JP2020110419A - Balloon catheter - Google Patents

Abstract

To provide a balloon catheter capable of reducing damage to a normal living body lumen tissue, and performing cutting and expansion of a narrow section with one device.SOLUTION: A balloon catheter 10 includes: a catheter shaft 20, which is a tubular body having a tip part and a base end part; an expandable balloon 30 disposed at the tip part of the catheter shaft 20; and a tip chip 60 disposed on a tip side of the balloon 30 to which at least one cutting part 70 capable of cutting a narrow section N of a living body lumen is fixed. The cutting part 70 includes a sharp part 71 formed with a sharp blade 75 protruding to the outside in the radial direction of the tip chip 60, and a pressing part 72 formed with a non-sharp pressing surface 78 directed to the outside in the radial direction, which is located on a base end side as compared to the sharp part 71, and outside in the radial direction as compared to the blade 75.SELECTED DRAWING: Figure 3

Description

The present invention relates to a balloon catheter with an expandable balloon.

Many devices are currently used to treat complex lesions. Considering that the concept of APC (Apply Use Use Criteria), which is a guideline for optimizing a procedure, has been spreading in recent years, there is a high possibility that treatment for a complicated lesion will be optimized in some cases. Therefore, it is essential to develop simpler treatment methods and devices for complex lesions.

By the way, percutaneous angioplasty is performed as a treatment method for coronary artery disease and atherosclerosis. In percutaneous angioplasty, a balloon catheter having a balloon at its distal end is used to physically expand the stenosis and secure blood flow. However, in the case of severe stenosis where calcification occurs, the blood vessel may not be able to be properly expanded only by the expansion by the balloon. Therefore, for example, Patent Document 1 proposes a catheter in which a sharp incision knife is provided on the tip side of the balloon. With this catheter, the stricture can be incised with a cutting knife before the balloon is placed in the stricture.

JP-A-7-67967

Since the incision blade of the catheter described in Patent Document 1 projects outward in the radial direction, it may damage a normal blood vessel during transportation to the stenosis.

The present invention has been made to solve the above-described problems, and provides a balloon catheter that can reduce damage to normal living body lumen tissue and can cut and dilate a stenosis part with one device. The purpose is to do.

A balloon catheter that achieves the above object is a catheter shaft that is a tubular body having a distal end portion and a proximal end portion, an expandable balloon disposed at the distal end portion of the catheter shaft, and a distal end side of the balloon, A distal tip to which at least one cutting portion capable of cutting a narrowed portion of a living body lumen is fixed, and the cutting portion is formed with a sharp blade projecting outward in a radial direction of the distal tip. A sharpened portion and a pressing portion which is located on the base end side of the sharpened portion and is radially outward of the blade, and which is formed with a non-sharp pressing surface facing radially outward. To do.

In the balloon catheter configured as described above, the narrowed portion can be cut by the sharp portion on the distal end side and the narrowed portion can be expanded by the pressing portion. Since the pressing part has a non-sharp pressing surface that is located radially outward of the sharp part, it becomes difficult for the sharp part to contact the living luminal tissue during transportation to the stenosis, and normal living luminal tissue is damaged. Can be reduced. Then, the balloon catheter can perform a plurality of treatments such as cutting and expanding the stenotic part by the cutting part and expanding the stenotic part by the balloon with one device.

In the sharp portion and the pressing portion, the distance from the axial center of the tip tip in the radial direction may decrease toward the tip side. This allows the balloon catheter to insert the sharp portion and the pressing portion into the narrowed portion from the tip side having a small outer diameter. Therefore, in the balloon catheter, the sharp portion can gradually cut the narrowed portion with a small resistance, and the pressing portion can gradually spread the narrowed portion cut by the sharp portion with a small resistance. Therefore, the balloon catheter can reduce the push-in resistance and can effectively make a cut in the narrowed portion and spread it.

The tip may be removable from the catheter shaft. Thereby, the cutting portion having appropriate characteristics can be arbitrarily selected according to the property of the narrowed portion.

