JP2008284019A - Medical balloon, stent delivery system, and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medical balloon having a layer to be easily formed without affecting the performance of an existing balloon catheter, without affecting a stent, and without dropping or movement of the stent when the balloon catheter on which the stent is mounted is inserted into a narrowed part; and a stent delivery system and a method of manufacturing the same. <P>SOLUTION: The medical balloon, the stent delivery system, and the method of manufacturing the same are provided. The medical balloon is characterized by a high-frictional thin film layer disposed on the surface of the balloon. The high-frictional thin film layer is treated with a low-molecular weight substance C having a hydroxy group after reacting a prepolymer A having at least two isocyanate groups in one molecule with at least one kind of substance B selected from a group consisting of lower diamine, lower diol and polyol. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention generally relates to a stent delivery system for introduction and placement of medical balloons and stents used for medical purposes, for example, dilatation treatment of stenosis formed in blood vessels, esophagus, trachea, urethra, bile ducts and the like. In particular, the present invention relates to a stent delivery system for introduction and placement of a stent in a stenosis of a coronary artery.

  Stents are roughly classified into the following two types according to the mechanism when expanded to a predetermined size. One is a stent made of a shape memory alloy or the like, and is a self-expandable stent that can be expanded without mechanically expanding the stent. The other is a stent that requires expansion of a mechanical stent, and is generally a balloon expandable type that is expanded by a known balloon catheter used to expand vessels, particularly arteries and veins. A stent (balloon-expandable stent).

  The balloon-expandable stent does not have an expansion function in the stent itself, and in order to place the stent in the desired stenosis, the stent attached to the balloon part of the balloon catheter is placed to the desired stenosis, and then the balloon is expanded. In general, a method of bringing the stent into close contact with the inner surface of the stenosis by plastically deforming the stent by the expansion force of the balloon is generally performed.

  When a balloon-expandable stent is placed by the above method, it is necessary to insert a balloon catheter with the stent attached to the balloon part to the stenosis part. At the time of insertion, there is a risk that the stent moves on the balloon and falls off the balloon catheter. is there. A balloon generally used for a balloon catheter has a shape in which a truncated cone-shaped tapered portion is formed before and after a straight tube portion that expands into a cylindrical shape, and a balloon expandable stent is formed on the outer surface of the straight tube portion. Is installed. Even if the stent moves on the front and back of the straight tube portion even if the stent moves on the balloon and does not fall off the balloon catheter at the time of insertion, one end of the stent will be located on the outer surface of the tapered portion of the balloon. . Since the balloon in this portion is expanded only in a tapered shape, the stent is insufficiently expanded, and there is an extremely high possibility that restenosis of the stenosis portion will occur.

  From the above viewpoint, a prior art for preventing the stent from dropping or moving to a balloon catheter used for placement of a balloon expandable stent is disclosed.

  Japanese Patent Application Laid-Open No. 2001-505116 discloses a technique for forming a layer of a compatible material on the outer surface of a balloon as a stent delivery system having a stent holding means for preventing the stent from moving from the balloon. A technique for implanting and placing a stent on the outer surface of a balloon having a layer is disclosed.

  In Japanese Patent Laid-Open No. 9-276414, as a stent delivery system having a stent holding means for preventing a stent from moving from a balloon, the affinity between a layer having a large friction coefficient and a layer having a large friction coefficient on the outer surface of the balloon And a technique for disposing a stent (saddle or sheet) on the inner tube existing inside the balloon and disposing a stent on the outer surface of the balloon on the sheet.

  In JP 2005-537097 public information, as a stent delivery system having a stent holding means for preventing the stent from moving from the balloon, in order to increase static friction on the outer surface of the balloon, a polyether monomer, a carboxylic acid-containing monomer, Techniques for coatings comprising hydrophilic monomers and photoderivatized monomers are disclosed.

  Although both are effective as a stent holding means, the design requirements for a balloon catheter are increased, and the performance as a delivery catheter is expected to be lowered.

  Japanese Patent No. 3408663 discloses an intravascular support device having means for encapsulating a stent. In this prior art, encapsulation is achieved by heating, pressurizing, and cooling the balloon so that it expands around the stent in the folded state.

  However, the heating, pressurizing, and cooling processes of the balloon cause thermal and physical damage to the balloon, and there is a concern that the pressure strength may be lowered, and the process may be complicated. In recent years, a stent coated with a drug (DES) has been increasingly used, and damage to the drug due to heating, pressurization, and cooling has occurred, and there is a concern about the decrease in utility.

