit 70B may be displayed on the display unit 71.

[0063] When ablation of the target area is complete, the energy supply to the temperature adjustment member 40 is stopped. The supply device 74 is then connected to the flow path LP of the catheter main body 20 via the handle 50, and the agitator 75 is disconnected from the flow path LP. The supply device 74 is then used to discharge fluid from the flow path LP, thereby deflating the balloon 25. Next, the second handle portion 52 is operated to expand the deflated balloon 25, as shown in FIG. 3 . The catheter main body 20, with the balloon 25 in an expanded state, is then removed from the body. This completes the procedure using the balloon catheter system 10.

[0064] As described above, by using the balloon catheter system 10 including the temperature sensor 45, the operator (surgeon) can accurately grasp the surface temperature of the balloon 25 during ablation treatment. The operator (surgeon) performs ablation treatment while confirming contact of the balloon with the target site using X-ray images. After confirming contact of the balloon with the target site using X-ray images, the operator (surgeon) manages the balloon's surface temperature and ablation time to perform ablation treatment. In such ablation treatment, the balloon's surface temperature, contact of the balloon with the target site, and ablation time are managed. A sufficient therapeutic effect can be expected from such ablation treatment.

[0065] However, even when ablation treatment is performed by monitoring the balloon surface temperature and contact with the target site using the above-described method and managing the ablation time, there are cases where ablation treatment is required again. The present inventors investigated this phenomenon and found that it is difficult to accurately determine whether or not the catheter is in contact with the target site based on X-ray images, and that treatment may be performed without sufficient contact between the catheter and the target site. After further investigation, the present inventors discovered that a balloon shape other than the conventionally used spherical shape can ensure stable contact between the catheter and the target site.

[0066] The shape of the balloon 25 according to this embodiment will be described below. The balloon 25 according to this embodiment allows the catheter 25 to come into more stable contact with the cylindrical target site.

[0067] As shown in FIG. 5A , the balloon 25 includes a cylinder portion 26. The cylinder portion 26 has a cylindrical shape when the balloon 25 is inflated to atmospheric pressure. The length of the cylinder portion 26 in the longitudinal direction LD is 15 mm or more. A balloon 25 including a cylinder portion 26 with a length of 15 mm or more can more stably ensure contact between the catheter and the cylindrical target site in the annular region. In addition, a balloon 25 including a cylinder portion 26 with a length of 15 mm or more can prevent the balloon 25 from slipping out of the cylindrical target site. A balloon 25 including a cylinder portion 26 with a length of 15 mm or more can more accurately determine whether the balloon 25 is in contact with the cylindrical target site in the annular region.

[0068] The state in which the balloon 25 is inflated to atmospheric pressure refers to a state in which air is introduced into the balloon 25 under atmospheric pressure from a deflated state of the balloon 25 until the internal pressure of the balloon 25 reaches 1 atmosphere. When the balloon 25 is inflated to atmospheric pressure, the relative movement of the outer cylindrical shaft 30 and the inner cylindrical shaft 35 in the longitudinal direction LD is not restricted but is allowed.

[0069] A cylindrical shape means that the maximum width change rate is 4.0% or less. The maximum width change rate is the ratio of the difference between the maximum width and the minimum width of the cylinder portion 26 to the maximum width. The maximum width change rate is expressed in "%". The maximum width change rate (%) is expressed as "Maximum width change rate = ((maximum width - minimum width) / maximum width) x 100".

[0070] The width W26 of the cylinder portion 26 (see FIG. 5A ) is the length (mm) in the direction perpendicular to the longitudinal direction LD. In an example in which the cylinder portion 26 is cylindrical, the width of the cylinder portion 26 is the diameter. The width W26 of the cylinder portion 26 is measured when the balloon 25 is inflated with air to atmospheric pressure.

[0071] By setting an upper limit on the maximum rate of change in width of the cylindrical portion 26 when the balloon 25 is inflated to atmospheric pressure, the balloon 25 can be brought into more stable contact with the target site compared to conventional spherical balloons. In addition, by setting an upper limit on this maximum rate of change, the balloon 25 can be prevented from slipping out of the cylindrical target site. By setting an upper limit on this maximum rate of change, contact of the balloon 25 with the cylindrical target site in the annular region can be more accurately determined compared to conventional spherical balloons.

