WO2025204185A1 - Balloon catheter - Google Patents

Abstract

A balloon catheter (1) includes: a balloon group (11) that includes a plurality of balloons (10) that are provided so as to be parallel to each other in the circumferential direction z; and a covering material (100) that is provided on the outside in the radial direction of the balloon group (11). The balloon group (11) has: a center region (121) that includes a midpoint (P3) in the longitudinal direction x; a distal region (122) that is further to the distal side than the center region (121); and a proximal region (123) that is further to the proximal side than the center region (121). The covering material (100) is provided at at least the distal region (122) and the proximal region (123), and the maximum outer diameter (D121) of the balloon catheter (1) at the center region (121) is smaller than the maximum outer diameter (D122) of the balloon catheter (1) at the distal region (122) and the maximum outer diameter (D123) of the balloon catheter (1) at the proximal region (123).

Description

Balloon catheter

The present invention relates to a balloon catheter.

When narrowed areas harden due to calcification and other factors form on the inner walls of blood vessels, diseases such as angina pectoris and myocardial infarction occur. One treatment for these conditions is angioplasty, which uses a balloon catheter to expand the narrowed area. Angioplasty is a minimally invasive treatment that does not require open chest surgery like bypass surgery, and is widely performed.

Aortic stenosis is a condition in which the aortic valve hardens due to calcification, making it difficult to open and impeding blood flow. Treatment for aortic stenosis can involve open-chest surgery and catheter placement of a biological valve (artificial valve), replacing the hardened aortic valve with a biological valve.

Placed bioprosthetic valves deteriorate over time due to calcification, wear, and other factors. When an implanted bioprosthetic valve deteriorates, it must be replaced. One procedure under consideration for replacing a bioprosthetic valve is to apply high pressure to the implanted bioprosthetic valve using a braided balloon catheter or multiple balloon catheters, causing it to deform or break; the valve's lumen is then expanded, and a new bioprosthetic valve is then placed inside the deformed or broken bioprosthetic valve using techniques such as transcatheter aortic valve replacement.

As examples of balloon catheters used for dilating hardened stenotic lesions and placing biological valves, Patent Document 1 discloses a catheter characterized by having an expansion means composed of multiple expansion elements, with the walls of the multiple expansion elements combined to form a substantially circular cross section when the expansion means is inflated. Patent Document 2 discloses a balloon catheter having multiple balloon members, with multiple outer balloon members arranged to surround the outer surface of an inner balloon member. Patent Document 3 discloses a balloon catheter having multiple balloons that expand independently without being affected by the other balloons and that are separated and do not come into contact with the other balloons after expansion. Patent Document 4 discloses a device having a perfusion balloon with an internal passage and a balloon arranged in the internal passage of the perfusion balloon. Patent Document 5 discloses a catheter including first, second, and third balloons that can be inflated and deflated independently of each other.

Special Publication No. 03-013907 US Patent Application Publication No. 2012/0209375 JP 2018-175550 A Special table 2018-536474 publication International Publication No. 2021/054189

However, with the above-mentioned conventional balloon catheters, when multiple balloons are inflated to dilate the narrowed area or to deform or destroy the placed biological valve, the balloons can move within the biological lumen, causing misalignment, making it difficult to dilate the narrowed area or to deform or destroy the placed biological valve, and taking a long time.

In light of the above circumstances, the present invention aims to provide a balloon catheter that is less likely to shift the balloon's position and can accurately apply pressure to the desired location.

A balloon catheter according to an embodiment of the present invention that can solve the above problems is as follows.
[1] A balloon group including a plurality of balloons arranged in parallel with each other in the circumferential direction;
a covering material disposed radially outward of the balloon group,
The balloons constituting the balloon group each have a straight pipe portion, a distal tapered portion located distal to the straight pipe portion, and a proximal tapered portion located proximal to the straight pipe portion,
The balloon group has a central region including a midpoint in a longitudinal direction, a distal region located distal to the central region, and a proximal region located proximal to the central region,
the coating is disposed on at least the distal region and the proximal region;
A balloon catheter, wherein the maximum outer diameter of the balloon catheter in the central region is smaller than the maximum outer diameter of the balloon catheter in the distal region and the maximum outer diameter of the balloon catheter in the proximal region.
[2] The balloon catheter according to [1], wherein the thickness of the covering material in the central region is smaller than the thickness of the covering material in the distal region and the thickness of the covering material in the proximal region.
[3] The covering material includes a distal covering material disposed in the distal region and a proximal covering material disposed in the proximal region,
The balloon catheter according to [1], wherein the covering material is not provided in the central region.
[4] The balloon catheter according to any one of [1] to [3], wherein the coefficient of friction of the outer surface of the balloon catheter in the central region is greater than the coefficient of friction of the outer surface of the balloon catheter in the distal region and the coefficient of friction of the outer surface of the balloon catheter in the proximal region.
[5] The balloon catheter according to any one of [1] to [4], wherein the covering material is a tubular body that has the property of shrinking at least in the radial direction when heat is applied.
[6] The balloon catheter according to any one of [1] to [5], wherein the covering material includes a fiber or a wire.
[7] The balloon catheter according to any one of [1] to [6], wherein the covering material includes a film-like material.
[8] The balloon catheter according to any one of [1] to [7], wherein the balloon group includes an inner balloon and a plurality of outer balloons arranged radially outward of the inner balloon.
[9] A device further comprising a shaft having a longitudinal direction,
The balloon catheter according to any one of [1] to [8], wherein a plurality of the inner balloons are arranged at different positions in the longitudinal direction of the shaft.

With the above-mentioned balloon catheter, a covering material is disposed in at least the distal and proximal regions, and the maximum outer diameter of the balloon catheter in the central region is smaller than the maximum outer diameter of the balloon catheter in the distal region and the maximum outer diameter of the balloon catheter in the proximal region, so that the central region of the balloon group has a concave shape when the balloon group is in an expanded state. Therefore, this concave portion of the balloon can hold the stenosis area, biological valve, etc., making it less likely for the balloon to shift position.

1 is an overall view of a balloon catheter according to an embodiment of the present invention. 2 is an enlarged view of a portion of the balloon catheter shown in FIG. 1 where a balloon is disposed. 3 shows a cross-sectional view of the balloon catheter shown in FIG. 1 taken along line III-III. 4 shows a cross-sectional view of the balloon catheter shown in FIG. 1 taken along line IV-IV. 2 shows a cross-sectional view of the balloon catheter shown in FIG. 1 taken along the line VV. 10 is an enlarged view of a portion of a balloon catheter according to another embodiment of the present invention in which a balloon is disposed. FIG. 7 shows a cross-sectional view of the balloon catheter shown in FIG. 6 along line VII-VII.

The present invention will be described below based on the following embodiments, but the present invention is not limited to these embodiments, and can of course be implemented with appropriate modifications within the scope of the intent described above and below, all of which are within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings; in such cases, reference should be made to the specification or other drawings. The dimensions of the various components in the drawings may differ from the actual dimensions, as priority is given to aiding understanding of the features of the present invention.

