Balloon catheter

Abstract

A balloon 13 of a balloon catheter includes a proximal end side leg portion 13a joined to an outer tube 15, and a proximal end side tapered portion 13b in which the diameter increases toward a side spaced apart from the proximal end side leg portion 13a. The balloon 13 is provided with an outer protrusion 32 that protrudes from an outer surface 25 of the balloon 13 and that extends along the outer surface 25. The outer protrusion 32 extends across the proximal end side leg portion 13a and the proximal end side tapered portion 13b. The outer protrusion 32 includes a first end portion 32a which is an end portion on the proximal end side leg portion 13a side, and a second end portion 32b which is an end portion on the proximal end side tapered portion 13b side. An apex portion 33 of the outer protrusion 32 is inclined with respect to the center axis line L of the balloon 13 so as to approach the center axis line L, going from the second end portion 32b side toward the first end portion 32a side.

Description

Balloon catheter CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-063954, filed on April 11, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to balloon catheters.

[0003] A balloon catheter includes a catheter body and an inflatable and deflated balloon attached to the distal end of the catheter body. The balloon is introduced into a narrowed area caused by a lesion or the like in a blood vessel in a deflated state, and then the balloon is inflated to dilate the narrowed area.

[0004] The balloon has a cylindrical straight tube section that has the largest diameter when inflated, a pair of tapered sections on either side of the straight tube section, and a pair of leg sections on either side of the pair of tapered sections. The pair of leg sections are cylindrical and respectively joined to the catheter body. Furthermore, the pair of tapered sections are adjacent to the leg sections and expand in diameter toward the side away from the adjacent leg section.

[0005] Some balloon catheters have linear elements extending axially from the outer surface of the balloon (see, for example, Patent Document 1). The elements protrude from the outer surface of the balloon and are located in the straight portion of the balloon. With such balloon catheters, the balloon is inflated inside the lesion, causing the elements to penetrate the lesion, thereby creating an incision in the lesion. This incision then facilitates dilation of the lesion.

[0006] Some balloon catheters have elements attached to the tapered portion of the balloon. With such a balloon catheter, when the lesion is large, it is possible to first insert only the tapered portion of the balloon into the lesion, and then inflate the balloon in this inserted state, thereby using the element on the tapered portion to make an incision in the lesion.

[0007] International Publication No. 2020 / 255923

[0008] In the balloon catheter described above, the elements are provided on the tapered portion of the balloon but not on the leg portion. This creates a step at the boundary between the tapered portion and the leg portion due to the elements. In this case, when the balloon is inserted into the body, the step may get caught on a stricture inside the body, potentially reducing the ease of insertion of the balloon.

[0009] The present disclosure has been made in consideration of the above circumstances, and has as its main object to provide a balloon catheter that can suppress a decrease in the insertability of the balloon.

[0010] In order to solve the above-mentioned problems, a first disclosed balloon catheter includes a catheter body and an inflatable and deflated balloon provided at a distal end of the catheter body, the balloon having a cylindrical leg portion joined to the catheter body and a tapered portion adjacent to the leg portion in the axial direction of the balloon and expanding in diameter toward a side away from the leg portion, the balloon is provided with an outer protrusion protruding from an outer surface of the balloon and extending along the outer surface, the outer protrusion including a first protrusion extending across the leg portion and the tapered portion, and of both longitudinal end portions of the first protrusion, an end on the leg portion side is a first end and an end on the tapered portion side is a second end, the first protrusion is the protruding end and has an apex extending in the longitudinal direction, the apex being inclined with respect to the central axis of the balloon as it approaches the central axis of the balloon from the second end side toward the first end side.

[0011] According to the first disclosure, the balloon has an outer protrusion, which is a first protrusion extending across the leg portion and tapered portion of the balloon. The first protrusion includes a first end portion that is the end portion on the leg portion side and a second end portion that is the end portion on the tapered portion side. The apex of the first protrusion is inclined with respect to the central axis of the balloon so as to approach the central axis from the second end portion toward the first end portion. In this case, it is possible to prevent a step from occurring at the first end portion of the first protrusion. Therefore, it is possible to prevent the first protrusion portion from getting caught on a stricture inside the body when the balloon is inserted into the body. This prevents a decrease in the insertability of the balloon.

[0012] The balloon catheter of the second disclosure is the same as the first disclosure, wherein the apex portion is continuous with the outer surface of the leg portion at the first end of the first projection.

[0013] According to the second disclosure, the apex of the first protrusion is continuous with the outer surface of the leg portion at the first end of the first protrusion. In this case, there is no step at the first end of the first protrusion. This further prevents the first protrusion from getting caught on a narrowed portion inside the body when the balloon is inserted into the body. This further prevents the balloon from being easily inserted.

[0014] The balloon catheter of the third disclosure is the second disclosure, wherein the apex portion is continuous with the outer surface of the tapered portion at the second end portion of the first protrusion.

[0015] According to the third disclosure, the apex of the first protruding portion is continuous with the outer surface of the tapered portion at the second end of the first protruding portion. In this case, there is no step at the first end of the first protruding portion, and there is also no step at the second end of the first protruding portion. This further reduces the deterioration of the balloon insertability.

[0016] The balloon catheter of the fourth disclosure is the balloon catheter of any of the first to third disclosures, wherein the balloon is the part that has the largest diameter when inflated and has a straight tube section located on the opposite side of the tapered section from the leg section, the second end of the first protrusion is located in the middle of the tapered section in the axial direction, and the area of ​​the tapered section that is closer to the straight tube section than the first protrusion is a non-protruding area where the outer protrusion does not exist.

