JP7705895B2 - Balloon for balloon catheter - Google Patents

Description

The present invention relates to a balloon for a balloon catheter.

When narrowed areas hardened by calcification form on the inner walls of blood vessels, it can lead to diseases such as angina and myocardial infarction. One treatment for these conditions is angioplasty, which uses a balloon catheter to expand the narrowed area. Angioplasty is a minimally invasive therapy that does not require open chest surgery like bypass surgery, and is widely used.

In angioplasty, it can be difficult to expand stenotic areas that have hardened due to calcification, etc., using a typical balloon catheter. A method is also used in which an indwelling expansion device called a stent is placed in the stenotic area to expand the stenotic area, but this can lead to ISR (In-Stent-Restenosis) lesions, in which the neointima of the blood vessel grows excessively after treatment, causing vascular stenosis again. In ISR lesions, the neointima is soft and has a slippery surface, so when a typical balloon catheter is used to expand the balloon, the position of the balloon may shift from the lesion, damaging the blood vessel.

As a balloon catheter that can expand the stenosis even in such calcified lesions or ISR lesions, a balloon catheter with a protrusion, blade, or scoring element for penetrating the stenosis has been developed. For example, Patent Document 1 discloses a balloon catheter having a scoring element made of a polymeric material with higher rigidity than the polymeric material forming the balloon body, and the scoring element is flattened at one end and the other end of the balloon. Patent Document 2 discloses a scoring balloon structure in which the height of the scoring element decreases along the tapered shape of the balloon, and Patent Document 3 discloses a balloon catheter in which an outer protrusion is provided on the straight tube part of the balloon and an inner protrusion is provided on the tapered part. In the above Patent Documents 1 to 3, the height of the scoring element decreases at both ends of the balloon, or an inner protrusion is provided instead of an outer protrusion. In contrast, there is also a balloon catheter with a high protrusion part in which the protrusion amount of the protrusion arranged on the distal tapered part is larger than the protrusion arranged on the straight tube part of the balloon (Patent Document 4).

US Patent Application Publication No. 2016/0128718 Special table 2014-506140 publication International Publication No. 2020/012851 International Publication No. 2020/012850

A balloon catheter is inserted into a body cavity in a deflated and folded state and delivered to a treatment site. Therefore, in the balloon catheters disclosed in the above Patent Documents 1 to 3, the height of the scoring element at the tip of the balloon is suppressed to prevent the outer diameter from becoming large so that it can be easily inserted into the body cavity, thereby attempting to improve the passability of the balloon. However, in such balloon catheters, the height of the scoring element is suppressed at both ends of the balloon, so that the expansion part of the balloon abuts against the body cavity wall during delivery of the balloon, and the contact area between the balloon and the body cavity wall during delivery is large. As a result, there was a risk of a decrease in the trackability of the balloon at the curved part of the body cavity (the ease with which the balloon follows the curve of the body cavity when the balloon is transported within the body cavity). In addition, since the expansion part of the balloon abuts against the body cavity wall while the balloon is transported to the lesion, there were cases where the expansion part of the balloon, which is expanded to act on the lesion during treatment, was damaged during transportation, causing an obstacle to treatment. In the balloon catheter disclosed in Patent Document 4, the height of the protrusion located on the tip taper section is increased in order to make it easier to make an incision in the lesion when the balloon is in an expanded state. However, there is room for improvement in terms of improving trackability when transporting the deflated balloon to the lesion and protecting the balloon expansion section during transport.

In view of the above circumstances, the present invention aims to provide a balloon for a balloon catheter that can improve trackability and protect the expansion portion of the balloon when transporting the deflated balloon within a body cavity.

One embodiment of a balloon for a balloon catheter of the present invention that can solve the above problems is a balloon for a balloon catheter having an expansion section, a proximal sleeve section located proximal to the expansion section, and a distal sleeve section located distal to the expansion section, and has a balloon body having an outer surface and an inner surface, and an outer protruding section that protrudes radially outward from the outer surface of the balloon body and extends in the longitudinal direction of the balloon body, and when the balloon is in a deflated state, satisfies at least one of the following (1) and (2).
(1) The radius of a first imaginary cylinder _C1 having a central axis parallel to the longitudinal axis direction, a bottom surface located at the distal end and the proximal end of the proximal sleeve portion, and at least a portion of a side surface circumscribed by the proximal sleeve portion, is greater than the radius of an imaginary circle _C0 circumscribed by the expansion portion in a radial cross section perpendicular to the longitudinal axis direction at the midpoint of the expansion portion in the longitudinal _axis direction.
(2) The radius of a second imaginary cylinder _C2 having a central axis parallel to the longitudinal axis direction, a bottom surface located at the distal end and the proximal end of the distal sleeve portion, and at least a portion of a side surface circumscribed by the distal sleeve portion, is greater than the radius of an imaginary circle _C0 circumscribed by the expansion portion in a radial cross section perpendicular to the longitudinal axis direction at the midpoint of the expansion portion in the longitudinal _axis direction.

The expansion portion has a main section that is 10% less than the distal end and 10% less than the proximal end in the longitudinal direction, and preferably satisfies at least one of the following (1) and (2) when the balloon is in a deflated state.
(1) The radius of the first imaginary cylinder _C1 is larger than the radius of a third imaginary cylinder _C3 having a central axis parallel to the longitudinal axis direction, whose bottom surfaces are located at the distal and proximal ends of the main section, and whose side surfaces are at least partially circumscribed by the main _section .
(2) The radius of the second imaginary cylinder _C2 is larger than the radius of a third imaginary cylinder _C3 having a central axis parallel to the longitudinal axis direction, whose bottom surfaces are located at the distal and proximal ends of the main section, and whose side surfaces are at least partially circumscribed by the main _section .

In the deflated state of the balloon, it is preferable that the balloon is folded.

It is preferable that the outer protrusion has a tip portion in a radial cross section and satisfies at least one of the following (1) and (2) when the balloon is in a deflated state.
(1) In the proximal sleeve portion, the tip portion is circumscribed on at least a portion of the side surface of the first imaginary cylinder _C1 .
(2) In the distal sleeve portion, the tip portion is circumscribed on at least a portion of the side surface of the second imaginary cylinder _C2 .

It is preferable that the outer protrusion has a tip portion in a radial cross section and satisfies at least one of the following (1) and (2) when the balloon is in a deflated state.
(1) In the proximal sleeve portion, only the tip portion is circumscribed by at least a portion of the side surface of the first imaginary cylinder _C1 .
(2) In the distal sleeve portion, only the tip portion is circumscribed by at least a portion of the side surface of the second imaginary cylinder _C2 .

In the deflated state of the balloon, the expansion portion preferably has wings that circumscribe an imaginary circle C ₀ .

When the balloon is in a deflated state, it is preferable that the expansion portion has wings and the outer protrusion is located other than the wings.

It is preferable that at least one of the following (1) and (2) is satisfied.
(1) The outer protrusion of the proximal sleeve portion and the outer protrusion of the expansion portion extend continuously in the longitudinal axis direction.
(2) The outer protrusion of the distal sleeve portion and the outer protrusion of the expansion portion extend continuously in the longitudinal axis direction.

In the deflated state of the balloon, it is preferable that the radius of the first imaginary cylinder _C1 in the proximal sleeve section is larger than the radius of the imaginary circle _C0 in the expansion section, and the radius of the second imaginary cylinder _C2 in the distal sleeve section is smaller than the radius of the imaginary circle _C0 . In this case, the expansion section has a main section that is obtained by removing 10% of each of the distal end and the proximal end in the longitudinal direction, and in the deflated state of the balloon, it is preferable that the radius of the first imaginary cylinder _C1 in the proximal sleeve _section is larger than the radius of the third imaginary cylinder _C3 having a central axis parallel to the longitudinal direction, the bottom surface of which is located at the distal end and the proximal end of the main section, and the main section circumscribes at least a part of the side surface, and the radius of the second imaginary cylinder _C2 in the distal sleeve section is smaller than the radius of the third imaginary cylinder _C3 . Furthermore, in this case, it is preferable that the distal sleeve section has an inner protruding portion that protrudes radially inward from the inner surface of the balloon body and extends in the longitudinal direction.

It is preferable that the outer protrusions are made from the same material as the balloon body.

According to the balloon for the balloon catheter, when the balloon is in a deflated state, the radius of the imaginary cylinder circumscribing at least one of the proximal sleeve portion and the distal sleeve portion is larger than the radius of the imaginary circle circumscribing the central portion of the expansion portion, thereby improving the trackability of the balloon and protecting the expansion portion of the balloon when the balloon is transported in a deflated state within a body cavity.