A balloon catheter according to an embodiment of the present invention has a balloon group including a plurality of balloons arranged parallel to one another in the circumferential direction, and a covering material arranged radially outward of the balloon group. The balloons constituting the balloon group have a straight tube section, a distal tapered section located distal to the straight tube section, and a proximal tapered section located proximal to the straight tube section. The balloon group has a central region including a midpoint in the longitudinal direction, a distal region located distal to the central region, and a proximal region located proximal to the central region. The covering material is arranged in at least the distal and proximal regions, and the maximum outer diameter of the balloon catheter in the central region is smaller than the maximum outer diameter of the balloon catheter in the distal region and the maximum outer diameter of the balloon catheter in the proximal region.

Balloon catheters according to embodiments of the present invention will now be described with reference to Figures 1 to 7. Figure 1 is an overall view of a balloon catheter according to one embodiment of the present invention, and Figure 2 is an enlarged view of the portion of the balloon catheter shown in Figure 1 where a balloon is located. Figure 3 is a III-III cross-sectional view of the balloon catheter shown in Figure 1, showing a cross-sectional view perpendicular to the longitudinal direction of the central region where a group of balloons is present. Figure 4 is a IV-IV cross-sectional view of the balloon catheter shown in Figure 1, showing a cross-sectional view perpendicular to the longitudinal direction of the distal region where a group of balloons is present. Figure 5 is a V-V cross-sectional view of the balloon catheter shown in Figure 1, showing a cross-sectional view perpendicular to the longitudinal direction of the proximal region where a group of balloons is present. Figure 6 is an enlarged view of the portion where a balloon is located in a balloon catheter according to another embodiment of the present invention, and Figure 7 is a VII-VII cross-sectional view of the balloon catheter shown in Figure 6, showing a cross-sectional view perpendicular to the longitudinal direction of the central region where a group of balloons is present.

As shown in Figures 1 to 7, the balloon catheter 1 has a balloon group 11 including multiple balloons 10 arranged in parallel with one another in the circumferential direction z, and a covering material 100 arranged radially outward of the balloon group 11.

The balloon 10 has a longitudinal direction x, a radial direction y connecting the centroid of the outer edge of the balloon 10 to a point on the outer edge in a cross section perpendicular to the longitudinal direction x, and a circumferential direction z along the outer edge of the balloon 10 in a cross section perpendicular to the longitudinal direction x. In this specification, the direction toward the user in the longitudinal direction x is referred to as the proximal side, and the direction opposite the proximal side, i.e., toward the patient being treated, is referred to as the distal side. Furthermore, when each component or part is divided into two equal parts in the longitudinal direction x of the balloon 10, the part of each component or part located on the distal side is referred to as the distal part of each component or part, and the part of each component or part located on the proximal side is referred to as the proximal part of each component or part. The distal end of each component or part is the end located most distally of each component or part. The proximal end of each component or part is the end located most proximal of each component or part. The term "end" includes the peripheral portion of the end. That is, the distal end refers to the distal end and the area surrounding the distal end, and the proximal end refers to the proximal end and the area surrounding the proximal end.

Components and parts other than the balloon 10 also have longitudinal, radial, and circumferential directions, which may or may not be the same as the longitudinal direction x, radial direction y, and circumferential direction z of the balloon 10. However, for ease of understanding, this specification will be described as assuming that all components and parts have the same longitudinal, radial, and circumferential directions as the longitudinal direction x, radial direction y, and circumferential direction z of the balloon 10.

A balloon group 11 having multiple balloons 10 is located at the distal portion of the balloon catheter 1. The balloon 10 can be expanded by introducing fluid into the inner cavity of the balloon 10, and can be deflated by discharging fluid from the inner cavity of the balloon 10. To control the expansion and contraction of the balloon 10, fluid can be introduced or discharged using an indeflator (balloon pressurizer). The fluid can be, for example, saline or a mixture of a contrast agent and saline. The fluid may also be pressurized fluid pressurized by a pump or the like.

Examples of materials that can be used to form the balloon 10 include polyamide resins such as nylon 11 and nylon 12, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyurethane resins, and thermoplastic elastomers such as polyether block amide copolymers.

As shown in Figures 2 and 6, the balloons 10 constituting the balloon group 11 have a straight tube section 111, a distal tapered section 112 located distal to the straight tube section 111, and a proximal tapered section 113 located proximal to the straight tube section 111. Since the balloon 10 has the straight tube section 111, the distal tapered section 112, and the proximal tapered section 113, it is also preferable that the balloon group 11 has a straight tube section, a distal tapered section located distal to the straight tube section, and a proximal tapered section located proximal to the straight tube section.

The straight tube portion 111 is preferably generally cylindrical and has approximately the same diameter in the longitudinal direction x, but may have different diameters in the longitudinal direction x. The distal tapered portion 112 and the proximal tapered portion 113 are preferably formed into a generally conical or truncated conical shape, with diameters decreasing as they move away from the straight tube portion 111. Because the straight tube portion 111 has the largest diameter, when the balloon group 11 is expanded at a lesion such as a stenosis, the straight tube portions of the balloons 10 constituting the balloon group 11 can sufficiently contact the lesion, facilitating treatment such as dilation of the lesion. Furthermore, because the distal tapered portion 112 and the proximal tapered portion 113 have reduced diameters, the outer diameters of the proximal and distal ends of the balloons 10 constituting the balloon group 11 can be reduced when the balloon group 11 is deflated, making it easier to insert the balloon catheter 1 into a body cavity.

The balloons 10 constituting the balloon group 11 preferably further have a distal sleeve portion 114 located distal to the distal tapered portion 112, and a proximal sleeve portion 115 located proximal to the proximal tapered portion 113. In the balloon 10, the straight tube portion 111, distal tapered portion 112, and proximal tapered portion 113 are portions that expand when fluid is introduced into the balloon 10, whereas the distal sleeve portion 114 and proximal sleeve portion 115 preferably do not expand. By not allowing the distal sleeve portion 114 and proximal sleeve portion 115 to expand, at least a portion of the distal sleeve portion 114 and at least a portion of the proximal sleeve portion 115 can be configured to be easily fixed to other objects, such as the shaft 70 of the balloon catheter 1. Details of the shaft 70 will be described later.

As shown in FIG. 2, the balloon group 11 has a central region 121 that includes a midpoint P3 in the longitudinal direction x, a distal region 122 that is located distal to the central region 121, and a proximal region 123 that is located proximal to the central region 121. In other words, the central region 121 is the portion that includes the midpoint P3 of the length of the balloon group 11 in the longitudinal direction x.

The central region 121 is a region that includes the midpoint P3 in the longitudinal direction x of the balloon group 11. The central region 121 is preferably a region that includes the midpoint in the longitudinal direction x of the straight pipe portion 111 of each balloon 10 included in the balloon group 11. The central region 121 is preferably a region that has a length in the longitudinal direction x that is 20% or more of the length of the straight pipe portion 111, more preferably a region that has a length of 25% or more of the length of the straight pipe portion 111, and even more preferably a region that has a length of 30% or more of the length of the straight pipe portion 111. By setting the lower limit of the length of the central region 121 in the longitudinal direction x within the above range, the size of the central region 121 becomes more likely to be appropriate.

The distal region 122 is a region located distal to the central region 121. In the longitudinal direction x, there may be a further region different from the central region 121 and the distal region 122 between the central region 121 and the distal region 122, but it is preferable that the central region 121 and the distal region 122 are adjacent to each other. In other words, it is preferable that the distal end of the central region 121 and the proximal end of the distal region 122 are in contact. Furthermore, there may be a further region different from the distal region 122 distal to the distal region 122, but it is preferable that the distal region 122 is a region that includes the distal end 111d of the straight tube section 111.