[0017] According to the fourth disclosure, the second end of the first protrusion is located in the axial middle of the tapered section, and the region of the tapered section closer to the straight tube section than the first protrusion is a non-protruding region where no outer protrusion exists. In this case, in the above-described configuration in which the first protrusion is provided across the leg section and the tapered section, the outer diameter (thickness) of the region of the tapered section closer to the straight tube section (non-protruding region) can be reduced, thereby improving the ease of insertion of the balloon.

[0018] The balloon catheter of the fifth disclosure is the balloon catheter of the fourth disclosure, wherein the straight tube portion is provided with a second protrusion as the outer protrusion, extending in the axial direction and positioned at the same position as the first protrusion in the circumferential direction of the balloon, and the non-protrusion region is provided with an inner protrusion that protrudes from the inner surface of the tapered portion and extends in the axial direction along the inner surface, and the inner protrusion is positioned at the same position as the first protrusion and the second protrusion in the circumferential direction.

[0019] According to the fifth disclosure, a second protrusion is provided as an outer protrusion on the straight tube portion of the balloon, and the second protrusion is located at the same circumferential position as the first protrusion. Furthermore, an inner protrusion is provided in the non-protruding region of the tapered portion, protruding from the inner surface of the tapered portion and extending axially along the inner surface. The inner protrusion is located at the same circumferential position as the first protrusion and the second protrusion. In this case, local changes in rigidity can be suppressed at the boundary between the non-protruding region and the straight tube portion. Furthermore, local changes in rigidity can be suppressed at the boundary between the region of the tapered portion closer to the leg portion than the non-protruding region (i.e., the region where the first protrusion is provided) and the non-protruding region. This can suppress the occurrence of kinking even when a portion of the tapered portion is configured as a non-protruding region.

[0020] A sixth disclosure relates to a balloon catheter according to any one of the first to third disclosures, wherein the balloon has a straight tube section, which is the section that has the largest diameter when inflated, and is provided on the opposite side of the leg section across the tapered section, and the straight tube section is provided with a second protrusion as the outer protrusion, extending in the axial direction and located at the same position as the first protrusion in the circumferential direction of the balloon, the second end of the first protrusion being located at a middle part of the tapered section in the axial direction, and a third protrusion as the outer protrusion, extending in the axial direction along the outer surface of the tapered section, is provided in a region of the tapered section closer to the straight tube section than the first protrusion, and the third protrusion is located at the same position as the first protrusion and the second protrusion in the circumferential direction, and the protrusion height from the outer surface of the balloon is equal to or less than half the protrusion height of the second protrusion.

[0021] According to the sixth disclosure, a second protrusion is provided as an outer protrusion on the straight tube section of the balloon. The second protrusion is located at the same circumferential position as the first protrusion on the balloon. Furthermore, a third protrusion is provided as an outer protrusion, extending in the axial direction along the outer surface of the tapered section, in a region of the tapered section closer to the straight tube section than the first protrusion. The third protrusion is located at the same circumferential position as the first and second protrusions on the balloon. In this case, the first protrusion, the second protrusion, and the third protrusion are arranged in series in the axial direction of the balloon, making it possible to suppress axial stretching of the balloon when the balloon is inflated.

[0022] Furthermore, the protruding height of the third protrusion from the outer surface of the balloon is set to be half or less of the protruding height of the second protrusion from the outer surface of the balloon. This prevents the outer diameter (thickness) of the tapered portion on the straight tube side from increasing, even in a configuration in which the third protrusion is provided on the tapered portion. This prevents a decrease in the insertability of the balloon.

[0023] A seventh disclosure of the balloon catheter is related to any of the first to third disclosures, wherein the catheter body includes an outer tube and an inner tube inserted into the outer tube and having an extending portion extending distally beyond the outer tube, the balloon is provided to cover the extending portion from the outside, the balloon has, as its leg portion, a base-side leg portion joined to the distal end of the outer tube and a distal-side leg portion joined to the extending portion, the tapered portion includes a base-side tapered portion adjacent to the distal side of the base-side leg portion and a distal-side tapered portion adjacent to the proximal side of the distal-side leg portion, and the first protrusion extends across the base-side leg portion and the base-side tapered portion.

[0024] The proximal leg portion of the balloon is joined to the outer tube, and the distal leg portion is joined to an extending portion of the inner tube inserted through the outer tube. In this configuration, the outer diameter of the proximal portion of the balloon is larger than the outer diameter of the distal portion of the balloon. Therefore, if a step is created, for example, due to the provision of an external protrusion in the proximal tapered portion, it is conceivable that the step may easily get caught on a narrowed portion when the balloon is withdrawn from the body. In this regard, in the seventh disclosure, the external protrusion is provided as a first protrusion extending across the proximal leg portion and the proximal tapered portion. This effectively prevents the external protrusion (first protrusion) from getting caught on a narrowed portion when the balloon is withdrawn from the body.

[0025] The balloon catheter of the eighth disclosure is any one of the first to third disclosures, wherein the apex has a first apex provided on the first end side and a second apex provided on the second end side, the first apex and the second apex are continuous, and the inclination angle of the first apex relative to the central axis is greater than the inclination angle of the second apex relative to the central axis.

[0026] According to the eighth disclosure, a corner is formed at the boundary between the first and second apexes of the first protrusion by the apexes, which makes it easier for the corner of the first protrusion to bite into the lesion when the balloon is inflated, thereby making it easier to make an incision in the lesion.

[0027] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0023] Figure 1 is a schematic overall side view showing the configuration of a balloon catheter.

[0024] Figure 2 is a side view of a balloon and its surroundings in an inflated state, showing the balloon and outer tube in longitudinal cross section.

[0025] (a) is a side view showing the balloon and its surroundings in an inflated state, (b) is a cross-sectional view of line A-A in (a), (c) is a cross-sectional view of line B-B in (a), (d) is a cross-sectional view of line C-C in (a), (e) is a cross-sectional view of line D-D in (a), and (f) is a cross-sectional view of line E-E in (a).