The balloon catheter may further include a stent disposed around the balloon and expandable by expanding the balloon. Thus, the balloon catheter can perform a plurality of treatments such as cutting and expanding the stenotic part by the cutting part, expanding the stenotic part by the balloon, and placing the stent with one device. Therefore, it is not necessary to replace the device, and the procedure is simple. Moreover, since the number of devices used can be reduced, medical economic efficiency is improved. Moreover, since the cutting portion is arranged not on the periphery of the balloon but on the distal end side of the balloon, the stent can be arranged on the periphery of the balloon.

The maximum distance of the pressing portion in the radial direction from the axial center of the distal tip may be larger than the maximum radius of the outer circumference of the stent. As a result, the stent can be prevented from being caught on another device or a living body lumen tissue within the living body lumen. Therefore, it is possible to prevent the stent from falling out of the balloon and preventing the surgeon from moving the balloon catheter.

It is a top view showing the balloon catheter concerning an embodiment. It is sectional drawing which shows the front-end|tip part of a balloon catheter. It is a top view which shows the front-end|tip part of a balloon catheter. It is a perspective view which shows a cutting part. It is a figure which shows the front-end|tip part of a balloon catheter, (A) is sectional drawing which follows the AA line of FIG. 3, (B) is sectional drawing which follows the BB line of FIG. It is sectional drawing which shows the state which the balloon of FIG.5(B) expanded. It is sectional drawing which shows the balloon catheter inserted in the blood vessel, (A) has the cutting part arrange|positioned in the stenosis part, (B) has the balloon arranged in the stenosis part, (C) shows the stenosis part by a balloon, The stent is expanded, and (D) shows the balloon deflated. It is a top view which shows the modification of a balloon catheter, (A) shows a 1st modification, (B) shows a 2nd modification, (C) shows a 3rd modification, (D) shows a 4th modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensions of the drawings may be exaggerated and different from the actual dimensions for convenience of description. In addition, in the present specification and the drawings, components having substantially the same function are designated by the same reference numeral, and a duplicate description will be omitted. In this specification, the side to be inserted into the lumen is referred to as the “tip side”, and the side to be operated is referred to as the “base side”.

The balloon catheter 10 according to the present embodiment is used for the treatment of pushing and expanding the narrowed portion of the blood vessel. The balloon catheter 10 is suitably used for treatment of, for example, chronic total occlusion lesion (Chronic Total Occlusion), calcified lesion, and lesion with high stenosis.

As shown in FIGS. 1 and 2, the balloon catheter 10 includes a long catheter shaft 20, a balloon 30 arranged at the distal end of the catheter shaft 20, and a distal tip 60 arranged on the distal side of the balloon 30. It has a hub 40 fixed to the proximal end of the catheter shaft 20 and a stent 50 arranged on the outer circumference of the balloon 30.

The catheter shaft 20 is an elongated tubular body having a distal end portion and a proximal end portion. The catheter shaft 20 includes an outer tube 21 which is a tube body, and an inner tube 22 which is a tube body arranged inside the outer tube 21. The proximal end of the outer tube 21 is fixed to the hub 40, and the distal end of the outer tube 21 is fixed to the proximal end of the balloon 30. The tip of the inner pipe 22 is located closer to the tip than the tip of the outer pipe 21. The base end portion of the inner pipe 22 is located closer to the base end side than the base end portion of the outer pipe 21. The base end of the inner tube 22 is fixed to the hub 40 on the base end side of the outer tube 21, and the tip of the inner tube 22 is fixed to the tip of the balloon 30.

An expansion lumen 23 is formed between the outer tube 21 and the inner tube 22 for allowing a fluid for expanding the balloon 30 to flow therethrough. A guide wire lumen 24 for passing a guide wire is formed inside the inner tube 22.

The outer tube 21 and the inner tube 22 preferably have a structure having appropriate flexibility and appropriate rigidity. The constituent material of the outer tube 21 and the inner tube 22 is, for example, polyolefin (for example, polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof). , Polyvinyl chloride, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, fluororesin, and other polymeric materials, or a mixture thereof, or a multilayer tube of the above two or more polymeric materials.