1 illustrates a side view of a balloon catheter according to one embodiment of the present invention. 2 is a longitudinal sectional view of the balloon catheter shown in FIG. 1 in an expanded state. FIG. 3 shows a plan view of the balloon shown in FIG. 2 as seen from the outer protrusion side. 4 shows a cross-sectional view taken along line IV-IV in FIG. FIG. 2 is a side view of the balloon catheter shown in FIG. 1 in a deflated state. FIG. 6 is a side view showing another example of the side view shown in FIG. 5 . 7 shows a cross-sectional view taken along the line VII-VII of FIG. FIG. 8 is a cross-sectional view showing another example of the cross-sectional view shown in FIG. 7 . FIG. 8 is a cross-sectional view showing still another example of the cross-sectional view shown in FIG. 7 . FIG. 8 is a cross-sectional view showing still another example of the cross-sectional view shown in FIG. 7 . XI-XI cross-sectional view of FIG. 5. FIG. 12 is a cross-sectional view showing another example of the cross-sectional view shown in FIG. 11 . FIG. 2 is a side view of a balloon for a balloon catheter according to another embodiment of the present invention in a deflated state. 1 is a radial cross-sectional view of a balloon for a balloon catheter according to one embodiment of the present invention in a folded state, taken at the midpoint in the longitudinal direction of an expansion section. FIG. FIG. 15 is a cross-sectional view showing another example of the cross-sectional view shown in FIG. 14 . FIG. 2 is a side view of a balloon for a balloon catheter according to yet another embodiment of the present invention in a deflated state. 17 shows a cross-sectional view taken along line XVII-XVII of FIG. 16. FIG. 18 is a cross-sectional view showing another example of the cross-sectional view shown in FIG. 17 . FIG. 2 illustrates a perspective view of a parison prior to expansion according to one embodiment of the present invention.

The present invention will be described in detail below based on the embodiments, but the present invention is not limited to the embodiments below, and can of course be modified appropriately within the scope of the intent described above and below, all of which are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to contributing to an understanding of the features of the present invention.

A balloon for a balloon catheter according to an embodiment of the present invention is a balloon for a balloon catheter having an expansion section, a proximal sleeve section located proximal to the expansion section, and a distal sleeve section located distal to the expansion section, and has a balloon body having an outer surface and an inner surface, and an outer protruding section that protrudes radially outward from the outer surface of the balloon body and extends in the longitudinal direction of the balloon body, and satisfies at least one of the following (1) and (2) when the balloon is in a deflated state.
(1) The radius of a first imaginary cylinder _C1 having a central axis parallel to the longitudinal axis direction, a bottom surface located at the distal end and the proximal end of the proximal sleeve portion, and at least a portion of a side surface circumscribed by the proximal sleeve portion, is greater than the radius of an imaginary circle _C0 circumscribed by the expansion portion in a radial cross section perpendicular to the longitudinal axis direction at the midpoint of the expansion portion in the longitudinal _axis direction.
(2) The radius of a second imaginary cylinder _C2 having a central axis parallel to the longitudinal axis direction, a bottom surface of which is located at the distal end and the proximal end of the distal sleeve portion and at least a portion of which is circumscribed by the distal sleeve portion, is greater than the radius of an imaginary circle _C0 circumscribed by the expansion portion in a radial cross section perpendicular to the longitudinal axis direction at the midpoint of the expansion portion in the longitudinal _axis direction.
In this way, in the deflated state of the balloon, at least one of the radius of the first imaginary cylinder C ₁ circumscribing the proximal sleeve portion and the radius of the second imaginary cylinder C ₂ circumscribing the distal sleeve portion is larger than the radius of the imaginary circle C ₀ circumscribing the expansion portion in the radial cross section at the midpoint in the longitudinal axis direction of the expansion portion, so that when the deflated balloon is transported in the body cavity, the proximal sleeve portion or the distal sleeve portion is brought into contact with the body cavity wall, making it difficult for the expansion portion to come into contact with the body cavity wall. This makes it possible to reduce the contact area of the balloon with the body cavity wall, and improve the trackability of the balloon (the ease with which the balloon follows the curvature of the body cavity when the balloon is transported in the body cavity). In addition, since the balloon can be transported to the lesion with the center of the expansion portion being made difficult to come into contact with the body cavity wall, the expansion portion that is expanded during treatment to act on the lesion portion can be protected from damage, making effective treatment possible. Furthermore, for example, if a drug is loaded on the expansion portion, loss of the drug can be prevented. In this specification, a balloon for a balloon catheter may be simply referred to as a "balloon."

A balloon for a balloon catheter will be described with reference to Figures 1 to 15. Figure 1 shows a side view of a balloon catheter according to one embodiment of the present invention. Figure 2 shows a longitudinal cross-sectional view of the balloon of the balloon catheter shown in Figure 1 in an expanded state, and Figure 3 shows a plan view of the balloon shown in Figure 2 as seen from the outer protrusion side. Figure 4 shows a IV-IV cross-sectional view of Figure 1. Figure 5 shows a side view of the balloon of the balloon catheter shown in Figure 1 in a contracted state, and Figure 6 shows a side view showing another example of the side view shown in Figure 5. Figure 7 shows a VII-VII cross-sectional view of Figure 5, that is, a radial cross-sectional view at the midpoint in the longitudinal direction of the expansion part. Figures 8 to 10 show cross-sectional views showing different examples of the cross-sectional view shown in Figure 7, that is, cross-sectional views showing examples with different lengths of wings and different numbers of outer protrusions. Figure 11 shows a XI-XI cross-sectional view of Figure 5, that is, a radial cross-sectional view of the proximal sleeve part, and Figure 12 shows a cross-sectional view showing another example of the cross-sectional view shown in Figure 11. Fig. 13 is a side view of a balloon for a balloon catheter according to another embodiment of the present invention in a deflated state. Fig. 14 is a radial cross-sectional view of the balloon of a balloon catheter according to an embodiment of the present invention in a folded state at the midpoint in the longitudinal direction of the expansion part. Fig. 15 is a cross-sectional view showing another example of the cross-sectional view shown in Fig. 14, i.e., a cross-sectional view showing an example in which the lengths of the wings are different.

In the present invention, the proximal side refers to the direction toward the user or surgeon with respect to the extension direction of the balloon catheter 1 or the longitudinal axis direction x of the shaft 3, and the distal side refers to the opposite direction of the proximal side, i.e., the direction toward the treatment target. Even if the member is not a long member such as the shaft 3, it has the same longitudinal axis direction x as the shaft 3. The radial direction y is a direction perpendicular to the longitudinal axis direction x and is a direction connecting the center of the balloon body 27 and a point on the circumscribing circle of the balloon body 27 in the expanded state in a cross section perpendicular to the longitudinal axis direction x. The circumferential direction z is a direction along the circumference of the circumscribing circle of the balloon body 27 in the expanded state in a cross section in the radial direction y.

As shown in Figures 1 and 2, the balloon catheter 1 has a shaft 3 and a balloon 2 provided on the outside of the shaft 3. The balloon catheter 1 has a distal side and a proximal side, and the balloon 2 is provided on the distal side of the shaft 3. The balloon catheter 1 is configured so that fluid is supplied to the inside of the balloon 2 through the shaft 3, and the expansion and contraction of the balloon 2 can be controlled using an indeflator (balloon pressurizer). The fluid may be a pressurized fluid pressurized by a pump or the like.

It is preferable that the shaft 3 has a fluid flow path therein and further has a guide wire insertion path. In order to configure the shaft 3 to have a fluid flow path and a guide wire insertion path therein, for example, the shaft 3 may have an outer tube 31 and an inner tube 32, the inner tube 32 functions as a guide wire insertion path, and the space between the inner tube 32 and the outer tube 31 functions as a fluid flow path. In this configuration in which the shaft 3 has the outer tube 31 and the inner tube 32, it is preferable that the inner tube 32 extends from the distal end of the outer tube 31 and penetrates distally of the balloon 2, the distal side of the balloon 2 is joined to the inner tube 32, and the proximal side of the balloon 2 is joined to the outer tube 31.

