Balloon catheter

Abstract

A balloon catheter used in combination with an endoscope is equipped with a balloon 20, a catheter shaft having an outer shaft extending proximally from the balloon 20, and linear members 24 disposed inside the balloon 20 and in contact with the balloon. When a direction perpendicular to the center line C10 of the balloon catheter is defined as direction X and a direction perpendicular to the center line C10 and direction X is defined as direction Y, the outer shaft includes a bending region having a tendency to bend in direction X, and the contact points 72 of the linear members 24 with the balloon 20 are provided, relative to the center line C10 of the balloon catheter 10, on the bend inner side X1 of the bending region in direction X or in direction Y .

Description

Balloon catheter

[0001] The present disclosure relates to a balloon catheter.

[0002] Patent Document 1 discloses a balloon catheter including a catheter shaft, a balloon provided on a distal portion of the catheter shaft, and a temperature sensor that detects a temperature related to the balloon.

[0003] Japanese Unexamined Patent Application Publication No. 2002-301087

[0004] The temperature sensor of Patent Document 1 is provided inside the balloon and functions as a linear member that contacts the balloon. Although details will be described later, the inventor of the present application has recognized that when a balloon catheter is used in combination with an endoscope, there is a problem that the balloon is likely to be torn depending on the position of the contact portion of the linear member with the balloon.

[0005] Accordingly, one object of the present disclosure is to provide a balloon catheter that is advantageous in suppressing a situation where the balloon is torn due to the influence of the contact portion of the linear member with the balloon.

[0006] The balloon catheter of the present disclosure is a balloon catheter used in combination with an endoscope, comprising: a balloon; a catheter shaft having an outer shaft extending proximally from the balloon; and a linear member disposed inside the balloon and in contact with the balloon, wherein when a direction perpendicular to the center line of the balloon catheter is defined as a first direction, and a direction perpendicular to both the center line and the first direction is defined as a second direction, the outer shaft includes a bent region provided with a bending habit to bend in the first direction, and the contact portion of the linear member with the balloon is provided on the bending inner side of the bent region in the first direction or in the second direction with respect to the center line of the balloon catheter.

[0007] According to the present disclosure, it is advantageous in suppressing a situation where the balloon is torn due to the influence of the contact portion of the linear member with the balloon.

[0008] Figure 1(A) is a first explanatory diagram schematically showing the usage state of the balloon catheter of the embodiment, and Figure 1(B) is a second explanatory diagram thereof. This is a schematic diagram showing the balloon catheter of the embodiment. This is a cross-sectional view of a part of the balloon catheter of the embodiment seen from a first direction. This is a perspective view showing the balloon of the embodiment. This is a cross-sectional view of a part of the balloon catheter of the embodiment seen from a second direction. This is a cross-sectional view taken along line VI-VI in Figure 3. This is a diagram showing the bending region of the proximal outer shaft. This is a cross-sectional view taken along line VIII-VIII in Figure 3. Figure 9(A) is an explanatory diagram regarding the effect of a balloon catheter of a reference embodiment, and Figure 9(B) is an explanatory diagram regarding the effect of a balloon catheter of the embodiment. This is an enlarged view of a part of Figure 5. This is a cross-sectional view taken along line XI-XI in Figure 10.

[0009] Embodiments for implementing the balloon catheter of this disclosure are described below. The same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted. In each drawing, components are omitted, enlarged, or reduced as appropriate for ease of explanation. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0010] Refer to Figure 1(A). First, the endoscope 12 used in conjunction with the balloon catheter 10 will be explained. The endoscope 12 is usually used when the balloon catheter 10 is intended to treat digestive organs such as the bile duct and pancreatic duct. Here, the endoscope 12 is shown in preparation for inserting the balloon catheter 10 into the biliary papilla 14a that opens to the inner surface of the duodenum 14.

[0011] The endoscope 12 comprises an endoscope body 12a that is inserted into the body and a standing base 12b that is rotatably attached to the endoscope body 12a. The endoscope body 12a has a channel 12c through which a balloon catheter 10 is inserted. The balloon catheter 10 is delivered laterally and externally from the endoscope body 12a by the standing base 12b via the channel 12c. The direction in which the balloon catheter 10 is delivered is adjusted by changing the rotation angle of the standing base 12b relative to the endoscope body 12a. By adjusting the direction in which the balloon catheter 10 is delivered by the standing base 12b, the position of the distal end of the balloon catheter 10 can be adjusted, making it easier to insert that distal end into a specific location in the body (in this case, the papilla 14a).

[0012] Refer to Figures 2 and 3. The balloon catheter 10 will be described. The balloon catheter 10 is used for procedures on living organs. Here, an example of its use in ablation of the digestive organs will be described. The specific example of this procedure is not limited to this, and may also be dilation of narrowed areas of living organs, etc. When used for ablation, the balloon catheter 10 is used by heating the fluid supplied into the balloon 20 with a heating member 26. By adjusting the temperature of the fluid inside the balloon 20 by heating with the heating member 26, the surface temperature of the balloon 20 is adjusted. Ablation is performed by bringing the balloon 20 with the adjusted surface temperature into contact with living tissue.

[0013] The balloon catheter 10 comprises a balloon 20, a catheter shaft 22 having a proximal outer shaft 54 ​​extending proximal to the balloon 20, and a linear member 24 that contacts the balloon 20. In Figure 3, etc., only the center line of the linear member 24 is schematically shown. In addition, the balloon catheter 10 may also include a heating member 26 capable of heating the fluid supplied into the balloon 20, and a handle device 28 provided on the proximal portion of the catheter shaft 22. Below, an overview of each component will be described, followed by a description of the main features of the balloon catheter 10.