[0072] There is no particular lower limit for the maximum rate of change in width of the cylinder portion 26 when the balloon 25 is inflated to atmospheric pressure. The maximum rate of change in width may be 0%, and the outer surface of the balloon 25 at the cylinder portion 26 may extend in the longitudinal direction LD. The outer surface of the balloon 25 at the cylinder portion 26 may be parallel to the longitudinal direction LD.

[0073] The maximum rate of change in width of the cylinder portion 26 when the balloon 25 is inflated to atmospheric pressure is 0% or more and 4.0% or less, or may be 0% or more and 3.5% or less, or 0% or more and 3.0% or less, or 0% or more and 2.5% or less, or may be 0% or more and 2.0% or less.

[0074] The length L26 of the cylinder portion 26 is the length of the cylinder portion 26 in the longitudinal direction LD. The length L26 of the cylinder portion 26 in the longitudinal direction LD may have a lower limit. By setting a lower limit for this length L26, the balloon 25 can be more stably brought into contact with the target site compared to conventional balloons having a spherical shape. In addition, by setting a lower limit for this length L26, it is possible to prevent the balloon 25 from slipping out of the cylindrical target site. By setting a lower limit for this length L26, it is possible to more accurately determine the contact of the balloon 25 with the cylindrical target site in the annular region compared to conventional balloons having a spherical shape.

[0075] The length L26 of the cylinder portion 26 in the longitudinal direction LD may have an upper limit. By setting an upper limit on the length L26, it is possible to prevent the balloon 25 and the balloon catheter 15 from becoming larger.

[0076] The length L26 of the cylinder portion 26 in the longitudinal direction LD is 15 mm to 40 mm, and may be 18 mm to 40 mm, 20 mm to 40 mm, or 25 mm to 35 mm. The length L26 of the cylinder portion 26 in the longitudinal direction LD is measured when the balloon 25 is inflated with air to atmospheric pressure.

[0077] The maximum value of the width W26 of the cylinder portion 26 may have a lower limit. By setting a lower limit on the maximum value of the width W26 of the cylinder portion 26, the balloon 25 can be brought into more stable contact with the target site. In addition, by setting a lower limit on the maximum value of the width W26 of the cylinder portion 26, it is possible to prevent the balloon 25 from slipping out of the cylindrical target site. By setting a lower limit on the maximum value of the width W26 of the cylinder portion 26, it is possible to more accurately determine the contact of the balloon 25 with the cylindrical target site in the annular region, compared to conventional balloons having a spherical shape.

[0078] The maximum value of the width W26 of the cylinder portion 26 may have an upper limit. By setting an upper limit on the maximum value of the width W26 of the cylinder portion 26, it is possible to prevent the balloon 25 and the balloon catheter 15 from becoming larger.

[0079] The maximum width W26 of the cylinder portion 26 is 15 mm to 40 mm, or may be 20 mm to 35 mm, or 25 mm to 30 mm. The maximum width W26 of the cylinder portion 26 is the maximum width measured when the balloon 25 is inflated with air to atmospheric pressure.

[0080] The ratio of the length L26 of the cylinder portion 26 to the maximum width W26 of the cylinder portion 26 (= L26 / maximum width W26) may have upper and lower limits. By setting upper and lower limits on the ratio (= L26 / maximum width W26), it is possible to more reliably prevent the balloon 25 from slipping out of the cylindrical target site compared to conventional spherical balloons. This ratio (= L26 / maximum width W26) may be 0.50 to 1.4, 0.60 to 1.3, 0.65 to 1.2, or 0.70 to 1.15.

[0081] The length L27 from the distal end 25a of the balloon 25 to the cylinder portion 26 may have an upper limit. This length L27 is the length in the longitudinal direction LD. Setting an upper limit on this length L27 makes it easier to position the cylinder portion 26 of the balloon 25 relative to the target site. Setting an upper limit on this length L27 makes it possible to prevent the balloon 25 from becoming larger. No lower limit is particularly set for the length L27 from the distal end 25a of the balloon 25 to the cylinder portion 26.