As shown in Figures 1 to 12, the balloon 2 for a balloon catheter has an expansion section 20, a proximal sleeve section 21 located proximal to the expansion section 20, and a distal sleeve section 22 located distal to the expansion section 20. The balloon 2 has a balloon body 27 having an outer surface and an inner surface, and an outer protrusion section 60 that protrudes outward in the radial direction y from the outer surface of the balloon body 27 and extends in the longitudinal axis direction x of the balloon body 27. When the balloon 2 is in a deflated state, at least one of the following (1) and (2) is satisfied.
(1) A first imaginary cylinder _C1 having a central axis parallel to the longitudinal axis direction x, a bottom surface of which is located at the distal end and proximal end of the proximal sleeve portion 21, and at least a portion of whose side surface is circumscribed by the proximal sleeve portion 21, has a radius _{r1 that} is greater than a radius _r0 of an imaginary circle C0 circumscribed by the expansion portion 20 in a cross section in the radial direction y perpendicular to the longitudinal axis direction x at the midpoint 20c of the longitudinal axis direction x of the expansion portion _{20 .}
(2) A second imaginary cylinder _C2 having a central axis parallel to the longitudinal axis direction x, a bottom surface of which is located at the distal end and proximal end of the distal sleeve portion 22, and at least a portion of whose side surface is circumscribed by the distal sleeve portion 22, has a radius _{r2 that} is greater than a radius _r0 of a virtual circle C0 circumscribed by the expansion portion 20 in a cross section in the radial direction y perpendicular to the longitudinal axis direction x at the midpoint 20c of the longitudinal axis direction x of _{the expansion portion 20 .}
In the contracted state of the balloon 2, at least one of the radius r1 of the first imaginary cylinder _C1 circumscribing the proximal sleeve portion ₂₁ and the radius r2 of the second imaginary cylinder _C2 circumscribing the distal sleeve portion ₂₂ is larger than the radius _r0 of the imaginary circle _C0 circumscribing the expansion portion 20 in the cross section in the radial direction y at the midpoint 20c of the longitudinal axis direction x of the expansion portion 20. Therefore, when the contracted balloon 2 is transported in the body cavity, the proximal sleeve portion 21 or the distal sleeve portion 22 is brought into contact with the body cavity wall, making it difficult for the expansion portion 20 to come into contact with the body cavity wall. This makes it possible to reduce the contact area of the balloon 2 with the body cavity wall, and improve the trackability of the balloon 2 (the ease with which the balloon 2 follows the curvature of the body cavity when the balloon 2 is transported in the body cavity). In addition, since the balloon 2 can be delivered to the lesion while preventing the center of the expansion section 20 from coming into contact with the body cavity wall, the expansion section 20, which is expanded during treatment to act on the lesion, can be protected from damage, enabling effective treatment. Furthermore, for example, if the expansion section 20 is loaded with a drug, loss of the drug can be prevented.

1 and 2, the balloon 2 has a proximal sleeve portion 21 and a distal sleeve portion 22, respectively, proximal and distal to the expansion portion 20. At least a portion of the proximal sleeve portion 21 and the distal sleeve portion 22 can be configured to be fixed to the shaft 3, and in the case where the shaft 3 has an outer tube 31 and an inner tube 32, at least a portion of the proximal sleeve portion 21 can be fixed to the outer tube 31, and at least a portion of the distal sleeve portion 22 can be fixed to the inner tube 32.

The expansion section 20 is a section that is expanded by supplying fluid to the inside of the balloon 2 through the shaft 3, and it is preferable that the proximal sleeve section 21 and the distal sleeve section 22, which are located proximal and distal to the expansion section 20, do not expand even when fluid is supplied to the inside of the balloon 2. This allows the fixation of the balloon 2 and the shaft 3 to be stabilized even when the balloon 2 is in an expanded state. In addition, as described below, when the balloon 2 is contracted from an expanded state, wings 29 are formed in the expansion section 20, but if the proximal sleeve section 21 and the distal sleeve section 22 do not expand, the wings 29 are not formed in the proximal sleeve section 21 and the distal sleeve section 22 even when the balloon 2 is contracted from an expanded state. This allows the wings 29 to be configured not to come into contact with the body cavity wall in the proximal sleeve section 21 and the distal sleeve section 22 when the balloon 2 is transported in the body cavity in a contracted state.

Although not shown, the expansion section 20 may have a straight tube section, a proximal taper section located proximal to the straight tube section, and a distal taper section located distal to the straight tube section. The straight tube section has the same diameter in the longitudinal axis direction x, and the proximal taper section and the distal taper section are preferably formed so as to reduce in diameter as they move away from the straight tube section. Since the expansion section 20 has a straight tube section with a maximum diameter, when the balloon 2 is expanded at a lesion such as a stenosis, the straight tube section can be in sufficient contact with the lesion, making it easier to expand or incise the lesion. In addition, since the expansion section 20 has a proximal taper section and a distal taper section with reduced diameter, when the balloon 2 is deflated, the outer diameter of the proximal end and the distal end of the balloon 2 can be reduced to reduce the step between the shaft 3 and the balloon 2, making it easier to insert the balloon 2 into the body cavity.

1 to 4, the balloon 2 has a balloon body 27 having an outer surface and an inner surface, and an outer protrusion 60 that protrudes outward in the radial direction y from the outer surface of the balloon body 27 and extends in the longitudinal axis direction x of the balloon body 27. The maximum length by which the outer protrusion 60 protrudes outward in the radial direction y from the outer surface of the balloon body 27 in the cross section in the radial direction y is preferably 1.2 times or more, more preferably 1.5 times or more, and even more preferably 2 times or more, and is also acceptable to be 100 times or less, 50 times or less, 30 times or less, or 10 times or less. In addition, the maximum length may be different in the longitudinal axis direction x. The outer protrusion 60 having a maximum length in the above range makes it easier to make an incision of an appropriate depth in the narrowed portion, making it easier to incise. Furthermore, since the balloon 2 has the outer protrusion 60, it is possible to improve the strength of the balloon 2 and suppress overexpansion of the balloon 2 when pressurized.

The number of outer protrusions 60 in the circumferential direction z of the balloon 2 may be multiple as shown in Figures 1 to 8 and 11, or may be one as shown in Figures 9, 10, and 12. When the balloon 2 has multiple outer protrusions 60 in the circumferential direction z, it is preferable that the multiple outer protrusions 60 are spaced apart in the circumferential direction z, and it is more preferable that they are arranged at equal intervals in the circumferential direction z. The separation distance is preferably longer than the maximum circumferential length of the outer protrusions 60. By arranging the outer protrusions 60 at intervals in the circumferential direction z, preferably at equal intervals, it becomes easier to fix the balloon 2 and to incise the stenosis.

The outer protrusions 60 extending in the longitudinal axis direction x on the outer surface of the balloon body 27 may be arranged at the same position in the circumferential direction z in the longitudinal axis direction x, that is, straight in the longitudinal axis direction x as shown in FIG. 3. If the outer protrusions 60 are arranged straight, the narrowed portion can be incised straight. Alternatively, although not shown, the outer protrusions 60 may be arranged at different positions in the circumferential direction z in the longitudinal axis direction x, for example, in a spiral shape that goes around the outer surface of the balloon body 27 in the circumferential direction z. With such an outer protrusion, the narrowed portion can be incised obliquely.

It is preferable that the balloon 2 satisfies at least one of the following (1) and (2).
(1) The outer protrusion 60 of the proximal sleeve portion 21 and the outer protrusion 60 of the expansion portion 20 extend continuously in the longitudinal axis direction x.
(2) The outer protrusion 60 of the distal sleeve portion 22 and the outer protrusion 60 of the expansion portion 20 extend continuously in the longitudinal axis direction x.
3 shows an embodiment that satisfies both of the above (1) and (2), i.e., the outer protrusion 60 of the proximal sleeve portion 21, the outer protrusion 60 of the expansion portion 20, and the outer protrusion 60 of the distal sleeve portion 22 extend continuously in the longitudinal axis direction x, but it is sufficient if at least one of the above (1) and (2) is satisfied. This makes it possible to further improve the strength of the balloon 2 and further suppress overexpansion of the balloon 2 when pressurized.