The distal region 122 is preferably a region having a length in the longitudinal direction x that is 20% or more of the length of the straight tube portion 111, more preferably a region having a length that is 25% or more of the length of the straight tube portion 111, and even more preferably a region having a length that is 30% or more of the length of the straight tube portion 111. By setting the lower limit of the length of the distal region 122 in the longitudinal direction x within the above range, the size of the distal region 122 is more likely to be appropriate.

The proximal region 123 is a region located proximal to the central region 121. In the longitudinal direction x, there may be a further region different from the central region 121 and the proximal region 123 between the central region 121 and the proximal region 123, but it is preferable that the central region 121 and the proximal region 123 are adjacent to each other. In other words, it is preferable that the proximal end of the central region 121 and the distal end of the proximal region 123 are in contact. Furthermore, there may be a further region different from the proximal region 123 proximal to the proximal region 123, but it is preferable that the proximal region 123 is a region that includes the proximal end 111p of the straight tube section 111.

The proximal region 123 is preferably a region having a length in the longitudinal direction x that is 20% or more of the length of the straight pipe section 111, more preferably a region having a length that is 25% or more of the length of the straight pipe section 111, and even more preferably a region having a length that is 30% or more of the length of the straight pipe section 111. By setting the lower limit of the length of the proximal region 123 in the longitudinal direction x within the above range, the size of the proximal region 123 is more likely to be appropriate.

As shown in Figures 1 to 6, the covering material 100 is a member disposed radially outward from the balloon group 11. The covering material 100 is disposed in at least the distal region 122 and the proximal region 123. In other words, the covering material 100 may or may not be disposed in the central region 121.

As shown in Figures 3 to 6, the maximum outer diameter D121 of the balloon catheter 1 in the central region 121 is smaller than the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123. In other words, the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 is larger than the maximum outer diameter D121 of the balloon catheter 1 in the central region 121, and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123 is larger than the maximum outer diameter D121 of the balloon catheter 1 in the central region 121. Note that the maximum outer diameter D121 of the balloon catheter 1 in the central region 121, the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122, and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123 refer to the outer diameters of the balloon group 11 when inflated. The balloon group 11 being inflated can be rephrased as the expanded state of the balloon group 11, and refers to a state in which fluid is introduced into the lumen of each of the multiple balloons 10 that make up the balloon group 11, and all of the balloons 10 that make up the balloon group 11 are inflated.

Because the maximum outer diameter D121 of the balloon catheter 1 in the central region 121 is smaller than the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123, when the balloon group 11 is inflated, the outer diameter of the balloon catheter 1 in the central region 121 becomes smaller than the outer diameters of the balloon catheter 1 in the distal region 122 and the proximal region 123, forming a concave portion in the central region 121. Because a stenosis, biological valve, etc. can be sandwiched and held in this concave portion of the balloon group 11, the balloon catheter 1 is less likely to shift position when inflated.

The maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 may be larger or smaller than the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123, but is preferably the same as the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123. The maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123 being the same means that the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 in the proximal region 123 are approximately the same, and specifically means that the maximum outer diameter D122 in the distal region 122 is between 90% and 110% of the maximum outer diameter D123 in the proximal region 123. By making the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123 the same, the expansion forces of the distal region 122 and the proximal region 123 when the balloon group 11 is expanded can be made to be approximately the same, making it easier to uniformly expand stenotic areas, biological valves, etc. held in the concave portion of the balloon group 11 from both sides of the concave shape.

The maximum outer diameter D121 of the balloon catheter 1 in the central region 121 is preferably 99% or less, more preferably 98% or less, and even more preferably 97% or less of the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123. By setting the upper limit of the ratio of the maximum outer diameter D121 of the balloon catheter 1 in the central region 121 to the maximum outer diameter D122 in the distal region 122 and the maximum outer diameter D123 in the proximal region 123 within the above range, a concave portion is more likely to be formed in the central region 121 of the balloon group 11, making it easier to clamp and hold a stenosis, a biological valve, etc. in this concave portion. Furthermore, the maximum outer diameter D121 of the balloon catheter 1 in the central region 121 is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more of the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123. By setting the lower limit of the ratio of the maximum outer diameter D121 of the balloon catheter 1 in the central region 121 to the maximum outer diameter D122 of the distal region 122 and the maximum outer diameter D123 of the proximal region 123 within the above range, it becomes easier to increase the expansion force of the balloon 10 even in the concave-shaped portions of the balloon group 11, enabling efficient expansion of stenotic areas, biological valves, etc.

3 to 5, the thickness T121 of the covering material 100 in the central region 121 is preferably smaller than the thickness T122 of the covering material 100 in the distal region 122 and the thickness T123 of the covering material 100 in the proximal region 123. In other words, the thickness T122 of the covering material 100 in the distal region 122 is preferably larger than the thickness T121 of the covering material 100 in the central region 121, and the thickness T123 of the covering material 100 in the proximal region 123 is preferably larger than the thickness T121 of the covering material 100 in the central region 121. By making the thickness T121 of the covering material 100 in the central region 121 smaller than the thickness T122 of the covering material 100 in the distal region 122 and the thickness T123 of the covering material 100 in the proximal region 123, the depth of the concave shape in the center of the balloon group 11 can be increased, making it easier to grasp a stenotic area, a biological valve, etc.

The thickness T122 of the coating material 100 in the distal region 122 may be greater than or less than the thickness T123 of the coating material 100 in the proximal region 123, but is preferably the same as the thickness T123 of the coating material 100 in the proximal region 123. The thickness T122 of the coating material 100 in the distal region 122 and the thickness T123 of the coating material 100 in the proximal region 123 being the same means that the thickness T122 of the coating material 100 in the distal region 122 is greater than or equal to 90% and less than 110% of the thickness T123 of the coating material 100 in the proximal region 123. By making the thickness T122 of the covering material 100 in the distal region 122 and the thickness T123 of the covering material 100 in the proximal region 123 the same, the expansion force in the distal region 122 and the expansion force in the proximal region 123 when the balloon group 11 is in an expanded state, as well as the outer diameter of the balloon catheter 1 in the distal region 122 and the outer diameter of the balloon catheter 1 in the proximal region 123, tend to be approximately the same, making it easier to stably expand stenotic areas, biological valves, etc. using the balloon catheter 1.

The thickness T121 of the covering material 100 in the central region 121 is preferably 80% or less, more preferably 70% or less, and even more preferably 60% or less of the thickness T122 of the covering material 100 in the distal region 122 and the thickness T123 of the covering material 100 in the proximal region 123. By setting the upper limit of the ratio of the thickness T121 of the covering material 100 in the central region 121 to the thickness T122 of the covering material 100 in the distal region 122 and the thickness T123 of the covering material 100 in the proximal region 123 within the above range, it becomes easier to ensure a sufficient difference between the thickness T121 of the covering material 100 in the central region 121 and the thickness T122 of the covering material 100 in the distal region 122 and the thickness T123 of the covering material 100 in the proximal region 123, making it easier to form a concave portion in the center of the balloon group 11. The lower limit of the ratio of the thickness T121 of the covering material 100 in the central region 121 to the thickness T122 of the covering material 100 in the distal region 122 and the thickness T123 of the covering material 100 in the proximal region 123 can be, for example, 1% or more, 5% or more, or 10% or more.