  In JP-T-2002-539888, a medical balloon to which an expandable and implantable medical device is attached, the surface of the medical balloon has a plurality of protrusions, and at least one part of the protrusions is Discloses a medical balloon that is at least partially disposed below the expandable and implantable medical device to grip the expandable and implantable medical device.

  Japanese Patent Application Publication No. 2002-539889 discloses a medical balloon having at least one position marking at the center.

  However, in these prior arts, when the protruding portion is incorporated into the balloon by the mold heat setting method, there is a concern that the balloon may be unevenly expanded at the marking site and the pressure strength is lowered, and the process may be complicated. The

Japanese Patent Application Publication No. 2004-527285 discloses a stent placement device that establishes a series of ridges in an area of a balloon. However, in this prior art, when the balloon is heated in the mold to form the ridge, not only the balloon is unevenly expanded at the ridge portion and the pressure strength is lowered, but also the process is complicated. The Furthermore, the above prior art does not disclose or suggest a protrusion on the balloon.
JP-T-2001-505116 JP-A-9-276414 Special table 2005-537097 public information Japanese Patent No. 3408663 Special Table 2002-539888 Special table 2002-539889 gazette Special Table 2004-527285

  Therefore, in view of the above problems, the problem to be solved by the present invention does not affect the performance of the existing balloon catheter, has a layer that can be easily formed, and does not affect the stent. It is an object of the present invention to provide a medical balloon, a stent delivery system, and a method for manufacturing the same, in which the stent is not dropped or moved when the balloon catheter with the stent is inserted to the stenosis.

Thus, the present invention
(1) A medical balloon comprising a high friction layer on the balloon surface, wherein the high friction layer comprises at least (A) a polyurethane prepolymer having two or more isocyanate groups in one molecule, and (B) a lower layer. After reacting with at least one substance selected from the group consisting of diamine, lower diol and polyol,
(C) A medical balloon formed by treatment with a low molecular weight substance having a hydroxyl group.

  (2) The total number of amine groups and hydroxyl groups in at least one substance selected from the group consisting of (B) the lower diamine, lower diol and polyol is the total number of isocyanate groups in the (A) polyurethane prepolymer. The medical balloon according to claim 1, wherein the medical balloon is at least 4 times.

  (3) The medical balloon according to (1) or (2), wherein the high friction layer has a thickness of 5 μm or less.

  (4) The medical balloon according to any one of (1) to (3), wherein at least one substance selected from the group consisting of (B) a lower diamine, a lower diol, and a polyol is castor oil.

  (5) The medical treatment according to any one of (1) to (4), wherein the low molecular weight substance having a hydroxyl group (C) is composed of at least one substance selected from the group consisting of water and lower alcohols. For balloons.

  (6) The medical balloon according to any one of (1) to (5), wherein the polyurethane prepolymer (A) is a composition of castor oil and 4,4′-diphenylmethane diisocyanate (hereinafter 4,4′-MDI). .

  (7) The medical balloon according to any one of (1) to (6), wherein when the balloon is folded, a protrusion is provided on the surface.

  (8) The medical balloon according to (7), wherein when the balloon is folded, at least one wing is formed on the surface, and the protrusion is located on the surface of the wing. balloon.

  (9) A stent delivery system comprising a stent that is expandable from a compressed first diameter to a second diameter that can be implanted in an affected area, and a balloon catheter, wherein the balloon catheter comprises (1) to ( 6) A stent delivery system comprising the medical balloon according to any one of 6) and an inflation lumen connected to the balloon so as to be in fluid communication.

  (10) A stent delivery catheter comprising a strut that is a linear element, expandable from a compressed first diameter to a second diameter that can be implanted in an affected area, and a balloon catheter, The balloon catheter includes the medical balloon according to (7) or (8), and an inflation lumen connected to the balloon so as to be in fluid communication, wherein the stent is in a folded state. A stent delivery system, wherein at least one protrusion of the balloon is sandwiched between struts.

  (11) The stent delivery system according to (9) or (10), further comprising at least one holding portion of the stent formed on at least one of a distal end and a proximal end of the balloon.

  (12) The stent delivery system according to (11), further comprising the holding portion being formed by the balloon.

