Balloon for balloon catheter, balloon catheter provided with same, and method for manufacturing balloon catheter

Abstract

Provided is a balloon for a balloon catheter, the balloon being capable of efficiently expanding a stenosis section by easily biting into the stenosis section by means of a protruding section provided on the balloon. A balloon (2) for a balloon catheter is provided with: a balloon main body (20); and a protruding section (28) that protrudes further toward the outside in the radial direction (y1) than the outer surface of the balloon main body section (20) and extends in the longitudinal direction (x1), the protruding section (28) having a tip region (28t) including an outer end (28T) and a base region (28b) positioned further toward the inside than the tip region (28t), the balloon main body section (20) and the protruding section (28) being configured from the same material. When the reference length in the direction perpendicular to the long axis direction (x1) is measured, the surface roughness of the base end region (28b) is smaller than the surface roughness of the tip end region (28t).

Description

Technical Field

[0001] The present invention relates to a balloon for a balloon catheter, a balloon catheter equipped with the balloon for a balloon catheter, and a method for manufacturing a balloon catheter using a cylindrical parison made of resin. Background Art

[0002] Diseases such as angina pectoris and myocardial infarction are caused by the formation of a stenosis in the inner wall of a blood vessel that has hardened due to calcification or the like. As one of the treatments for these diseases, there is angioplasty, which uses a balloon catheter to dilate the stenosis. Angioplasty is a low-invasive treatment that does not require open-chest surgery such as bypass surgery and is widely performed.

[0003] In angioplasty, it is sometimes difficult for ordinary balloon catheters to dilate a stenosis that has hardened due to calcification, etc. In addition, although a method of dilating a stenosis by leaving an indwelling dilation device called a stent in the stenosis is also used, there are cases where, for example, excessive proliferation of the neointimal membrane of the blood vessel occurs after this treatment, and the blood vessel stenosis occurs again, such as ISR (In-Stent-Restenosis) lesions. In ISR lesions, the neointimal membrane is soft and the surface is slippery, so when ordinary balloon catheters are used for balloon dilation, the position of the balloon may deviate from the lesion and damage the blood vessel.

[0004] As a balloon catheter that can dilate a stenosis even with such calcified lesions, ISR lesions, etc., a balloon catheter has been developed in which a protrusion, a braided layer, and a scoring element are provided on the balloon for biting into the stenosis. For example, Patent Document 1 discloses a method for manufacturing a balloon, which has the following steps, namely, in a balloon having a protrusion and a portion where the inner surface of the balloon is arranged relative to each other, at least a portion of the adjacent inner surface is welded to each other, thereby forming a protrusion. Patent Document 2 discloses a balloon having wrinkles formed as a protrusion and using a mold to form wrinkles on the balloon.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-12678

[0006] Patent Document 2: Japanese Patent Application No. 2005-511187

[0007] However, although the protrusion of the conventional balloon abuts against the stenosis, it does not bite sufficiently into hardened calcified lesions and ISR lesions with slippery surfaces, and there is room for improvement in terms of efficient dilation of the stenosis. Summary of the invention

[0008] In view of the above circumstances, an object of the present invention is to provide a balloon for a balloon catheter that can efficiently dilate a stenosis by allowing a protrusion provided on the balloon to easily bite into the stenosis, a balloon catheter having the balloon for a balloon catheter, and a method for manufacturing the balloon catheter.

[0009] The balloon for a balloon catheter according to an embodiment of the present invention that can solve the above-mentioned problems is as follows.

[0010] [1] A balloon for a balloon catheter, having a longitudinal axis and a radial direction, wherein the balloon for a balloon catheter comprises: a balloon body having an outer surface and an inner surface; and a protrusion protruding outward from the outer surface of the balloon body toward the radial direction and extending along the longitudinal axis, wherein in a cross section perpendicular to the longitudinal axis, the protrusion comprises a front end region including an outer end in the radial direction and a base end region located on the inner side of the radial direction than the front end region, the balloon body and the protrusion are made of the same material, and when the surface roughness of the protrusion is measured for a reference length in a direction perpendicular to the longitudinal axis, the surface roughness of the base end region is smaller than the surface roughness of the front end region.

[0011] The balloon for a balloon catheter according to an embodiment of the present invention is preferably the following [2] or [3].

[0012] [2] A balloon for a balloon catheter according to [1], wherein when the surface roughness of the protrusion and the balloon body is measured for a reference length in a direction perpendicular to the longitudinal direction, the surface roughness of the balloon body is greater than the surface roughness of the base end region.

[0013] [3] A balloon for a balloon catheter according to [1], wherein when the surface roughness of the protrusion and the balloon body is measured for a reference length in a direction perpendicular to the longitudinal direction, the surface roughness of the balloon body is greater than the surface roughness of the front end region.

[0014] The present invention also provides the following contents.

[0015] [4] A balloon catheter comprising the balloon for a balloon catheter according to any one of [1] to [3] above.

[0016] The present invention also provides a first method for manufacturing the balloon catheter described in the above [4]. The first method for manufacturing the balloon catheter according to an embodiment of the present invention is as follows.

[0017] [5] A method for manufacturing the balloon catheter described in [4], comprising: preparing a cylindrical parison made of resin; preparing a mold having a long axis direction and a radial direction, and having an inner cavity extending along the long axis direction and into which the parison is inserted, the inner cavity being formed by a groove portion recessed outward in the radial direction and extending along the long axis direction, and a cylindrical wall portion outside the groove portion; inserting a cathode conductive component having an outer shape along the cylindrical wall portion in a cross-section in the long axis direction into the inner cavity of the mold and causing the cathode conductive component to abut against the cylindrical wall portion without abutting against the groove portion; connecting the cathode conductive component to the negative electrode of a power source and connecting the outer wall of the mold to the positive electrode of the power source. The steps of: connecting; introducing electrolyte into the inner cavity of the mold in the radial outer side of the cathode conductive component; supplying power from the power supply to perform electrolytic grinding; inserting the preform into the inner cavity of the mold after removing the electrolyte and removing the cathode conductive component from the inner cavity of the mold; and introducing fluid into the inner cavity of the preform to expand the preform so that the outer wall of the preform abuts against the groove portion and the cylindrical wall portion of the mold, wherein, in a cross-section perpendicular to the major axis direction, the groove portion has a groove front end region having a long radial distance from the centroid of the inner cavity of the mold and a groove base end region having a shorter radial distance from the centroid than the groove front end region.

[0018] The first manufacturing method according to the embodiment of the present invention is preferably the following [6].

[0019] [6] The method according to [5], wherein when the cathode conductive component is brought into contact with the cylindrical wall, no gap is formed between the cathode conductive component and the cylindrical wall.

[0020] The present invention also provides a second method for manufacturing the balloon catheter described in the above [4]. The first method for manufacturing the balloon catheter according to the embodiment of the present invention is as follows.

[0021] [7] A method for manufacturing the balloon catheter described in [4], comprising: preparing a cylindrical parison made of resin; preparing a mold having a long axis direction and a radial direction, and having an inner cavity extending along the long axis direction and into which the parison is inserted, the inner cavity being formed by a groove portion recessed outward in the radial direction and extending along the long axis direction and a cylindrical wall portion outside the groove portion; inserting the parison into the inner cavity of the mold; heating the mold; and introducing a fluid into the inner cavity of the parison to expand the parison so that the outer wall of the parison abuts against the groove portion and the cylindrical wall portion of the mold. The following steps are adopted: in a section perpendicular to the major axis direction, the groove portion comprises a groove front end region whose radial distance from the centroid of the inner cavity of the mold is long, and a groove base end region whose radial distance from the centroid is shorter than that of the groove front end region; in a section perpendicular to the major axis direction, the mold comprises a first region with low thermal conductivity, a second region with higher thermal conductivity than the first region, and a third region with higher thermal conductivity than the second region; in a section perpendicular to the major axis direction, the first region is located at the cylindrical wall portion, the second region is located at the groove front end region, and the third region is located at the groove base end region.

[0022] The second manufacturing method according to the embodiment of the present invention is preferably the following [8] or [9].

[0023] [8] According to the method described in [7], the first region is composed of a first component formed of a material (L) with low thermal conductivity, the second region and the third region include a second component formed of a material (H) with higher thermal conductivity than the material (L), and the radial thickness of the second component in the third region is thicker than the radial thickness of the second component in the second region.

[0024] [9] The method according to [8], wherein an average value of the radial thickness of the second component in the second region is greater than or equal to 1.2 times an average value of the radial thickness of the second component in the second region.

[0025] According to the balloon for balloon catheter and the manufacturing method of balloon catheter, the protrusion as a whole can easily bite into the stenosis formed in the lesion such as hardened calcified lesion, so that the stenosis can be efficiently cut. In addition, even if the lesion is slippery, it is not easy to deviate from the desired position when the protrusion bites, so that the desired part can be easily cut. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A side view showing a balloon catheter according to an embodiment of the present invention.