[0026] (a) is a side view showing the balloon and its surroundings in a deflated state, and (b) is a cross-sectional view of line F-F in (a).

[0027] Figure 3 is an enlarged side view of the proximal end side of the balloon in Figure 2.

[0028] Figure 4 is an enlarged side view of the proximal end side of a balloon in another embodiment, showing the balloon in longitudinal cross section.

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present disclosure will now be described with reference to the accompanying drawings. Fig. 1 is a schematic side view showing the overall configuration of a balloon catheter.

[0029] As shown in FIG. 1, the balloon catheter 10 includes a catheter body 11, a hub 12 attached to the base end (proximal end) of the catheter body 11, and a balloon 13 attached to the tip side (distal end) of the catheter body 11.

[0030] The catheter main body 11 includes an outer tube 15 and an inner tube 16 inserted into the outer tube 15. The outer tube 15 is formed in a tubular shape from a resin material and has a lumen 15a (see FIG. 2) extending therein in the entire axial direction. The base end of the outer tube 15 is joined to the hub 12, and the tip end of the outer tube 15 is joined to the balloon 13. The lumen 15a of the outer tube 15 communicates with the interior of the hub 12 and the interior of the balloon 13. The lumen 15a of the outer tube 15 serves as a fluid lumen through which a compressed fluid flows when the balloon 13 is inflated or deflated.

[0031] The inner tube 16 is formed into a tubular shape from a resin material and has a lumen 16a (see FIG. 2 ) extending throughout the entire axial direction. The base end of the inner tube 16 is joined to a midpoint in the axial direction of the outer tube 15. The inner tube 16 also has an extension portion 17 that extends distally beyond the outer tube 15. The extension portion 17 is inserted into the balloon 13 and is covered from the outside by the balloon 13. The distal end of the extension portion 17 is joined to the distal end of the balloon 13.

[0032] The lumen 16a of the inner tube 16 serves as a guidewire lumen through which a guidewire G is inserted. A proximal opening 18 of the lumen 16a is located midway along the axial direction of the balloon catheter 10. This makes the balloon catheter 10 an RX-type catheter. The proximal opening 18 of the lumen 16a may also be located at the proximal end of the balloon catheter 10. In that case, the balloon catheter 10 would be an over-the-wire-type catheter.

[0033] Next, the configuration of the balloon 13 and its surroundings will be described with reference to Figures 2 to 4. Figure 2 is a side view of the balloon 13 and its surroundings in an inflated state, showing the balloon 13 and the outer tube 15 in a longitudinal cross section. Figure 3 (a) is a side view showing the configuration of the balloon 13 and its surroundings in an inflated state, (b) is a cross-sectional view taken along line A-A of (a), (c) is a cross-sectional view taken along line B-B of (a), (d) is a cross-sectional view taken along line C-C of (a), (e) is a cross-sectional view taken along line D-D of (a), and (f) is a cross-sectional view taken along line E-E of (a). Figure 4 (a) is a side view of the configuration of the balloon 13 and its surroundings in a deflated state, and (b) is a cross-sectional view taken along line F-F of (a).

[0034] The balloon 13 is made of a thermoplastic resin material, such as polyamide elastomer. As shown in Figures 2 and 3(a), the balloon 13 is formed in a cylindrical (tubular) shape with a circular cross section as a whole. The balloon 13 has a base leg portion 13a, a base tapered portion 13b adjacent to the distal end of the base leg portion 13a, a straight tube portion 13c adjacent to the distal end of the base tapered portion 13b, a distal tapered portion 13d adjacent to the distal end of the straight tube portion 13c, and a distal leg portion 13e adjacent to the distal end of the distal tapered portion 13d.

[0035] The proximal leg portion 13a is cylindrical and is joined to the distal end of the outer tube 15. The proximal tapered portion 13b is tapered and increases in diameter from the distal end of the proximal leg portion 13a toward the distal end. The straight tube portion 13c is cylindrical and extends with a constant diameter from the distal end of the proximal tapered portion 13b toward the distal end. The straight tube portion 13c is the portion whose diameter becomes largest when the balloon 13 is inflated.

[0036] The distal tapered section 13d is tapered from the distal end of the straight tube section 13c toward the distal end. The distal leg section 13e extends from the distal end of the distal tapered section 13d toward the distal end and is cylindrical. The distal leg section 13e is joined to the distal end of the inner tube 16. The outer diameter of the distal leg section 13e is smaller than the outer diameter of the proximal leg section 13a.

[0037] When compressed fluid is supplied to the interior of the balloon 13 through the lumen 15a of the outer tube 15, the balloon 13 enters an expanded state. On the other hand, when negative pressure is applied to the lumen 15a of the outer tube 15 and the compressed fluid is discharged from the interior of the balloon 13, the balloon 13 enters a deflated state. As shown in FIGS. 4( a) and 4(b), the balloon 13 has multiple (specifically, three) wing portions 27 that are formed in the deflated state. These wing portions 27 are spaced equally spaced around the circumference of the balloon 13. When the balloon 13 enters a deflated state, each wing portion 27 is folded around the circumference of the balloon 13 and wrapped around the inner tube 16.

[0038] A pair of radiography rings 19 are attached to the inner tube 16 on the inside of the balloon 13. The radiography rings 19 are intended to improve the visibility of the balloon 13 under X-ray projection and to facilitate the positioning of the balloon 13 at the target treatment site.