[0014] Refer to Figure 2. The handle device 28 may include a handle 30 grasped by the operator and first and second hubs 32A and 32B through which the catheter shaft 22 is inserted. The handle device 28 may also include a connector 38 for electrically connecting the power supply 34 and the information processing device 36. The handle device 28 may be provided with a wire port 40 for inserting a guide wire into the balloon catheter 10, a supply port 44 for supplying fluid from a fluid supply device 42 to inflate the balloon 20, and a discharge port 48 for discharging fluid to a fluid discharge device 46. The fluid supply device 42 and the fluid discharge device 46 are configured using an indeflerator, syringe, pump, etc. Specific examples of the fluid for inflating the balloon 20 are not particularly limited and may include various liquids such as contrast agents, saline solution, and sterile water, as well as semi-solid materials such as gels.

[0015] Refer to Figures 3 and 4. Unless otherwise specified, the positional relationships of each component are described based on the case where the balloon 20 is in an expanded state and the catheter shaft 22 is extended in a straight line. Furthermore, the positional relationships of each component are described below with reference to the centerline C10 of the balloon catheter 10. The centerline C10 of the balloon catheter 10 refers to the centerline of the balloon 20 in an expanded state within the axial range where the balloon 20 is present, and to the centerline of the catheter shaft 22 within the axial range where the balloon 20 is not present. The direction along the centerline C10 of the balloon catheter 10 is simply called the axial direction, and the radial and circumferential directions relative to the centerline C10 are called the radial direction and circumferential direction. Also, one side in the axial direction is called the distal side, and the other side is called the proximal side.

[0016] The balloon 20 is expandable by fluid supplied from the proximal side of the catheter shaft 22. Figures 1 and 2 show the balloon 20 in a deflated state, while Figures 3 and 4 show the balloon 20 in an expanded state. The balloon 20 may be made of various resin materials used for balloons, such as polyamide resin or polyurethane. The balloon 20 comprises an expandable portion 20a that can be expanded by fluid supplied inside, and sleeve portions 20b provided on both axial sides of the expandable portion 20a. The balloon 20 in this embodiment is a cylindrical balloon. The expandable portion 20a of this balloon 20 comprises a pair of cone portions 20c provided at both axial ends of the expandable portion 20a, and a cylindrical portion 20d provided between the pair of cone portions 20c. The specific example of the balloon 20 is not limited to this, and a spherical balloon or the like may also be used. Each sleeve portion 20b is fixed to a part of the catheter shaft 22 by welding, adhesive, or the like. Here, we show an example in which the proximal sleeve portion 20b is fixed to the proximal outer shaft 54, which will be described later, and the distal sleeve portion 20b is fixed to the distal outer shaft 58, which will be described later.

[0017] The balloon 20 comprises a main body portion 20e that forms a fluid chamber 50, and an insertion passage forming portion 20f that forms an insertion passage 52 between itself and the main body portion 20e on its radially outward side. Fluid is supplied to the fluid chamber 50 to expand the balloon 20. The main body portion 20e constitutes the expansion portion 20a and the sleeve portion 20b of the balloon 20. In this embodiment, the insertion passage forming portion 20f is provided integrally with the main body portion 20e and is composed of a protruding portion 20g that extends radially outward from the main body portion 20e. A portion of the distal part of the linear member 24 is inserted through the insertion passage 52. The balloon 20 may also have a pair of insertion passages 52 through which each of the two linear members 24 is inserted, as in this embodiment. In this case, the balloon 20 comprises a pair of protruding portions 20g that form each of the pair of insertion passages 52.

[0018] Refer to Figures 3 and 5. The catheter shaft 22 is flexible and can be bent. The catheter shaft 22 is inserted into the body, at least in its distal portion. The catheter shaft 22 supports the balloon 20. To achieve this, at least the sleeve portion 20b on the proximal side of the balloon 20 is fixed to the catheter shaft 22. Alternatively, to achieve this, the sleeve portion 20b on the distal side of the balloon 20 may also be fixed to the catheter shaft 22.

[0019] The catheter shaft 22 comprises at least one shaft 54, 56, or 58. The catheter shaft 22 includes a proximal outer shaft 54 ​​as such a shaft. The catheter shaft 22 may also include an inner shaft 56 inserted into the first lumen 60 of the proximal outer shaft 54, and a distal outer shaft 58 positioned distal to the proximal outer shaft 54 ​​as other shafts. Each shaft 54, 56, or 58 is constructed from various resin materials such as polyolefin resin, fluororesin, polyamide, polyether block amide, or polyurethane.

[0020] The proximal outer shaft 54 ​​extends proximal to the balloon 20 from a position that radially overlaps with at least a portion of the balloon 20. A handle device 28 is provided on the proximal portion of the proximal outer shaft 54 ​​(see Figure 2).

[0021] The inner shaft 56 is drawn distally from the first lumen 60 of the proximal outer shaft 54 ​​and then passes axially through the inside of the balloon 20. The inner shaft 56 has a guide wire lumen 56a through which a guide wire inserted from the wire port 40 of the handle device 28 is inserted.

[0022] The distal outer shaft 58 has a shaft hole 58a through which the inner shaft 56 is inserted within the balloon 20. The center line C58a of the shaft hole 58a is positioned offset from the center line C60 of the first lumen 60 of the proximal outer shaft 54. The distal outer shaft 58 is fixed to the inner shaft 56 by welding, adhesive, or the like.