[0082] The length L27 from the distal end 25a of the balloon 25 to the cylinder portion 26 is 0.5 mm or more and 30 mm or less, or may be 1 mm or more and 20 mm or less, 2 mm or more and 15 mm or less, or 3 mm or more and 15 mm or less. Note that the length L27 from the distal end 25a of the balloon 25 to the cylinder portion 26 is the length in the longitudinal direction LD measured when the balloon 25 is inflated with air to atmospheric pressure.

[0083] The length L25 of the balloon 25 is the length in the longitudinal direction LD of the balloon 25. The length L25 of the balloon 25 may be 20 mm or more and 50 mm or less, 20 mm or more and 40 mm or less, 25 mm or more and 40 mm or less, or 25 mm or more and 30 mm or less. Note that the length L25 of the balloon 25 is the length in the longitudinal direction LD measured when the balloon 25 is inflated with air to atmospheric pressure.

[0084] As shown in FIG. 5A, the balloon 25 may include at least one of a distal end portion 27 and a proximal end portion 28 in addition to the cylinder portion 26 .

[0085] The tip portion 27 connects to the cylinder portion 26 from the distal side in the longitudinal direction LD. The tip portion 27 may be adjacent to the cylinder portion 26. The tip portion 27 may constitute the distal end 25a of the balloon 25. The width of the tip portion 27 (the length in a direction perpendicular to the longitudinal direction LD) may taper toward the distal end 25a in the longitudinal direction LD. A tip portion 27 that tapers toward the distal end 25a makes it easier to insert the catheter body 20 into the body. A tip portion 27 that tapers toward the distal end 25a makes it easier to guide the catheter 25 toward a target site.

[0086] The proximal end 28 connects to the cylinder portion 26 from the proximal side in the longitudinal direction LD. The proximal end 28 may be adjacent to the cylinder portion 26. The proximal end 28 may constitute the proximal end 25b of the balloon 25. The width of the proximal end 28 (the length in a direction perpendicular to the longitudinal direction LD) may taper toward the proximal end 25b in the longitudinal direction LD. A proximal end 28 that tapers toward the proximal end 25b can more effectively prevent the balloon 25 from slipping out of the tubular target site. A proximal end 28 that tapers toward the proximal end 25b can prevent the catheter 25 from becoming too large, improving the maneuverability of the balloon 25 inside the body. A proximal end 28 that tapers toward the proximal end 25b can make it easier to remove the catheter body 20 from the body.

[0087] As shown in Figure 5B, the balloon 25 may or may not include a distal end 27 with a short length. As shown in Figure 5C, the balloon 25 may or may not include a proximal end 28 with a short length. As shown in Figure 5D, the balloon 25 may or may not include both a distal end 27 and a proximal end 28 with a short length.

[0088] As shown in FIGS. 6A and 6B, the width W26 of the cylinder portion 26 may vary along the longitudinal direction LD, with the maximum rate of change in width being 4.0% or less.

[0089] 6A , the cylinder portion 26 has a minimum width W26 at an intermediate portion 26c in the longitudinal direction LD. The width W26 of the cylinder portion 26 increases from the intermediate portion 26c toward the distal side in the longitudinal direction LD. The width W26 of the cylinder portion 26 may have a maximum width at a distal end portion 26a in the longitudinal direction LD. The width W26 of the cylinder portion 26 increases from the intermediate portion 26c toward the proximal side in the longitudinal direction LD. The width W26 of the cylinder portion 26 may have a maximum width at a base end portion 26b in the longitudinal direction LD.

[0090] Note that, "the width W26 increasing toward the distal side (or the proximal side) in the longitudinal direction LD" means that the width W26 does not have to change in some regions in the longitudinal direction LD. "The width W26 increasing toward the distal side (or the proximal side) in the longitudinal direction LD" means that the width W26 changes so as not to decrease toward the distal side (proximal side).