[0039] The balloon 13 is provided with outer protrusions 31, 32 that protrude from the outer surface 25 of the balloon 13 toward the outer periphery of the balloon 13 (in other words, radially outward from the balloon 13). The outer protrusions 31, 32 extend linearly along the outer surface 25 of the balloon 13 in the axial direction of the balloon 13 (hereinafter, also referred to as the "axial direction" for short). The outer protrusions 31, 32 are intended to create incisions (cracks) in the lesion when the balloon 13 is inflated to dilate the lesion. With the present balloon catheter 10, even if the lesion has hardened due to calcification or the like, the outer protrusions 31, 32 can create incisions in the lesion, thereby facilitating dilation of the lesion. Therefore, the present balloon catheter 10 is configured as a balloon catheter with a scoring function.

[0040] Of the outer protrusions 31, 32, the outer protrusion 31 is provided on the straight tube portion 13c of the balloon 13, and the outer protrusion 32 is provided across the base-side leg portion 13a and the base-side tapered portion 13b. Each outer protrusion 31, 32 is formed integrally with the balloon 13. The outer protrusion 31 corresponds to the "second protrusion," and the outer protrusion 32 corresponds to the "first protrusion." Furthermore, the distal tapered portion 13d and the distal leg portion 13e of the balloon 13 are not provided with an outer protrusion.

[0041] The outer protrusions 31 extend in the axial direction of the balloon 13 along the outer surface 25c of the straight pipe portion 13c, specifically across the entire axial length of the straight pipe portion 13c. As shown in FIG. 3(e), the outer protrusions 31 are arranged at predetermined intervals (specifically, at equal intervals) around the circumferential direction of the balloon 13. In this embodiment, three outer protrusions 31 are arranged at 120° intervals. Each outer protrusion 31 has a cross section (specifically, a cross section perpendicular to the longitudinal direction of the outer protrusion 31) that forms a mountain shape that protrudes radially outward from the balloon 13, specifically, a triangular shape. However, the cross section of the outer protrusion 31 does not necessarily have to be triangular and may have other shapes. For example, the cross section of the outer protrusion 31 may be a quadrilateral shape, such as a rectangular or trapezoidal shape, or may be a pentagonal or semicircular shape.

[0042] Next, the outer protrusion 32 will be described with reference to Figures 3(b), 3(c), 5, and 6. Figure 5 is an enlarged side view of the proximal end side of the balloon 13 in Figure 3(a). Figure 6 is an enlarged side view of the proximal end side of the balloon 13 in Figure 2.

[0043] 5 and 6 , the outer protrusion 32 extends in the axial direction of the balloon 13, straddling the proximal leg portion 13a and the proximal tapered portion 13b. In this case, the outer protrusion 32 extends in the axial direction along the outer surface 25a of the proximal leg portion 13a and the outer surface 25b of the proximal tapered portion 13b. Note that the outer surface 25a of the proximal leg portion 13a, the outer surface 25b of the proximal tapered portion 13b, and the outer surface 25c of the straight tube portion 13c are all included in the outer surface 25 of the balloon 13.

[0044] 3(b) and 3(c), the outer protrusions 32 are arranged at predetermined intervals (specifically, at equal intervals) in the circumferential direction of the balloon 13. In this embodiment, three outer protrusions 32 are arranged at 120° intervals. Each outer protrusion 32 is arranged in the same position as each outer protrusion 31 of the straight pipe portion 13c in the circumferential direction of the balloon 13. Furthermore, the hardness of each outer protrusion 32 is higher than the hardness of the outer protrusion 31.

[0045] As shown in FIG. 5 , of the longitudinal ends of the outer protrusion 32, the end closest to the base leg 13a is the first end 32a, and the end closest to the base tapered portion 13b is the second end 32b. The first end 32a is the base end of the outer protrusion 32, and the second end 32b is the tip end of the outer protrusion 32. The first end 32a is located in the axially intermediate portion of the base leg 13a. The second end 32b is located in the axially intermediate portion of the base tapered portion 13b. Specifically, the second end 32b is located in the axially central portion of the base tapered portion 13b or closer to the base end (in other words, closer to the base leg 13a).

[0046] Each outer protrusion 32 has a first portion 34a including a first end 32a and a second portion 34b including a second end 32b. The first portion 34a and the second portion 34b are adjacent to each other in the longitudinal direction of the outer protrusion 32. As shown in FIG. 3(b), the first portion 34a has a trapezoidal cross section (specifically, a cross section perpendicular to the longitudinal direction of the outer protrusion 32). As shown in FIG. 3(c), the second portion 34b has a mountain-like cross section (specifically, a cross section perpendicular to the longitudinal direction of the outer protrusion 32) that protrudes radially outward from the balloon 13, specifically, a triangular cross section.

[0047] The cross section of the first portion 34a does not necessarily have to be trapezoidal and may have other shapes. For example, the cross section of the first portion 34a may be triangular, pentagonal, semicircular, or a quadrilateral shape other than a trapezoid, such as a rectangular shape. The cross section of the second portion 34b does not necessarily have to be triangular and may have other shapes. For example, the cross section of the second portion 34b may be quadrilateral, such as a rectangular or trapezoidal shape, or may be pentagonal or semicircular. The cross sections of the first portion 34a and the second portion 34b do not necessarily have to have different shapes and may have the same shape. In other words, the cross section of the outer protrusion 32 may have the same shape throughout the entire longitudinal direction of the outer protrusion 32.

[0048] The protruding end of the outer protrusion 32 is an apex 33. The apex 33 of the outer protrusion 32 extends in the longitudinal direction of the outer protrusion 32, more specifically, extends over the entire longitudinal direction of the outer protrusion 32. The apex 33 of the outer protrusion 32 is the end of the outer protrusion 32 that is on the radially outer side of the balloon 13, in other words, the end of the outer protrusion 32 that is farthest (farthest) from the central axis L of the balloon 13.