Alternatively, although not shown, in the contracted state of the balloon 2, as long as at least one of the radius r 1 of the first imaginary cylinder C ₁ circumscribing the proximal sleeve portion ₂₁ and the radius r 2 of the second imaginary cylinder C ₂ circumscribing the distal sleeve portion ₂₂ is larger than the radius r ₀ of the imaginary circle C ₀ circumscribing the expansion portion 20 in the cross section in the radial direction y at the midpoint 20c of the longitudinal axis direction x of the expansion portion 20, the outer protrusions 60 of the proximal sleeve portion 21, the expansion portion 20, and the distal sleeve portion 22 do not have to extend continuously in the longitudinal axis direction x, and there may be a portion where the outer protrusions 60 are not arranged. This makes it possible to provide a portion where the outer diameter of the balloon 2 in the contracted state is small, thereby reducing the contact area of the balloon 2 with the body cavity wall and improving trackability.

As shown in FIG. 4, the outer protrusion 60 has a tip 61 in the cross section in the radial direction y. The tip 61 makes it easier to make an incision in the stenosis, so the stenosis can be incised while preventing dissection of the vascular intima. The tip 61 is the part of the outer protrusion 60 that protrudes most outward in the radial direction y from the outer surface of the balloon body 27, and may have a shape with an acute angle as shown in FIG. 4, a shape with an obtuse angle, a curved shape, or a flat shape. From the viewpoint of ease of making an incision, it is preferable that the tip 61 has a shape with an acute angle. The shape of the outer protrusion 60 in the cross section in the radial direction y may be any shape, and may be a substantially triangular shape as shown in FIG. 4, or may be a polygonal, sectoral, wedge-shaped, convex, spindle-shaped, etc.

As shown in Fig. 5 and Fig. 7, the contracted state of the balloon 2 is a state before a fluid is supplied to the inside of the balloon 2 or after a fluid is discharged from the inside of the balloon 2, and in the contracted state of the balloon 2, the expansion section 20 has a portion where the inner surface of the balloon body 27 is close to the shaft 3 and the wings 29. In the embodiment shown in Fig. 5 and Fig. 7, the shaft 3 has an outer tube 31 and an inner tube 32, and the expansion section 20 has a portion where the inner surface of the balloon body 27 is close to the inner tube 32 and the wings 29 in the contracted state of the balloon 2. In the contracted state of the balloon 2, it is preferable that the wings 29 are formed so as to go around the shaft 3 in the circumferential direction z. Before supplying a fluid to the inside of the balloon 2, particularly in the contracted state of the balloon 2 before use, as shown in Figs. 7 to 10, it is preferable that the wings 29 go around the shaft 3 in the circumferential direction z, and that the balloon membranes are in close contact with each other in the portion where the outer protrusion 60 is not provided, and that the wings 29 are in close contact with the outer protrusion 60 in the portion where the outer protrusion 60 is provided. It is also preferable that the balloon 2 be in a contracted state having the above-described configuration when the fluid is discharged from the balloon 2 that was once expanded after use of the balloon 2. This makes it possible to easily reduce the radius r0 of the imaginary circle C0 circumscribing the expansion section ₂₀ in a cross section in the radial direction y perpendicular to the longitudinal axis x at the midpoint _20c of the longitudinal axis x of the expansion section 20.

As shown in FIG. 5, the balloon 2 satisfies at least one of the following (1) and (2) in a deflated state.
(1) A first imaginary cylinder _C1 having a central axis parallel to the longitudinal axis direction x, a bottom surface located at the distal end and proximal end of the proximal sleeve portion 21, and at least a portion of a side surface circumscribed by the proximal sleeve portion 21, has a radius _r1 that is greater than a radius r0 of a virtual circle _C0 circumscribed by the expansion portion 20 in a cross section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of _the expansion portion ₂₀ .
(2) A second imaginary cylinder _C2 having a central axis parallel to the longitudinal axis direction x, a bottom surface of which is located at the distal end and proximal end of the distal sleeve portion 22, and at least a portion of whose side surface is circumscribed by the distal sleeve portion 22, has a radius _r2 that is greater than a radius _r0 of a virtual circle C0 circumscribed by the expansion portion 20 in a cross section in the radial direction y at the midpoint 20c in the longitudinal axis direction x _of the expansion portion ₂₀ .
FIG. 5 shows an embodiment that satisfies both (1) and (2), but it is sufficient that at least one of (1) and (2) is satisfied. When both (1) and (2) are satisfied, the radius r ₁ of the first imaginary cylinder C ₁ circumscribed by the proximal sleeve portion 21 and the radius r ₂ of the second imaginary cylinder C ₂ circumscribed by the distal sleeve portion 22 may be the same or one may be larger. With the above configuration, when the balloon 2 in a contracted state is transported in the body cavity, the proximal sleeve portion 21 or the distal sleeve portion 22 is brought into contact with the body cavity wall, making it difficult for the expansion portion 20 to come into contact with the body cavity wall. As a result, the expansion portion 20, which has a relatively large area, is less likely to come into contact with the body cavity wall, so that the contact area of the balloon 2 with the body cavity wall during transportation can be reduced, and the trackability of the balloon 2 can be improved. In addition, since the expansion portion 20 is less likely to come into contact with the body cavity wall, the expansion portion 20, which is expanded during treatment to act on the lesion, can be protected from damage, making effective treatment possible. Furthermore, for example, if the expansion section 20 is loaded with a drug, loss of the drug can be prevented.

Here, the above condition (1) is that the proximal sleeve portion 21 is circumscribed on at least a part of the side surface of the first imaginary cylinder _C1 , which has a central axis parallel to the longitudinal axis direction x and has bottom surfaces at the distal end and the proximal end of the proximal sleeve portion 21. In other words, when the proximal sleeve portion 21 is accommodated inside the first imaginary cylinder _C1 so that the longitudinal axis direction x coincides, the proximal sleeve portion 21 is in contact with at least a part of the side surface of the first imaginary cylinder _C1 , and when the diameter of the proximal sleeve portion 21 varies in the longitudinal axis direction x, the part having the maximum diameter is in contact with the side surface of the first imaginary cylinder _C1 . The above condition (2) for the distal sleeve portion 22 can be understood in the same manner as above.

When the proximal end of the expansion section 20 is the 0% position and the distal end is the 100% position in the longitudinal axis direction x, the midpoint 20c in the longitudinal axis direction x of the expansion section 20 corresponds to the 50% position, but it is preferable that at least one of the radius r1 of the first virtual cylinder C1 circumscribing the proximal sleeve section 21 and the radius r2 of the second virtual cylinder _C2 circumscribing the distal sleeve section ₂₂ is larger than the radius of each virtual circle circumscribing the expansion section 20 in the radial direction y cross section at the 40% position and the 60% position. Moreover, it is more preferable that at least one of the radius _r1 and the radius _r2 is larger than the radius of _each virtual circle circumscribing the expansion section 20 in the radial direction y cross section at the 30% position and the 70% position, and it is even more preferable that at least one of the radius _r1 and the radius _r2 is larger than the radius of each virtual circle circumscribing the expansion section 20 in the radial direction y cross section at the ₂₀ % position and the 80% position. This makes it less likely that the expansion portion 20 will come into contact with the wall of the body cavity when the deflated balloon 2 is transported within the body cavity, making it easier to improve the trackability of the balloon 2 and protect the expansion portion 20.

In the case where the expansion section 20 has a proximal tapered section, a straight tube section, and a distal tapered section, it is preferable that at least one of the radius _r1 of the first imaginary cylinder _C1 circumscribing the proximal sleeve section 21 and the radius r2 of the second imaginary cylinder _C2 circumscribing the distal sleeve section ₂₂ is larger than the radius of the straight tube section. This makes it difficult for the straight tube section, which has a relatively large area, to come into contact with the wall of the body cavity when the balloon 2 in a deflated state is transported inside the body cavity, thereby improving the trackability of the balloon 2 and protecting the straight tube section.

The entire sleeve portion does not need to be circumscribed on each imaginary cylinder. For example, as shown in FIG. 6, the distal end of the distal sleeve portion 22 may have a portion that is not circumscribed on the second imaginary cylinder _C2 . With this configuration, the diameter of the tip portion in the advancing direction can be reduced when the deflated balloon 2 is inserted into the body cavity, improving the insertability. Alternatively, although not shown, the proximal end of the proximal sleeve portion 21 may have a portion that is not circumscribed on the first imaginary cylinder _C1 . With this configuration, the diameter of the tip portion in the advancing direction can be reduced when the deflated balloon 2 is retracted from the lesion, improving the insertability.