As shown in Figures 6 and 7, the covering material 100 preferably includes a distal covering material 101 disposed in the distal region 122 and a proximal covering material 102 disposed in the proximal region 123, with no covering material 100 disposed in the central region 121. Since the covering material 100 includes the distal covering material 101 and the proximal covering material 102 and no covering material 100 disposed in the central region 121, the covering material 100 is present in the distal region 122 and the proximal region 123, but is absent in the central region 121. As a result, the difference between the outer diameter of the balloon group 11 in the central region 121 and the outer diameter of the balloon group 11 in the distal region 122 and the proximal region 123 can be increased, making it easier to form a deep concave portion in the center of the balloon group 11.

The thickness of the distal covering material 101 may be different from the thickness of the proximal covering material 102, but is preferably the same. Having the same thickness for the distal covering material 101 and the proximal covering material 102 means that the thickness of the distal covering material 101 is between 90% and 110% of the thickness of the proximal covering material 102. Having the same thickness for the distal covering material 101 and the proximal covering material 102 makes it easier for the outer diameter and expansion force of the balloon catheter 1 to be similar in the distal region 122 and the proximal region 123 of the balloon group 11.

The balloon catheter 1 may have one or more distal covering materials 101. The balloon catheter 1 may have one or more proximal covering materials 102. The number of distal covering materials 101 may be the same as or different from the number of proximal covering materials 102. If the balloon catheter 1 has multiple distal covering materials 101 or multiple proximal covering materials 102, it is preferable that the multiple distal covering materials 101 and multiple proximal covering materials 102 are arranged in the longitudinal direction x.

It is preferable that the coefficient of friction of the outer surface of the balloon catheter 1 in the central region 121 is greater than the coefficient of friction of the outer surface of the balloon catheter 1 in the distal region 122 and the coefficient of friction of the outer surface of the balloon catheter 1 in the proximal region 123. In other words, it is preferable that the coefficient of friction of the outer surface of the balloon catheter 1 in the distal region 122 is less than the coefficient of friction of the outer surface of the balloon catheter 1 in the central region 121, and that the coefficient of friction of the outer surface of the balloon catheter 1 in the proximal region 123 is less than the coefficient of friction of the outer surface of the balloon catheter 1 in the central region 121. By having the coefficient of friction of the outer surface of the balloon catheter 1 in the central region 121 greater than the coefficient of friction of the outer surface in the distal region 122 and the coefficient of friction of the outer surface in the proximal region 123, the slipperiness of the balloon group 11 in the central region 121 can be made lower than the slipperiness in the distal region 122 and the proximal region 123. As a result, the slipperiness of the concave portion located in the center of the balloon group 11 is reduced, making it harder for the stenotic area or biological valve that the concave portion grips to slip, thereby improving the effectiveness of preventing displacement of the balloon group 11. The coefficient of friction of the outer surface of the balloon catheter 1 can be determined in accordance with JIS K7125, "Test method for friction coefficient of plastic films and sheets."

Methods for making the coefficient of friction of the outer surface of the balloon catheter 1 in the central region 121 greater than the coefficient of friction of the outer surface of the balloon catheter 1 in the distal region 122 and the coefficient of friction of the outer surface of the balloon catheter 1 in the proximal region 123 include, for example, arranging a member with a higher coefficient of friction than the distal covering material 101 and the proximal covering material 102 on the outer surface of the central region 121, coating the outer surface of the balloon 10 located in the central region 121 with a material with a high coefficient of friction, forming fine irregularities on the outer surface of the balloon 10 located in the central region 121, or constructing the distal covering material 101 and the proximal covering material 102 from a material with a lower coefficient of friction than the outer surface of the central region 121. In particular, a method for making the coefficient of friction of the outer surface of the balloon catheter 1 in the central region 121 greater than the coefficients of friction of the outer surface of the balloon catheter 1 in the distal region 122 and the proximal region 123 is preferably to construct the distal covering material 101 and the proximal covering material 102 from a material having a lower coefficient of friction than the outer surface of the central region 121. By constructing the distal covering material 101 and the proximal covering material 102 from a material having a lower coefficient of friction than the outer surface of the central region 121, the coefficient of friction of the central region 121 can be easily made higher than the coefficients of friction of the distal region 122 and the proximal region 123, and the strength of the balloon group 11 can also be easily increased.

The dressing material 100 is preferably a tubular body that has the property of shrinking at least in the radial direction y when heat is applied. Examples of tubular bodies that have the property of shrinking at least in the radial direction y when heat is applied include heat-shrink tubing. When the dressing material 100 is a tubular body that has the property of shrinking at least in the radial direction y when heat is applied, it becomes easier to adhere the dressing material 100 to the balloon group 11 and firmly fix it. This makes it less likely that the dressing material 100 will come off the balloon group 11 and scatter in a biological lumen, etc.

It is also preferable that the covering material 100 contains fibers or wires. Specific examples include covering materials 100 that have a braided structure in which fibers or wires are woven, a structure in which fibers or wires are wound in at least one of the longitudinal direction x and the circumferential direction z, or a layered structure that includes fibers or wires.

Examples of materials constituting the fibers or wires contained in the covering material 100 include metal wires such as stainless steel, carbon steel, and nickel-titanium alloys, as well as polyamide resins (e.g., nylon), polyolefin resins (e.g., polyethylene and polypropylene), polyester resins (e.g., PET), aromatic polyether ketone resins (e.g., PEEK), polyimide resins, aromatic polyamide resins (e.g., aramid), and fluorine-based resins (e.g., PTFE, PFA, FEP, ETFE). The fibers or wires contained in the covering material 100 may have a monofilament structure or a multifilament structure.

It is also preferable that the dressing material 100 includes a film-like material. The film-like material may be made of a single material, such as a synthetic resin, or may be made of multiple materials, such as a base material and a filler.

Examples of materials that make up the film-like substance or the base material of the film-like substance include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, polyimide resins, fluorine-based resins, vinyl chloride resins, silicone resins, natural rubber, and synthetic rubber. The material that makes up the filler may be an organic material, an inorganic material, or an organic-inorganic composite material. Examples of organic materials include thermosetting resins such as phenol, epoxy, and urea, and thermoplastic resins such as polyester, polyvinylidene chloride, polystyrene, and polymethacrylate. Examples of inorganic materials include shirasu, perlite, glass, silica, alumina, zirconia, and carbon. The shape of the filler may be, for example, particulate (e.g., spherical), acicular, fibrous, or plate-like.

As shown in Figures 3 to 7, the balloon group 11 preferably includes an inner balloon 40 and multiple outer balloons 50 arranged radially outward of the inner balloon 40. That is, the balloon group 11 preferably includes an inner balloon 40 and multiple outer balloons 50 arranged along the outer periphery of the inner balloon 40. By including the inner balloon 40 and multiple outer balloons 50 arranged radially outward of the inner balloon 40, the multiple outer balloons 50 suppress the outward expansion of the inner balloon 40, and the inner balloon 40 suppresses the inward expansion of the multiple outer balloons 50. As a result, the inner balloon 40 and the multiple outer balloons 50 mutually suppress their respective expansions, thereby increasing the pressure resistance of the balloon group 11 and increasing the hardness of the multiple balloons 10 that make up the balloon group 11, thereby improving their expansion force. Furthermore, the inner balloon 40 and the multiple outer balloons 50 mutually suppress their respective expansions, making it difficult for the multiple balloons 10 that make up the balloon group 11 to inflate. Therefore, even when high pressure is applied to each of the balloons 10 that make up the balloon group 11, over-expansion of the balloons 10 is suppressed, preventing the balloon group 11 from expanding beyond the intended outer diameter, reducing damage to the aortic valve and other internal lumen of the body and improving safety.