[0091] In the example shown in Fig. 6B, the width W26 of the cylinder portion 26 decreases from the distal side to the proximal side in the longitudinal direction LD. In the example shown in Fig. 6B, the width W26 of the cylinder portion 26 has a maximum value at the tip end 26a in the longitudinal direction LD. The width W26 of the cylinder portion 26 has a minimum value at the base end 26b in the longitudinal direction LD.

[0092] Note that, "the width W26 becomes smaller from the distal side to the proximal side in the longitudinal direction LD" means that the width W26 does not have to change in some regions in the longitudinal direction LD. "The width W26 becomes smaller from the distal side to the proximal side in the longitudinal direction LD" means that the width W26 changes so as not to become larger toward the proximal side.

[0093] 6A and 6B, it is possible to reduce the volume of the balloon 25. It is also possible to reduce the amount of heat required for heating or cooling using the temperature adjustment member 40.

[0094] Here, some of the results of tests conducted by the present inventors to confirm the effects of this embodiment will be described. In the following tests, the pulmonary vein leading to the left atrium was assumed to be the target site for ablation treatment. Multiple balloons with different shapes were fabricated. The fabricated balloons were used to construct the balloon catheter system shown in Figures 1 to 4. Using the resulting balloon catheter system, it was determined whether or not the balloon came into contact with the pulmonary vein model.

[0095] The size and shape of pulmonary veins vary greatly from subject to subject. Therefore, Tests A to C were conducted in which the balloon of a balloon catheter was brought into contact with three types of pulmonary vein models shown in Figures 7A to 7C. Test A used pulmonary vein model A shown in Figure 7A. In pulmonary vein model A shown in Figure 7A, the pulmonary veins had a cylindrical shape. Test B used pulmonary vein model B shown in Figure 7B. In pulmonary vein model B shown in Figure 7B, the pulmonary veins had an elliptical cylindrical shape. Test C used pulmonary vein model C shown in Figure 7C. Pulmonary vein model C shown in Figure 7C had a shape simulating the left atrium and pulmonary veins. Pulmonary vein model C was created by measuring the shapes of the left atrium and pulmonary veins of an actual patient and reproducing the measurement results using a 3D printer.

[0096] For pulmonary vein models A, B, and C, the direction in which the pulmonary veins extend was defined as a first direction D1. In pulmonary vein models B and C, the pulmonary veins were flattened into an elliptical shape. In pulmonary vein models B and C, the major axes were in a second direction D2 perpendicular to the first direction D1. In pulmonary vein models B and C, the maximum inner diameter IDAL was along the second direction D2. In pulmonary vein models B and C, the minor axes were in a third direction D3 perpendicular to the first direction D1. In pulmonary vein models B and C, the minimum inner diameter IDAS was along the third direction D3.

[0097] In order to clarify the relationship between directions between the drawings, Figures 7A to 8, 12A, and 12B show a common first direction D1, second direction D2, and third direction D3 using arrows with common symbols. The tip of the arrow is the first side of each direction. The side opposite the tip of the arrow is the second side of each direction. Arrows pointing toward the front of the paper in a direction perpendicular to the paper surface are indicated by symbols with a dot in a circle, as shown in Figure 8, for example.

[0098] The balloon catheter 15 was inserted into the pulmonary vein model so that the longitudinal direction LD of the balloon catheter 15 was parallel to the axial direction D1 of the pulmonary vein model. As shown in Figure 8, the insertion length DX was the length along the axial direction D1 of the pulmonary vein model (the longitudinal direction LD of the inserted balloon catheter 15) from the open end of the pulmonary vein model to the distal end of the balloon inserted into the pulmonary vein model. In Test A, Test B, and Test C, the insertion length DX was 10 mm, 15 mm, and 20 mm, respectively.

[0099] A fluid containing a coloring material was supplied to a balloon inserted into the pulmonary vein model by an insertion length DX. The balloon was inflated by supplying the fluid containing the coloring material. The fluid was supplied to the balloon in 1 cc increments, gradually inflating the balloon. Each time 1 cc of fluid was supplied to the balloon, contact between the balloon and the pulmonary vein model was confirmed. If contact was detected between the balloon and the pulmonary vein model, the contact length along the longitudinal direction LD of the balloon catheter 15 (the axial direction of the pulmonary vein model) was measured.