With reference to Figs. 7 to 10, the virtual circle _C0 circumscribing the expansion portion 20 in the cross section in the radial direction y at the midpoint 20c of the longitudinal axis direction x of the expansion portion 20 in the contracted state of the balloon 2 will be described. Figs. 7 and 8 show an example of the virtual circle _C0 in the case of a balloon 2 having three outer protrusions 60. As shown in Fig. 7, in the case of a balloon 2 having a relatively large diameter of the expansion portion 20, the length of the wing 29 going around in the circumferential direction z is relatively long, and in such a case, the wing 29 may be circumscribing the virtual circle _C0 . As shown in Fig. 8, in the case of a balloon 2 having a relatively small diameter of the expansion portion 20, the length of the wing 29 going around in the circumferential direction z is relatively short, and in such a case, the outer protrusion 60 may be circumscribing the virtual circle _C0 . Figs. 9 and 10 show an example of the virtual circle _C0 in the case of a balloon 2 having one outer protrusion 60. As shown in Fig. 10, in the example of the balloon 2 in which the diameter of the expansion section 20 is relatively large, the length of the wing 29 going around in the circumferential direction z is relatively long, and in such a case, the wing 29 may be circumscribed on the imaginary circle _C0 . As shown in Fig. 9, in the example of the balloon 2 in which the diameter of the expansion section 20 is relatively small, the length of the wing 29 going around in the circumferential direction z is relatively short, and in such a case, the outer protrusion 60 and the wing 29 may be circumscribed on the imaginary circle _C0 . When the outer protrusion 60 is circumscribed on the imaginary circle _C0 , the tip 61 may be circumscribed on the imaginary circle _C0 . In either case, at least one _of the radius _r1 of the first imaginary cylinder _C1 on which the proximal sleeve section 21 is circumscribed and the radius _r2 of the second imaginary cylinder _C2 on which the distal sleeve section 22 is circumscribed is larger than the radius _r0 of the imaginary circle C0, so that the outer protrusion 60 and the wing 29 of the straight tube section 20 are less likely to abut on the body cavity wall.

11 and 12, a description will be given of the first imaginary cylinder C1 in the case where the radius r1 of the first imaginary cylinder _C1 circumscribing the proximal sleeve portion ₂₁ is larger than the radius _r0 of the imaginary circle C0 circumscribing the expansion portion 20 in the cross section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of the expansion portion ₂₀ in the contracted state of the balloon _2. FIG. 11 shows an example of the first imaginary cylinder C1 in the case of a balloon 2 having three outer protrusions 60, and FIG. 12 shows an example of the first imaginary cylinder _C1 in the case of a balloon 2 having one outer protrusion 60. FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG. 5, and FIG. 5 shows an aspect in which the proximal sleeve portion 21 circumscribs the first imaginary cylinder _C1 over the entire longitudinal axis direction x, but the balloon 2 according to the embodiment of the present invention is not limited to FIG. 5, and it is sufficient that a part of the proximal sleeve portion 21 has the cross section shown in FIG. 11. Similarly, in the aspect shown in FIG. 12, it is sufficient that a part of the proximal sleeve portion 21 has the cross section shown in FIG. 12. 11 and 12, in the non-expanded proximal sleeve portion 21, the wings 29 are not formed even when the balloon 2 is in a deflated state, and in the embodiment shown in Fig. 11, the outer protrusion 60 can circumscribe the first imaginary cylinder _C1 . In other embodiments, including the embodiment shown in Fig. 12, the outer protrusion 60 and the balloon body 27 may circumscribe the first imaginary cylinder _C1 . The first imaginary cylinder _C1 can be regarded as the body cavity wall when the balloon 2 is transported within the body cavity, and as shown in Figs. 11 and 12, the proximal sleeve portion 21 abuts against the body cavity wall with a small contact area, thereby ensuring a transport path for the balloon 2 and improving the trackability of the balloon 2.

As shown in FIG. 12 , even if, for example, one outer protrusion 60 is provided on the proximal sleeve portion 21 and multiple outer protrusions 60 are provided on the expansion portion 20, at least one of the radii r1 and r2 can be made larger than the radius r0 by contracting the balloon 2 so that the wings ₂₉ of the expansion portion 20 are in close contact with the balloon membranes and are in close contact with the outer protrusions ₆₀ in the portions where the outer protrusions ₆₀ are provided.

In the contracted state of the balloon 2, the radius r2 of the second imaginary cylinder C2 circumscribing the distal sleeve portion 22 is larger than the radius _r0 of the imaginary circle _C0 circumscribing the expansion portion 20 in the cross section in the radial direction _y at the midpoint _20c in the longitudinal axis direction x of the expansion portion _20. Although not shown, the second imaginary cylinder C2 can be similarly understood by referring to Figures 11 and 12 used to explain the proximal sleeve portion 21 above.

From the viewpoint of protecting the expansion section 20, as shown in Figures 5 and 6, in a deflated state of the balloon 2, it is preferable that both the radius r1 of the first virtual cylinder _C1 circumscribing the proximal sleeve section ₂₁ and the radius r2 of the second virtual cylinder C2 circumscribing the distal sleeve section 22 are larger _than the radius r0 of the virtual circle _C0 circumscribing the expansion section ₂₀ in a cross section in the radial direction y at the midpoint _20c of the longitudinal axis direction x of the expansion section 20. From the viewpoint of ease of insertion during transportation of the balloon 2, it is preferable that either the radius r1 of the first virtual cylinder _C1 circumscribing the proximal sleeve section 21 or the radius _r2 of the second virtual cylinder _C2 circumscribing the distal sleeve section 22 is larger than the radius _r0 of the virtual circle C0 circumscribing the expansion section ₂₀ in a cross section in the radial direction y at the midpoint 20c of the longitudinal axis direction x of the expansion _{section 20} . In particular, when only the radius _r1 of the first imaginary cylinder _C1 circumscribed by the proximal sleeve portion 21 is larger than the radius _r0 , the outer diameter of the distal sleeve portion 22, which is the tip side when inserted into the body cavity, can be reduced, making it easier to transport the balloon 2 inside the body cavity. Furthermore, by making the radius r1 larger than the radius _r0 , the proximal sleeve portion ₂₁ abuts against the body cavity wall when transporting the balloon 2 inside the body cavity to support the body cavity wall on the proximal side of the balloon 2, making it possible to ensure a transport path for the balloon 2 while making it difficult for the expansion portion 20 to abut against the body cavity wall, thereby improving the trackability of the balloon 2 and protecting the expansion portion 20. When the radius _r2 of the distal sleeve portion 22 is larger than the radius _r0 , the distal sleeve portion 22 abuts against the body cavity wall during transportation of the balloon 2, thereby securing a transportation path for the balloon 2. This has the advantage of preventing a deterioration in the insertability of the balloon 2 due to the expansion portion 20 abutting against the body cavity wall, causing the tip of the balloon membrane to roll up, etc., thereby disrupting the contracted state of the balloon 2.

The radii _r0 , _r1 , and _r2 can be adjusted by changing the radial y length of the outer protrusion 60 in the radial y cross section in the expansion section 20, the proximal sleeve section 21, and the distal sleeve section 22, but the radius _r0 can also be adjusted regardless of the radial y length of the outer protrusion 60 depending on how the expansion section 20 is contracted, and as a result, the relationship between the radius _r0 and the radii _r1 and _r2 can be adjusted. That is, when the balloon 2 is contracted, the balloon 2 is contracted so that the balloon membranes are in close contact with each other in the portion where the outer protrusion 60 is not present, and so that the wings 29 are in close contact with the outer protrusion 60 in the portion where the outer protrusion 60 is arranged, thereby making the radius _r0 smaller than at least one of the radii _r1 and _r2 . With this method, the radius _r0 can be adjusted in the expansion section 20, the proximal sleeve section 21, and the distal sleeve section 22 regardless of the radial y length of the outer protrusion 60 in the radial y cross section, and as a result, the relationship between the radius _r0 and the radii _r1 and _r2 can be adjusted.