The number of inner balloons 40 may be multiple, but is preferably one. In other words, the balloon group 11 preferably has one inner balloon 40 and multiple outer balloons 50. Having only one inner balloon 40 makes it less likely for the inner balloon 40 to move inside the multiple outer balloons 50 when the balloon group 11 is inflated. As a result, the inner balloon 40 can more easily suppress the inflation of the multiple outer balloons 50, which increases the hardness of the multiple balloons 10 that make up the balloon group 11 and makes it easier to increase the inflation force.

The number of outer balloons 50 included in the balloon group 11 is preferably three or more, more preferably four or more, and even more preferably five or more. Setting the lower limit of the number of outer balloons 50 included in the balloon group 11 within the above range makes it easier for the outer balloons 50 to surround the outer periphery of the inner balloon 40, making it easier for the outer balloons 50 to suppress the expansion of the inner balloon 40. As a result, when fluid is introduced into the lumen of both the inner balloon 40 and the outer balloons 50 to expand the balloon group 11, the inner balloon 40 becomes less likely to expand, increasing the hardness of the inner balloon 40 and making it easier to increase the expansion force of the balloon group 11. Furthermore, the number of outer balloons 50 included in the balloon group 11 is preferably 20 or less, more preferably 12 or less, even more preferably 10 or less, and particularly preferably 8 or less. By setting the upper limit of the number of outer balloons 50 included in the balloon group 11 within the above range, the outer balloons 50 are less likely to move in the circumferential direction z when the balloon group 11 is inflated, making it easier for the multiple outer balloons 50 to suppress the inflation of the inner balloon 40.

The materials listed as materials for constructing the balloon 10 can be used as materials for constructing the inner balloon 40 and the outer balloon 50. The material for constructing the outer balloon 50 may be the same as the material for constructing the inner balloon 40, or it may be different.

The materials constituting each of the multiple outer balloons 50 included in the balloon group 11 may be different, but are preferably the same. In other words, it is preferable that the balloon group 11 includes multiple outer balloons 50 made from the same material. By making each of the multiple outer balloons 50 out of the same material, the degree of expansion, hardness, etc. of each of the multiple outer balloons 50 in the circumferential direction z can be made to be approximately the same.

When the balloon group 11 is in an expanded state, the maximum outer diameters of the multiple outer balloons 50 included in the balloon group 11 may be different, but are preferably the same. The multiple outer balloons 50 included in the balloon group 11 having the same maximum outer diameter means that the maximum outer diameters of the multiple outer balloons 50 are approximately the same; specifically, it means that the maximum outer diameter of one outer balloon 50 is between 90% and 110% of the maximum outer diameters of all the other outer balloons 50. When the balloon group 11 is in an expanded state, the multiple outer balloons 50 included in the balloon group 11 have the same maximum outer diameter, making it easier to align the timing of expansion of all of the outer balloons 50 included in the balloon group 11 and to control the expansion of the balloon group 11.

When the balloon group 11 is in an expanded state, the maximum outer diameter of the inner balloon 40 may be the same as or different from the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. The fact that the maximum outer diameter of the inner balloon 40 is the same as the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11 means that the maximum outer diameter of the inner balloon 40 and the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11 are approximately the same. Specifically, this means that the maximum outer diameter of the inner balloon 40 is between 90% and 110% of the average value of the maximum outer diameters of each of the multiple outer balloons 50. When the balloon group 11 is in an expanded state, the maximum outer diameter of the inner balloon 40 is the same as the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11, which makes it easier to balance the force that attempts to expand the inner balloon 40 with the force that attempts to suppress the expansion of the inner balloon 40 due to the expansion of the multiple outer balloons 50. As a result, the rigidity of the balloon group 11 is increased, making it easier to increase the expansion force of the balloon group 11.

When the balloon group 11 is in an expanded state, the maximum outer diameter of the inner balloon 40 is preferably larger than the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. When the balloon group 11 is in an expanded state, the maximum outer diameter of the inner balloon 40 is larger than the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11, which makes it easier to evenly arrange the multiple outer balloons 50 along the outer periphery of the expanded inner balloon 40. Therefore, when the balloon group 11 is deflated, the multiple outer balloons 50 are more likely to fold, making it possible to reduce the outer diameter of the balloon catheter 1 at the portion where the balloon group 11 is located.

When the balloon group 11 is in an expanded state, the maximum outer diameter of the inner balloon 40 is preferably 1.10 times or more, more preferably 1.15 times or more, and even more preferably 1.20 times or more, the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. By setting the lower limit of the ratio between the maximum outer diameter of the inner balloon 40 and the maximum outer diameter of each of the outer balloons 50 when the balloon group 11 is in an expanded state within the above range, it becomes easier to evenly arrange the multiple outer balloons 50 along the outer periphery of the inner balloon 40. Furthermore, when the balloon group 11 is in an expanded state, the maximum outer diameter of the inner balloon 40 is preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less, the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. By setting the upper limit of the ratio between the maximum outer diameter of the inner balloon 40 and the maximum outer diameter of the outer balloon 50 when the balloon group 11 is in the expanded state within the above range, it becomes easier to reduce the outer diameter of the portion of the balloon catheter 1 where the balloon group 11 is located when the balloon 10 is in the deflated state, making the balloon catheter 1 less invasive.

When the balloon group 11 is in an expanded state, the length L50 from the distal end 50d of the outer balloon 50 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x of each of the multiple outer balloons 50 included in the balloon group 11 may be different, but is preferably the same. The length L50 from the distal end 50d of the outer balloon 50 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x of each of the multiple outer balloons 50 included in the balloon group 11 being the same means that the length L50 in the longitudinal direction x of each of the multiple outer balloons 50 included in the balloon group 11 is approximately the same; specifically, this means that the length L50 in the longitudinal direction x of one outer balloon 50 is between 90% and 110% of the length L50 in the longitudinal direction x of all the other outer balloons 50. When the balloon group 11 is in an expanded state, the length L50 in the longitudinal direction x of the multiple outer balloons 50 included in the balloon group 11 is the same, which makes it easier to synchronize the expansion timing of all outer balloons 50 and makes it easier to control the expansion of the balloon group 11.

When the balloon group 11 is in an expanded state, the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40 in the longitudinal direction x is preferably shorter than the length L50 from the distal end 50d of the outer balloon 50 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. By making the length L40 of the inner balloon 40 shorter than the length L50 of the outer balloon 50, the inner balloon 40 is restrained by the outer balloon 50 during expansion of the balloon group 11, making it less likely for the inner balloon 40 to shift position. This makes it easier for the balloon group 11 to expand more in areas where the inner balloon 40 is present than in areas where the inner balloon 40 is not present, making it easier to apply pressure to areas where the inner balloon 40 is present, allowing for accurate application of pressure to the desired location. Furthermore, the balloon group 11 is less likely to expand more in areas where the inner balloon 40 is not present, making it more difficult to apply pressure, which reduces the likelihood of stress being placed on areas that are not the desired location, thereby improving the minimally invasive nature of the balloon catheter 1.