[0100] <Test A> In Test A, the inner diameter IDA of pulmonary vein model A was set to 15 mm. According to page 53 of the aforementioned Non-Patent Document 1, the diameter of the pulmonary vein ostium in a normal human is 10 to 13 mm, and the diameter of the pulmonary vein ostium in a patient with atrial fibrillation is 14 to 16 mm. In other words, the inner diameter IDA of pulmonary vein model A was the size of a typical pulmonary vein.

[0101] For Test A, balloons E1, E2, E3, and CE1 were prepared. Balloons E1, E2, and E3 were balloons according to the present embodiment and included cylinder portions of 10 mm or more. Balloon CE1 was spherical. Balloons E1, E2, E3, and CE1 were made of polyurethane. The wall thickness of balloons E1, E2, E3, and CE1 was 20 μm. Various dimensions of balloons E1, E2, E3, and CE1 are shown in Table 1.

[0102] The "L25" column in Table 1 indicates the length L25 of the balloon in the longitudinal direction LD (see FIG. 5A). The "L26" column in Table 1 indicates the length L26 of the cylinder portion in the longitudinal direction LD (see FIG. 5A). The "L27" column in Table 1 indicates the distance L27 from the distal end of the balloon to the cylinder portion in the longitudinal direction LD (see FIG. 5A). The "W26" column in Table 1 indicates the maximum value W26X of the width W26 of the cylinder portion. The "width W26" in Table 1 for balloon CE1 indicates the diameter of the balloon CE1, which has a substantially spherical shape. The "L26 / W26X" column in Table 1 indicates the ratio of the length L26 to the maximum width W26X.

[0103] When the balloon and pulmonary vein model A were in contact, the contact length DY (mm) between the balloon and pulmonary vein model A in the longitudinal direction LD was measured. In Test A, the contact length DY (mm) was the contact length in the longitudinal direction LD between the inner surface of the pulmonary vein model A and the outer surface of the balloon 25 at the center position in the third direction of the pulmonary vein model A when observed from the first side in the second direction D2 (observation in Figure 8). In Figure 8, the contact area between the inner surface of the pulmonary vein model A and the outer surface of the balloon 25 is schematically shown as a matte finish area. The maximum value of the contact length DY measured for each 1 cc increase in the injection volume is shown in the "DY" column of Table 1. The maximum value of the contact length DY is listed for each insertion length DX in Table 1.

[0104] Fig. 9 is a graph showing the relationship between the injection amount and the contact length DY in a test using pulmonary vein model A with an insertion length of 10 mm. Fig. 10 is a graph showing the relationship between the injection amount and the contact length DY in a test using pulmonary vein model A with an insertion length of 15 mm. Fig. 11 is a graph showing the relationship between the injection amount and the contact length DY in a test using pulmonary vein model A with an insertion length of 20 mm.

[0105]

[0106] By adjusting the amount of injection into the balloon, an annular contact area between the balloon and the pulmonary vein model A could be ensured regardless of which balloon was used.

[0107] In Test A using a cylindrical pulmonary vein model A, the balloons E1, E2, and E3 with cylinder portions were able to increase the contact length DY compared to the conventional spherical balloon CE1. In Test A using a cylindrical pulmonary vein model A, the balloons E1, E2, and E3 with cylinder portions were less likely to come out of the pulmonary vein model A even when a large amount of injection was performed compared to the conventional spherical balloon CE1. In Test A using a cylindrical pulmonary vein model A, the balloons E1, E2, and E3 with cylinder portions were able to more easily determine the contact area between the pulmonary vein model A and the balloon compared to the conventional spherical balloon CE1.

[0108] The superior effect of the cylindrical balloon was more pronounced in the test results where the insertion length DX was set to 10 mm among the insertion lengths DX of 10 mm, 15 mm, and 20 mm. That is, the insertion length of the catheter body into the pulmonary vein was shortened, while the balloon and the target site were able to contact each other more stably in the annular region.