As shown in FIG. 13, the expansion section 20 has a main section 20m obtained by removing 10% of each of the distal and proximal ends in the longitudinal axis direction x. When the balloon 2 is in a deflated state, it is preferable that at least one of the following (1) and (2) is satisfied.
(1) The radius r1 of the first imaginary cylinder _C1 is _{larger than} the radius r3 of a third imaginary cylinder _C3 having a central axis parallel to the longitudinal axis direction _{x ,} whose bottom surfaces are located at the distal and proximal ends of the main section 20m and whose side surfaces are circumscribed by the main section 20m at least partially.
(2) The radius r2 of the second imaginary cylinder _C2 is _{larger than} the radius r3 of a third imaginary cylinder _C3 having a central axis parallel to the longitudinal axis direction _{x ,} whose bottom surfaces are located at the distal and proximal ends of the main section 20m and whose side surfaces are circumscribed by the main section 20m at least partially.
In the contracted state of the balloon 2, at least one of the radius r 1 of the first imaginary cylinder C ₁ circumscribing the proximal sleeve portion ₂₁ and the radius r ₂ of the second imaginary cylinder C ₂ circumscribing the distal sleeve portion 22 is larger than the radius r ₃ of the third imaginary cylinder C ₃ circumscribing the main section 20m of the expansion section 20, so that when the contracted balloon 2 is transported in the body cavity, the entire main section 20m of the expansion section 20 is unlikely to come into contact with the body cavity wall. This makes it possible to further reduce the contact area of the balloon 2 with the body cavity wall, and to further improve the trackability of the balloon 2. In addition, since the balloon 2 can be transported to the lesion while making it difficult for the entire main section 20m of the expansion section 20 to come into contact with the body cavity wall, the main section 20m, which is expanded during treatment to act on the lesion, can be protected from damage, and, for example, when a drug is loaded on the main section 20m, the loss of the drug can be prevented.

The main section 20m is a section excluding 10% each in the longitudinal axis direction x from the distal end and proximal end of the expansion section 20, i.e., the portion of the expansion section 20 that is the smallest in diameter in the expanded state. In other words, the main section 20m is a section that has a certain or greater diameter in the expanded state. As a result, in the contracted state of the balloon 2, a wing 29 having a certain or greater length that goes around in the circumferential direction z is formed in the main section 20m, and by contracting the balloon 2 so that the wing 29 comes into close contact with the outer protrusion 60, the radius _r0 can be made smaller than at least one of the radii _r1 and _r2 .

In the above embodiment, the radius r ₃ of the third virtual cylinder C ₃ circumscribing the main section 20 m of the expansion section 20 may be larger than, equal to, or smaller than the radius r ₀ of the virtual circle C 0 circumscribing the expansion section 20 in a cross section in the radial direction y perpendicular to the longitudinal axis direction x at the midpoint 20c of the longitudinal axis direction x of the expansion section _20. Considering that at least one of the radius r 1 of the first virtual cylinder C ₁ circumscribing the proximal sleeve section ₂₁ and the radius r 2 of the second virtual cylinder C ₂ circumscribing the distal sleeve section 22 is larger than _{the radius r 0 ,} it is preferable that the radius r ₃ of the third virtual cylinder C ₃ circumscribing the main section 20 m is larger than the radius r _0. This makes it possible to further suppress the diameter of the central part of the expansion section 20 with respect to the proximal end or distal end of the balloon 2 in the contracted state, which is preferable from the viewpoint of improving trackability and protecting the expansion section 20.

In the contracted state of the balloon 2, the balloon 2 is preferably folded. The balloon 2 in the contracted state before supplying a fluid to the inside of the balloon 2 or after the fluid is discharged from the inside of the balloon 2 can be folded by hand or by using various folding machines, etc., to obtain the folded state of the balloon 2. In the folded state, the wings 29 are folded so as to tightly orbit the shaft 3 and do not float from the shaft 3, so that the wings 29 can be prevented from contacting the body cavity wall during transportation. This makes it possible to easily reduce the radius r ₀ , so that the expansion part 20 can be made less likely to contact the body cavity wall, and the trackability of the balloon 2 can be further improved. In addition, since the expansion part 20 is less likely to contact the body cavity wall, it is possible to better protect the expansion part 20, which is expanded during treatment to act on the lesion, from damage.

For example, as shown in Fig. 14 and Fig. 15, in the folded state of the balloon 2, the wing 29 may be tightly folded and the outer protrusion 60 may be deformed in the circumferential direction z of the wing 20. By folding in this manner, the radius _r0 can be made smaller more easily. Examples of a method for folding the balloon 2 in this manner include forming a shape in the balloon 2 by hand or using various folding machines. By folding the balloon 2 in this manner, the radius _r0 can be adjusted regardless of the length of the outer protrusion 60 in the radial direction y, and as a result, the relationship between the radius _r0 and the radius _r1 and the radius _r2 can be adjusted. That is, the outer protrusion 60 deforms in the circumferential direction z of the wing 29 to make the radius _r0 smaller, and the radius _r0 can be made smaller than at least one of the radius _r1 and the radius _r2 .

In addition, since the main section 20m is a section having the wings 29 having a certain length or more that go around in the circumferential direction z, if the outer protrusions 60 are folded so as to deform in the circumferential direction z of the wings 29 over the entire main section 20m of the expansion section 20, the radius _r3 of the third imaginary cylinder _C3 circumscribing the main section 20m can be easily reduced, and the radius _r3 can be made smaller than at least one of the radii _r1 and _r2 . This makes it difficult for the entire main section 20m to come into contact with the body cavity wall, and the contact area of the balloon 2 with the body cavity wall can be further reduced.

The outer protrusion 60 has a tip 61 in a cross section in the radial direction y, and preferably satisfies at least one of the following (1) and (2) when the balloon 2 is in a deflated state.
(1) In the proximal sleeve portion 21, the tip portion 61 is circumscribed by at least a portion of the side surface of the first imaginary cylinder _C1 .
(2) In the distal sleeve portion 22, the tip portion 61 is circumscribed by at least a portion of the side surface of the second imaginary cylinder _C2 .
The tip 61 is circumscribed on the imaginary cylinder, so that the area of the sleeve portion circumscribed on the imaginary cylinder can be reduced. The imaginary cylinder can be regarded as the body cavity wall when the balloon 2 is transported in the body cavity, and the sleeve portion abuts on the body cavity wall with a small contact area, so that the transport path of the balloon 2 can be secured and the trackability of the balloon 2 can be improved. In this case, as shown in FIG. 11, only the tip 61 may be circumscribed on the imaginary cylinder, or as shown in FIG. 12, the tip 61 and the balloon body 27 may be circumscribed on the imaginary cylinder, or, although not shown, the tip 61 and other parts, for example, parts of the outer protrusion 60 other than the tip 61, may be circumscribed on the imaginary cylinder. Although FIG. 11 and FIG. 12 show the proximal sleeve portion 21 circumscribed on the first imaginary cylinder C ₁ , the distal sleeve portion 22 circumscribed on the second imaginary cylinder C ₂ can be understood in the same manner with reference to FIG. 11 and FIG. 12.

The outer protrusion 60 has a tip 61 in a cross section in the radial direction y, and preferably satisfies at least one of the following (1) and (2) when the balloon 2 is in a deflated state.
(1) In the proximal sleeve portion 21, only the tip portion 61 is in circumscribing at least a portion of the side surface of the first imaginary cylinder _C1 .
(2) In the distal sleeve portion 22, only the tip portion 61 is in circumscribing at least a portion of the side surface of the second imaginary cylinder _C2 .
Since only the tip portion 61 is circumscribed on the imaginary cylinder, the area of the sleeve portion circumscribed on the imaginary cylinder can be made smaller. The imaginary cylinder can be regarded as the body cavity wall when the balloon 2 is transported in the body cavity, and the sleeve portion abuts against the body cavity wall with a smaller contact area, thereby securing the transport path of the balloon 2 and further improving the trackability of the balloon 2. In this case, the sleeve portion can be configured such that a plurality of outer protrusions 60 are arranged at intervals in the circumferential direction z, as shown in FIG. 11, for example. FIG. 11 shows the proximal sleeve portion 21 circumscribed on the first imaginary cylinder C ₁ , but the distal sleeve portion 22 circumscribed on the second imaginary cylinder C ₂ can also be understood in the same manner with reference to FIG.

In the deflated state of the balloon 2, the expansion section 20 preferably has a wing 29, and the wing 29 is preferably circumscribed about the imaginary circle C _0. As can be seen by comparing Fig. 7 with Fig. 8 or Fig. 9 with Fig. 10, the length of the wing 29 circumferentially in the circumferential direction z can be adjusted by adjusting the diameter of the balloon body 27, but the wing 29 can be configured to circumscribe the imaginary circle C ₀ by making the wing 29 have a certain length or more. For example, if the wing 29 is configured to circumscribe the imaginary circle C ₀ as shown in Fig. 7 and Fig. 10, it is easy to protect the outer protrusion 60 from damage, and even if the expansion section 20 abuts against the body cavity wall when the balloon 2 is transported inside the body cavity, the outer protrusion 60 acting on the diseased part is unlikely to abut against the body cavity wall, so that the outer protrusion 60 can be prevented from acting on the body cavity wall at an unintended location.