[0023] The inner shaft 56 comprises a proximal insertion portion 56b that is inserted into the first lumen 60 of the proximal outer shaft 54, a distal insertion portion 56c that is inserted into the shaft hole 58a of the distal outer shaft 58, and a connecting portion 56d that connects the proximal insertion portion 56b and the distal insertion portion 56c. The center line (not shown) of the connecting portion 56d extends diagonally so as it moves distally in the axial direction, it approaches the center line C58a of the shaft hole 58a from the center line C60 of the first lumen 60. The connecting portion 56d is provided by bending a part of the inner shaft 56. This connecting portion 56d allows the inner shaft 56 to be inserted inside the center line C60 of the first lumen 60 and the center line C58a of the shaft hole 58a, even if they are misaligned.

[0024] Refer to Figures 5 and 6. Hereinafter, the direction perpendicular to the center line C10 of the balloon catheter 10 will be referred to as the first direction (hereinafter referred to as the X direction), and the direction perpendicular to the center line C10 and the X direction will be referred to as the second direction (hereinafter referred to as the Y direction).

[0025] At least one lumen 60, 62 is formed in the proximal outer shaft 54. This lumen 60, 62 includes a first lumen 60 that is eccentric in the X direction with respect to the center line C54 of the proximal outer shaft 54, and a second lumen 62 that is provided on the opposite side of the eccentricity direction D of the first lumen 60. Here, "eccentricity" means that the center line C60 of the first lumen 60 is eccentric with respect to the center line C54 of the proximal outer shaft 54. Here, "eccentricity direction D" means the direction from the center line C54 of the proximal outer shaft 54 ​​toward the center line C60 of the first lumen 60. Here, "center line C60 of the first lumen 60" means the geometric center of the shape formed by the inner circumferential surface that forms the lumen 60.

[0026] The first and second lumens 60 and 62 may be the lumens with the largest cross-sectional area among the multiple lumens formed in the proximal outer shaft 54. Here, cross-sectional area refers to the cross-sectional area in a cross section perpendicular to the axial direction. The second lumen 62 may be formed to extend elongated in the circumferential direction with respect to the center line C60 of the first lumen 60. One of the first lumen 60 and the second lumen 62 becomes a supply lumen through which the fluid supplied into the balloon 20 flows, and the other becomes a discharge lumen through which the fluid discharged from inside the balloon 20 flows. In this embodiment, the first lumen 60 is the discharge lumen and the second lumen 62 is the supply lumen. Fluid is supplied into the balloon 20 from the fluid supply device 42 via the supply port 44 of the handle device 28 and the supply lumen. From inside the balloon 20, the fluid is discharged to the fluid supply device 42 via the discharge lumen and the discharge port 48 of the handle device 28.

[0027] The proximal outer shaft 54 ​​includes a partition wall portion 54a separating the first lumen 60 and the second lumen 62, and an outer peripheral wall portion 54b separating the space outside the proximal outer shaft 54 ​​from the first and second lumens 60 and 62. The partition wall portion 54a is connected to the outer peripheral wall portion 54b at both ends in the longitudinal direction intersecting its wall thickness direction in a cross section perpendicular to the axial direction. The partition wall portion 54a may be formed to extend in a circumferential direction with respect to the center line C60 of the first lumen 60.

[0028] Refer to Figure 3. The linear member 24 may be composed of a temperature sensor 64 for detecting the temperature of the balloon 20, as in this embodiment. The temperature sensor 64 in this embodiment is a thermocouple, but it may also be composed of a thermistor or the like. The temperature sensor 64 in this embodiment is located on the surface side of the main body 20e and detects the temperature of the surface side of the main body 20e as the temperature of the balloon 20. In addition, the temperature sensor 64 may be located inside the main body 20e and detect the temperature of the fluid supplied into the balloon 20 as the temperature of the balloon 20. The balloon catheter 10 in this embodiment has a total of two linear members 24, but the number is not particularly limited and may be one or three or more.

[0029] The temperature sensor 64 includes a temperature detection unit 64a that detects an electrical signal indicating the temperature of the balloon 20, and a sensor wiring 64b that is electrically connected to the temperature detection unit 64a. The temperature detection unit 64a is provided at the distal end of the linear member 24, and the sensor wiring 64b constitutes the portion of the linear member 24 that is closer to the temperature detection unit 64a. In this embodiment, a pair of sensor wirings 64b are electrically connected to one temperature detection unit 64a. The sensor wiring 64b is electrically connected to a connector 38 via the first lumen 60 of the proximal outer shaft 54, and is electrically connected to an information processing device 36 via the connector 38. The temperature detection unit 64a outputs the detected electrical signal to the information processing device 36 via the sensor wiring 64b. The information processing device 36 can obtain a value indicating the temperature of the balloon 20 by performing various signal processing on the electrical signal detected by the temperature detection unit 64a.

[0030] The linear member 24 is linear in shape as a whole. At least a portion of the linear member 24 is placed inside the balloon 20. In order to satisfy the condition of "placed inside the balloon 20", as in this embodiment, it may be placed in the space formed inside the balloon 20 without being embedded in the balloon 20. Alternatively, in order to satisfy this condition, it may be placed inside the balloon 20 in a state where it is embedded in the balloon 20 and integrated with it. In order to satisfy the condition of "placed inside the space formed inside the balloon 20", the linear member 24 in this embodiment is inserted into the insertion passage 52 of the balloon 20. Alternatively, in order to satisfy this condition, the linear member 24 may be placed inside the fluid chamber 50 formed by the main body portion 20e of the balloon 20. The distal end of the linear member 24 in this embodiment is provided to be located in the axial middle portion of the balloon 20.

[0031] Refer to Figures 3 and 5. The heating element 26 is placed inside the balloon 20. The heating element 26 is attached to the catheter shaft 22 by adhesive, impact, or the like. The heating element 26 may also be attached to the distal outer shaft 58, as in this embodiment. In this embodiment, the heating elements 26 are provided in pairs with space between them inside the balloon 20. The number of heating elements 26 is not particularly limited and may be one, three or more.