[0027] Figure 2 A perspective view showing a balloon for a balloon catheter according to an embodiment of the present invention.

[0028] Figure 3 A cross-sectional view perpendicular to the longitudinal direction of a balloon for a balloon catheter according to an embodiment of the present invention is shown.

[0029] Figure 4 Indicates Figure 3 A cross-sectional view of a modified example of .

[0030] Figure 5 An example of an image obtained when measuring the surface roughness of the protruding portion of the balloon for a balloon catheter according to one embodiment of the present invention is shown.

[0031] Figure 6 A perspective view showing a parison before expansion according to one embodiment of the present invention.

[0032] Figure 7 A cross-sectional view in the long-axis direction of a first mold used in a first manufacturing method according to an embodiment of the present invention is shown.

[0033] Figure 8 express Figure 7 A VIII-VIII cross-sectional view of the first mold is shown.

[0034] Fig. 9 Indicates Figure 8 The cross-sectional view perpendicular to the long axis direction of the first mold is shown when the cathode conductive component is inserted into the inner cavity of the first mold.

[0035] Fig.10 A schematic diagram illustrating a first manufacturing method according to an embodiment of the present invention is shown.

[0036] Fig.11 express Fig.10 XI-XI sectional view.

[0037] Fig.12 A cross-sectional view perpendicular to the long-axis direction of a second mold used in a second manufacturing method according to an embodiment of the present invention is shown.

[0038] Fig.13 Indicates Fig.12 A cross-sectional view of a modified example of . DETAILED DESCRIPTION

[0039] The present invention is described below based on the embodiments, but the present invention is of course not limited by the following embodiments, and can undoubtedly be implemented with appropriate changes within the scope of the above / below-mentioned subject matter, which are all included in the technical scope of the present invention. In addition, in each of the drawings, for convenience, there are cases where hatching, component figure marks, etc. are omitted. In this case, please refer to the specification and other drawings. In addition, the sizes of various components in the drawings are preferentially conducive to understanding the features of the present invention, and therefore there are cases where they are different from the actual sizes.

[0040] 1. Balloon for balloon catheter

[0041] The balloon for a balloon catheter involved in an embodiment of the present invention is a balloon for a balloon catheter having a long axis direction and a radial direction, wherein the balloon comprises: a balloon main body having an outer surface and an inner surface; and a protrusion protruding radially outward from the outer surface of the balloon main body and extending along the long axis direction, in a cross section perpendicular to the long axis direction, the protrusion has a front end region including a radial outer end and a base end region located radially inward of the front end region, the balloon main body and the protrusion are made of the same material, and when the surface roughness of the protrusion is measured for a reference length in a direction perpendicular to the long axis direction, the surface roughness of the base end region is smaller than the surface roughness of the front end region.

[0042] The expansion of the stenosis based on the balloon catheter is carried out by expanding the balloon arranged at the distal end of the balloon catheter after delivering it to the stenosis, so that the protrusion arranged on the outer surface of the balloon body part bites into the stenosis and cuts the stenosis. At this time, when the protrusion invades the stenosis along with the expansion of the balloon, at the final stage of the proximal region of the protrusion entering the stenosis, the resistance to the protrusion pushing into the stenosis becomes large, resulting in the protrusion not easily invading the stenosis, and the surface roughness of the proximal region when the surface roughness in the direction perpendicular to the long axis direction is measured is less than the surface roughness of the front end region, so that the friction resistance of the protrusion as a whole can invade the stenosis. Thus, the efficient incision of the stenosis can be performed. In addition, the surface roughness of the front end region is greater than the surface roughness of the proximal region, so that even if it is a slippery lesion, it is not easy to deviate from the desired position when the protrusion bites, so that the desired part can be easily incised.

[0043] In this specification, a balloon for a balloon catheter may be simply referred to as a "balloon".

[0044] Below, refer to Figure 1 to Figure 5 A balloon for a balloon catheter according to an embodiment of the present invention will be described. Figure 1 It is a side view of a balloon catheter according to one embodiment of the present invention. Figure 2This is a perspective view showing a balloon for a balloon catheter according to an embodiment of the present invention, and illustrates the distal side of the balloon. Figure 3 A cross-sectional view perpendicular to the long axis direction of a balloon for a balloon catheter according to an embodiment of the present invention is shown. Figure 4 Indicates Figure 3 A cross-sectional view of a modified example of . Figure 5 An example of an image obtained when the surface roughness of the protrusion of the balloon for a balloon catheter according to one embodiment of the present invention is measured using a laser microscope is shown.

[0045] like Figure 1 As shown, the balloon 2 is used for the balloon catheter 1. The balloon 2 is connected to the distal end of the distal side shaft 31, and the balloon 2 can be expanded by introducing a fluid through the inner cavity of the distal side shaft 31, and the balloon 2 can be contracted by discharging the fluid. In order to control the expansion and contraction of the balloon 2, an inflator (balloon pressurizer) can be used to introduce or discharge the fluid. The fluid can also be a pressurized fluid pressurized by a pump or the like. The balloon catheter 1 will be described in detail in the item "2. Balloon Catheter".

[0046] The balloon 2 has a long axis direction x1, a circumferential direction z1 along the outer edge of the balloon 2 in a section perpendicular to the long axis direction x1, and a radial direction y1 connecting the centroid of the outer edge of the balloon 2 and a point on the outer edge of the balloon 2 in a section perpendicular to the long axis direction x1. In this specification, the direction on the hand side of the user with respect to the long axis direction x1 is referred to as the proximal side, and the direction opposite to the proximal side, that is, the direction on the side of the treatment subject, is referred to as the distal side.

[0047] Parts and components other than the balloon 2 have their own long axis direction, radial direction and circumferential direction, which may be the same as or different from the long axis direction x1, radial direction y1 and circumferential direction z1 of the balloon 2. For ease of understanding in this specification, it is assumed that all parts and components have the same long axis direction, radial direction and circumferential direction as the long axis direction x1, radial direction y1 and circumferential direction z1 of the balloon 2 for explanation.

[0048] The balloon 2 has a proximal end and a distal end in the long axis direction x1. Figure 1As shown, it is preferably provided with: a straight tube portion 23; a proximal side tapered portion 22, which is located at a position closer to the proximal side than the straight tube portion 23; a proximal side sleeve portion 21, which is located at a position closer to the proximal side than the proximal side tapered portion 22; a distal side tapered portion 24, which is located at a position closer to the proximal side than the straight tube portion; and a distal side sleeve portion 25, which is located at a position closer to the distal side than the distal side tapered portion 24. The straight tube portion 23 is preferably substantially cylindrical with substantially the same diameter in the long axis direction x1, but may also have different diameters in the long axis direction x1. The proximal side tapered portion 22 and the distal side tapered portion 24 are preferably formed into a substantially conical shape by reducing their diameters as they move away from the straight tube portion 23. The straight tube portion 23 has a maximum diameter, so that when the balloon 2 is expanded in a lesion such as a stenotic portion, the straight tube portion 23 is in full contact with the lesion and treatment such as expansion of the lesion can be easily performed. In addition, the proximal taper 22 and the distal taper 24 are reduced in diameter, so that when the balloon 2 is deflated, the outer diameters of the proximal and distal ends of the balloon 2 can be reduced to reduce the height difference between the distal shaft 31 and the balloon 2, thereby making it easier to insert the balloon 2 into the body cavity.

[0049] Preferably, the proximal tapered portion 22, the straight tube portion 23, and the distal tapered portion 24 are portions that expand when a fluid is introduced into the balloon 2, whereas the proximal sleeve portion 21 and the distal sleeve portion 25 do not expand. It is possible to configure such that at least a portion of the proximal sleeve portion 21 that does not expand is fixed to the distal shaft 31, and at least a portion of the distal sleeve portion 25 is fixed to the inner shaft 60.

[0050] The balloon 2 includes a balloon body 20 having an outer surface and an inner surface, and a protrusion 28 that protrudes outward in the radial direction y1 from the outer surface of the balloon body 20 and extends in the longitudinal direction x1.

[0051] The balloon body 20 defines the basic shape of the balloon 2, and the protrusion 28 is preferably provided on the outer side of the balloon body 20 in any pattern such as linear, dot, mesh, or spiral. By providing the protrusion 28 on the outer side of the balloon body 20, it is possible to impart a scoring function to the protrusion 28, so that cracks can be introduced into the calcified stenosis during angioplasty to expand the balloon. In addition, the protrusion 28 can also contribute to improving the strength of the balloon 2 and suppressing over-expansion during pressurization.