The balloon 30 is arranged on the outer circumference of the distal end portion of the catheter shaft 20. The proximal end portion of the balloon 30 is fixed to the outer peripheral surface of the distal end portion of the outer tube 21. The tip of the balloon 30 is fixed to the outer peripheral surface of the tip of the inner tube 22. The inside of the balloon 30 communicates with the expansion lumen 23. The balloon 30 is folded so as to wind around the outer circumference of the catheter shaft 20. When the expansion fluid flows into the balloon 30, the folded portion expands and expands. The balloon 30 may be expanded by expanding elastically from the rubber-like material itself, instead of expanding by expanding from the folded state.

The constituent material of the balloon 30 preferably has a certain degree of flexibility, for example, polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof. And the like, thermoplastic resins such as soft polyvinyl chloride resin, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, fluororesin, silicone rubber, latex rubber and the like.

The stent 50 is a so-called balloon expandable stent that expands (plastically deforms) by the expanding force of the balloon 30. The stent 50 is arranged on the outer peripheral surface of the balloon 30 which is folded and deflated. The stent 50 includes a plurality of struts 51 formed in an annular shape while being folded back in zigzag along the axial direction of the balloon 30. The plurality of struts 51 are arranged and connected along the axial direction of the balloon 30. The struts 51 can be plastically deformed to expand the diameter by expanding the balloon 30. The form of the stent 50 is not particularly limited as long as it can be expanded in diameter by the balloon 30.

The constituent material of the stent 50 is preferably a biocompatible metal, for example, an iron-based alloy such as stainless steel, tantalum (tantalum alloy), platinum (platinum alloy), gold (gold alloy), cobalt such as cobalt chromium alloy. Examples include base alloys, titanium alloys, niobium alloys, and the like. The constituent material of the stent 50 may be resin.

As shown in FIGS. 2 to 5, the distal tip 60 includes a connecting portion 61 that is connected to the inner tube 22 located on the distal side of the balloon 30 and a distal tubular portion 62 that extends from the connecting portion 61 in the distal direction. The cutting portion 70 is disposed on the tip outer peripheral surface 66 which is the outer peripheral surface of the tip tubular portion 62.

The connecting portion 61 covers the distal end portion of the inner pipe 22 and is fixed to the inner pipe 22. The method of fixing the connecting portion 61 to the inner pipe 22 is not particularly limited, but, for example, fusion bonding or adhesion can be applied. A taper portion 64 is formed on the tip side of the connecting portion 61 so as to taper toward the tip side.

The distal tubular portion 62 is a tubular body having a smaller outer diameter than the connecting portion 61 and located closer to the distal end than the connecting portion 61. The tip tubular portion 62 is connected to the tip end side of the tapered portion 64. The distal tubular portion 62 has a substantially uniform outer diameter and inner diameter along the axial direction. A distal end lumen 65 that communicates with the guide wire lumen 24 is formed inside the distal end tubular portion 62. The outer diameter of the distal tubular portion 62 is, for example, 0.413 to 0.724 mm, preferably 0.421 to 0.620 mm, and more preferably 0.430 to 0.517 mm. The inner diameter of the distal tubular portion 62 is, for example, 0.370 to 0.684 mm, preferably 0.370 to 0.580 mm, and more preferably 0.370 to 0.477 mm. The outer diameters of the connecting portion 61 and the distal tubular portion 62 may be the same. In this case, the tapered portion 64 is unnecessary.

The cutting portion 70 is a portion for cutting the narrowed portion N (see FIG. 7). It should be noted that here, “cutting” includes both cutting without cutting the object to be cut and cutting so as to cut the object to be cut. The cutting portions 70 are arranged on the distal outer peripheral surface 66 of the distal tubular portion 62 so as to be evenly arranged in the circumferential direction. The number of cutting portions 70 may be one or more, but is preferably 2 to 4 and is 3 in this embodiment.

Each of the cutting portions 70 is formed on the outer peripheral surface 66 of the distal end so as to extend in the axial direction of the tubular tubular portion 62. Each cutting portion 70 includes a sharp portion 71, a pressing portion 72 located on the proximal end side of the sharp portion 71, and a proximal end inclined portion 73 located on the proximal end side of the pressing portion 72.