[0032] The heating element 26 is electrically connected to the power supply 34 via corresponding heating element wiring 66 and a connector 38. The heating element 26 heats the fluid inside the balloon 20 with power supplied from the power supply 34 via the heating element wiring 66. In this embodiment, the heating element 26 is heated by a direct resistance heating method, but the heating method is not particularly limited, and an indirect resistance heating method, ultrasonic heating method, laser heating method, etc., may be used. The heating element wiring 66 is electrically connected to the connector 38, for example, via the shaft hole 58a of the distal outer shaft 58 and the first lumen 60 of the proximal outer shaft 54.

[0033] We will now move on to describing the main features of the balloon catheter 10. Refer to Figure 7. Figure 7 shows the proximal outer shaft 54 ​​bent in the bending region 70, which will be described next. In Figure 7, with respect to the center line C10 of the balloon catheter 10, the inner bending side X1, which is the center of the bend shape of the bending region 70, and the outer bending side X2, which is the opposite side of the inner bending side X1. The inner bending side X1 is one side in the X direction with respect to the center line C10 of the balloon catheter 10, and the outer bending side X2 is the other side in the X direction with respect to the center line C10.

[0034] The proximal outer shaft 54 ​​has a bendable region 70 that is pre-bent in the X direction. Here, "bends in the X direction" means that the bend in the X direction as it moves axially within the bendable region 70. Here, "pre-bent" means that the proximal outer shaft 54 ​​is bent in its natural state without any external force being applied to it. The bendable region 70 is bent in the same direction in the X direction toward the axial direction of the catheter shaft 22.

[0035] The bending region 70 may be provided in at least a part of the distal portion of the proximal outer shaft 54. To satisfy the condition of "at least a part of the distal portion of the proximal outer shaft 54," the bending region 70 may be provided at a length of at least 1 / 5 of the total length of the proximal outer shaft 54. To satisfy this condition, other parts of the proximal outer shaft 54, such as the proximal portion, may extend straight. To satisfy this condition, the bending region 70 is preferably provided in a part close to the balloon 20, and may be provided in a part of the range that is continuous from the distal end to the proximal end of the proximal outer shaft 54. In this embodiment, the bending region 70 is provided in the portion from the distal end of the proximal outer shaft 54 ​​to the handle device 28, as shown in Figure 2. By providing the bending region 70, the proximal outer shaft 54 ​​may be provided with a winding portion 54c that is wound around at least one turn.

[0036] Refer to Figure 8. We will examine the contact point 72 of the linear member 24 with respect to the balloon 20 (hereinafter referred to as the balloon contact point 72). Here, "contact" includes not only the case where the linear member 24 directly contacts the balloon 20, as in this embodiment, but also the case where the linear member 24 contacts the balloon 20 via another member. In this embodiment, the balloon contact point 72 is the insertion point of the balloon 20 into the insertion passage 52. At the balloon contact point 72, the linear member 24 maintains its position relative to the balloon 20 and is in contact with the balloon 20 whether the balloon 20 is in an expanded or contracted state. In order to maintain the position of the linear member 24 relative to the balloon 20 at the balloon contact point 72, the linear member 24 may be inserted into the insertion passage 52 of the balloon 20, as in this embodiment. Alternatively, the linear member 24 may be attached to the balloon 20 by adhesive or the like to achieve the same objective.

[0037] Hereinafter, in a cross-section perpendicular to the axial direction, the circumferential range within ±45° of the radius line L1 extending inward X1 along the X direction relative to the center line C10 of the balloon catheter 10 is called the inward bending range R1, and the circumferential range within ±45° of the radius line L2 extending outward X2 along the X direction relative to the center line C10 is called the outward bending range R2. Furthermore, the circumferential range within ±45° of the radius line L3 extending on both sides in the Y direction along the Y direction relative to the center line C10 is called the lateral range R3.

[0038] The positional condition is that, with respect to a specific object, it must be located in the inner bending area X1 of the bending region 70 in the X direction or in the Y direction relative to the center line C10 of the balloon catheter 10. Here, "located in the inner bending area X1 of the bending region 70 in the X direction" means located within the aforementioned inner bending range R1. To satisfy this condition, the specific object only needs to be located at any position within the inner bending range R1, and it is not essential that it be located on the radius line L1. Here, "located in the Y direction" means located within the aforementioned lateral range R3. To satisfy this condition, the specific object only needs to be located at any position within the lateral range R3, and it is not essential that it be located on the radius line L3. When this positional condition is satisfied, the specific object will be located in a place that avoids the aforementioned outer bending range R2.

[0039] In this embodiment, the balloon contact points 72 of the linear member 24 satisfy the positional conditions described here. These positional conditions only need to be met when the balloon 20 is in an expanded state. In this embodiment, the balloon contact points 72 are located in the Y direction, that is, in the lateral range R3. If there are multiple linear members 24, it is sufficient that the balloon contact points 72 of at least one linear member 24 satisfy this condition. In this embodiment, the balloon contact points 72 of multiple linear members 24 satisfy this condition. In this embodiment, in addition to each of the insertion passages 52 of the balloon 20, the protruding portions 20g of the balloon 20 also satisfy the positional conditions described here. In this embodiment, the balloon contact points 72 of each pair of linear members 24 are individually located on both sides in the Y direction with respect to the centerline C10 of the balloon catheter 10. That is, these balloon contact points 72 are individually located within the lateral range R3 on both sides in the Y direction. In this case as well, it is sufficient that these balloon contact points 72 are located at any position within the individual lateral range R3, and it is not essential that they be located on the radius line L3. In this embodiment, in addition to the pair of insertion passages 52, the pair of protruding portions 20g also satisfy the same conditions.