[0052] It is preferable that the protrusion 28 is provided in the straight tube portion 23. Thus, the protrusion 28 provided in the straight tube portion 23 which is most likely to come into contact with the lesion portion can easily dilate the stenosed portion.

[0053] like Figure 1 and Figure 2As shown, the protrusion 28 may also be provided in the straight tube portion 23, the cone portion and the sleeve portion, that is, the portion of the balloon 2 covering the entire area in the long axis direction x1. By also providing the protrusion 28 in portions other than the straight tube portion 23, the strength of the balloon 2 and the effect of suppressing over-expansion during pressurization can be improved. Alternatively, although not shown, the protrusion 28 may be provided in the straight tube portion 23, but not provided in the cone portion and the sleeve portion, or provided lower than the straight tube portion 23, or may be provided in at least a portion of the cone portion and the sleeve portion. By having portions in the cone portion and the sleeve portion where the protrusion 28 is not provided and portions provided lower than the straight tube portion 23, the passing performance of the balloon 2 can be improved.

[0054] Preferably, the protrusion 28 is made of the same material as the balloon body 20, and preferably the balloon body 20 and the protrusion 28 are integrally formed. By making the balloon body 20 and the protrusion 28 of the same material, the softness of the balloon 2 can be maintained and the protrusion 28 can be prevented from damaging the outer side of the balloon body 20. By forming the balloon body 20 and the protrusion 28 integrally, the protrusion 28 can be prevented from falling off the balloon body 20. Alternatively, as long as it has a certain degree of compatibility with the material forming the balloon body 20, the material forming the protrusion 28 can also be different from the material forming the balloon body 20. Such a balloon 2 can be manufactured, for example, by placing a parison obtained by extrusion molding in a mold having a groove and performing blow molding. The preferred method for manufacturing the balloon will be described in detail in the items "3. First method for manufacturing a balloon catheter" and "4. Second method for manufacturing a balloon catheter".

[0055] The balloon 2 may also have an inner protrusion that protrudes inward in the radial direction y1 from the inner surface of the balloon body 20. Preferably, the protrusion 28 and the inner protrusion are arranged at the same position in the circumferential direction z1. Preferably, the inner protrusion is integrally formed with the balloon body 20 and the protrusion 28, and preferably, the inner protrusion is formed of the same material as the balloon body 20. Alternatively, as long as the material forming the balloon body 20 has a certain degree of compatibility with the material forming the balloon body 20, the material forming the inner protrusion may be different from the material forming the balloon body 20.

[0056] You can Figure 3 As shown, a protrusion 28 is provided in the circumferential direction z1, which can also be Figure 4 As shown, a plurality of protrusions 28 are provided in the circumferential direction z1. When the balloon 2 has a plurality of protrusions 28 in the circumferential direction z1, the plurality of protrusions 28 are preferably separated in the circumferential direction z1, and more preferably arranged at equal intervals in the circumferential direction z1. The separation distance is preferably longer than the maximum circumference of the protrusion 28.

[0057] In the present invention, the protrusion 28 is a portion formed to be thicker than the membrane thickness of a predetermined position of the balloon body 20 on the outer side in the radial direction y1. The predetermined position is when one protrusion 28 is provided, such as Figure 3 As shown in the circumferential direction z1, the position A opposite to the outer end 28T of the protrusion 28 in the radial direction y1 is provided. Figure 4 Shown is a position B corresponding to the midpoint in the circumferential direction z1 of the outer side end 28T of the protrusion 28 adjacent in the circumferential direction z1.

[0058] The maximum height of the radial direction y1 of the protrusion 28 is preferably 1.2 times or more, more preferably 1.5 times or more, and further preferably 2 times or more of the film thickness at the above-mentioned specified position of the balloon body 20. In addition, it is also allowed to be less than 100 times, less than 50 times, less than 30 times, and less than 10 times. As long as the maximum height of the radial direction y1 of the protrusion 28 is within the above range, it is easy to introduce an incision of appropriate depth in the stenosis and form a crack.

[0059] The cross-sectional shape of the section perpendicular to the long axis direction x1 of the protrusion 28 can be any, for example, it can be a triangle, a quadrilateral, a polygon, a semicircle, a part of a circle, a roughly circular shape, a fan-shaped, a wedge-shaped, a convex shape, a spindle shape, and a combination thereof. In addition, the triangle, quadrilateral, and polygon include shapes with clear corner vertices and straight sides, so-called rounded polygons with rounded corners, and shapes with at least a part of the side being a curve. Alternatively, the cross-sectional shape of the protrusion 28 can also be an irregular shape with concave-convex, notches, etc.

[0060] When the protrusion 28 is formed in a linear or dot shape, it is preferable that the protrusion 28 is arranged to extend along the long axis direction x1. Alternatively, the protrusion 28 may be arranged to extend in a spiral shape around the long axis.

[0061] like Figure 3 and Figure 4 As shown, in a cross section perpendicular to the major axis direction x1, the protrusion 28 comprises: a front end region 28t including an outer end 28T in the radial direction y1; and a base end region 28b located on the inner side of the radial direction y1 than the front end region 28t, and when the surface roughness of the protrusion 28 is measured for a reference length in a direction perpendicular to the major axis direction x1, the surface roughness of the base end region 28b is smaller than the surface roughness of the front end region 28t.

[0062] The protrusion 28 bites into the narrow part and forms cracks by expanding the balloon 2 delivered to the narrow part, thereby expanding the narrow part. At this time, the front end area 28t that first bites into the narrow part bites in a state with relatively low resistance to pushing. In contrast, in the base end area 28b that bites in the final stage, the resistance to pushing becomes large, making it difficult for the protrusion 28 as a whole to invade the narrow part. However, when the surface roughness of the base end area 28b in the direction perpendicular to the long axis direction x1 is measured, the surface roughness of the base end area 28b is smaller than the surface roughness of the front end area 28t, so that the friction resistance of the base end area 28b becomes small, and the protrusion 28 as a whole can invade the narrow part. As a result, cracks can be easily formed in the narrow part, so that the narrow part can be efficiently cut. In addition, when the surface roughness in the direction perpendicular to the long axis direction x1 is measured, the surface roughness of the front end area 28t is larger than that of the base end area 28b, so even if it is a slippery lesion, it is not easy to deviate from the desired position when the protrusion 28 starts to bite, so that the desired part can be easily cut.

[0063] The surface roughness is the arithmetic mean roughness Ra of the roughness curve under the reference length, and the reference length is 100 μm. The above arithmetic mean roughness Ra is equivalent to the arithmetic mean roughness Ra specified in JIS B 0601 (2001). The measurement can be performed using, for example, a laser microscope VK-X3000 equipped with a white light interferometer manufactured by Keyence Corporation. For example Figure 5 The results are shown in the table below. Figure 2 An example of an image obtained when the surface roughness of region R is measured. Figure 5 The arrow in is the direction perpendicular to the major axis direction x1.

[0064] The surface roughness of the base end region 28b is obtained by measuring a roughness curve of 100 μm in a direction perpendicular to the long axis direction x1 from the base end 28B in the radial direction y1 of the protrusion 28. The base end 28B of the protrusion 28 is a portion of the protrusion 28 where the film thickness begins to become thicker toward the outside in the radial direction y1 compared to the film thickness at the above-mentioned predetermined position of the balloon body 20.

[0065] The surface roughness of the tip region 28t is obtained, for example, by measuring a roughness curve of 100 μm from the outer end 28T in a direction perpendicular to the long axis direction x1. At this time, when the length from the base end 28B of the protrusion 28 to the outer end 28T in the direction perpendicular to the long axis direction x1 is less than twice the reference length of 100 μm, that is, 200 μm, the reference length of 100 μm from the outer end 28T in the direction perpendicular to the long axis direction x1 and the reference length of 100 μm from the base end 28B in the direction perpendicular to the long axis direction x1 overlap in the direction perpendicular to the long axis direction x1, but by measuring the surface roughness by the above method, the roughness of the tip region 28t and the base end region 28b can be obtained.

[0066] Alternatively, the surface roughness of the tip region 28t can be obtained by measuring a roughness curve of 100 μm in the direction perpendicular to the major axis direction x1, which is closer to the outer end 28T than a point 100 μm from the base end 28B. In this case, when the length from the base end 28B to the outer end 28T of the protrusion 28 in the direction perpendicular to the major axis direction x1 exceeds twice the reference length of 100 μm, that is, 200 μm, the reference length of 100 μm in the tip region 28t can be a length of 100 μm from a point 100 μm from the base end 28B to the outer end 28T in the direction perpendicular to the major axis direction x1, or a length of 100 μm from the outer end 28T to the base end 28B in the direction perpendicular to the major axis direction x1. In this case, the surface roughness of the front end region 28t may be obtained by taking the surface roughness obtained by measuring a reference length of 100 μm from a point 100 μm from the base end 28B toward the outer end 28T in a direction perpendicular to the major axis direction x1 and the average value of the surface roughness obtained by measuring a reference length of 100 μm from the outer end 28T toward the base end 28B in a direction perpendicular to the major axis direction x1.