When the balloon group 11 is in an expanded state, the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40 in the longitudinal direction x is preferably 95% or less, more preferably 90% or less, and even more preferably 85% or less of the length L50 from the distal end 50d of the outer balloon 50 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. By setting the upper limit of the ratio of the length L40 of the inner balloon 40 to the length L50 of the outer balloon 50 within the above range, a balloon catheter 1 can be made that makes it easy to apply high pressure accurately to the desired location. Furthermore, when the balloon group 11 is in an expanded state, the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40 in the longitudinal direction x is preferably at least 20%, more preferably at least 25%, and even more preferably at least 30% of the length L50 from the distal end 50d of the outer balloon 50 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. By setting the lower limit of the ratio of the length L40 of the inner balloon 40 to the length L50 of the outer balloon 50 within the above range, it becomes easier to apply pressure to a sufficient area of the target site using the balloon catheter 1, making it easier to efficiently dilate a stenotic site and deform or destroy a biological valve.

As shown in Figures 2 and 6, it is preferable that the distal end 40d of the inner balloon 40 is located proximal to the distal end 50d of the outer balloon 50, and that the proximal end 40p of the inner balloon 40 is located distal to the proximal end 50p of the outer balloon 50. By configuring the distal end 40d of the inner balloon 40 to be proximal to the distal end 50d of the outer balloon 50 and the proximal end 40p of the inner balloon 40 to be distal to the proximal end 50p of the outer balloon 50, the distal end of the inner balloon 40 and the distal end of the outer balloon 50 are less likely to overlap, and the proximal end of the inner balloon 40 and the proximal end of the outer balloon 50 are less likely to overlap. As a result, when the balloon group 11 is in a deflated state, the outer diameter of the portion of the balloon catheter 1 where the balloon group 11 is located can be easily reduced.

When the balloon group 11 is in an expanded state, it is preferable that the distal end of the distal tapered portion of the inner balloon 40 is proximal to the proximal end of the distal tapered portion of the outer balloon 50, and that the proximal end of the proximal tapered portion of the inner balloon 40 is distal to the distal end of the proximal tapered portion of the outer balloon 50. Since the distal end of the distal tapered portion of the inner balloon 40 is proximal to the proximal end of the distal tapered portion of the outer balloon 50 and the proximal end of the proximal tapered portion of the inner balloon 40 is distal to the distal end of the proximal tapered portion of the outer balloon 50, the positions of the distal tapered portion of the inner balloon 40 and the distal tapered portion of the outer balloon 50 do not overlap, and the positions of the proximal tapered portion of the inner balloon 40 and the proximal tapered portion of the outer balloon 50 do not overlap. As a result, the outer diameter of the balloon group 11 is less likely to increase when the balloon group 11 is in an expanded state, making it easier to improve minimal invasiveness.

It is preferable that the distance from the distal end 40d of the inner balloon 40 to the distal end 50d of the outer balloon 50 in the longitudinal direction x be approximately the same as the distance from the proximal end 40p of the inner balloon 40 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. In other words, it is preferable that the distance from the distal end 40d of the inner balloon 40 to the distal end 50d of the outer balloon 50 in the longitudinal direction x be greater than or equal to 90% and less than or equal to 110% of the distance from the proximal end 40p of the inner balloon 40 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. By having the distance from the distal end 40d of the inner balloon 40 to the distal end 50d of the outer balloon 50 be approximately the same as the distance from the proximal end 40p of the inner balloon 40 to the proximal end 50p of the outer balloon 50, the inner balloon 40 is more likely to be positioned in the central portion of the balloon group 11 in the longitudinal direction x. As a result, the area where the load is applied by expanding the balloon group 11 tends to be the center of the balloon group 11, making it easier to adjust the area where pressure is applied by the balloon group 11.

It is preferable that the position of the midpoint of the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40 in the longitudinal direction x coincides with the position of the midpoint of the length L50 from the distal end 50d of the outer balloon 50 that constitutes the balloon group 11 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. By having the position of the midpoint of the length L40 of the inner balloon 40 coincide with the position of the midpoint of the length L50 of the outer balloon 50 that constitutes the balloon group 11 in the longitudinal direction x, the balloon 10 is most likely to expand at the midpoint of the length of the balloon group 11 in the longitudinal direction x, making it easier for the balloon group 11 to apply high pressure to the target area.

3 to 7, the balloon group 11 includes a first outer balloon 51 and a second outer balloon 52 adjacent to the first outer balloon 51 on one side of the inner balloon 40 in the circumferential direction z. When the balloon group 11 is in an expanded state, the first outer balloon 51 and the second outer balloon 52 are preferably in contact with each other. That is, when the balloon group 11 is inflated, the outer surfaces of at least one pair of adjacent outer balloons 50 are preferably in contact with each other. Because the first outer balloon 51 and the second outer balloon 52 are in contact with each other when the balloon group 11 is inflated, when a fluid is introduced into the balloons 10 constituting the balloon group 11 to inflate the balloons 10, the adjacent first outer balloon 51 and second outer balloon 52 mutually suppress the expansion of each other. Therefore, the pressure of the fluid pumped into the lumen of the first outer balloon 51 and the second outer balloon 52 increases, increasing the hardness of both the first outer balloon 51 and the second outer balloon 52 and increasing the expansion force of the balloon group 11.

When the balloon group 11 is in an expanded state, it is preferable that all of the outer balloons 50 that make up the balloon group 11 are in contact with adjacent outer balloons 50. Specifically, in the case of a balloon catheter 1 configured as shown in FIG. 3, it is preferable that each outer balloon 50 be in contact with the outer balloons 50 located on both sides of itself in the circumferential direction z. When the balloon group 11 is in an expanded state, all of the outer balloons 50 that make up the balloon group 11 are in contact with adjacent outer balloons 50. As a result, when the balloon group 11 is expanded, all of the outer balloons 50 that make up the balloon group 11 suppress each other's expansion, and the internal pressure of all of the outer balloons 50 increases. This increases the hardness of the balloon group 11 as a whole, further increasing the expansion force of the balloon group 11.

As shown in FIG. 3 , when the balloon group 11 is in an expanded state, the outer balloon 50 of the balloon group 11 preferably contacts the outer peripheral surface of the inner balloon 40. That is, when the balloon group 11 is in an expanded state, it is preferable that at least one of the outer balloons 50 of the balloon group 11 contacts the outer surface of the inner balloon 40. When the balloon group 11 is in an expanded state, the outer balloon 50 of the balloon group 11 contacts the outer peripheral surface of the inner balloon 40, which makes it easier for the inner balloon 40 and the outer balloon 50 to mutually suppress each other's expansion when the balloon group 11 is expanded. As a result, both the inner balloon 40 and the outer balloon 50 are less likely to inflate, which makes it easier to increase the expansion force of the balloon group 11. Furthermore, since the inner balloon 40 and the outer balloon 50 mutually suppress their expansion, this also has the effect of preventing the inner balloon 40 and the outer balloon 50 from expanding too much when fluid is introduced into both the inner balloon 40 and the outer balloon 50 to place the balloon group 11 in a high-pressure state.