The sharp portion 71 has a bottom surface on the tip outer peripheral surface 66, and has a substantially triangular pyramid shape having a top portion 74 at a position distant from the tip outer peripheral surface 66 to the outer side in the radial direction of the tip tubular portion 62. The outer side in the radial direction is a direction orthogonal to the axis X of the distal tip 60 (the distal tubular portion 62) and a direction away from the axis X. The sharpened portion 71 includes a blade 75 that projects radially outward from the distal tubular portion 62, and two distal end side surfaces 76 that sandwich the blade 75. The blade 75 is located on one side of the triangular pyramid that forms the sharp portion 71, and extends substantially linearly from the top portion 74 toward the tip side. The blade 75 does not have to extend substantially linearly. The blade 75 has a distance from the axial center X of the distal tubular portion 62 that decreases toward the distal end side, and the most distal end portion 77 of the blade 75 located closest to the distal end is located on the distal end outer peripheral surface 66. Although the position of the most distal end portion 77 preferably coincides with the position of the most distal end of the distal tubular portion 62, it may be located closer to the base end side than the most distal end of the distal tubular portion 62. The two tip side surfaces 76 sandwiching the blade 75 of the sharp portion 71 are substantially triangular with the same size. The blade 75 has a sharp portion at least at a part between the top portion 74 and the tip end portion 77. That is, the blade 75 may have a non-sharp portion in a part between the top portion 74 and the tip end portion 77. For example, the apex 74 may be sharp but not sharp. When the top portion 74 is not sharp, it is possible to suppress damage to the living tissue.

The length L1 of the sharp portion 71 along the axis X is, for example, 0.205 to 1.422 mm, preferably 0.327 to 1.300 mm, and more preferably 0.449 to 1.179 mm. The cutting edge angle θ of the sharp portion of the blade 75 is, for example, 10.0 to 60.0 degrees, preferably 20.0 to 52.5 degrees, and more preferably 30.0 to 45.0 degrees. .. The blade edge angle θ is an angle formed by the blade 75, that is, an angle formed by the two tip side surfaces 76, in a cross section orthogonal to the direction in which the blade 75 extends. The blade 75 has a higher cutting ability as the blade edge angle θ is smaller, but is more likely to be damaged or deformed. The blade 75 has a larger cutting edge angle θ, but has a lower cutting ability, but is less likely to be damaged or deformed. The blade 75 extends linearly, but is not limited to this and may extend, for example, in a curved shape.

On a plane passing through the blade 75 and the axis X, the angle α formed by the blade 75 with respect to the axis X is, for example, 1.5 to 68.4 degrees, preferably 8.2 to 61.8 degrees, and more preferably Is 14.9 to 55.6 degrees. The maximum height H1 from the tip outer peripheral surface 66 of the sharp portion 71 to the outside in the radial direction is, for example, 0.038 to 0.519 mm, preferably 0.086 to 0.473 mm, and more preferably 0.134 to. It is 0.436 mm.

The pressing portion 72 is located on the base end side of the sharp portion 71 and protrudes radially outward from the tip outer peripheral surface 66. The pressing portion 72 includes a pressing surface 78 provided at a position radially outward from the tip outer peripheral surface 66, and two intermediate side surfaces 79 that sandwich the pressing surface 78. The pressing portion 72 has a portion located on the base end side of the blade 75 and on the outer side in the radial direction of the blade 75. A maximum outer diameter portion 80 is formed on the most proximal side of the pressing portion 72. The pressing surface 78 is a smooth and non-sharp flat surface that faces outward in the radial direction. The pressing surface 78 is formed by an isosceles triangle having the apex at the apex 74 and having a base on the base end side of the apex 74. The distance from the axis X of the pressing surface 78 increases toward the base end side. The two intermediate side surfaces 79 that sandwich the pressing surface 78 are substantially rectangular with the same dimensions. In the cross section orthogonal to the axis X, the pressing portion 72 is formed in a substantially trapezoidal shape having a side on the intermediate side surface 79 and an upper side on the pressing surface 78. The trapezoid is preferably a substantially isosceles trapezoid in which the upper side is shorter than the lower side and the lengths of the two side sides are equal, but the present invention is not limited to this.

The diameter of the circumscribing circle C (see FIG. 5) that is in contact with all the maximum outer diameter portions 80 provided in the three cutting portions 70 is larger than the maximum outer diameter of the stent 50 when placed on the balloon 30. The diameter of the circumscribed circle C may be equal to or smaller than the maximum outer diameter of the stent 50 arranged on the balloon 30. The diameter of the circumscribed circle C is smaller than the outer diameter of the expanded balloon 30, as shown in FIG.