(13)
(9) It is a manufacturing method of the stent delivery system in any one of (12),
(A) preparing a balloon forming parison;
(B) applying a first pressure to the parison to expand it radially, releasing the first pressure and preparing a medical balloon;
(C) connecting a tube for a delivery catheter having an inflation lumen to the medical balloon so that the medical balloon and the inflation lumen are in fluid communication with each other to obtain a stent delivery catheter;
(D) forming a layer composed of (A) and (B) on the medical balloon; and (e) folding the coated medical balloon after contacting with (C). Steps,
(F) preparing a medical stent having a stent strut that is a linear element and implantable in an affected area;
(G) placing the medical balloon in the lumen of the stent and crimping the stent to the compressed first diameter;
A method for manufacturing a stent delivery system.

(14)
(13) The method for producing a stent delivery system according to (13), wherein in the step (d), the method for forming a layer is a coating.

(15)
(13) or (14), wherein the step (e) further comprises disposing the medical balloon in the lumen of a tube having an inner diameter smaller than the inner diameter of the stent, Applying a second pressure to the medical balloon and then releasing and removing the tube;
And (g) crimping the stent to the compressed first diameter such that at least one protrusion of the balloon is sandwiched by the stent struts.
I will provide a.

  Since the high-friction layer is stably formed in the medical balloon of the present invention, when the balloon is placed in the stent delivery system, the balloon is folded and the stent is caused to swell the balloon by the layer. It is easy to be fixed to. The medical balloon of the present invention can easily fix the stent without affecting the basic performance of the balloon. In addition, a high friction layer that is safe and suitable for a living body can be easily formed.

  In addition, the stent delivery system to which the balloon of the present invention is applied enables the stent to be firmly fixed to the balloon.

  Moreover, the manufacturing method of the stent delivery system of the present invention can be used for various existing balloons. Further, it is possible to stably form the protruding portion, and the stent can be firmly fixed to the balloon.

  The best embodiment of the medical balloon and stent delivery system according to the present invention will be described in detail below.

  First, the medical balloon of the present invention will be described. A preferred medical balloon of the present invention is a balloon for treating a stenosis in a living body, and is a medical balloon provided with a high friction layer on the surface of the balloon, wherein the high friction layer comprises (A) one molecule. A polyurethane prepolymer having two or more isocyanate groups and (B) a low molecular weight substance having a hydroxyl group after being formed from at least one substance selected from the group consisting of a lower diamine, a lower diol and a polyol. It is a medical balloon characterized by being formed through the processing according to the above. The high friction layer preferably has a higher friction than the surface of the shaft connected to the balloon.

  In the present invention, the total number of isocyanate groups in the (A) polyurethane prepolymer is the total number of amine groups and hydroxyl groups in at least one substance selected from the group consisting of (B) a lower diamine, a lower diol and a polyol. The ratio of (B) and (A) is preferably adjusted within the range of 4 times or less from the viewpoint of adhesion and stability between the high friction layer and the balloon. The thickness of the high friction layer is more preferably 5 μm or less because it does not affect the performance of the balloon.

  In the present invention, (B) at least one substance selected from the group consisting of lower diamine, lower diol and polyol, which forms a high friction layer, includes lower diamines such as benzidine and p-phenylenediamine. Examples include aliphatic diamines such as diamine, ethylenediamine, and butanediamine. The lower diol includes aliphatic glycols such as propylene glycol and ethylene glycol and alicyclic glycols, butanediol, propylenediol, hexanediol, cyclohexanedimethanol and other aliphatic diols, naphthylenediol, bisphenol A and other aromatic diols. Examples are diols. Polyols include polyether polyols such as polyester polyols, poly (oxypropylene ether) polyols, poly (oxyethylene-propylene ether) polyols, branched derivatives of polymer polyols such as acrylic polyols, castor oil and derivatives thereof, glycerin, Examples include methylolpropane, trimethylolethane, 1,2,6-hexanetriol, pentaerythritol, sorbitol, mannitol and the like. Of these, castor oil is preferable from the viewpoint of adhesion, flexibility, and safety of the high friction layer.

  In the present invention, the (C) low molecular weight substance having a hydroxyl group is preferably a substance composed of at least one substance selected from the group consisting of water and lower alcohols from the viewpoint of handling and safety. Furthermore, the prepolymer is a composition of an isocyanate compound having a functional group having two isocyanate groups in one molecule and a polyol. Examples of the isocyanate compound include 2,4-tolylene diisocyanate, 2,6- Tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, p-phenylene diisocyanate, 3,3′-dimethylphenyl 4,4′-diisocyanate, metaxylylene diisocyanate, dianisidine diisocyanate, m-xylene diisocyanate, tetramethylxylene diisocyanate, Aromatic diisocyanates such as 1,5-naphthalene diisocyanate, trans-vinylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 1, Aliphatic diisocyanates such as 6-hexamethylene diisocyanate, trans-1,4-cyclohexane diisocyanate, cis-1,4-cyclohexane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and isophorone diisocyanate are used. However, 4,4′-MDI is preferable from the viewpoint of physical properties and reactivity, and the prepolymer is more preferably a composition of 4,4′-MDI and castor oil.