It is more preferable that when the balloon group 11 is in an expanded state, all of the outer balloons 50 constituting the balloon group 11 are in contact with the outer peripheral surface of the inner balloon 40. When the balloon group 11 is in an expanded state, all of the outer balloons 50 constituting the balloon group 11 are in contact with the outer peripheral surface of the inner balloon 40, which increases the effect of the inner balloons 40 and the outer balloons 50 suppressing each other's expansion, making it easier to further increase the expansion force of the balloon group 11.

As shown in Figures 1, 2, and 6, the balloon catheter 1 preferably further includes a shaft 70 having a longitudinal direction x. The distal portion of the shaft 70 is connected to the balloon 10, and the fluid that inflates and deflates the balloon 10 is preferably introduced and discharged through the lumen of the shaft 70.

The shaft 70 is preferably made of resin, metal, or a combination of resin and metal. Using resin as the material for the shaft 70 makes it easier to impart flexibility and elasticity to the shaft 70. Furthermore, using metal as the material for the shaft 70 can improve the deliverability of the balloon catheter 1. Examples of resins that can be used to make the shaft 70 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine-based resins, vinyl chloride resins, silicone resins, natural rubber, and synthetic rubber. These may be used alone or in combination. Examples of metals that can be used to make the shaft 70 include stainless steels such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloys, Co-Cr alloys, or combinations thereof. The shaft 70 may also have a layered structure made of different or the same materials.

1 shows a so-called rapid exchange type balloon catheter 1 having a guidewire port 191 midway from the distal side to the proximal side of the shaft 70 and a guidewire tube 192 that functions as a guidewire passageway from the guidewire port 191 to the distal side of the shaft 70. When the balloon catheter 1 is a rapid exchange type, the balloon catheter 1 preferably has a distal shaft 75 and a proximal shaft 76, and the distal shaft 75 and the proximal shaft 76 may be separate members, with the proximal end of the distal shaft 75 connected to the distal end of the proximal shaft 76 to form the shaft 70 extending from the balloon 10 to the proximal end of the balloon catheter 1. When the shaft 70 is composed of the distal shaft 75 and the proximal shaft 76 that are separate members, the distal shaft 75 may be formed from resin and the proximal shaft 76 may be formed from metal, for example. Alternatively, a single shaft 70 may extend from the balloon 10 to the proximal end of the balloon catheter 1, and the distal shaft 75 and the proximal shaft 76 may be made up of multiple tubular members.

Alternatively, although not shown, the present invention can also be applied to so-called over-the-wire balloon catheters, which have a guidewire passage extending from the distal to the proximal side of the shaft. When the balloon catheter is an over-the-wire type, it is preferable that the inflation lumen and guidewire lumen extend to a hub located on the proximal side, and that the proximal openings of each lumen be provided in a bifurcated hub.

It is preferable that the shaft 70 has a fluid flow path and a guidewire insertion path inside. To configure the shaft 70 to have a fluid flow path and a guidewire insertion path inside, for example, a guidewire tube 192 arranged inside the shaft 70 can function as the guidewire insertion path, with the space between the shaft 70 and the guidewire tube 192 functioning as a fluid flow path. In such a configuration, it is preferable that the guidewire tube 192 extends from the distal end of the shaft 70 and passes through the balloon 10, with the distal side of the balloon 10 connected to the guidewire tube 192 and the proximal side of the balloon 10 connected to the shaft 70.

It is preferable that multiple inner balloons 40 are arranged at different positions in the longitudinal direction x of the shaft 70. By arranging multiple inner balloons 40 at different positions in the longitudinal direction x of the shaft 70, when the balloon group 11 is inflated, the portions between the multiple inner balloons 40 do not expand, or can expand less than other portions of the inner balloon 40. As a result, the outer balloon 50 is less likely to expand significantly in the portions of the balloon group 11 located between the multiple inner balloons 40, making it easier to increase the depth of the concave portion formed in the center of the balloon group 11, and more effectively preventing the balloon group 11 from shifting position.

In the balloon group 11, it is preferable that multiple inner balloons 40 are arranged in series with each other and multiple outer balloons 50 are arranged in parallel with each other radially outward of the inner balloons 40. That is, it is preferable that multiple inner balloons 40 are arranged in a line in the longitudinal direction x and multiple outer balloons 50 are arranged along the outer periphery of the inner balloons 40. By arranging multiple inner balloons 40 in series with each other and multiple outer balloons 50 in parallel with each other radially outward of the inner balloons 40, the multiple outer balloons 50 suppress the outward expansion of the inner balloons 40, and the inner balloons 40 suppress the inward expansion of the multiple outer balloons 50, so that the inner balloons 40 and the multiple outer balloons 50 mutually suppress their respective expansions. As a result, the balloon group 11 has a high pressure resistance, and the hardness of the multiple balloons 10 constituting the balloon group 11 is increased, improving their expansion force. Furthermore, because the inner balloon 40 and the multiple outer balloons 50 mutually suppress their respective expansions, the multiple balloons 10 constituting the balloon group 11 are less likely to inflate. Therefore, even when high pressure is applied to each of the balloons 10 that make up the balloon group 11, over-expansion of the balloons 10 is suppressed, preventing the balloon group 11 from expanding beyond the intended outer diameter, reducing damage to the aortic valve and other internal lumen of the body and improving safety.

The shaft 70 has a guidewire lumen 93 extending in the longitudinal direction x and through which a guidewire is inserted, and further has a guidewire tube 192 having an inner cavity communicating with the guidewire lumen 93, with the guidewire tube 192 preferably being disposed in the inner cavity of the inner balloon 40. Because the balloon catheter 1 has a guidewire tube 192 having an inner cavity communicating with the guidewire lumen 93, it becomes easy to insert the guidewire into the balloon catheter 1, and the balloon catheter 1 can be transported into the body along the guidewire. Furthermore, by inserting the guidewire into the guidewire tube 192, it is possible to prevent the guidewire from damaging the balloon 10, etc.

The guidewire tube 192 may be made of, for example, polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyetherketone resins such as PEEK, polyetherpolyamide resins, polyurethane resins, polyimide resins, fluorine-containing resins such as PTFE, PFA, and ETFE, and synthetic resins such as polyvinyl chloride resins. Among these, polyimide resins are preferred as the material for the guidewire tube 192. Using polyimide resin as the material for the guidewire tube 192 improves the slipperiness of the guidewire tube 192. This makes it easier to insert a guidewire into the lumen of the guidewire tube 192 and advance the balloon catheter 1 along the guidewire into the body. The guidewire tube 192 may also have a multi-layer structure including a braided layer such as a metal braid. The multi-layer structure of the guidewire tube 192 improves the strength of the guidewire tube 192, its slipperiness relative to the guidewire, and its kink resistance.

As shown in FIG. 1, the proximal end of the guidewire tube 192 is preferably connected to the distal end of the shaft 70. When the shaft 70 has a distal shaft 75 and a proximal shaft 76, the proximal end of the guidewire tube 192 is preferably connected to the distal end of the distal shaft 75. By connecting the proximal end of the guidewire tube 192 to the distal end of the shaft 70, the outer diameter of the balloon catheter 1 is less likely to become large, thereby improving minimal invasiveness.