As shown in FIGS. 2 to 4, the length L2 of the pressing portion 72 along the axis X is, for example, 0.205 to 1.422 mm, preferably 0.327 to 1.300 mm, and more preferably 0. It is 0.449 to 1.179 mm. In a plane passing through the center of gravity of the pressing surface 78 and the axis X, the angle β formed by the pressing surface 78 with respect to the axis X is larger than 0 degrees and smaller than the angle α. The angle β is, for example, 0.0 to 68.0 degrees, preferably 8.4 to 61.0 degrees, and more preferably 16.7 to 55.0 degrees. The difference H2 between the maximum height of the pressing portion 72 from the tip outer peripheral surface 66 to the radial outside and the maximum height H1 of the sharp portion 71 from the tip outer peripheral surface 66 to the radial outside is 0.000 to 2.006 mm, for example. Yes, it is preferably 0.189 to 1.805 mm, more preferably 0.379 to 1.604 mm.

The base end inclined portion 73 is located on the base end side of the sharpened portion 71, and protrudes radially outward from the tip outer peripheral surface 66. The base end inclined portion 73 includes a base end inclined surface 81 extending from one side of the pressing surface 78 on the base end side toward the base end side, and two base end side surfaces 82 sandwiching the base end inclined surface 81. The base end inclined surface 81 is a smooth and non-sharp flat surface, and is formed by an isosceles triangle having a base on one side of the pressing surface 78 on the base end side and an apex on the tip outer peripheral surface 66. The distance from the axis X of the base end inclined surface 81 becomes larger toward the tip end side. The two base end side surfaces 82 sandwiching the base end inclined surface 81 are substantially triangular with the same size. One side of the base side surface 82 coincides with one side of the intermediate side surface 79 on the base side, and the other side of the base side surface 82 coincides with a side of the base inclined surface 81.

In the cross section orthogonal to the axis X, the base end inclined portion 73 is a substantially isosceles trapezoid having a side on the base end side surface 82 and an upper side on the base end inclined surface 81. The shape of the base end inclined portion 73 is not particularly limited. For example, the base end inclined surface 81 may be a quadrangle instead of a triangle.

The length L3 of the base end inclined portion 73 along the axis X is, for example, 0.205 to 0.474 mm, preferably 0.232 to 0.447 mm, and more preferably 0.259 to 0.420 mm. is there. In a plane passing through the center of gravity of the base end inclined surface 81 and the axis X, the angle γ formed by the base end inclined surface 81 with respect to the axis X is, for example, 4.6 to 85.3 degrees, and preferably 12.7. -77.8 degrees, and more preferably 20.7-71.4 degrees.

It should be noted that each surface forming the cutting portion 70 does not have to be a flat surface, and may be, for example, a convex curved surface or a concave curved surface. For example, if the two tip side surfaces 76 are concave curved surfaces, the blade tip angle θ of the blade 75 sandwiched between the two tip side surfaces 76 can be formed small. Further, if the pressing surface 78 is a convex curved surface, it is possible to reduce damage to the living tissue with which the pressing surface 78 is in contact. In addition, the sides of the cutting portion 70 that are adjacent to each other in the outer contour may be chamfered with a curved surface or a flat surface, except for the portion where the sharp blade 75 is formed. Further, the parts of the cutting part 70 other than the blade 75 may be entirely formed into a curved surface so that the boundary between adjacent surfaces of the outer contour is not visible. Therefore, the shapes such as the triangle, the quadrangle, and the trapezoid described above do not have to be the strict triangle, the quadrangle, and the trapezoid due to the chamfering process, the uneven shape of the surface, and the influence of the curvature of the outer peripheral surface 66 of the tip.

Each part of the tip chip 60 may be integrally formed, but may be a separate member. For example, the distal tubular portion 62 may be a part of the inner tube 22.