[0040] The effects of the balloon catheter will now be explained in relation to the features described above. On the surface of the balloon 20, undulating convex areas 74 are provided around the balloon contact points 72 of the linear member 24 with respect to the balloon 20. These undulating areas 74 are provided at the locations of the protruding portion 20g, for example, when the balloon 20 has a ridge portion 20g, regardless of whether the balloon 20 is in an expanded or contracted state. Furthermore, when the balloon 20 has a multilayer structure, these undulating areas 74 are provided at the locations of the linear member 24, regardless of whether the balloon 20 is in an expanded or contracted state, because the outer layer member (insertion passage forming portion 20f) of the balloon 20 is in close contact with the linear member 24. Also, when the linear member 24 is positioned inside the main body portion 20e of the balloon 20, these undulating areas 74 are provided at the locations of the linear member 24, because the main body portion 20e is in close contact with the linear member 24 when the balloon 20 is in a contracted state.

[0041] Refer to Figures 1(B) and 9. Figure 9 is a schematic cross-sectional view showing the A-A section of Figure 1(B). Figure 9(A) shows the A-A section of a reference balloon catheter 10'. In the reference balloon catheter 10, an example is shown in which the undulating portion 74 of the balloon 20 is provided on the outer bending X2 in the X direction with respect to its center line C10. Figure 9(B) shows the A-A section of the embodiment balloon catheter 10.

[0042] The portion of the balloon catheter 10 located on the outer bending side X2 in the X direction relative to the center line C10 of the balloon catheter 10 is called the outer portion 10a of the balloon catheter 10. This outer portion 10a of the balloon catheter 10 exists not only in the axial range where the proximal outer shaft 54 ​​is located, but also in the axial range where the proximal outer shaft 54 ​​is not located. This outer portion 10a is also the portion located in the aforementioned outer bending range R2.

[0043] When the balloon catheter 10 is used in combination with the endoscope 12, the balloon catheter 10 is advanced from the standing platform 12b while adjusting the amount of bending of the bending region 70 of the proximal outer shaft 54 ​​using the standing platform 12b. In order to appropriately adjust the amount of bending of the bending region 70 in this way, it is necessary to advance the balloon catheter 10 while mainly applying the outer portion 10a of the balloon catheter 10 to the standing platform 12b, that is, the portion X2 on the outer side of the bending region 70 of the proximal outer shaft 54 ​​(see also Figure 1(A)). There is no particular method for applying the outer portion 10a of the balloon catheter 10 to the standing platform 12b, and various methods can be used. For example, to achieve this, the circumferential orientation of the balloon catheter 10 relative to the endoscope 12 may be adjusted in advance outside the body before inserting the balloon catheter 10 into the channel 12c. Consider the case in which the balloon catheter 10 has sufficient rigidity to transmit torque. In this case, the circumferential orientation of the balloon catheter 10 relative to the endoscope 12 may be adjusted by rotating the proximal portion of the balloon catheter 10 outside the body while the distal portion of the balloon catheter 10 remains inserted into the endoscope 12.

[0044] Here, consider a case where, when the balloon 20 is in an expanded state, the balloon contact portion 72 of the linear member 24 is located on the outer portion 10a of the balloon catheter 10'. In this case, as shown in FIG. 9(A), when the balloon 20 is in a deflated state, an undulating portion 74 of the balloon 20 is provided on the outer portion 10a of the balloon catheter 10 that mainly abuts against the upright stand 12b. In this case, there is a problem that the undulating portion 74 of the balloon 20 easily comes into contact with the upright stand 12b. If the undulating portion 74 of the balloon 20 comes into contact with the upright stand 12b in this manner, the balloon 20 may be torn by being caught at the undulating portion 74, and there is a risk that the linear member 24 will jump out from the inside of the balloon 20 to the outside.

[0045] As a countermeasure against this problem, in the present embodiment, the balloon contact portion 72 of the linear member 24 is provided not on the bending outer side X2 in the X direction with respect to the center line C10 of the balloon catheter 10, but on the bending inner side X1 in the X direction or in the Y direction with respect to the center line C10. Thereby, as shown in FIG. 9(B), when the balloon 20 is in a deflated state, the undulating portion 74 of the balloon 20 is similarly provided on the bending inner side X1 in the X direction or in the Y direction with respect to the center line C10 of the balloon catheter 10. In other words, when the balloon 20 is in a deflated state, the undulating portion 74 of the balloon 20 is provided at a position that avoids as much as possible the outer portion 10a of the balloon catheter 10 that mainly abuts against the upright stand 12b. Therefore, when the balloon catheter 10 is delivered while mainly causing the outer portion 10a of the balloon catheter 10 to abut against the upright stand 12b, it is possible to make it difficult for the undulating portion 74 of the balloon 20 to come into contact with the upright stand 12b, thereby suppressing a situation in which the balloon 20 is torn. That is, this is advantageous in suppressing a situation in which the balloon 20 is torn due to the influence of the balloon contact portion 72 of the linear member 24.

[0046] When removing the balloon catheter 10 from the treatment site (for example, the bile duct) outside the body, the guide wire that guides the balloon catheter 10 may be left in the treatment site. In this case, the guide wire may be fixed in place by sandwiching it between the standing platform 12b and the endoscope body 12a to prevent it from being removed together with the balloon catheter 10. To prevent the guide wire sandwiched between the standing platform 12b from slipping and shifting, an edge portion 12d (see Figure 1(B)) is usually provided at the tip of the standing platform 12b.