[0049] The apex 33 of the outer protrusion 32 is inclined with respect to the central axis L of the balloon 13 so as to approach the central axis L of the balloon 13 from the second end 32b side toward the first end 32a side of the outer protrusion 32. More specifically, the apex 33 of the outer protrusion 32 is inclined as described above over the entire longitudinal length of the outer protrusion 32.

[0050] Of the apexes 33 of the outer protrusion 32, the apex 33 of the first portion 34a is the first apex 33a, and the apex 33 of the second portion 34b is the second apex 33b. That is, the apex 33 of the outer protrusion 32 has a first apex 33a provided on the first end 32a side and a second apex 33b provided on the second end 32b side. The first apex 33a and the second apex 33b are continuous at the boundary between the apexes 33a and 33b. The first apex 33a is continuous with the outer surface 25a of the base-side leg portion 13a at the first end 32a of the outer protrusion 32. The second apex 33b is continuous with the outer surface 25b of the base-side tapered portion 13b at the second end 32b of the outer protrusion 32.

[0051] The first apex 33a has a planar shape extending in the longitudinal direction of the outer protrusion 32. The second apex 33b has a linear shape extending in the longitudinal direction of the outer protrusion 32. More specifically, the first apex 33a has a triangular surface that is convex toward the second apex 33b, and the apex of the triangle on the second apex 33b side is continuous with the second apex 33b.

[0052] The inclination angle α of the first apex 33a with respect to the central axis L of the balloon 13 is larger than the inclination angle β of the second apex 33b with respect to the central axis L of the balloon 13. In this case, a corner 35 is formed by the apexes 33a and 33b at the boundary between the first apex 33a and the second apex 33b. The inclination angle α of the first apex 33a is equal to or smaller than the inclination angle γ of the outer surface 25b of the proximal tapered portion 13b with respect to the central axis L of the balloon 13.

[0053] The region of the base-end tapered portion 13b closer to the straight pipe portion 13c than the outer protrusion 32 (in other words, the region of the base-end tapered portion 13b closer to the tip side than the outer protrusion 32) is a non-protrusion region 37 where no outer protrusion exists. More specifically, the non-protrusion region 37 is a region of the base-end tapered portion 13b closer to the straight pipe portion 13c than the second end 32b of the outer protrusion 32 (in other words, closer to the tip side).

[0054] 6, the proximal tapered portion 13b is provided with inner protrusions 43, 44 that protrude from the inner surface 41 of the proximal tapered portion 13b toward the inner periphery of the balloon 13 (in other words, toward the radially inner side of the balloon 13). The inner protrusions 43, 44 extend linearly in the axial direction of the balloon 13 along the inner surface 41 of the proximal tapered portion 13b.

[0055] Of the inner protrusions 43, 44, the inner protrusion 43 is provided in the non-protrusion region 37 of the base-side tapered portion 13b, and more specifically, extends over the entire axial area of ​​the non-protrusion region 37. The inner protrusion 44 is provided in a region of the base-side tapered portion 13b closer to the base-side leg portion 13a (in other words, closer to the base end) than the inner protrusion 43. The inner protrusions 43, 44 are provided continuously in the longitudinal direction of the inner protrusions 43, 44, and these continuous inner protrusions 43, 44 extend over the entire axial area of ​​the base-side tapered portion 13b. The inner protrusion 43 corresponds to the "inner protrusion" described in the claims.

[0056] 3(d), a plurality of inner protrusions 43 are arranged at predetermined intervals (specifically, equal intervals) in the circumferential direction of the balloon 13, and in this embodiment, three inner protrusions 43 are arranged at 120° intervals. Each inner protrusion 43 has a semicircular cross section (specifically, a cross section perpendicular to the longitudinal direction of the inner protrusion 43) that is convex toward the inside in the radial direction of the balloon 13. However, the inner protrusions 43 do not necessarily have to have a semicircular cross section, and may have other shapes, such as a triangular or rectangular cross section.

[0057] Each inner protrusion 43 is located at the same position as each outer protrusion 31 in the circumferential direction of the balloon 13. In addition, each inner protrusion 43 is located at the same position as each outer protrusion 32 in the circumferential direction of the balloon 13.

[0058] 3(c), multiple inner protrusions 44 are arranged at predetermined intervals (specifically, equal intervals) around the circumference of the balloon 13, and in this embodiment, three inner protrusions 44 are arranged at 120° intervals. Each inner protrusion 44 has a semicircular cross section (specifically, a cross section perpendicular to the longitudinal direction of the inner protrusion 43) that is convex toward the inside in the radial direction of the balloon 13. However, the inner protrusions 44 do not necessarily have to have a semicircular cross section, and may have other shapes, such as a triangular or rectangular cross section.

[0059] Each inner protrusion 44 is located at the same position as each inner protrusion 43 in the circumferential direction of the balloon 13. Also, each inner protrusion 44 is located at the same position as each outer protrusion 32 in the circumferential direction of the balloon 13. The protrusion height H2 of each inner protrusion 44 from the inner surface 41 of the base-end tapered portion 13b is smaller than the protrusion height H1 of each inner protrusion 43 from the inner surface 41. Specifically, the protrusion height H2 of each inner protrusion 44 is equal to or less than half the protrusion height H1 of each inner protrusion 43.

[0060] 2, the distal tapered portion 13d of the balloon 13 is provided with an inward protrusion 47 that protrudes from the inner surface 45 of the distal tapered portion 13d toward the inner periphery of the balloon 13 (in other words, toward the radially inner side of the balloon 13). The inward protrusion 47 extends linearly in the axial direction along the inner surface 45 of the distal tapered portion 13d, and more specifically, extends across the entire axial area of ​​the distal tapered portion 13d.