[0067] The surface roughness of each region is preferably determined as the average value of the arithmetic mean roughness obtained from the roughness curve measured at a predetermined interval for a predetermined number of reference lengths in the long axis direction x1. Thus, the influence of the deviation of the surface roughness caused by the position in the long axis direction x1 can be reduced. The predetermined interval can be set to 2 μm, for example, and the predetermined number of reference lengths can be set to 31, for example. In this case, the surface roughness of an area of ​​60 μm×100 μm can be obtained.

[0068] The surface roughness of each region can be compared at the same position in the long axis direction x1 or at different positions in the long axis direction x1, but it is preferred to compare at the same position in the long axis direction x1. By making the surface roughness of the base end region 28b arranged at the same position in the long axis direction x1 smaller than the surface roughness of the front end region 28t, it is possible to form a structure in which the protrusion 28 at this position is easy to bite into the narrow part. For example, the surface roughness of each region can be compared in the straight tube portion 23, and it is preferred that the surface roughness of the base end region 28b in the straight tube portion 23 is smaller than the surface roughness of the front end region 28t. In addition, when a plurality of protrusions 28 are provided, it is sufficient to measure the surface roughness of any one of the protrusions 28.

[0069] The surface roughness of the base end region 28b is preferably 0.9 times or less, more preferably 0.8 times or less, further preferably 0.6 times or less, and may be 0.5 times or less, 0.4 times or less, and preferably 0.01 times or more, more preferably 0.05 times or more, further preferably 0.1 times or more of the surface roughness of the front end region 28t. If it is within the above range, the entire protrusion 28 can easily bite into the stenosis, so that the balloon 2 can be easily cut at the desired position.

[0070] like Figure 4 As shown, when a plurality of protrusions 28 are provided, it is preferred that the surface roughness of the base end region 28b is smaller than the surface roughness of the tip end region 28t in all the protrusions 28. This makes it easier to cut open the narrow portion.

[0071] As the material constituting the balloon main body 20 and the protrusion 28, for example, polyolefin resins such as polyethylene, polypropylene, ethylene-propylene copolymer, polyester resins such as polyethylene terephthalate, polyester elastomers, polyurethane, polyurethane elastomers, polyphenylene sulfide resins, polyamide, polyamide elastomers, polyamide resins, fluorine resins, silicone resins, natural rubbers such as latex rubber, etc. can be cited. These can be used only one kind, and two or more kinds can also be used in combination. Among them, polyamide resins, polyester resins, and polyurethane resins are preferred, and polyamide resins such as nylon 12 and nylon 11 are more preferred, and nylon 12 is particularly preferred. From the viewpoint of the filmization and flexibility of the balloon main body 20, it is preferred to use an elastomer resin, and polyamide elastomers such as polyamide ether elastomers are preferably used.

[0072] When the surface roughness of the protrusion 28 and the balloon body 20 is measured for a reference length in a direction perpendicular to the long axis direction x1, it is preferred that the surface roughness of the balloon body 20 is greater than the surface roughness of the base end region 28b. In the balloon 2 according to the embodiment of the present invention, the surface roughness of the base end region 28b is small, so that the protrusion 28 as a whole easily intrudes into the stenosis, but the surface roughness of the balloon body 20 is greater than the surface roughness of the base end region 28b, so that even the balloon body 20 can be prevented from intruding into the stenosis, and thus the crack can be prevented from being too large.

[0073] The surface roughness of the balloon body 20 is preferably 1.2 times or more, more preferably 1.5 times or more, further preferably 2 times or more, particularly preferably 3 times or more, and preferably 10 times or less, more preferably 9 times or less, further preferably 8 times or less, of the surface roughness of the base end region 28b.

[0074] When the surface roughness of the protrusion 28 and the balloon body 20 is measured for the reference length in the direction perpendicular to the long axis direction x1, the surface roughness of the balloon body 20 is preferably greater than the surface roughness of the front end region 28t. Thus, the relationship between the surface roughness of each region of the balloon body 20 and the protrusion 28 can be made "base end region 28b<front end region 28t<balloon body 20", and the balloon body 20 with a large area in contact with the blood vessel wall has the largest surface roughness when measured in the direction perpendicular to the long axis direction x1, so that the resistance of the balloon body 20 to the blood vessel wall can be increased, and the balloon 2 can be easily fixed at the desired position. Thus, the balloon 2 can be fixed at the desired position for treatment.

[0075] The surface roughness of the balloon main body 20 is preferably 1.05 times or more, more preferably 1.1 times or more, further preferably 1.2 times or more, particularly preferably 1.5 times or more, and preferably 8 times or less, more preferably 7 times or less, further preferably 6 times or less, of the surface roughness of the front end region 28t.

[0076] 2. Balloon Catheter

[0077] The balloon catheter 1 according to the embodiment of the present invention includes the balloon 2 for balloon catheters. Figure 1 As shown, the balloon 2 is connected to the distal end of the distal side shaft 31 .

[0078] Figure 1 , a so-called RX (Rapid Exchange) type balloon catheter 1 is shown, which has a guidewire port 50 midway from the distal side to the proximal side of the shaft 30, and has an inner shaft 60 that functions as a guidewire insertion passage from the guidewire port 50 to the distal side of the shaft 30. Preferably, the balloon catheter 1 has a distal shaft 31 and a proximal shaft 32, and the distal shaft 31 and the proximal shaft 32 are independent components, and the shaft 30 extending from the balloon 2 to the proximal end of the balloon catheter 1 can be formed by connecting the proximal end of the distal shaft 31 with the distal end of the proximal shaft 32. Alternatively, one shaft 30 may extend from the balloon 2 to the proximal end of the balloon catheter 1, and the distal shaft 31 and the proximal shaft 32 may be further formed by a plurality of tube components.

[0079] The shaft 30 preferably has a fluid flow path and a guide wire insertion path inside. In order to form a structure in which the shaft 30 has a fluid flow path and a guide wire insertion path inside, for example, the following structure can be cited: the inner shaft 60 arranged on the inner side of the shaft 30 functions as a guide wire insertion path, and the space between the shaft 30 and the inner shaft 60 functions as a fluid flow path. In the case of such a structure, the inner shaft 60 preferably extends from the distal end of the shaft 30 and penetrates the balloon 2, the distal side of the balloon 2 is connected to the inner shaft 60, and the proximal side of the balloon 2 is connected to the shaft 30.

[0080] Preferably, the shaft 30 is made of resin, metal or a combination of resin and metal. Resin is used as the constituent material of the shaft, thereby easily giving flexibility and elasticity to the shaft 30. In addition, metal is used as the constituent material of the shaft 30, thereby being able to improve the delivery of the balloon catheter 1. As the resin constituting the shaft 30, for example, polyamide resin, polyester resin, polyurethane resin, polyolefin resin, fluorine resin, vinyl chloride resin, silicone resin, natural rubber, synthetic rubber, etc. can be cited. These can be used only one kind, or two or more kinds can be used in combination. As the metal constituting the shaft 30, for example, stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloy, Co-Cr alloy or a combination thereof can be cited. In the case where the shaft 30 is composed of a distal shaft 31 and a proximal shaft 32 of independent components, for example, it can be the following structure, that is, the distal shaft 31 is formed by a resin, and the proximal shaft 32 is formed by a metal. In addition, the shaft 30 may have a laminated structure formed of different materials or the same material.

[0081] The balloon 2 and the shaft 30 can be joined by bonding with an adhesive, welding, installing an annular member at a position where the end of the balloon 2 overlaps the shaft 30, and caulking, etc. Among them, it is preferred that the balloon 2 and the shaft 30 are joined by welding. The balloon 2 and the shaft 30 are welded, so that even if the balloon 2 is repeatedly expanded or contracted, the joining between the balloon 2 and the shaft 30 is not easily released, and the joining strength can be improved.

[0082] Preferably, a front end component 70 is provided at the distal end of the balloon catheter 1. The front end component 70 may be provided at the distal end of the balloon catheter 1 by being connected to the distal end of the balloon 2 as a component independent of the inner shaft 60, or the inner shaft 60 extending to the distal side of the distal end of the balloon 2 may function as the front end component 70.

[0083] X-ray opaque markers 80 may be arranged on the inner shaft 60 inside the balloon 2 at the portion where the balloon 2 is located in the longitudinal direction x1, so that the position of the balloon 2 can be confirmed under X-ray fluoroscopy. The X-ray opaque markers 80 are preferably arranged at positions corresponding to both ends of the straight tube portion 23 of the balloon 2, and may also be arranged at positions corresponding to the center of the straight tube portion 23 in the longitudinal direction x1.