[0047] For example, when removing the balloon catheter 10 from the body as described above, it is necessary to clamp the guidewire with the standing platform 12b immediately after the balloon catheter 10 passes through the gap between the standing platform 12b and the endoscope body 12a. In order to achieve this, there is a first case in which the standing platform 12b is rotated from its initial position to narrow this gap as much as possible, and the balloon catheter 10 is then passed through this gap. In addition, there is a second case in which, when inserting the balloon catheter 10 into a specific location in the body (for example, the papilla 14a), the direction in which the balloon catheter 10 is advanced is adjusted by the standing platform 12b in order to align the balloon catheter 10, as described above. If the balloon 20 has a raised portion 74, for example in these first and second cases, the raised portion 74 of the balloon 20 may get caught on the edge portion 12d of the standing platform 12b. According to this embodiment, in such cases, it is possible to prevent the uneven portion 74 of the balloon 20 from getting caught on the edge portion 12d of the standing base 12b, and thereby it is effective in preventing the balloon 20 from bursting.

[0048] Reference is made to Fig. 8. The linear member 24 is inserted through the insertion passage 52. In this case, the linear member 24 is arranged radially outward of the main body 20e. In this case, compared to a case where the linear member 24 is arranged inside the main body 20e, the undulation at the undulating portion 74 of the balloon 20 generated around the balloon contact portion 72 of the linear member 24 tends to be larger. For this reason, the undulating portion 74 of the balloon 20 is likely to be caught on the upright table 12b, which easily causes the problem that the balloon 20 is torn. In this regard, the present embodiment is effective in that even with a structure in which such a problem is likely to occur, the above-described configuration can suppress the situation where the balloon 20 is torn.

[0049] Consider a case where a temperature sensor 64 is used as the linear member 24. In this case, it may be required to measure the temperature by the temperature sensor 64 at a position as close as possible to the surface of the balloon 20. In the present embodiment, as described above, the temperature sensor 64 is arranged radially outward of the main body 20e. Therefore, compared to a case where the temperature sensor 64 is arranged inside the main body 20e, the temperature can be measured at a position closer to the surface of the balloon 20.

[0050] As a method for arranging the linear member 24 radially outward with respect to the main body 20e, besides the case where the insertion passage forming portion 20f is configured by the protruding ridge portion 20g as in the present embodiment, there is a case where the balloon 20 has a multilayer structure. When the balloon 20 has such a multilayer structure, there is a problem that when the balloon 20 is to be expanded, the state in which the outer layer member and the inner layer member are in close contact with each other due to friction or the like is maintained, so that the balloon 20 cannot be expanded stably. In this regard, when the insertion passage forming portion 20f is configured by the protruding ridge portion 20g as in the present embodiment, unlike the multilayer structure, the state in which the outer layer member and the inner layer member are in close contact is not maintained, so the balloon 20 can be expanded stably.

[0051] Further, when the insertion passage forming portion 20f is configured by the protruding ridge portion 20g, the undulation at the undulating portion 74 of the balloon 20 generated around the balloon contact portion 72 of the linear member 24 is particularly likely to be large. For this reason, the structure results in that the aforementioned problem of the balloon 20 tearing is more likely to occur, but even in such a case, the aforementioned configuration is effective in that such a situation can be suppressed.

[0052] Furthermore, when the balloon 20 has a multilayer structure, it is easier to ensure tensile strength by orienting the molecules of the resin material constituting the balloon 20 through stretching. In contrast, when the insertion passage forming portion 20f of the balloon 20 is composed of a protruding portion 20g, it is difficult to orient the molecules of the resin material in the protruding portion 20g through stretching, and thus difficult to ensure tensile strength. Even when such problems exist, it is effective in preventing rupture by making it difficult for the undulating portion 74 of the balloon 20 to come into contact with the standing base 12b.

[0053] Other features of the balloon catheter 10 will be described. Refer to Figure 6. The proximal outer shaft 54 ​​is configured to be more difficult to bend in the Y direction than in the X direction. The proximal outer shaft 54 ​​will have bending anisotropy with different degrees of difficulty in bending in the X and Y directions. Here, difficulty in bending means that the bending stiffness is small in the specific direction mentioned. To compare the magnitude of such difficulty in bending, the measured value of bending stiffness obtained by a three-point bending test may be used. In this case, the proximal outer shaft 54 ​​can be straightened out and heated to remove its bending tendency, and then the three-point bending test can be performed using a specimen obtained by cutting the straightened proximal outer shaft 54.

[0054] The manufacturing process of the balloon catheter 10 may include, for example, an outer shaft manufacturing process to obtain a linearly extending proximal outer shaft 54 ​​by extrusion molding or the like, an assembly process to assemble the balloon catheter 10 using the proximal outer shaft 54, a bending process to bend the portion of the proximal outer shaft 54 ​​that is to become the bending region 70, and a heating process to heat the balloon catheter 10. In the bending process, in order to make the balloon catheter 10 compact, the portion of the linearly extending proximal outer shaft 54 ​​that is to become the bending region 70 is bent and then held in that bent state. In this bending process, the proximal outer shaft 54 ​​is bent with elastic deformation, so internal stress that generates a restoring force remains in the proximal outer shaft 54. This internal stress is released when the proximal outer shaft 54 ​​is heated in the subsequent heating process. As a result, a bend is created in the portion that was bent in the bending process, and a bending region 70 is provided in the proximal outer shaft 54. The heating process is performed, for example, to sterilize the balloon catheter 10 by heating.

[0055] In this embodiment, the proximal outer shaft 54 ​​is configured to be more difficult to bend in the Y direction than in the X direction. Therefore, in the aforementioned bending process, simply bending the proximal outer shaft 54 ​​in the direction that makes it easier to bend naturally causes the area that should become the bending region 70 to be bent in the X direction. Thus, by going through the subsequent heating process, a bending region 70 that has been given a tendency to bend in the X direction can be easily created in the proximal outer shaft 54 ​​during the manufacturing process of the balloon catheter 10.