[0109] <Test B> In Test B, the inner diameter IDAS (see FIG. 12A), which is the minor axis of pulmonary vein model B, was set to 10 mm, and the inner diameter IDAL (see FIG. 12A), which is the major axis of pulmonary vein model B, was set to 25 mm.

[0110] Test B used balloons E2, E3, and CE1 similar to those used in Test A. The dimensions of balloons E2, E3, and CE1 are shown in Table 2, similar to Table 1.

[0111] When the balloon was in contact with the pulmonary vein model B, the contact length DY (mm) and contact length DZ (mm) in the longitudinal direction LD between the balloon and the pulmonary vein model B were measured. The maximum measured contact length DY is shown for each insertion length DX in the "DY" column of Table 2. The maximum measured contact length DZ is shown for each insertion length DX in the "DZ" column of Table 2.

[0112] The contact length DY (mm) in Test B was measured in the same manner as Test A. In Test B, the contact length DZ (mm) listed in Table 2 was the contact length in the longitudinal direction LD between the inner surface of pulmonary vein model B and the outer surface of balloon 25 at the center position in second direction D2 of pulmonary vein model B when observed from the first side in third direction D3.

[0113] FIG. 13A is a graph showing the relationship between the injection amount and the contact length DY in a test using pulmonary vein model B with an insertion length of 10 mm. FIG. 13B is a graph showing the relationship between the injection amount and the contact length DZ in a test using pulmonary vein model B with an insertion length of 10 mm. FIG. 14A is a graph showing the relationship between the injection amount and the contact length DY in a test using pulmonary vein model B with an insertion length of 15 mm. FIG. 14B is a graph showing the relationship between the injection amount and the contact length DZ in a test using pulmonary vein model B with an insertion length of 15 mm. FIG. 15A is a graph showing the relationship between the injection amount and the contact length DY in a test using pulmonary vein model B with an insertion length of 20 mm. FIG. 15B is a graph showing the relationship between the injection amount and the contact length DZ in a test using pulmonary vein model B with an insertion length of 20 mm.

[0114]

[0115] By adjusting the amount of injection into the balloon, an annular contact area between the balloon and the pulmonary vein model B could be ensured regardless of which balloon was used.

[0116] In Test B using an elliptical cylindrical pulmonary vein model B, the balloons E2 and E3 with cylindrical portions were able to increase the contact length DY compared to the conventional spherical balloon CE1. In Test B using an elliptical cylindrical pulmonary vein model B, the balloons E2 and E3 with cylindrical portions were less likely to slip out of the pulmonary vein model B even when a large amount of injection was performed compared to the conventional spherical balloon CE1. In Test B using an elliptical cylindrical pulmonary vein model B, the balloons E2 and E3 with cylindrical portions were able to more clearly distinguish the contact area between the pulmonary vein model B and the balloon compared to the conventional spherical balloon CE1.

[0117] In Test B, the superior effect of the cylinder-containing balloon was even more pronounced when the insertion length DX was set to 10 mm among the insertion lengths DX of 10 mm, 15 mm, and 20 mm. That is, the balloon and the target site can be more stably contacted in the annular region while shortening the insertion length of the catheter body into the pulmonary vein. It is particularly noteworthy that, for the cylinder-containing balloons E2 and E3, when the insertion length DX was shortened to 10 mm and 15 mm, the contact length DY was increased without increasing the contact length DZ.

[0118] <Test C> Pulmonary vein model C was used in Test C. At the opening (entrance) of the pulmonary vein of pulmonary vein model C, the inner diameter IDAS, which is the minor axis, was 13 mm. At the opening (entrance) of the pulmonary vein of pulmonary vein model C, the inner diameter IDAL, which is the major axis, was 27 mm.

[0119] Test C used balloons E2, E3, and CE1 similar to those used in Test B. Table 3 shows the dimensions of balloons E2, E3, and CE1, similar to Table 2.