The constituent material of the tip 60 is not particularly limited, but examples thereof include metals (including alloys) and resins. Examples of metals include stainless steel, aluminum, aluminum alloys, titanium, titanium alloys, copper, copper alloys, tantalum, and cobalt alloys. The resin is, for example, polyvinyl chloride, polyethylene, polypropylene, cyclic polyolefin, polystyrene, poly-(4-methylpentene-1), polycarbonate, acrylic resin, acrylonitrile-butadiene-styrene copolymer, polyethylene terephthalate, polyethylene naphthalate, etc. Polyester, butadiene-styrene copolymer, polyamide (for example, nylon 6, nylon 6.6, nylon 6/10, nylon 12) and the like.

As shown in FIG. 1, the hub 40 includes a first opening 41 that communicates with the expansion lumen 23 and allows the expansion fluid to flow in and out, and a second opening 42 that communicates with the guidewire lumen 24. When the expansion fluid flows in from the first opening 41, the expansion fluid flows into the inside of the balloon 30 via the expansion lumen 23. As a result, the balloon 30 is expanded. A guide wire can be inserted into the second opening 42.

Next, a method of using the balloon catheter 10 described above will be described by taking as an example the case of expanding a blood vessel having a calcified narrowed portion N.

First, the operator percutaneously introduces the guide wire 90 (see FIG. 7A) into the blood vessel. Next, the operator inserts the guide wire 90 into the guide wire lumen 24 from the distal end side of the balloon catheter 10 to insert the balloon catheter 10 into the blood vessel. Next, the operator advances the guide wire 90 to the target narrowed portion N under fluoroscopy and passes the narrowed portion N. Then, the balloon catheter 10 is advanced along the guide wire 90. At this time, since the pressing portion 72 has the smooth pressing surface 78 located radially outward of the sharp portion 71, the sharp portion 71 is unlikely to contact the blood vessel. Therefore, normal blood vessel damage is suppressed. The diameter of the maximum outer diameter portion 80 of the pressing portion 72 is larger than the maximum outer diameter of the stent 50. Therefore, in the balloon catheter 10, when the stent 50 is caught on a blood vessel or another device (guiding catheter, sheath introducer, etc.), the stent 50 falls off from the balloon 30 or the operator cannot move the balloon catheter 10. Can be suppressed.

After advancing the balloon catheter 10 to the vicinity of the stenosis N, the operator pushes the tip 60 having the cutting portion 70 into the stenosis N as shown in FIG. 7(A). As a result, the narrowed portion N is cut by the blade 75 located at the tip of the cutting portion 70. Then, when the operator further pushes the tip 60, the narrowed portion N cut by the blade 75 is spread by the pressing surface 78 located radially outside the blade 75.

Next, as shown in FIG. 7B, the operator further pushes in the balloon catheter 10 to place the balloon 30 and the stent 50 in the stenosis N. At this time, the outer diameter of the stent 50 is smaller than the circumscribing circle C (see FIG. 5) in contact with the maximum outer diameter portion 80 of the cutting portion 70, so that the balloon 30 and the stent 50 are less likely to be caught in the narrowed portion N. Therefore, the balloon catheter 10 can prevent the stent 50 from falling off the balloon 30 and preventing the operator from moving the balloon catheter 10.

Next, the surgeon causes the expansion fluid to flow in through the first opening 41 of the hub 40. As a result, as shown in FIG. 7C, the expansion fluid flows into the balloon 30 via the expansion lumen 23, and expands the balloon 30. The balloon 30 can be expanded more than the maximum outer diameter part 80 of the cutting part 70, and can expand the blood vessel. When the balloon 30 expands, the stent 50 arranged on the balloon 30 also expands.

Next, the operator discharges the inflation fluid from the balloon 30. Thereby, as shown in FIG. 7D, the balloon 30 is deflated, and the stent 50 is left indwelled in the stenosis portion N. Next, the operator can perform post-expansion by expanding the balloon 30 to expand the stenosis N and the stent 50 as many times as necessary. Note that the post expansion may not be performed. Then, the operator removes the balloon catheter 10 and the guide wire 90. At this time, since the distance from the axial center X of the base end inclined surface 81 located in the base end inclined portion 73 becomes smaller toward the base end side, the guiding tip 60 having the cutting portion 70 is guided. It can be smoothly accommodated in a catheter or sheath introducer.