[0084] A hub 5 may be provided on the proximal side of the shaft 30 , and preferably, a fluid injection portion 6 communicating with a flow path of a fluid supplied to the inside of the balloon 2 is provided on the hub 5 .

[0085] The joining of the shaft 30 and the hub 5 may be, for example, bonding with an adhesive, welding, etc. Among them, it is preferred that the shaft 30 and the hub 5 are joined by bonding. The shaft 30 and the hub 5 are bonded, so that, for example, when the shaft 30 is made of a material with high flexibility and the hub 5 is made of a material with high rigidity, the joining strength between the shaft 30 and the hub 5 can be increased to improve the durability of the balloon catheter 1.

[0086] Although not shown in the figure, the present invention can also be applied to a so-called integral exchange balloon catheter having a guidewire insertion passage from the distal side to the proximal side of the shaft. In the case of the Over-The-Wire type, it is preferred that the inflation lumen and the guidewire lumen extend to a hub disposed on the hand side, and the proximal opening of each lumen is disposed at a hub of a two-pronged structure.

[0087] In the case of a rapid exchange catheter, it is preferable to appropriately apply the coating to the outer wall of the distal shaft 31 and / or the proximal shaft 32, and it is more preferable to apply the coating to both the distal shaft 31 and the proximal shaft 32. In the case of a full exchange catheter, it is preferable to appropriately apply the coating to the outer wall of the outer shaft.

[0088] The coating may be a hydrophilic coating or a hydrophobic coating according to the purpose, and may be implemented by immersing the shaft 30 in a hydrophilic coating agent or a hydrophobic coating agent, or coating the outer wall of the shaft 30 with a hydrophilic coating agent or a hydrophobic coating agent, or covering the outer wall of the shaft 30 with a hydrophilic coating agent or a hydrophobic coating agent. The coating agent may also contain a drug or an additive.

[0089] Examples of the hydrophilic coating agent include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinyl pyrrolidone, and methyl vinyl ether maleic anhydride copolymer, and hydrophilic coating agents prepared by any combination thereof.

[0090] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic polyurethane resin, carbon coating, diamond coating, diamond-like carbon (DLC) coating, ceramic coating, and substances with low surface free energy terminated with alkyl or perfluoroalkyl groups.

[0091] 3. The first method for manufacturing a balloon catheter

[0092] The first method for manufacturing a balloon catheter according to an embodiment of the present invention is the method for manufacturing the above-mentioned balloon catheter, which comprises: a step of preparing a cylindrical parison made of resin; a step of preparing a mold, the mold having a long axis direction and a radial direction, and having an inner cavity extending along the long axis direction and into which the parison is inserted, the inner cavity being formed by a groove portion recessed radially outward and extending along the long axis direction and a cylindrical wall portion outside the groove portion; a step of inserting into the inner cavity of the mold a cathode conductive component having an outer shape along the cylindrical wall portion in a cross section in the long axis direction and causing the cathode conductive component to abut against the cylindrical wall portion but not against the groove portion; a step of connecting the cathode conductive component to the negative electrode of a power source and connecting the outer wall of the mold to the positive electrode of a power source; introducing an electrolyte into the inner cavity of the mold radially outside the cathode conductive component; supplying power from the power source to perform electrolytic grinding; after removing the electrolyte and removing the cathode conductive component from the inner cavity of the mold, inserting the preform into the inner cavity of the mold; and introducing a fluid into the inner cavity of the preform to expand the preform so that the outer wall of the preform abuts against the above-mentioned groove portion and cylindrical wall portion of the mold, wherein, in a cross-section perpendicular to the major axis direction, the groove portion has a groove front end region whose radial distance from the centroid of the inner cavity of the mold is long and a groove base end region whose radial distance from the centroid is shorter than the groove front end region.

[0093] By making the cathode conductive component contact the cylindrical wall of the mold but not contact the groove of the mold, and introducing electrolyte into the inner cavity of the mold in the radial outer side of the cathode conductive component to connect the cathode conductive component to the negative electrode of the power supply and connect the outer wall of the mold to the positive electrode of the power supply, the cylindrical wall of the mold is not electrolytically polished, but only the groove of the mold is electrolytically polished. At this time, the groove of the mold has a groove front end region with a long radial distance from the centroid of the inner cavity of the mold, and a groove base end region with a shorter radial distance from the centroid of the inner cavity of the mold than the groove front end region, so that the groove front end region is far from the cathode conductive component, and the groove base end region is close to the cathode conductive component. As a result, in the groove of the mold, the groove front end region is less likely to be electrolytically polished, and the groove base end region is more likely to be electrolytically polished, and a mold having a groove front end region with a larger surface roughness and a groove base end region with a smaller surface roughness can be prepared. The parison is arranged in the inner cavity of the mold and expanded, thereby transferring the shape with large surface roughness to the portion abutting against the front end area of ​​the groove of the parison, and transferring the shape with small surface roughness to the portion abutting against the base end area of ​​the groove, thereby manufacturing "1. Balloon for balloon catheter" having a surface roughness of the base end area smaller than the surface roughness of the front end area, "2. Balloon catheter".

[0094] Reference Figure 6 to Figure 11 A first method for manufacturing a balloon catheter according to an embodiment of the present invention will be described. Figure 6 A perspective view showing a parison before expansion according to one embodiment of the present invention. Figure 7 A cross-sectional view in the long-axis direction of a first mold used in a first manufacturing method according to an embodiment of the present invention is shown. Figure 8 express Figure 7 The VIII-VIII cross-sectional view of the first mold shown, Fig. 9 Indicates Figure 8 The cross-sectional view perpendicular to the long axis direction of the first mold is shown when the cathode conductive component is inserted into the inner cavity of the first mold. Fig.10 FIG. 2 is a schematic diagram for explaining a first manufacturing method according to an embodiment of the present invention. Fig.11 express Fig.10 XI-XI sectional view.

[0095] First, prepare the parison 300. Figure 6 As shown, the parison 300 is made of resin and is a cylindrical component having an inner cavity 305. The parison 300 is produced, for example, by extrusion molding. The parison 300 has a first end 301 and a second end 302, and extends along a long axis direction x2 from the first end 301 toward the second end 302. The parison 300 has a radial direction y2 and a circumferential direction z2 similarly to the balloon 2.

[0096] The cross-sectional shape of the parison 300 perpendicular to the long axis direction x2 can also be roughly uniform in the long axis direction x2. As a result, the productivity of the parison 300 can be improved. Alternatively, the cross-sectional shape of the parison 300 perpendicular to the long axis direction x2 can also be different depending on the position of the long axis direction x2. For example, it can also be configured so that the outer diameter of a portion of the parison 300 in the long axis direction x2 is larger than that of other portions, and the portion with the larger outer diameter is formed into the straight tube portion 23 of the balloon 2. In order to manufacture a parison 300 whose outer diameter is different depending on the position of the long axis direction x2 in this way, blow molding can also be performed in advance using a mold.

[0097] like Figure 6 As shown, the pre-expanded parison 300 may also have a protrusion 308 whose thickness increases toward the outer side of the radial direction y2. The protrusion 308 is brought into contact with the groove 110 of the first mold 100 and the groove 210 of the second mold 200 described later, thereby facilitating the formation of the protrusion 28 of the balloon 2.

[0098] like Figure 6 As shown, a plurality of protrusions 308 may be provided in the circumferential direction z2, and although not shown, a single protrusion 308 may be provided in the circumferential direction z2. When a plurality of protrusions 308 are provided in the circumferential direction z2, the plurality of protrusions 308 are preferably separated in the circumferential direction z2, and more preferably are arranged at equal intervals in the circumferential direction z2.

[0099] As a material constituting the parison 300 , the description of the resin constituting the balloon body 20 and the protrusion 28 described in the item “1. Balloon for balloon catheter” can be referred to.

[0100] like Figure 7 As shown in FIG. 1 , the first mold 100 used in the first manufacturing method of the present invention has a long axis direction x3, a radial direction y3, and a circumferential direction z3, and has an inner cavity 105 extending along the long axis direction x3 and into which the parison 300 is inserted. It is preferred that a portion of the parison 300 in the long axis direction x2 is arranged in the inner cavity 105 of the first mold 100. It is preferred that the long axis direction x2 of the parison 300 coincides with the long axis direction x3 of the first mold 100. Thus, it is easy to arrange the parison 300 in the inner cavity 105 of the first mold 100.