[0056] To provide the aforementioned bending anisotropy, the proximal outer shaft 54 ​​may have the first and second lumens 60 and 62 described above. Furthermore, the partition wall portion 54a of the proximal outer shaft 54 ​​is not connected to the outer peripheral wall portion 54b at locations other than both ends of the partition wall portion 54a. As a result, when the proximal outer shaft 54 ​​tries to bend in the Y direction, the partition wall portion 54a provides significant resistance, making it difficult to bend in the Y direction. Conversely, when the proximal outer shaft 54 ​​tries to bend in the X direction, the partition wall portion 54a and the outer peripheral wall portion 54b are not connected except at both ends, so the partition wall portion 54a does not provide significant resistance, making it difficult to bend in the X direction. In other words, by forming the first and second lumens 60 and 62 described above, bending anisotropy can be provided to the proximal outer shaft 54 ​​without embedding a bending limiting member (described later) in the proximal outer shaft 54. Therefore, simplifying the structure of the proximal outer shaft 54 ​​is advantageous in reducing manufacturing costs.

[0057] In addition, to give the proximal outer shaft 54 ​​bending anisotropy, a bending limiting member (not shown) that limits bending in the Y direction may be embedded in the proximal outer shaft 54. The bending limiting member is configured to reduce the difficulty of bending in the X direction while increasing the difficulty of bending in the Y direction. To achieve this, the bending limiting member may be made of, for example, a leaf spring that extends elongated in the Y direction. Alternatively, the bending limiting member may be made of two rod springs embedded at locations spaced apart in the Y direction from the center line C54 of the proximal outer shaft 54.

[0058] Refer to Figures 10 and 11. The balloon catheter 10 includes a covering tube 82 that covers the catheter shaft 22 and forms an internal tube space 80 between the catheter shaft 22 and the covering tube 82. The covering tube 82 covers an axial range that straddles the boundary 84 between the balloon 20 and the catheter shaft 22. In this embodiment, the covering tube 82 covers an axial range that straddles the boundary 84 proximal to the balloon 20. The covering tube 82 is fixed to the balloon 20 by welding or the like on the balloon 20 side in the axial direction relative to the internal tube space 80. The covering tube 82 is also fixed to the catheter shaft 22 by welding or the like on the opposite side of the balloon 20 in the axial direction relative to the internal tube space 80. As a result, the internal tube space 80 is airtight with respect to the external space outside the balloon catheter 10. To make the internal tube space 80 airtight, the insertion passage 52 of the balloon 20 may be filled with adhesive or the like.

[0059] The catheter shaft 22 has an insertion lumen 86 through which the linear member 24 is inserted, and an extraction hole 88 for drawing the linear member 24 out from the inside of the catheter shaft 22 (insertion lumen 86) into the tube space 80. The insertion lumen 86 and the extraction hole 88 are formed in the shaft that constitutes the catheter shaft 22, and in this embodiment they are formed in the proximal outer shaft 54. The insertion lumen 86 may also be formed by the first lumen 60 of the proximal outer shaft 54, as in this embodiment.

[0060] The lead-out hole 88 is formed in the outer peripheral wall of the shaft that separates the insertion lumen 86 from the space outside the shaft that forms the insertion lumen 86. The linear member 24 passes through the insertion lumen 86, the lead-out hole 88, and the internal space 80 of the tube in that order before being inserted into the insertion passage 52 of the balloon 20. In this embodiment, two linear members 24 are led out to the outside from a common lead-out hole 88. One linear member 24 is positioned to extend from the lead-out hole 88 toward one side in the circumferential direction and is inserted into one insertion passage 52 of the balloon 20. The other linear member 24 is positioned to extend from the lead-out hole 88 toward the other side in the circumferential direction and is inserted into the other insertion passage 52 of the balloon 20.

[0061] Preferably, the withdrawal hole 88 may be provided at a position that satisfies the positional conditions described above. That is, the withdrawal hole 88 may be provided in the inner bending direction X1 of the bending region 70 in the X direction or in the Y direction with respect to the center line C10 of the balloon catheter 10. Here, we show the case in which the withdrawal hole 88 is provided in the inner bending direction X1 of the bending region 70 in the X direction. Furthermore, this inner bending direction is shown as an example where it is the eccentric direction D of the first lumen 60.

[0062] The balloon catheter 10 does not necessarily have to be equipped with a deflection mechanism for deflecting the distal end of the catheter shaft 22 in a specific direction, as in this embodiment. This deflection mechanism typically comprises a plurality of tension wires inserted into a lumen formed in the catheter shaft 22 and an operating member provided on the handle device 28. The operating member allows the operator to pull any of the plurality of tension wires proximal to the operating member, thereby deflecting the distal end of the catheter shaft 22 in a specific direction. By not providing such a deflection mechanism, the structure of the balloon catheter 10 can be simplified.

[0063] For example, the outer diameter of the temperature detection section 64a of the linear member 24 is Φ0.2 mm, the outer diameter of the sensor wiring 64b is Φ0.08 to Φ0.12 mm, and the wall thickness of the main body portion 20e of the balloon 20 is 0.05 mm. Also, for example, if the outer diameter of the main body portion 20e of the balloon 20 is Φ4 mm to Φ6 mm, the amount of protrusion at the undulating portion 74 of the balloon 20 will be approximately 0.25 mm. Here, the amount of protrusion refers to the amount of radial outward protrusion at the undulating portion 74 of the balloon 20 from the outer circumferential surface of the circular balloon 20, assuming that the balloon 20 is circular and does not have undulating portions 74 in a cross section perpendicular to the axial direction. The ratio of the amount of protrusion at the undulating portion 74 of the balloon 20 to the outer diameter of the main body portion 20e of the balloon 20 is preferably 15% or less, and can be, for example, 4.2% to 6.3%.