7 to 10 show an embodiment with three vanes 29, but the number of vanes 29 is not particularly limited as long as the balloon 2 can be deflated, and may be, for example, two or more vanes, more preferably three or more vanes, or four or more vanes, or five or more vanes. Also, for example, ten or fewer vanes 29 are preferred, eight or fewer vanes are more preferred, and six or fewer vanes are even more preferred. If the number of vanes 29 is within the above range, the balloon 2 can be easily deflated.

In the deflated state of the balloon 2, it is preferable that the expansion section 20 has the vanes 29, and the outer protrusions 60 are arranged somewhere other than the vanes 29. If the outer protrusions 60 are arranged somewhere other than the vanes 29, the balloon 2 can be easily deflated because the outer protrusions 60 do not impede the rotation of the vanes 29. In addition, by arranging the outer protrusions 60 somewhere other than the vanes 29, the outer protrusions 60 can be easily covered by the vanes 29 in the deflated state of the balloon 2. This makes it easy to configure the vanes 29 to circumscribe the imaginary circle _C0 in the deflated state of the balloon 2.

Next, a balloon for a balloon catheter according to another embodiment of the present invention will be described with reference to Figures 16 to 18. Figure 16 shows a side view of a balloon for a balloon catheter according to yet another embodiment of the present invention in a deflated state. Figure 17 shows a cross-sectional view taken along line XVII-XVII of Figure 16, i.e., a radial cross-sectional view of the distal sleeve portion, and Figure 18 shows a cross-sectional view showing another example of the cross-sectional view shown in Figure 17.

As shown in FIG. 16, in the contracted state of the balloon 2, it is preferable that the radius r ₁ of the first imaginary cylinder C ₁ in the proximal sleeve portion 21 is larger than the radius r ₀ of the imaginary circle C ₀ in the expansion portion 20, and the radius r ₂ of the second imaginary cylinder C ₂ in the distal sleeve portion 22 is smaller than the radius r ₀ of the imaginary circle C _0. With this configuration, the outer diameter of the distal sleeve portion 22, which is the tip side when inserted into the body cavity, can be reduced, and the transportation of the balloon 2 in the body cavity can be facilitated. In addition, since the radius r ₁ is larger than the radius r ₀ , when the balloon 2 is transported in the body cavity, the proximal sleeve portion 21 abuts against the body cavity wall to support the body cavity wall on the proximal side of the balloon 2, and the transportation path of the balloon 2 is secured while the expansion portion 20 is difficult to abut against the body cavity wall, and the trackability of the balloon 2 can be improved and the expansion portion 20 can be protected. In this way, with the above configuration, the balloon 2 can be easily inserted, while the trackability is improved and the expansion portion 20 can be easily protected.

17, the above configuration may be formed by shortening the length in the radial direction y of the outer protrusion 60 in the radial direction y cross section of the distal sleeve portion 22, or by not providing the outer protrusion 60 on the distal sleeve portion 22. By shortening the length in the radial direction y of the outer protrusion 60 or by not providing the outer protrusion 60, the radius _r2 of the second imaginary cylinder _C2 circumscribing the distal sleeve portion 22 can be reduced.

Alternatively, in order to reduce the radius _r2 , as shown in FIG. 18, the distal sleeve portion 22 preferably has an inner protrusion 70 that protrudes inward in the radial direction y from the inner surface of the balloon body 27 and extends in the longitudinal axis direction x. In this case, as shown in FIG. 18, an outer protrusion 60 having a short length in the radial direction y in a cross section in the radial direction y may also be provided, or, although not shown, the outer protrusion 60 may not be provided. By providing the inner protrusion 70, it is possible to improve the strength of the balloon 2 and suppress overexpansion of the balloon 2 when pressurized, even if the length of the outer protrusion 60 in the radial direction y is short or the outer protrusion 60 is not provided. When the outer protrusion 60 is provided together with the inner protrusion 70, it is preferable that the inner protrusion 70 and the outer protrusion 60 are provided at the same position in the circumferential direction z. This makes it easier to improve the strength of the balloon 2 and suppress overexpansion of the balloon 2 when pressurized.

16, the expansion section 20 has a main section 20m that is obtained by removing 10% of each of the distal end and the proximal end in the longitudinal axis direction x, and in the deflated state of the balloon 2, it is preferable that the radius _r1 of the first imaginary cylinder _C1 in the proximal sleeve section 21 is larger than the radius _r3 of the third imaginary cylinder C3 having a central axis parallel to the longitudinal axis direction _x , the bottom surface of which is located at the distal end and the proximal end of the main section 20m, and the main section 20m circumscribes at least a part of the side surface, and the radius _{r2 of} the second imaginary cylinder _C2 in the distal sleeve section 22 is smaller than the radius _r3 of the third imaginary cylinder _C3 . With this configuration, it is possible to make it difficult for the entire main section 20m of the expansion section 20 to come into contact with the body cavity wall when the balloon 2 in the deflated state is transported inside the body cavity. In addition, the outer diameter of the distal sleeve portion 22, which is the tip side when inserted into the body cavity, can be reduced, making it easier to transport the balloon 2 inside the body cavity. By making the radius _r1 larger than the radius _r3 , the proximal sleeve portion 21 abuts against the body cavity wall when transporting the balloon 2 inside the body cavity, supporting the body cavity wall on the proximal side of the balloon 2, thereby making it difficult for the entire main section 20m of the expansion portion 20 to abut against the body cavity wall while securing a transport path for the balloon 2, thereby making it possible to provide a balloon 2 that can be easily inserted, yet has improved trackability and makes it easier to protect the expansion portion 20.

Examples of materials constituting the balloon body 27 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyester resins such as polyethylene terephthalate and polyester elastomer, polyurethane resins such as polyurethane and polyurethane elastomer, polyphenylene sulfide resins, polyamide resins such as polyamide and polyamide elastomer, fluorine resins, silicone resins, and natural rubbers such as latex rubber. These may be used alone or in combination of two or more. Among them, polyamide resins, polyester resins, and polyurethane resins are preferably used. In particular, elastomer resins are preferably used in terms of thinning and flexibility of the balloon body 27. For example, among polyamide resins, nylon 12, nylon 11, and the like are suitable as resins constituting the balloon body 27, and nylon 12 is more suitable because it can be molded relatively easily during blow molding. In addition, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferably used in terms of thinning and flexibility of the balloon body 27. Among these, polyether ester amide elastomer is preferably used because it has high yield strength and provides good dimensional stability to the balloon body 27 .

It is preferable that the outer protrusion 60 is made of the same material as the balloon body 27. If the outer protrusion 60 is made of the same material as the balloon body 27, the flexibility of the balloon 2 can be maintained while the outer protrusion 60 is less likely to damage the outer surface of the balloon body 27. It is preferable that the balloon body 27 and the outer protrusion 60 are integrally molded. This makes it possible to prevent the outer protrusion 60 from falling off the balloon body 27. In a mode in which the inner protrusion 70 is formed, it is preferable that the inner protrusion 70 is also made of the same material as the balloon body 27 for the same reasons as above.

The balloon 2 can be manufactured by placing a cylindrical parison 200 made of resin in a mold having a groove in the inner cavity, as shown in FIG. 19, and performing biaxial stretch blow molding. The outer protrusion 60 can be formed, for example, by inserting the parison 200 into the inner cavity of the mold, making the thick part 220 of the parison 200 enter the groove of the mold, and introducing a fluid into the inner cavity 210 of the parison 200 to expand the parison 200. The radial y length of the outer protrusion 60 in the radial y cross section can be adjusted by the thickness of the thick part 220 of the parison 200 and the depth of the groove of the mold. The inner protrusion 70 can be formed, for example, by pressing the thick part 220 of the parison 200 against a part of the mold without a groove, and introducing a fluid into the inner cavity 210 of the parison 200 to expand the parison 200. Furthermore, to form the outer protrusion 60 and the inner protrusion 70 having a short length in the radial direction y in a cross section in the radial direction y, for example, the thick wall portion 220 of the parison 200 can be pressed against a shallow groove portion of a mold, and a fluid can be introduced into the inner cavity 210 of the parison 200 to expand the parison 200. For the material constituting the parison 200, the description of the material constituting the balloon body 27 above can be referred to.