[0061] As shown in FIG. 3( f ), multiple inner protrusions 47 are arranged at predetermined intervals (more specifically, equal intervals) around the circumferential direction of the balloon 13. In this embodiment, three inner protrusions 47 are arranged at 120° intervals. Each inner protrusion 47 has a semicircular cross section (more specifically, a cross section perpendicular to the longitudinal direction of the inner protrusion 47) that is convex toward the inside of the balloon 13 in the radial direction. However, the inner protrusions 47 do not necessarily have to have a semicircular cross section, and may have other shapes, such as a triangular or rectangular cross section. Furthermore, each inner protrusion 47 is located at the same position around the circumferential direction of the balloon 13 as each outer protrusion 31.

[0062] Next, a method of using the balloon catheter 10 will be described. Here, a procedure for dilating a lesion occurring in a blood vessel using the balloon catheter 10 will be described.

[0063] First, a guiding catheter is inserted into a sheath introducer inserted into a blood vessel, and the distal end opening of the guiding catheter is introduced to the coronary artery ostium. Next, a guidewire G is inserted into the guiding catheter, and the inserted guidewire G is introduced from the coronary artery ostium to the peripheral site via the lesion.

[0064] Next, the balloon catheter 10 is introduced into the guiding catheter along the guide wire G. After the introduction, the balloon 13 is introduced (placed) toward the lesion while being pushed and pulled. During this introduction, the balloon 13 is kept in a deflated state.

[0065] When the balloon 13 reaches the lesion, the balloon 13 is inflated. This causes the outer protrusions 31 of the straight tube portion 13c to be pressed against the lesion, causing incisions (cracks) in the lesion. This allows the lesion to be destroyed or otherwise expanded outward using the incisions as a trigger. Furthermore, if the lesion is large, the outer protrusions 32 as well as the outer protrusions 31 are pressed against the lesion. In this case, incisions are made in the lesion by each of the outer protrusions 31 and 32.

[0066] After the balloon 13 has completed dilating the lesion, the balloon 13 is deflated. The balloon 13 is then withdrawn from the body in this deflated state. As described above, the apex 33 of the outer protrusion 32 is inclined from the second end 32b toward the first end 32a so as to approach the central axis L of the balloon 13. This prevents the outer protrusion 32 from getting caught on a stenosis inside the body (inside a blood vessel) when the balloon 13 is withdrawn from the body. This completes the series of operations.

[0067] Although the balloon catheter 10 is primarily used by being introduced into blood vessels as described above, it can also be applied to "tubes" or "body cavities" other than blood vessels, such as the urinary tract or digestive tract.

[0068] According to the configuration of this embodiment described above in detail, the following excellent effects can be obtained.

[0069] The balloon 13 is provided with an outer protrusion 32 that extends across the base-end leg portion 13a and base-end tapered portion 13b, which are adjacent in the axial direction of the balloon 13. The apex 33 of the outer protrusion 32 is inclined with respect to the central axis L of the balloon 13 so as to approach the central axis L of the balloon 13 as it moves from the second end 32b side to the first end 32a side. In this case, it is possible to prevent a step from occurring at the first end 32a of the outer protrusion 32. Therefore, it is possible to prevent the outer protrusion 32 from getting caught on a narrowed portion inside the body when the balloon 13 is inserted into the body. This prevents a decrease in the insertability of the balloon 13.

[0070] The apex 33 of the outer protrusion 32 is continuous with the outer surface 25a of the base-end leg portion 13a at the first end 32a of the outer protrusion 32. In this case, there is no step at the first end 32a of the outer protrusion 32. This further prevents the outer protrusion 32 from getting caught on a narrowed portion inside the body when the balloon 13 is inserted into the body. This further prevents the insertion ease of the balloon 13 from being reduced.

[0071] The apex 33 of the outer protrusion 32 is continuous with the outer surface 25b of the proximal tapered portion 13b at the second end 32b of the outer protrusion 32. In this case, not only is there no step at the first end 32a of the outer protrusion 32, but there is also no step at the second end 32b of the outer protrusion 32. This further reduces the deterioration of the insertability of the balloon 13.

[0072] The second end 32b of the outer protrusion 32 is located in the axially intermediate portion of the proximal tapered portion 13b. The region of the proximal tapered portion 13b closer to the straight tube portion 13c than the outer protrusion 32 is a non-protrusion region 37 where no outer protrusion is present. In this case, in the above-described configuration in which the outer protrusion 32 is provided across the proximal leg portion 13a and the proximal tapered portion 13b, the profile of the region of the proximal tapered portion 13b closer to the straight tube portion 13c (non-protrusion region 37) can be made smaller. This improves the insertability of the balloon 13.

[0073] The non-protruding region 37 of the proximal tapered portion 13b is provided with an inner protruding portion 43 that protrudes from the inner surface 41 of the proximal tapered portion 13b and extends axially along the inner surface 41. The inner protruding portion 43 is disposed at the same circumferential position of the balloon 13 as the outer protruding portions 31, 32. In this case, local changes in rigidity can be suppressed at the boundary between the non-protruding region 37 and the straight tube portion 13c. Furthermore, local changes in rigidity can be suppressed at the boundary between the non-protruding region 37 and a region of the proximal tapered portion 13b closer to the proximal leg portion 13a than the non-protruding region 37 (i.e., the region where the outer protruding portion 32 is provided). This suppresses the occurrence of kinking in a configuration in which a portion of the proximal tapered portion 13b is the non-protruding region 37.

[0074] The apex 33 of the outer protrusion 32 includes a first apex 33a provided on the first end 32a side and a second apex 33b provided on the second end 32b side. The inclination angle α of the first apex 33a with respect to the central axis L of the balloon 13 is larger than the inclination angle β of the second apex 33b with respect to the central axis L of the balloon 13. In this case, a corner 35 is formed by the apexes 33a and 33b at the boundary between the first apex 33a and the second apex 33b. This makes it easier for the corner 35 of the outer protrusion 32 to bite into the lesion when the balloon 13 is inflated, thereby making it easier to make an incision in the lesion.