As described above, the balloon catheter 10 according to the present embodiment has a catheter shaft 20 that is a tubular body having a distal end portion and a proximal end portion, an expandable balloon 30 arranged at the distal end portion of the catheter shaft 20, and a balloon. A distal end tip 60, which is disposed on the distal end side of 30, and to which at least one cutting portion 70 capable of cutting the narrowed portion N of the living body lumen is fixed, and the cutting portion 70 has a diameter of the distal end tip 60. A sharpened portion 71 on which a sharpened blade 75 protruding outward in the direction is formed, and a non-sharpened pressing surface which is located on the base end side of the sharpened portion 71 and on the radial outer side of the blade 75 and faces the radial outer side. And a pressing portion 72 on which 78 is formed.

In the balloon catheter 10 configured as described above, the narrowed portion N can be cut by the sharp portion 71 on the distal end side, and the narrowed portion N can be expanded by the pressing portion 72. Since the pressing portion 72 has the non-sharp pressing surface 78 located radially outward of the sharp portion 71, it becomes difficult for the sharp portion 71 to come into contact with the living body lumen tissue during transportation to the stenosis portion N, so that a normal living body can be obtained. Damage to luminal tissue can be reduced. Then, the balloon catheter 10 can perform a plurality of treatments such as cutting and expanding the narrowed portion N by the cutting portion 70 and expanding the narrowed portion N by the balloon 30 with one device. Therefore, it is not necessary to replace the device, and the procedure is simple. Moreover, since the number of devices used can be reduced, medical economic efficiency is improved.

Further, in the sharp portion 71 and the pressing portion 72, the radial distance from the axial center of the distal end tip 60 decreases toward the distal end side. As a result, the balloon catheter 10 can insert the sharp portion 71 and the pressing portion 72 into the narrowed portion N from the tip end side having a small outer diameter. Therefore, in the balloon catheter 10, the sharp portion 71 can gradually cut the narrowed portion N with a small resistance, and the pressing portion 72 can gradually spread the narrowed portion N cut by the sharp portion 71 with a small resistance. it can. Therefore, the balloon catheter 10 can reduce the pushing resistance, and can effectively make a notch in the narrowed portion N and spread it.

In addition, the balloon catheter 10 further has a stent 50 which is arranged around the balloon 30 and which can be expanded by expanding the balloon 30. As a result, the balloon catheter 10 can perform a plurality of treatments such as cutting and expanding the narrowed portion N by the cutting portion 70, expanding the narrowed portion N by the balloon 30, and placing the stent 50 with one device. Also, post-expansion of the stent 50 may be further possible after placement of the stent 50. Therefore, it is not necessary to replace the device, and the procedure is simple. Moreover, since the number of devices used can be reduced, medical economic efficiency is improved. Moreover, since the cutting portion 70 is arranged not on the periphery of the balloon 30 but on the distal end side of the balloon 30, the stent 50 can be arranged on the periphery of the balloon 30.

The maximum distance of the pressing portion 72 in the radial direction from the axis X of the distal tip 60 is larger than the maximum radius of the outer circumference of the stent 50. As a result, the stent 50 can be prevented from being caught by another device or living tissue within the living body lumen. Therefore, it is possible to prevent the stent 50 from falling off the balloon 30 and preventing the operator from moving the balloon catheter 10.

The present invention also includes a treatment method for expanding the living body lumen having the stenosis N by using the balloon catheter 10. In the treatment method, at least one blade 75 capable of cutting the narrowed portion N of the living body lumen, a non-sharpness that is located on the proximal end side of the blade 75 and on the outer side in the radial direction of the blade 75 and faces the outer side in the radial direction. Inserting a single balloon catheter 10 having a different pressing surface 78, an expandable balloon 30 located proximal to the pressing surface 78, and a stent 50 arranged around the balloon 30 into a body lumen. The step of cutting the narrowed portion N with the blade 75, the step of expanding the cut narrowed portion N with the pressing surface 78, the further expansion of the expanded narrowed portion N with the balloon 30, and the expansion of the stent 50 with the narrowing. Dwelling in part N. In the treatment method configured as described above, a single balloon catheter 10 can perform a plurality of treatments in which the stenosis N is cut, the stenosis N is expanded in two stages, and the stent 50 is placed. Therefore, it is not necessary to replace the device, and the procedure is simple. Moreover, since the number of devices used can be reduced, medical economic efficiency is improved.