[0101] Preferably, the first mold 100 includes, in the long-axis direction x3, a first mold straight tube portion 100C that forms the straight tube portion 23 of the balloon 2, two first mold taper portions 100T that are arranged on both sides of the first mold straight tube portion 100C and form the taper portion of the balloon 2, and two first mold sleeve portions 100S that are arranged on a side farther from the first mold straight tube portion 100C than the first mold taper portions 100T and form the sleeve portion of the balloon 2. Thus, it is possible to form the straight tube portion 23 of the balloon 2 by the first mold straight tube portion 100C, the proximal taper portion 22 and the distal taper portion 24 of the balloon 2 by the first mold taper portion 100T, and the proximal sleeve portion 21 and the distal sleeve portion 25 of the balloon 2 by the first mold sleeve portion 100S.

[0102] The first mold 100 may be composed of one component or multiple components. Figure 7 As shown, the mold can be formed by connecting a plurality of mold parts in the longitudinal direction x3. For example, the first mold straight tube portion 100C, the first mold cone portion 100T, and the first mold sleeve portion 100S can be different mold parts, which are connected to each other in the longitudinal direction x3. In addition, the first mold 100 can be divided in the radial direction y3. Thus, it is easy to insert the cathode conductive component 130 described later into the inner cavity 105 of the first mold 100. Figure 7 As shown, each mold component can be joined by joining adjacent mold components together. Although not shown, magnets can be attached to adjacent mold components to join them together by the attraction of the magnets.

[0103] like Figure 8As shown, the inner cavity 105 of the first mold 100 is formed by a groove 110 that is recessed to the outside of the radial direction y3 and extends along the long axis direction x3, and a cylindrical wall 120 outside the groove 110. After the electrolytic grinding step described later, the parison 300 is inserted into the inner cavity 105 of the first mold 100, and a fluid is introduced into the inner cavity 305 of the parison 300 to expand the parison 300. At this time, the parison 300 enters the groove 110, and the portion that enters the groove 110 is formed as the protrusion 28 of the balloon 2, and the portion that abuts against the cylindrical wall 120 is formed as the balloon body 20. Thus, the balloon 2 having the balloon body 20 and the protrusion 28 can be formed from the parison 300.

[0104] like Figure 8 As shown, a plurality of grooves 110 may be provided in the circumferential direction z3, and although not shown, a single groove 110 may be provided in the circumferential direction z3. When a plurality of grooves 110 are provided in the circumferential direction z3, the grooves 110 are preferably separated in the circumferential direction z3, and more preferably arranged at equal intervals in the circumferential direction z3.

[0105] In the cross section perpendicular to the long axis direction x3, the groove portion 110 has a groove front end region 110t having a long distance in the radial direction y3 from the centroid O1 of the inner cavity 105 of the first mold 100, and a groove base end region 110b having a shorter distance in the radial direction y3 from the centroid O1 than the groove front end region 110t. The groove front end region 110t can form the front end region 28t of the balloon 2, and the groove base end region 110b can form the base end region 28b of the balloon 2.

[0106] The groove 110 is preferably provided in the first mold straight tube portion 100C of the first mold 100. Thus, the protrusion 28 can be formed in the straight tube portion 23 of the balloon 2, and thus the efficiency of cutting the stenosis portion by the balloon 2 can be improved.

[0107] The groove 110 may also be provided in at least one of the two first mold tapers 100T of the first mold 100. Thus, the protrusion 28 can be formed in the proximal taper 22 and / or the distal taper 24 of the balloon 2, thereby improving the anti-slip performance of the balloon 2 relative to the narrow part. When the groove 110 is provided in the first mold taper 100T, the depth of the groove 110 provided in the first mold taper 110T is preferably less than the depth of the groove 110 provided in the first mold straight tube portion 100C. Thus, the height of the protrusion 28 formed in the proximal taper 22 and / or the distal taper 24 of the balloon 2 can be made less than the height of the protrusion 28 formed in the straight tube portion 23, thereby improving the passing performance of the balloon 2. If the groove 110 is not provided in the first mold taper 100T, the protrusion 28 is not formed in the proximal taper 22 and / or the distal taper 24 of the balloon 2, or the height of the protrusion 28 is formed low, thereby further improving the passing performance of the balloon 2. In this case, the inner protrusion may be formed in the portion where the protrusion 28 is not formed or the height of the protrusion 28 is formed low.

[0108] The groove 110 may be provided in the first mold sleeve portion 100S of the first mold 100, or may not be provided in the first mold sleeve portion 100S of the first mold 100. When the groove 110 is provided in the first mold sleeve portion 100S, it is preferred that the depth of the groove 110 provided in the first mold sleeve portion 100S is shallower than the depth of the groove 110 provided in the first mold straight tube portion 100C. Thus, the height of the protrusion 28 formed in the proximal sleeve portion 21 and / or the distal sleeve portion 25 can be made lower than the height of the protrusion formed in the straight tube portion 23, thereby improving the passing performance of the balloon 2. If the groove 110 is not provided in the first mold sleeve portion 100S of the balloon 2, the protrusion 28 is not formed in the proximal sleeve portion 21 and / or the distal sleeve portion 25 of the balloon 2, thereby further improving the passing performance of the balloon 2.

[0109] Before inserting the parison 300 into the inner cavity 105 of the first mold 100, the inner cavity 105 is electrolytically ground. During the electrolytic grinding, the cathode conductive component 130 is inserted into the inner cavity 105. Fig. 9 As shown, the cathode conductive member 130 has an outer diameter along the cylindrical wall portion 120 in the cross section in the long axis direction x3, and when the cathode conductive member 130 is inserted into the inner cavity 105 of the first mold 100, the cathode conductive member 130 is in contact with the cylindrical wall portion 120 and not in contact with the groove portion 110. That is, the cathode conductive member 130 has a region where the outer wall is along the cylindrical wall portion 120 and a region where there is a gap between the outer wall of the cathode conductive member 130 and the wall of the inner cavity 105 of the first mold 100 due to the groove portion 110. Therefore, the cathode conductive member 130 is arranged close to the groove base end region 110b and away from the groove front end region 110t.

[0110] The shape of the cathode conductive component 130 may be cylindrical or solid as long as the outer shape of the cathode conductive component 130 has a shape along the cylindrical wall portion 120 of the first mold 100. In the region where there is a gap between the outer wall of the cathode conductive component 130 and the wall of the inner cavity 105 of the first mold 100 due to the groove portion 110, it is preferred that the cathode conductive component 130 does not protrude in the radial direction y3. Thus, it is easy to arrange the cathode conductive component 130 close to the groove base end region 110b and away from the groove front end region 110t.

[0111] like Fig.10 As shown, the cathode conductive member 130 is connected to the negative electrode 141 of the power source 140, and the outer wall of the first mold 100 is connected to the positive electrode 142 of the power source 140. The first mold 100 is made of metal and functions as an anode.

[0112] like Fig.11 As shown, the electrolyte 150 is introduced into the inner cavity 105 of the first mold 100, that is, the groove 110, which is located radially outside the cathode conductive component 130. Fig.10 As shown, this step can also be performed by immersing the first mold 100 having the cathode conductive member 130 inserted in the inner cavity 105 in the electrolytic tank 160 filled with the electrolyte 150. In this configuration state, if power is supplied from the power supply 140 to apply a voltage between the cathode conductive member 130 and the first mold 100 functioning as an anode, the metal element on the surface of the inner cavity 105 of the first mold 100 functioning as an anode that contacts the electrolyte 150 is dissolved in the electrolyte 150, and thus the surface of the inner cavity 105 of the first mold 100 that contacts the electrolyte 150 is electrolytically polished.

[0113] Here, the cathode conductive component 130 has an outer diameter along the inner cylinder wall 120, so the cathode conductive component 130 is arranged away from the groove front end area 110t and close to the groove base end area 110b. As a result, the inter-electrode distance between the cathode conductive component 130 and the groove base end area 110b is short and the current density becomes high, thereby increasing the amount of electrolytic grinding of the groove base end area 110b. In contrast, the inter-electrode distance between the cathode conductive component 130 and the groove front end area 110t is long and the current density becomes low, so the amount of electrolytic grinding of the groove front end area 110t is less than the electrolytic grinding material of the groove base end area 110b. As a result, the inner cavity 105 of the first mold 100 is processed so that the groove base end area 110b is ground more smoothly and the groove front end area 110t has a rougher surface.

[0114] After the electrolytic grinding, the electrolyte 150 is removed from the inner cavity 105 of the first mold 100. This step may also be performed by lifting the first mold 100 with the cathode conductive member 130 inserted in the inner cavity 105 from the electrolytic tank 160.

[0115] After the cathode conductive component 130 is removed from the inner cavity 105 of the first mold 100, the parison 300 is inserted into the inner cavity 105 of the first mold 100, and a fluid is introduced into the inner cavity 305 of the parison 300 to expand the parison 300 so that the outer wall of the parison 300 abuts against the groove portion 110 and the cylindrical wall portion 120 of the first mold 100. At this time, it is preferred to blow mold the parison 300 by heating the first mold 100. The heating of the first mold 100 can be performed by a known method such as a method of heating using a heater arranged outside the first mold 100 or a method of heating the first mold 100 itself by induction heating. Through these steps, it is possible to manufacture a balloon 2 having a protrusion 28 with a small surface roughness of the base end region 28b formed by the groove base end region 110b that is polished smoother and a large surface roughness of the front end region 28t formed by the groove front end region 110t having a rougher surface.