Examples of materials constituting the shaft 3 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine resins, vinyl chloride resins, silicone resins, and natural rubber. These may be used alone or in combination of two or more. Of these, it is preferable that the material constituting the shaft 3 is at least one of polyamide resins, polyolefin resins, and fluorine resins. This can increase the slipperiness of the surface of the shaft 3 and improve the insertability of the balloon catheter 1 within the body cavity.

The balloon 2 and the shaft 3 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 2 and the shaft 3 and crimping the member, among others. Of these, it is preferable that the balloon 2 and the shaft 3 are joined by welding. By welding the balloon 2 and the shaft 3, the bond between the balloon 2 and the shaft 3 is unlikely to come undone even if the balloon 2 is repeatedly expanded and contracted, and the bond strength between the balloon 2 and the shaft 3 can be easily increased.

As shown in FIG. 1, the balloon catheter 1 may have a hub 4 on the proximal side of the shaft 3, and the hub 4 may have a fluid injection section 7 that is connected to a flow path of the fluid supplied to the inside of the balloon 2. The hub 4 preferably has a guidewire insertion section 5 that is connected to the insertion path of the guidewire. The balloon catheter 1 has a hub 4 equipped with a fluid injection section 7 and a guidewire insertion section 5, so that the balloon 2 can be easily expanded and contracted by supplying fluid to the inside of the balloon 2, and the balloon catheter 1 can be easily delivered to the treatment site along the guidewire. As shown in FIG. 1, the balloon 2 according to the embodiment of the present invention can be applied not only to a so-called over-the-wire type balloon catheter in which the guidewire is inserted from the distal side to the proximal side of the shaft 3, but also to a so-called rapid exchange type balloon catheter in which the guidewire is inserted halfway from the distal side to the proximal side of the shaft.

The shaft 3 and the hub 4 can be joined by, for example, bonding with an adhesive, welding, etc. Among these, it is preferable that the shaft 3 and the hub 4 are joined by adhesion. By bonding the shaft 3 and the hub 4, the bond strength between the shaft 3 and the hub 4 can be increased and the durability of the balloon catheter 1 can be increased when the shaft 3 and the hub 4 are made of different materials, for example, when the shaft 3 is made of a highly flexible material and the hub 4 is made of a highly rigid material.

This application claims the benefit of priority based on Japanese Patent Application No. 2021-8307, filed on January 21, 2021. The entire contents of the specification of Japanese Patent Application No. 2021-8307, filed on January 21, 2021, are incorporated by reference into this application.

1: Balloon catheter 2: Balloon 3: Shaft 4: Hub 5: Guide wire insertion section 7: Fluid injection section 20: Expansion section 20c: Midpoint of the expansion section in the longitudinal direction 20m: Main section of the expansion section 21: Proximal sleeve section 22: Distal sleeve section 27: Balloon body 29: Wing 31: Outer tube 32: Inner tube 60: Outer protrusion 61: Tip section 70: Inner protrusion 200: Parison 210: Lump 220 of parison: Thick section of parison C ₀ : Virtual circle C ₁ circumscribing the expansion section at the midpoint of the longitudinal direction: First virtual cylinder C ₂ circumscribing the proximal sleeve section: Second virtual cylinder C ₃ circumscribing the distal sleeve section: Third virtual cylinder r ₀ circumscribing the main section of the expansion section: Radius r ₁ of virtual circle C ₀ : Radius r ₂ of first virtual cylinder C ₁ : Radius r of second virtual cylinder C _{2 3} : Radius of the _third virtual cylinder C3 x: Longitudinal axis direction y: Radial direction z: Circumferential direction

Claims (11)

A balloon for a balloon catheter having an expansion section, a proximal sleeve section located proximally of the expansion section, and a distal sleeve section located distally of the expansion section,
The balloon has an outer surface and an inner surface, and an outer protrusion that protrudes radially outward from the outer surface of the balloon and extends in the longitudinal axis direction of the balloon,
The expansion portion has a main section that is excluding 10% of the distal end and 10% of the proximal end in the longitudinal direction,
In a deflated state of the balloon, wings are formed in the entire main section, and the wings are not formed in the entire proximal sleeve section and the distal sleeve section,
A balloon for a balloon catheter, which satisfies at least one of the following (1) and (2) when the balloon is in a deflated state:
(1) A first imaginary cylinder _C1 having a central axis parallel to the longitudinal axis direction , a first bottom surface and a second bottom surface located at the distal end and the proximal end of the proximal sleeve portion, respectively , and at least a portion of a side surface of which is circumscribed by the proximal sleeve portion, has a radius that is greater than a radius of an imaginary circle _C0 circumscribed by the expansion portion in a radial cross section perpendicular to the longitudinal axis direction at the midpoint of the longitudinal axis direction _of the expansion portion , and is also greater than a radius of a third imaginary cylinder C3 having a central axis parallel to the longitudinal _axis direction, a first bottom surface and a second bottom surface located at the distal end and the proximal end of the main section, respectively, and at least a portion of a side surface of which is circumscribed by the main section _.
(2) A second imaginary cylinder _C2 having a central axis parallel to the longitudinal axis direction , a first bottom surface and a second bottom surface located at the distal end and proximal end of the distal sleeve portion, respectively , and at least a portion of a side surface of which is circumscribed by the distal sleeve portion, has a radius that is greater than a radius of an imaginary circle _C0 circumscribed by the expansion portion in a radial cross section perpendicular to the longitudinal axis direction at the midpoint of the longitudinal axis direction of the expansion _portion , and is also greater than a radius of a third imaginary cylinder C3 having a central axis parallel to the longitudinal axis direction, _a first bottom surface and a second bottom surface located at the distal end and proximal end of the main section, respectively, and at least a portion of a side surface of which is circumscribed by the main section _. 2. The balloon for a balloon catheter according to claim 1 , wherein the balloon is folded in a deflated state. 3. The balloon for a balloon catheter according to claim 1, wherein the outer protrusion has a tip portion in the radial cross section, and satisfies at least one of the following (1) and (2) when the balloon is in a deflated state.
(1) In the proximal sleeve portion, the tip portion is circumscribed on at least a part of the side surface of the first imaginary cylinder _C1 .
(2) In the distal sleeve portion, the tip portion is circumscribed on at least a part of the side surface of the second imaginary cylinder _C2 . The balloon for a balloon catheter according to any one of claims 1 to 3 , wherein the outer protrusion has a tip portion in the radial cross section, and satisfies at least one of the following (1) and (2) when the balloon is in a deflated state.
(1) In the proximal sleeve portion, only the tip portion is circumscribed by at least a portion of the side surface of the first imaginary cylinder _C1 .
(2) In the distal sleeve portion, only the tip portion is circumscribing at least a part of the side surface of the second imaginary cylinder _C2 . 5. The balloon for a balloon catheter according to claim 1 , wherein, in a deflated state of the balloon, the expansion portion has wings, and the wings circumscribe the imaginary circle _C0 . 6. The balloon for a balloon catheter according to claim 1 , wherein, in a deflated state of the balloon, the expansion portion has wings, and the outer protrusion is disposed outside the wings. The balloon for a balloon catheter according to any one of claims 1 to 6 , which satisfies at least one of the following (1) and (2):
(1) The outer protrusion of the proximal sleeve portion and the outer protrusion of the extension portion extend continuously in the longitudinal axis direction.
(2) The outer protrusion of the distal sleeve portion and the outer protrusion of the extension portion extend continuously in the longitudinal axis direction. 8. The balloon for a balloon catheter according to claim 1, wherein, in a deflated state of the balloon, a radius of the first imaginary cylinder _C1 in the proximal sleeve portion is greater than a radius of the imaginary circle _C0 in the expansion portion, and a radius of the _second imaginary cylinder C2 in the distal sleeve portion is smaller than a radius of the imaginary circle _C0 . 9. The balloon for a balloon catheter according to claim 8, wherein, in a deflated state of the balloon , a radius of the first imaginary cylinder _C1 in the proximal sleeve portion is greater than a radius of the third imaginary cylinder _C3 , and a radius of the _second imaginary cylinder C2 in the distal sleeve portion is smaller than a radius of the third imaginary cylinder _C3 . 10. The balloon for a balloon catheter according to claim 8 or 9 , wherein the distal sleeve portion has an inner protrusion that protrudes radially inward beyond the inner surface of the balloon body and extends in the longitudinal axis direction. The balloon for a balloon catheter according to any one of claims 1 to 10 , wherein the outer protrusion is made of the same material as the balloon body.

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