The present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, the balloon catheter 10 according to the above-described embodiment is an over-the-wire type, but may be a rapid exchange type.

The living body lumen into which the balloon catheter 10 is inserted is not limited to a blood vessel, and may be, for example, a bile duct, a trachea, an esophagus, a urethra, or another organ. Further, in the balloon catheter 10, the stent 50 may not be arranged on the balloon 30.

Although the base end of the cutting portion 70 of the distal tip 60 is located at the base end of the distal tubular portion 62, it may be located at the base end of the connecting portion 61. That is, the cutting portion 70 may be formed over the entire axial length of the tip 60.

Further, as in the first modified example shown in FIG. 8A, the distal tip 60 may be attachable to and detachable from the catheter shaft 20. A female screw 67 is formed inside the connecting portion 61 of the distal end tip 60. A male screw 25 that can be screwed into the female screw 67 is formed on the catheter shaft 20 located on the distal side of the balloon 30. Thus, the distal tip 60 can be detachably connected to the catheter shaft 20 by screwing the male thread 25 into the female thread 67. If the distal tip 60 is attachable to and detachable from the catheter shaft 20, the operator can arbitrarily select a cutting portion 70 having appropriate characteristics (shape of blade 75, physical properties, etc.) according to the characteristics of the narrowed portion N. ..

The form in which the distal tip 60 is attachable to and detachable from the catheter shaft 20 is not limited. For example, as in the second modified example shown in FIG. 8B, the first magnet 68 is arranged at the proximal end portion of the distal tip 60, and the first magnet is attached to the catheter shaft 20 located on the distal side of the balloon 30. The second magnet 26 that can be connected to 68 by magnetic force may be arranged. Note that one of the first magnet 68 and the second magnet 26 may be a magnetic body instead of a magnet. If at least one is a magnet, it can be connected by magnetic force.

Further, as in the third modification shown in FIG. 8C, the removable tip 60 may have a cover 69 that covers the tip of the balloon 30. The cover 69 can prevent the stent 50 from falling off the balloon 30.

Further, as in the fourth modified example shown in FIG. 8D, in the detachable distal tip 60, the cylindrical distal tubular portion 62 may not be provided with the cutting portion 70. The distal tubular portion 62 can have various hardnesses. For example, the distal tubular portion 62 may be formed of a hard metal and have high rigidity. When the distal tubular portion 62 has high rigidity, the distal tip 60 can improve the passability to a hard lesion including calcification. Alternatively, the distal tubular portion 62 may be made of a flexible resin material or the like to have flexibility. When the distal tubular portion 62 is flexible, the distal tip 60 can improve the passability at the bent portion of the blood vessel.

10 Balloon catheter 20 Catheter shaft 23 Expansion lumen 24 Guide wire lumen 30 Balloon 50 Stent 61 Connecting part 62 Tip tubular part 66 Tip outer peripheral surface 70 Cutting part 71 Sharp part 72 Pressing part 73 Base end inclined part 75 Blade 78 Pressing face 80 Maximum outside Diameter part 81 Base end inclined surface X axis center

Claims (5)

A catheter shaft which is a tubular body having a distal end portion and a proximal end portion,
An expandable balloon located at the tip of the catheter shaft,
A distal tip disposed on the distal end side of the balloon and having at least one cutting portion capable of cutting a narrowed portion of a living body lumen fixed thereto;
The cutting portion, a sharp portion formed with a sharp blade protruding outward in the radial direction of the tip,
A balloon catheter, comprising: a pressing portion that is located on the proximal end side of the sharp portion and radially outward of the blade, and that has a non-sharp pressing surface that faces radially outward. The balloon catheter according to claim 1, wherein the sharp portion and the pressing portion have a distance from the axial center of the distal tip in the radial direction that decreases toward the distal end side. The balloon catheter according to claim 1, wherein the tip is detachable from the catheter shaft. The balloon catheter according to any one of claims 1 to 3, further comprising a stent disposed around the balloon and expandable by expanding the balloon. The balloon catheter according to claim 4, wherein the maximum distance of the pressing portion in the radial direction from the axial center of the distal tip is larger than the maximum radius of the outer circumference of the stent.

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