[0116] In the electrolytic grinding step, the cathode conductive component 130 abuts against the cylindrical wall 120, so that the electrolyte 150 is not easy to penetrate between the cathode conductive component 130 and the cylindrical wall 120. As a result, the surface of the cylindrical wall 120 is not easily electrolytically ground, and the rough surface can be kept unchanged. As a result, a balloon 2 can be manufactured in which the surface roughness of the balloon body 20 is greater than the surface roughness of the protrusion 28.

[0117] In the step of bringing the cathode conductive component 130 into contact with the cylindrical wall 120, preferably no gap is formed between the cathode conductive component 130 and the cylindrical wall 120. Thus, the surface of the cylindrical wall 120 can be prevented from being electrolytically polished, making it easier to make the surface roughness of the balloon body 20 greater than the surface roughness of the protrusion 28.

[0118] The material constituting the first mold 100 is preferably metal, more preferably iron, copper, aluminum or alloys thereof. For example, stainless steel etc. can be cited as iron alloys, brass etc. can be cited as copper alloys, and duralumin etc. can be cited as aluminum alloys. From the perspective of having sufficient conductivity, strength, and ease of processing, the first mold 100 is preferably made of stainless steel.

[0119] The material constituting the cathode conductive member 130 is not particularly limited as long as it has sufficient conductivity, and examples thereof include metals such as stainless steel, titanium, copper, aluminum, platinum, and gold, or alloys thereof.

[0120] The electrolyte 150 is not particularly limited and may be appropriately selected from known alcohol or sulfuric acid aqueous solutions according to the material constituting the first mold 100. When the electrolytic tank 160 is used, it is preferably formed of a material that is not corroded by the electrolyte 150.

[0121] 4. Second method for manufacturing balloon catheter

[0122] The second method for manufacturing a balloon catheter according to an embodiment of the present invention is the method for manufacturing the balloon catheter, which comprises: a step of preparing a cylindrical parison made of resin; a step of preparing a mold, the mold having a long axis direction and a radial direction, and having an inner cavity extending along the long axis direction and into which the parison is inserted, the inner cavity being formed by a groove portion recessed radially outward and extending along the long axis direction and a cylindrical wall portion outside the groove portion; a step of inserting the parison into the inner cavity of the mold; a step of heating the mold; and a step of introducing a fluid into the inner cavity of the parison to expand the parison so that the outer wall of the parison is aligned with the inner cavity of the mold. The step of abutting the groove portion and the cylindrical wall portion of the mold, in a section perpendicular to the long axis direction, the groove portion has a groove front end region whose radial distance from the centroid of the inner cavity of the mold is long and a groove base end region whose radial distance from the centroid is shorter than that of the groove front end region, in a section perpendicular to the long axis direction, the mold has a first region with low thermal conductivity, a second region with higher thermal conductivity than the first region, and a third region with higher thermal conductivity than the second region, in a section perpendicular to the long axis direction, the first region is located on the cylindrical wall portion, the second region is located on the groove front end region, and the third region is located on the groove base end region.

[0123] The second region is located in the groove front end region, and the third region having a higher thermal conductivity than the second region is located in the groove base end region, so that when the parison is inserted into the inner cavity of the mold and the mold is heated to expand the parison so that the outer wall of the parison abuts against the inner cavity of the mold, the portion abutting against the groove front end region where the second region having a low thermal conductivity is located is formed as a front end region with a large surface roughness because the resin is not easy to soften, while the portion abutting against the groove base end region where the third region having a high thermal conductivity is located is formed as a base end region with a small surface roughness because the resin is easy to soften. In addition, the first region having a lower thermal conductivity than the second region is located in the cylindrical wall portion of the mold, so that the surface roughness of the balloon body formed by the cylindrical wall portion of the mold can be increased.

[0124] Reference Fig.12 and Fig.13 A second method for manufacturing the balloon catheter according to the embodiment of the present invention will be described. Fig.12 A cross-sectional view perpendicular to the long axis direction of a second mold used in a second manufacturing method according to an embodiment of the present invention is shown. Fig.13 Indicates Fig.12 A cross-sectional view of a modified example of .

[0125] First, a parison is prepared. The parison used in the second manufacturing method is the same as the parison 300 used in the first manufacturing method. The description and the description of the parison 300 described in the above-mentioned "3. First manufacturing method of the balloon catheter" can be referred to. Figure 6 . Below, refer to Figure 6 The parison used in the second manufacturing method will be described using the same reference numerals.

[0126] Next, the second mold 200 used in the second manufacturing method is prepared. The second mold 200 has a long axis direction x4, a radial direction y4, and a circumferential direction z4, and has an inner cavity 205 extending in the long axis direction x4 and into which the parison 300 is inserted, and the inner cavity 205 is formed by a groove portion 210 recessed to the outside in the radial direction y4 and extending in the long axis direction x4, and a cylindrical wall portion 220 outside the groove portion 210. In addition, in a cross section perpendicular to the long axis direction x4, the groove portion 210 has a groove front end region 210t having a long distance in the radial direction y4 from the centroid O2 of the inner cavity 205 of the second mold 200, and a groove base end region 210b having a shorter distance in the radial direction y4 from the centroid O2 than the groove front end region 210t.

[0127] The groove 210, groove front end region 210t and groove base end region 210b of the second mold 200 are respectively the same as the groove 110, groove front end region 110t and groove base end region 110b of the first mold 100, and the description of the above-mentioned "3. First method for manufacturing a balloon catheter" can be referred to. In addition, with respect to the second mold 200, except for the following special descriptions, the second mold 200 is the same as the first mold 100, and the description of the above-mentioned "3. First method for manufacturing a balloon catheter" and Figure 7 .

[0128] like Fig.12 and Fig.13 As shown, in a cross section perpendicular to the long axis direction x4, the second mold 200 has a first region 201 with low thermal conductivity, a second region 202 with higher thermal conductivity than the first region 201, and a third region 203 with higher thermal conductivity than the second region 202, the first region 201 is located in the cylindrical wall portion 220, the second region 202 is located in the front end region 210t of the groove, and the third region 203 is located in the base end region 210b of the groove.

[0129] The parison 300 is inserted into the inner cavity 205 of the second mold 200 having such a structure, and the second mold 200 is heated, and a fluid is introduced into the inner cavity 305 of the parison 300 to expand the parison 300, so that the outer wall of the parison 300 abuts against the groove portion 210 and the cylindrical wall portion 220 of the second mold 200. At this time, the parison 300 is preferably blow-molded by heating the second mold 200. The heating of the second mold 200 can be performed by a known method such as a method of heating with a heater arranged outside the second mold 200, a method of heating the second mold 200 itself by induction heating, and the like. Through these steps, the parison 300 abutting against the groove base end region 210b where the third region 203 with high thermal conductivity is located is heated to a higher temperature, resulting in smoothing of the resin and reduction of the surface roughness, while the parison 300 abutting against the groove front end region 210t where the second region 202 with lower thermal conductivity than the third region 203 is located is heated to a lower temperature than the parison 300 abutting against the groove base end region 210b, resulting in suppression of smoothing of the resin. Thus, the balloon 2 having a lower surface roughness in the base end region 28b than in the front end region 28t can be manufactured.

[0130] The first region 201 with the lowest thermal conductivity is located in the cylindrical wall portion 220 of the second mold 200, so that the parison 300 abutting against the cylindrical wall portion 220 is heated to a lower temperature and the smoothing of the resin is further suppressed. Thus, the balloon 2 having a surface roughness greater than that of the protrusion 28 can be manufactured.

[0131] It can also be constructed such that the first region 201 is composed of a first component 250 formed by a material (L) with low thermal conductivity, the second region 202 and the third region 203 include a second component 260 formed by a material (H) with higher thermal conductivity than the material (L), and the radial y4 thickness of the second component 260 of the third region 203 is thicker than the radial y4 thickness of the second component 260 of the second region 202, thereby the thermal conductivity of the third region 203 is higher than the thermal conductivity of the second region 202.

[0132] like Fig.12As shown, the second mold 200 may also be configured such that the second component 260 having a thin thickness in the second region 202 and a thick thickness in the third region 203 and the first component 250 having the same thickness as the second component 260 in the third region 203 are connected in the circumferential direction z4. When there are a plurality of grooves 210 in the circumferential direction z4, it is preferred that the second component 260 is also arranged to match the position of the grooves 210 in the circumferential direction z4. In this case, in the second region 202, air is usually present outside the second component 260 in the radial direction y4, but the thermal conductivity of air is much lower than that of metal, so the third region 203 of the second component 260 formed of a material (H) with high thermal conductivity can have a higher thermal conductivity than the second region 202 of the second component 260 with a thin thickness.