[0064] Next, we will describe the transformation forms of each component described so far.

[0065] The balloon 20 may have a multilayer structure comprising an inner layer member and an outer layer member. In this case, the inner layer member may constitute the main body portion 20e, and the outer layer member may constitute the insertion passage forming portion 20f. In other words, the main body portion 20e and the insertion passage forming portion 20f may be separate components. Alternatively, the balloon 20 may consist only of the main body portion 20e and not have the insertion passage forming portion 20f. In this case, the main body portion 20e of the balloon 20 may be composed of a single layer structure.

[0066] The catheter shaft 22 does not necessarily have an inner shaft 56. The number and arrangement of lumens in the proximal outer shaft 54 ​​are not particularly limited. For example, a first lumen 60 may be formed on the centerline C54 of the proximal outer shaft 54, and multiple lumens, including a second lumen 62, may be formed surrounding the first lumen 60. In addition, the proximal outer shaft 54 ​​may have only one lumen.

[0067] The proximal outer shaft 54 ​​may have the same resistance to bending in the X and Y directions. In this case, care can be taken during the bending process to ensure that the proximal outer shaft 54 ​​always bends in the X direction, and then a subsequent heating process can be performed to create a bent region 70 that has a bent shape in the X direction. In the heating process, a mold may be prepared in which a cavity (groove) with a shape corresponding to the desired shape of the bent region 70 is formed, and the proximal outer shaft 54 ​​may be heated with the proximal outer shaft 54 ​​inserted into the cavity. This ensures that a proximal outer shaft 54 ​​having a bent region 70 with a bent shape can be reliably obtained.

[0068] The covering tube 82 may cover an axial range that spans the distal boundary between the balloon 20 and the catheter shaft 22. In this case, for example, the distal outer shaft 58 may be omitted, and an insertion lumen 86 and an exit hole 88 may be formed in the inner shaft 56. In this case, in addition to the insertion lumen 86 and exit hole 88 of the inner shaft 56, a part of the linear member 24 may be inserted from the distal side into the insertion passage 52 of the balloon 20 via the internal space 80 of the tube. The exit hole 88 may be provided on the outer side of the bend X2 in the X direction with respect to the center line C10 of the balloon catheter 10.

[0069] The balloon catheter 10 may be equipped with a deflection mechanism. The deflection mechanism may deflect the distal end of the catheter shaft 22 in either the X direction or the Y direction.

[0070] The contents of each component described in the embodiments above are illustrative. The abstract technical ideas derived from these should not be interpreted restrictively to the contents of this specification. Many design changes, such as modifications, additions, and deletions, are possible for each component described in the embodiments. Such modifications are emphasized with the notation "this form" or "embodiment." However, design changes are also permitted for contents without such notation. Any combination of the above components is also valid. The hatching applied to the cross-sections in the drawings does not limit the material to which the hatching is applied. The structures and numerical values ​​mentioned in the embodiments and variations naturally include those that can be considered identical when considering manufacturing tolerances, etc. Components composed of a single member in the description herein may be composed of multiple members. Similarly, components composed of multiple members may be composed of a single member.

[0071] This disclosure relates to balloon catheters.

[0072] 10...Balloon catheter, 12...Endoscope, 20...Balloon, 20e...Main body, 20f...Insertion passage forming section, 20g...Protruding section, 22...Catheter shaft, 24...Linear member, 50...Fluid chamber, 52...Insertion passage, 56...Inner shaft, 60...First lumen, 62...Second lumen, 70...Bending region, 72...Contact point, 80...Internal space of tube, 82...Coating tube, 88...Outlet hole.

Claims

1. A balloon catheter used in combination with an endoscope, comprising: a balloon; a catheter shaft having an outer shaft extending proximal to the balloon; and a linear member disposed inside the balloon and in contact with the balloon, wherein when the direction perpendicular to the centerline of the balloon catheter is defined as the first direction, and the direction perpendicular to the centerline and the first direction is defined as the second direction, the outer shaft has a bent region that is curved in the first direction, and the contact point of the linear member with respect to the balloon is located inside the bend of the bent region in the first direction or in the second direction relative to the centerline of the balloon catheter.

2. The balloon catheter according to claim 1, wherein the outer shaft is configured to be less likely to bend in the second direction than in the first direction.

3. The balloon catheter according to claim 1 or 2, wherein the outer shaft is formed having a first lumen eccentric in the first direction with respect to the center line of the outer shaft, and a second lumen provided on the opposite side of the eccentricity direction of the first lumen.

4. The balloon catheter according to claim 3, wherein the catheter shaft comprises an inner shaft inserted into the first lumen.

5. The balloon catheter according to any one of claims 1 to 4, wherein the bending region is provided in at least a part of the distal portion of the outer shaft.

6. A balloon catheter according to any one of claims 1 to 5, comprising a covering tube that covers the catheter shaft and forms an internal tube space between itself and the catheter shaft, wherein the catheter shaft has an extraction hole formed therein for drawing out the linear member from inside the catheter shaft into the internal tube space, and the extraction hole is provided on the inside of the bend in the bending region in the first direction or in the second direction with respect to the center line of the outer shaft.

7. The balloon catheter according to any one of claims 1 to 6, comprising a main body portion that forms a fluid chamber and an insertion passage forming portion that forms an insertion passage between itself and the main body portion radially outward from the main body portion, wherein the linear member is inserted into the insertion passage.

8. The balloon catheter according to claim 7, wherein the insertion passage forming portion is provided integrally with the main body portion and is composed of a ridge portion that protrudes radially outward from the main body portion.

9. The balloon catheter according to any one of claims 1 to 8, which is not provided with a deflection mechanism for deflecting the distal end of the catheter shaft in a specific direction.

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