[0120] When the balloon and pulmonary vein model C were in contact with each other, the contact lengths DY1 (mm), DY2 (mm), and DZ (mm) between the balloon and pulmonary vein model C in the longitudinal direction LD were measured. The maximum measured contact length DY1 is shown for each insertion length DX in the "DY1" column of Table 3. The contact length DY1 (mm) in Test C was measured in the same manner as the contact length DY in Test B. That is, the contact length DY1 (mm) listed in Table 3 was the contact length in the longitudinal direction LD between the inner surface of the pulmonary vein model C and the outer surface of the balloon 25 at the center position in the third direction D3 of the pulmonary vein model C when observed from the first side in the second direction D2.

[0121] The maximum measured contact length DY2 is shown for each insertion length DX in the "DY2" column in Table 3. In Test C, the contact length DY2 (mm) listed in Table 3 was the contact length in the longitudinal direction LD between the inner surface of the pulmonary vein model C and the outer surface of the balloon 25 at the center position in the third direction D3 of the pulmonary vein model C when observed from the second side in the second direction D2.

[0122] The maximum measured contact length DZ is shown for each insertion length DX in the "DZ" column of Table 3. In Test C, the contact length DZ (mm) listed in Table 3 was measured in the same manner as the measured length DZ in Test B.

[0123] 16A is a graph showing the relationship between the injection amount and the contact length DY1 in a test using pulmonary vein model C with an insertion length of 10 mm. FIG. 16B is a graph showing the relationship between the injection amount and the contact length DZ in a test using pulmonary vein model C with an insertion length of 10 mm. FIG. 16C is a graph showing the relationship between the injection amount and the contact length DY2 in a test using pulmonary vein model C with an insertion length of 10 mm.

[0124] 17A is a graph showing the relationship between the injection amount and the contact length DY1 in a test using pulmonary vein model C with an insertion length of 15 mm. FIG. 17B is a graph showing the relationship between the injection amount and the contact length DZ in a test using pulmonary vein model C with an insertion length of 15 mm. FIG. 17C is a graph showing the relationship between the injection amount and the contact length DY2 in a test using pulmonary vein model C with an insertion length of 15 mm.

[0125] Fig. 18A is a graph showing the relationship between the injection amount and the contact length DY1 in a test in which the insertion length was set to 20 mm using pulmonary vein model C. Fig. 18B is a graph showing the relationship between the injection amount and the contact length DZ in a test in which the insertion length was set to 20 mm using pulmonary vein model B. Fig. 18C is a graph showing the relationship between the injection amount and the contact length DY2 in a test in which the insertion length was set to 20 mm using pulmonary vein model C.

[0126]

[0127] In Test C using a pulmonary vein model C simulating human pulmonary veins, the balloons E2 and E3 with cylindrical portions were able to increase the contact lengths DY1 and DY2 compared to the conventional balloon CE1 with a spherical shape. In Test C using a pulmonary vein model C simulating human pulmonary veins, the balloons E2 and E3 with cylindrical portions were less likely to come out of the pulmonary vein model C even when a large amount of injection was performed compared to the conventional balloon CE1 with a spherical shape. In Test C using a pulmonary vein model C simulating human pulmonary veins, the balloons E2 and E3 with cylindrical portions were able to more clearly distinguish the contact area between the pulmonary vein model C and the balloon compared to the conventional balloon CE1 with a spherical shape.

[0128] In Test C, the excellent effect of the balloon having a cylindrical portion was even more pronounced when the insertion length DX was set to 10 mm or 15 mm out of the insertion lengths DX of 10 mm, 15 mm, and 20 mm. In other words, the insertion length of the catheter body into the pulmonary vein can be shortened while still achieving more stable contact between the balloon and the target site in the annular region.