[0133] Or, if Fig.13 As shown, the second mold 200 may also be configured to insert the second component 260 into the cylindrical first component 250 in parallel with the long axis direction x4. When there are multiple grooves 210 in the circumferential direction z4, it is preferred that the second component 260 is also arranged to match the position of the grooves 210 in the circumferential direction z4. In this case, in the second region 202, the first component 250 exists outside the radial direction y4 of the second component 260, but the thermal conductivity of the first component 250 is lower than that of the second component 260, so the third region 203 of the second component 260 formed of a material (H) with high thermal conductivity can have higher thermal conductivity than the second region 202 of the second component 260 with thin thickness.

[0134] The average value of the thickness of the second component 260 in the radial direction y4 of the third region 203 is preferably 1.2 times or more of the average value of the thickness of the second component 260 in the radial direction y4 of the second region 202. The average value of the thickness of the second component 260 in the radial direction y4 of the third region 203 is more preferably 1.5 times or more of the average value of the thickness of the second component 260 in the radial direction y4 of the second region 202, further preferably 2 times or more, particularly preferably 3 times or more, and preferably 10 times or less, more preferably 9 times or less, and further preferably 8 times or less. In this way, by changing the thickness of the second component 260 in the radial direction y4 of the second region 202 and the third region 203, the thermal conductivity of the third region 203 can be easily adjusted relative to the thermal conductivity of the second region 202. Thus, the surface roughness of the base end region 28b and the front end region 28t of the formed balloon 2 can be easily adjusted.

[0135] The material (L) with low thermal conductivity constituting the first member 250 is preferably copper, aluminum or an alloy thereof, and is more preferably an alloy of copper and beryllium (beryllium copper) from the viewpoint of high thermal conductivity and strength. The material (H) constituting the second member 260 and having a higher thermal conductivity than the material (L) is preferably iron or an alloy thereof, and is more preferably stainless steel from the viewpoint of durability and strength.

[0136] This application claims the benefit of priority based on Japanese Patent Application No. 2022-123511 filed on August 2, 2022. The entire contents of the specification of Japanese Patent Application No. 2022-123511 filed on August 2, 2022 are incorporated herein by reference.

[0137] Description of Reference Numerals

[0138] 1…balloon catheter; 2…balloon for balloon catheter; 5…hub; 6…fluid injection portion; 20…balloon body; 21…proximal sleeve portion; 22…proximal taper portion; 23…straight tube portion; 24…distal taper portion; 25…distal sleeve portion; 28…protrusion; 28b…base end region; 28B…base end; 28t…front end region; 28T…outer end; 30…shaft; 31…distal shaft; 32…proximal shaft; 50…guide wire port; 60…inner shaft; 70…front end member; 80…X Radiopaque marker; 100…first mold; 100C…straight tube portion of first mold; 100S…sleeve portion of first mold; 100T…cone portion of first mold; 105…inner cavity of first mold; 110…groove portion of first mold; 110b…groove base end region of first mold; 110t…groove front end region of first mold; 120…cylindrical wall portion of first mold; 130…cathode conductive component; 140…power source; 141…negative electrode of power source; 142…positive electrode of power source; 150…electrolysis liquid; 160…electrolytic tank; 200…second mold; 201…first region; 202…second region; 203…third region; 205…inner cavity of second mold; 210…groove of second mold; 210b…groove base region of second mold; 210t…groove front region of second mold; 220…cylindrical wall of second mold; 250…first component; 260…second component; 300…parison; 301…first end of parison; 302…second end of parison; 305… Inner cavity; 308…the protrusion of the parison; O1…the centroid of the inner cavity of the first mold; O2…the centroid of the inner cavity of the second mold; x1…the long axis direction of the balloon; y1…the radial direction of the balloon; z1…the circumferential direction of the balloon; x2…the long axis direction of the parison; y2…the radial direction of the parison; z2…the circumferential direction of the parison; x3…the long axis direction of the first mold; y3…the radial direction of the first mold; z3…the circumferential direction of the first mold; x4…the long axis direction of the second mold; y4…the radial direction of the second mold; z4…the circumferential direction of the second mold.

Claims

1. A balloon for a balloon catheter, having a long axis direction and a radial direction, characterized in that: The balloon for the balloon catheter comprises: a balloon body having an outer surface and an inner surface; and a protrusion protruding outward in the radial direction from the outer surface of the balloon body and extending along the long axis direction. In a cross section perpendicular to the long axis direction, the protrusion has a front end region including an outer end in the radial direction and a base end region located radially inward of the front end region. The balloon body and the protrusion are made of the same material. When the surface roughness of the protrusion is measured with respect to a reference length in a direction perpendicular to the major axis direction, the surface roughness of the base end region is smaller than the surface roughness of the tip end region.

2. The balloon for a balloon catheter according to claim 1, characterized in that: When the surface roughness of the protrusion and the balloon body is measured with respect to a reference length in a direction perpendicular to the long axis direction, the surface roughness of the balloon body is greater than the surface roughness of the base end region.

3. The balloon for a balloon catheter according to claim 1, characterized in that: When the surface roughness of the protrusion and the balloon body is measured with respect to a reference length in a direction perpendicular to the long axis direction, the surface roughness of the balloon body is greater than the surface roughness of the tip region.

4. A balloon catheter, characterized in that: A balloon for a balloon catheter according to any one of claims 1 to 3.

5. A method for manufacturing the balloon catheter according to claim 4, characterized in that: have: a step of preparing a cylindrical parison made of resin; A step of preparing a mold, the mold having a long axis direction and a radial direction, and having an inner cavity extending along the long axis direction and into which the parison is inserted, the inner cavity being formed by a groove portion recessed toward the outside in the radial direction and extending along the long axis direction and a cylindrical wall portion other than the groove portion; A step of inserting a cathode conductive member having an outer shape along the cylindrical wall portion in a cross section in the longitudinal direction into the inner cavity of the mold and causing the cathode conductive member to abut against the cylindrical wall portion without abutting against the groove portion; The step of connecting the cathode conductive component to the negative electrode of a power source and connecting the outer wall of the mold to the positive electrode of the power source; A step of introducing an electrolyte into the inner cavity of the mold on the radially outer side of the cathode conductive component; The step of supplying electric power from the power source to perform electrolytic grinding; a step of inserting the parison into the inner cavity of the mold after removing the electrolyte and removing the cathode conductive component from the inner cavity of the mold; as well as a step of introducing a fluid into the inner cavity of the parison to expand the parison so that the outer wall of the parison abuts against the groove portion and the cylindrical wall portion of the mold, In a cross section perpendicular to the major axis direction, the groove portion has a groove front end region having a long radial distance from the centroid of the inner cavity of the mold and a groove base end region having a shorter radial distance from the centroid than the groove front end region.

6. The method according to claim 5, characterized in that When the cathode conductive member is brought into contact with the cylindrical wall portion, no gap is formed between the cathode conductive member and the cylindrical wall portion.

7. A method for manufacturing the balloon catheter according to claim 4, characterized in that: have: a step of preparing a cylindrical parison made of resin; A step of preparing a mold, the mold having a long axis direction and a radial direction, and having an inner cavity extending along the long axis direction and into which the parison is inserted, the inner cavity being formed by a groove portion recessed toward the outside in the radial direction and extending along the long axis direction and a cylindrical wall portion other than the groove portion; The step of inserting the parison into the inner cavity of the mold; a step of heating the mold; as well as a step of introducing a fluid into the inner cavity of the parison to expand the parison so that the outer wall of the parison abuts against the groove portion and the cylindrical wall portion of the mold, In a cross section perpendicular to the long axis direction, the groove portion has a groove front end region having a long radial distance from the centroid of the inner cavity of the mold and a groove base end region having a shorter radial distance from the centroid than the groove front end region. In a cross section perpendicular to the long axis direction, the mold has a first region with low thermal conductivity, a second region with higher thermal conductivity than the first region, and a third region with higher thermal conductivity than the second region. In a cross section perpendicular to the long axis direction, the first region is located in the cylindrical wall portion, the second region is located in the groove front end region, and the third region is located in the groove base end region.

8. The method according to claim 7, characterized in that The first region is composed of a first component formed of a material (L) with low thermal conductivity, the second region and the third region include a second component formed of a material (H) with higher thermal conductivity than the material (L), and the radial thickness of the second component in the third region is thicker than the radial thickness of the second component in the second region.

9. The method according to claim 8, characterized in that An average value of the radial thickness of the second member in the third region is 1.2 times or more the average value of the radial thickness of the second member in the second region.

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