[0075] The length of the outer protrusion 32 is considered to be shorter than the length of the outer protrusion 31. Therefore, there is a concern that the outer protrusion 32 may collapse when an incision is made in the lesion with the outer protrusion 32. In this regard, the hardness of the outer protrusion 32 is greater than the hardness of the outer protrusion 31, and therefore, the outer protrusion 32 can be prevented from collapsing when an incision is made in the lesion with the outer protrusion 32.

[0076] Since the distal leg portion 13e and the distal tapered portion 13d of the balloon 13 do not have outward protrusions, it is possible to reduce the profile of the distal portion of the balloon 13. This improves the insertability of the balloon 13 when it is introduced into the body.

[0077] The present disclosure is not limited to the above-described embodiment, and may be implemented, for example, as follows.

[0078] (1) The apex 33 of the outer protrusion 32 may be configured not to be continuous with the outer surface 25a of the proximal leg portion 13a at the first end 32a of the outer protrusion 32. In this case, although a step will be formed at the first end 32a of the outer protrusion 32, the apex 33 of the outer protrusion 32 is inclined so as to approach the central axis L of the balloon 13 as it moves from the second end 32b side to the first end 32a side, making it possible to reduce the step. Therefore, when the balloon 13 is inserted into the body, the outer protrusion 32 can be prevented from getting caught on a narrowed portion inside the body.

[0079] Furthermore, the apex 33 of the outer protrusion 32 may not be continuous with the outer surface 25b of the base end tapered portion 13b at the second end 32b of the outer protrusion 32.

[0080] (2) In the above embodiment, the inclination angle of the apex 33 of the outer protrusion 32 relative to the central axis L of the balloon 13 is changed in the middle of the longitudinal direction of the outer protrusion 32, but the inclination angle of the apex 33 of the outer protrusion 32 may be constant throughout the entire longitudinal direction of the outer protrusion 32.

[0081] (3) In the above embodiment, the outer protrusion 32 (corresponding to the first protrusion) is provided across the proximal leg portion 13a and the proximal tapered portion 13b. However, instead of or in addition to this, the first protrusion may be provided across the distal leg portion 13e and the distal tapered portion 13d. In this case, of both longitudinal ends of the first protrusion, the end closer to the distal leg portion 13e is defined as the first end, and the end closer to the distal tapered portion 13d is defined as the second end. The apex of the first protrusion is inclined with respect to the central axis L of the balloon 13 so as to approach the central axis L from the second end toward the first end. This configuration can effectively prevent the first protrusion from getting caught on a narrowed portion inside the body when the balloon 13 is introduced into the body.

[0082] In the above configuration, the apex of the first protrusion may be continuous with the outer surface of the distal leg portion 13 e at the first end of the first protrusion. Alternatively, the apex of the first protrusion may be continuous with the outer surface of the distal tapered portion 13 d at the second end of the first protrusion. This further prevents the first protrusion from getting caught on a narrowed portion inside the body when the balloon 13 is introduced into the body.

[0083] (4) In the above embodiment, the hardness of the outer protrusion 32 is higher than the hardness of the outer protrusion 31, but the hardness of the outer protrusion 32 may be the same as the hardness of the outer protrusion 31 or may be lower than the hardness of the outer protrusion 31.

[0084] (5) In the above embodiment, the balloon 13 is provided with the inner protrusions 43, 44, and 47 in addition to the outer protrusions 31 and 32. However, it is also possible to not provide one or more of the inner protrusions 43, 44, and 47. For example, it is possible to not provide the inner protrusion 44 or not provide the inner protrusion 43.

[0085] (6) In the above embodiment, the second end 32b of the outer protrusion 32 is located at the middle position in the axial direction of the base-side tapered portion 13b. However, the second end 32b of the outer protrusion 32 may be located at the axial tip of the base-side tapered portion 13b. In this case, the outer protrusion 32 is provided over the entire axial area of ​​the base-side tapered portion 13b.

[0086] (7) In the above embodiment, the first apex 33a of the outer protrusion 32 is formed in a planar shape. However, the first apex 33a may be formed in a linear shape, similar to the second apex 33b.

[0087] (8) In the above embodiment, the region of the base-end tapered portion 13b closer to the straight pipe portion 13c than the outward protrusion 32 is the non-protruding region 37. However, this may be changed so that an outward protrusion is provided in the region of the base-end tapered portion 13b closer to the straight pipe portion 13c than the outward protrusion 32. A specific example of this is shown in FIG.

[0088] In the example shown in FIG. 7 , an outer protrusion 51 extending in the axial direction along the outer surface 25b of the proximal tapered portion 13b is provided in a region of the proximal tapered portion 13b closer to the straight tube portion 13c than the outer protrusion 32. The outer protrusions 51 (specifically, three) are arranged at predetermined intervals (specifically, equal intervals) around the circumferential direction of the balloon 13. Each outer protrusion 51 has a cross section (specifically, a cross section perpendicular to the longitudinal direction of the outer protrusion 51) that forms a mountain shape that protrudes radially outward from the balloon 13, specifically, a triangular shape. However, the cross section of the outer protrusion 51 does not necessarily have to be triangular and may have other shapes. For example, the cross section of the outer protrusion 51 may have a quadrangular shape, such as a rectangular shape or a trapezoidal shape, or may have a pentagonal or semicircular shape. The outer protrusion 51 corresponds to the "third protrusion."