The balloon 10 and shaft 70 can be joined by bonding with an adhesive, welding, or by attaching a ring-shaped member to the overlapping portion of the end of the balloon 10 and the shaft 70 and crimping. Among these, it is preferable that the balloon 10 and the shaft 70 be joined by welding. By joining the balloon 10 and the shaft 70 by welding, the bond between the balloon 10 and the shaft 70 is less likely to come undone even when the balloon 10 is repeatedly expanded or contracted, and the bond strength can be improved.

A tip member 193 is preferably provided at the distal end of the balloon catheter 1. The tip member 193 may be provided at the distal end of the balloon catheter 1 as a separate member from the guidewire tube 192 by being connected to the distal end of the balloon 10, or the guidewire tube 192 extending distally beyond the distal end of the balloon 10 may function as the tip member 193.

As shown in Figures 1, 2, and 6, a radiopaque marker 194 may be placed on the guidewire tube 192 inside the balloon 10 at the location where the balloon 10 is located in the longitudinal axis direction x, so that the position of the balloon 10 can be confirmed under X-ray fluoroscopy.

The position on the guidewire tube 192 where the radiopaque marker 194 is located may be, for example, the midpoint of the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40, the proximal and distal ends of the straight tube portion of the inner balloon 40, or the proximal and distal ends of the straight tube portion of the outer balloon 50. In particular, the position on the guidewire tube 192 where the radiopaque marker 194 is located is preferably the proximal and distal ends of the straight tube portion of the inner balloon 40. By locating the radiopaque marker 194 on the guidewire tube 192 at the proximal and distal ends of the straight tube portion of the inner balloon 40, it becomes easier to confirm the position where the balloon group 11 is significantly expanded by the inner balloon 40. As a result, the balloon catheter 1 can be designed to easily apply pressure to the desired location.

As shown in FIG. 1, a hub 5 may be provided on the proximal side of the shaft 70. The hub 5 may also be provided with a fluid injection section 6 that is connected to a flow path for fluid supplied to the interior of the balloon 10.

The shaft 70 and hub 5 can be joined by, for example, bonding with an adhesive or welding. Among these, it is preferable that the shaft 70 and hub 5 be joined by adhesive. By joining the shaft 70 and hub 5 by adhesive, the bond strength between the shaft 70 and hub 5 can be increased, thereby improving the durability of the balloon catheter 1, even when the shaft 70 and hub 5 are made of different materials, such as when the shaft 70 is made of a highly flexible material and the hub 5 is made of a highly rigid material.

If the balloon catheter 1 is a rapid exchange type, a coating may be applied to the outer wall of at least one of the distal shaft 75 and the proximal shaft 76, or a coating may be applied to the outer wall of both the distal shaft 75 and the proximal shaft 76. If the balloon catheter 1 is an over-the-wire type, a coating may be applied to the outer wall of the outer shaft.

The coating applied to the shaft 70 can be a hydrophilic or hydrophobic coating depending on the purpose, and can be applied by immersing the shaft 70 in a hydrophilic or hydrophobic coating agent, applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 70, or covering the outer wall of the shaft 70 with a hydrophilic or hydrophobic coating agent. The coating agent may contain drugs, additives, etc.

Hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, methyl vinyl ether maleic anhydride copolymer, and hydrophilic coating agents made from any combination thereof.

Hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coating, diamond coating, diamond-like carbon (DLC) coating, ceramic coating, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

The balloon catheter 1 of the present invention is preferably used to expand an aortic valve, deform a biological valve placed in the heart, or destroy a biological valve. Specifically, the balloon catheter 1 of the present invention is preferably used for the purpose of expanding an aortic valve that has hardened due to calcification or the like, or for the purpose of deforming or destroying an artificial valve annulus of a biological valve to replace a deteriorated biological valve placed in the heart. The balloon catheter 1 of the present invention is preferably used because it is easy to apply high pressure to the area where the inner balloon 40 is located, making it easy to expand a hardened aortic valve and deform or destroy a biological valve, which conventional balloon catheters were unable to sufficiently expand.

This application claims the benefit of priority based on Japanese Patent Application No. 2024-047738, filed March 25, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-047738, filed March 25, 2024, are incorporated herein by reference.

1: Balloon catheter 5: Hub 6: Fluid injection section 10: Balloon 11: Balloon group 40: Inner balloon 40d: Distal end of inner balloon 40p: Proximal end of inner balloon 50: Outer balloon 50d: Distal end of outer balloon 50p: Proximal end of outer balloon 51: First outer balloon 52: Second outer balloon 70: Shaft 75: Distal shaft 76: Proximal shaft 93: Guidewire lumen 100: Coating material 101: Distal coating material 102: Proximal coating material 111: Straight tube section 111d: Distal end of straight tube section 111p: Proximal end of straight tube section 112: Distal tapered section 113: Proximal tapered section 114: Distal sleeve Sleeve portion 115: proximal sleeve portion 121: central region 122: distal region 123: proximal region 191: guidewire port 192: guidewire tube 193: distal tip member 194: X-ray opaque marker P3: midpoint of balloon group in longitudinal direction D121: maximum outer diameter of balloon catheter in central region D122: maximum outer diameter of balloon catheter in distal region D123: maximum outer diameter of balloon catheter in proximal region T121: thickness of coating material in central region T122: thickness of coating material in distal region T123: thickness of coating material in proximal region L40: length of inner balloon L50: length of outer balloon

Claims (9)

a balloon group including a plurality of balloons arranged in parallel with each other in the circumferential direction;
a covering material disposed radially outward of the balloon group,
The balloons constituting the balloon group each have a straight pipe portion, a distal tapered portion located distal to the straight pipe portion, and a proximal tapered portion located proximal to the straight pipe portion,
The balloon group has a central region including a midpoint in a longitudinal direction, a distal region located distal to the central region, and a proximal region located proximal to the central region,
the coating is disposed on at least the distal region and the proximal region;
A balloon catheter, wherein the maximum outer diameter of the balloon catheter in the central region is smaller than the maximum outer diameter of the balloon catheter in the distal region and the maximum outer diameter of the balloon catheter in the proximal region. The balloon catheter of claim 1, wherein the thickness of the coating material in the central region is less than the thickness of the coating material in the distal region and the thickness of the coating material in the proximal region. the covering material includes a distal covering material disposed on the distal region and a proximal covering material disposed on the proximal region;
The balloon catheter according to claim 1 , wherein the central region is free of the covering material. The balloon catheter of claim 1, wherein the coefficient of friction of the outer surface of the balloon catheter in the central region is greater than the coefficient of friction of the outer surface of the balloon catheter in the distal region and the coefficient of friction of the outer surface of the balloon catheter in the proximal region. The balloon catheter according to claim 1, wherein the covering material is a tubular body that has the property of shrinking at least in the radial direction when heat is applied. The balloon catheter according to claim 1, wherein the coating material includes fibers or wires. The balloon catheter according to claim 1, wherein the covering material includes a film-like material. The balloon catheter according to claim 1, wherein the balloon group includes an inner balloon and a plurality of outer balloons arranged radially outward of the inner balloon. a shaft having a longitudinal direction;
The balloon catheter according to claim 8, wherein a plurality of the inner balloons are arranged at different positions in the longitudinal direction of the shaft.