[0129] In the present embodiment described above, the balloon catheter 15 includes a balloon 25, an outer cylindrical shaft 30, and an inner cylindrical shaft 35. The outer cylindrical shaft 30 is connected to the proximal end 25b of the balloon 25. The inner cylindrical shaft 35 passes through the outer cylindrical shaft 30 and extends into the balloon 25. The inner cylindrical shaft 35 is connected to the distal end 25a of the balloon 25. The balloon 25 includes a cylinder portion 26 having a length of 15 mm or more. The cylinder portion 26 has a cylindrical shape when the balloon 25 is inflated to atmospheric pressure. The balloon catheter of this embodiment allows for more stable contact between the balloon 25 and the target site. The balloon catheter of this embodiment can prevent the balloon 25 from slipping out of the target site and retracting. The balloon catheter of this embodiment allows for more clear observation of the contact area between the balloon 25 and the target site in X-ray imaging.

[0130] Although the present embodiment has been described with reference to specific examples, the above-described specific examples do not limit the present embodiment. The above-described embodiment can be implemented with various other specific examples, and various omissions, substitutions, changes, additions, etc. can be made without departing from the spirit of the present invention.

[0131] In the above specific example, the balloon catheter 15 includes a single temperature sensor 45. The balloon catheter 15 may include multiple temperature sensors 45. The balloon catheter 15 may not include a temperature sensor 45.

[0132] This embodiment can be used in a balloon catheter system and a balloon catheter for treating arrhythmia such as atrial fibrillation, endometriosis, cancer, and the like.

[0133] LD: longitudinal direction, LP: flow path, 10: balloon catheter system, 15: balloon catheter, 25: balloon, 25a: distal end, 25b: proximal end, 26: cylinder portion, 26c: intermediate portion, 27: tip portion, 28: base end portion, 30: outer cylindrical shaft, 30a: distal end, 35: inner cylindrical shaft, 35a: distal end, 40: temperature adjustment member, 45: temperature sensor, 74: supply device, 75: stirring device

Claims

1. A balloon catheter comprising: a balloon; an outer cylindrical shaft connected to the proximal end of the balloon; and an inner cylindrical shaft passing through the outer cylindrical shaft, extending into the balloon, and connected to the distal end of the balloon, wherein the balloon includes a cylinder portion having a length of 15 mm or more, and the cylinder portion has a cylindrical shape when the balloon is inflated to atmospheric pressure.

2. The balloon catheter according to claim 1, wherein the length of the cylinder portion is 15 mm or more and 40 mm or less.

3. A balloon catheter according to claim 1 or 2, wherein the maximum width of the cylinder portion is 15 mm or more and 40 mm or less.

4. A balloon catheter according to any one of claims 1 to 3, wherein the ratio of the length of said cylinder portion to the maximum width of said cylinder portion is 0.50 or more and 1.4 or less.

5. A balloon catheter according to any one of claims 1 to 4, wherein the length of the balloon from the distal end of the balloon to the cylinder portion is 0.5 mm or more and 30 mm or less.

6. A balloon catheter according to any one of claims 1 to 5, wherein the length of the balloon is 20 mm or more and 50 mm or less.

7. A balloon catheter according to any one of claims 1 to 6, wherein the width of the cylinder portion gradually decreases from the distal side to the proximal side.

8. A balloon catheter according to any one of claims 1 to 7, wherein the cylinder portion has a minimum width at an intermediate portion, the width of the cylinder portion gradually increases from the intermediate portion toward the proximal side, and the width of the cylinder portion gradually increases from the intermediate portion toward the distal side.

9. A balloon catheter according to any one of claims 1 to 8, wherein the balloon comprises a tip portion connected to the cylinder portion from the distal side and constituting the distal end, and a base portion connected to the cylinder portion from the proximal side and constituting the proximal end, the tip portion tapering toward the distal end, and the base portion tapering toward the proximal end.

10. A balloon catheter system comprising: a balloon catheter according to any one of claims 1 to 9; a supply device that supplies fluid to a flow path formed between the outer cylindrical shaft and the inner cylindrical shaft and leading to the inside of the balloon; and a stirring device that repeatedly supplies fluid to and discharges fluid from the flow path.

11. The balloon catheter system of claim 10, wherein the balloon catheter further includes a temperature adjustment member for heating or cooling a fluid within the balloon, and a temperature sensor for obtaining information regarding the temperature of the fluid, and the amount of energy supplied to the temperature adjustment member is adjusted based on the information regarding the temperature obtained by the temperature sensor.

Images