[0089] Each outer protrusion 51 is disposed at the same position as each outer protrusion 32 in the circumferential direction of the balloon 13. Furthermore, each outer protrusion 51 is disposed at the same position as each outer protrusion 31 of the straight tube portion 13c in the circumferential direction of the balloon 13. In this case, each outer protrusion 51 is continuous with the outer protrusion 32 and the outer protrusion 31, respectively. With this configuration, the outer protrusions 31, 32, and 51 are disposed in series in the axial direction of the balloon 13, making it possible to prevent the balloon 13 from stretching in the axial direction when the balloon 13 is inflated.

[0090] Each outer protrusion 51 has a protruding height H3 from the outer surface 25 of the balloon 13 (specifically, the outer surface 25b of the proximal tapered portion 13b). Each outer protrusion 31 has a protruding height H4 from the outer surface 25 of the balloon 13 (specifically, the outer surface 25c of the straight tube portion 13c). The protruding height H3 of each outer protrusion 51 is less than half the protruding height H4 of each outer protrusion 31. This configuration, in which the outer protrusion 51 is provided on the proximal tapered portion 13b, prevents the outer diameter (thickness) of the region of the proximal tapered portion 13b on the straight tube portion 13c side from increasing. This prevents a decrease in the insertability of the balloon 13. The protruding height H3 of each outer protrusion 51 is lower than the protruding height H1 of the inner protrusion 43 (see FIG. 6).

[0091] (9) As described in the above embodiment, the cross-sectional shape of the outer protrusions 31, 32 may be semicircular. Furthermore, as described in (8) above, the cross-sectional shape of the outer protrusion 51 may be semicircular. When the cross-sectional shape of the outer protrusion is semicircular, the apex of the outer protrusion extends linearly in the longitudinal direction of the outer protrusion. In this case, the distance between the apex of the outer protrusion and the outer surface 25 of the balloon 13 in the cross-section of the outer protrusion is the same as the radius of the outer protrusion.

[0092] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0093] 10...balloon catheter, 11...catheter body, 13...balloon, 13a...base end leg portion, 13b...base end tapered portion, 13c...straight tube portion, 15...outer tube, 16...inner tube, 31...outer protrusion (corresponding to second protrusion), 32...outer protrusion (corresponding to first protrusion), 33...apex, 37...non-protrusion region, 43...inner protrusion, 51...outer protrusion (corresponding to third protrusion).

Claims

1. A balloon catheter comprising: a catheter body; and an inflatable and deflatable balloon provided at the distal end of the catheter body, wherein the balloon has: a cylindrical leg portion joined to the catheter body; and a tapered portion adjacent to the leg portion in the axial direction of the balloon and expanding in diameter toward the side away from the leg portion, wherein the balloon is provided with an outer protrusion that protrudes from the outer surface of the balloon and extends along the outer surface, and the outer protrusion has a first protrusion that extends across the leg portion and the tapered portion, and of both longitudinal end portions of the first protrusion, the end on the leg portion side is a first end and the end on the tapered portion side is a second end, the first protrusion is the end on the protruding side and has an apex that extends in the longitudinal direction, and the apex is inclined with respect to the central axis of the balloon so as to approach the central axis of the balloon as it moves from the second end side to the first end side.

2. The balloon catheter according to claim 1, wherein said apex is continuous with the outer surface of said leg portion at said first end of said first projection.

3. The balloon catheter according to claim 2, wherein said apex is continuous with the outer surface of said tapered portion at said second end of said first projection.

4. A balloon catheter as claimed in any one of claims 1 to 3, wherein the balloon has a straight tube section which is the part which has the largest diameter when inflated and is located on the opposite side of the tapered section from the leg section, the second end of the first protrusion is located in the middle of the tapered section in the axial direction, and the area of ​​the tapered section which is closer to the straight tube section than the first protrusion is a non-protruding area where no outer protrusion exists.

5. A balloon catheter as described in claim 4, wherein the straight tube section is provided with a second protrusion as the outer protrusion, extending in the axial direction and positioned at the same position as the first protrusion in the circumferential direction of the balloon; and the non-protrusion region is provided with an inner protrusion that protrudes from the inner surface of the tapered section and extends in the axial direction along the inner surface, and the inner protrusion is positioned at the same position as the first protrusion and the second protrusion in the circumferential direction.

6. A balloon catheter according to any one of claims 1 to 3, wherein the balloon has a straight tube section which is the part which has the largest diameter when inflated and is provided on the opposite side of the leg section with the tapered section in between, the straight tube section is provided with a second protrusion which extends in the axial direction and is located at the same position as the first protrusion in the circumferential direction of the balloon as the outer protrusion, the second end of the first protrusion is located at a midpoint in the axial direction of the tapered section, and a third protrusion which extends in the axial direction along the outer surface of the tapered section is provided in an area of ​​the tapered section closer to the straight tube section than the first protrusion, the third protrusion being located at the same position in the circumferential direction as the first protrusion and the second protrusion, and the protrusion height from the outer surface of the balloon is less than half the protrusion height of the second protrusion.

7. A balloon catheter according to any one of claims 1 to 3, wherein the catheter body comprises: an outer tube; and an inner tube inserted into the outer tube and having an extending portion extending further distally than the outer tube; the balloon is provided so as to cover the extending portion from the outside; the balloon has, as its leg portion, a base leg portion joined to the distal end of the outer tube and a distal leg portion joined to the extending portion; the tapered portion has a base tapered portion adjacent to the distal side of the base leg portion and a distal tapered portion adjacent to the base side of the distal leg portion; and the first protrusion extends across the base leg portion and the base tapered portion.

8. A balloon catheter as claimed in any one of claims 1 to 3, wherein the apex has a first apex provided on the first end side and a second apex provided on the second end side, the first apex and the second apex are continuous, and the inclination angle of the first apex relative to the central axis is greater than the inclination angle of the second apex relative to the central axis.

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