  When the medical balloon of the present invention is folded, it is preferably a balloon having a protrusion on the surface in order to prevent the stent from moving further from the balloon. Further, when the balloon is folded, it has at least one wing on the surface, and the protrusion is formed on the surface of the wing, so that the balloon performance is hardly affected. More preferable.

  In a state where the balloon is folded, two or more sheets can be formed from the viewpoint that at least a part of the balloon is sandwiched between the stent struts, which are linear elements of the stent, so that a protrusion is easily formed. It is preferable that it can be folded into a wing shape and can be folded into an elongated shape by winding the wing along the inner tube 3 while reducing the pressure inside the balloon.

  The balloon is not particularly limited in shape, material, structure, etc. as long as it can be folded, but the balloon has a cylindrical straight tube portion and a truncated cone-shaped tapered portion on the distal end side of the straight tube portion. The shape has a truncated cone-shaped tapered portion on the rear end side, and the taper angle in the tapered portion is not limited, and an arbitrary angle can be selected.

  Next, the stent delivery system of the present invention will be described with reference to FIG. In a preferred stent delivery system of the present invention, referring to FIG. 1, a balloon 1 is connected to a distal end portion of a stent delivery catheter, and a stent 10 is mounted on the balloon. Here, the balloon 1 is connected to the inflation lumen 6 so as to be in fluid communication. In this example, the stent delivery catheter includes an outer tube 2, an inner tube 3 that constitutes a guide wire lumen 5, and an X-ray opaque marker 4.

  In the example of FIG. 1, an outer tube 2 and an inner tube 3 are arranged in a coaxial double tube, and are determined by a guide wire lumen 5 and an inner surface of the outer tube 2 and an outer surface of the inner tube 3 inside the inner tube. A co-axial structure with an inflation lumen 6 is shown, but a bi-axial structure with a dual lumen tube in which the guide wire lumen 5 and the inflation lumen 6 are arranged in parallel. But you can. Moreover, even if it is structures other than illustrated above, the effect of this invention is not restrict | limited at all.

  The stent delivery catheter according to the present invention is either a high-speed exchange type catheter having a guide wire lumen 5 only at the distal end side of the catheter, or an over-the-wire type catheter having a guide wire lumen 5 over the entire length of the catheter. It is also possible to take the structure.

  The stent in the present invention needs to be expandable from the compressed first diameter to the second diameter that can be implanted in the affected area. Moreover, you may have a stent strut which is a linear element. Referring to FIG. 1, the stent 10 in this example is a balloon expandable stent, which is composed of stent struts, and the structure in which the stent struts are uniformly narrowed when disposed in a contracted state on the outer surface of the balloon 1. However, the material and manufacturing method of the stent are not limited and can be arbitrarily selected.

  In the example of FIG. 1, from the viewpoint of using a general balloon catheter, the balloon 1 in this example includes a cylindrical straight tube portion 1A and a truncated cone-shaped tapered portion 1B on the distal end side of the straight tube portion. This is a shape having a truncated cone-shaped tapered portion 1C on the rear end side of the straight pipe portion. The taper angle in the taper portions 1B and 1C is not limited, and an arbitrary angle can be selected. By disposing the contracted stent 10 on the outer surface of the folded balloon 1, preferably on the outer surface of the straight tube portion 1A, the stent 10 can be inserted into the body using a balloon catheter. At this time, the protrusion on the outer surface of the balloon 1, preferably the outer surface of the straight tube portion 1A on which the stent 10 is disposed, preferably a part of the wing, is sandwiched between the stent struts of the stent 10 to form a protrusion. More preferably. Any number of protrusions can be selected for this protrusion.

  Furthermore, it is more preferred to have stent 12 at the distal and proximal ends of balloon 1 to aid in stent delivery by providing a smooth transition between stent 10 and the catheter surface. From the viewpoint of avoiding an increase in the number of parts of the balloon catheter and complication of the process, the holding portion 12 is more preferably formed by the balloon 1.

  As such a holding portion, a structure having an outer diameter larger than that of the stent, flexible, in contact with the end portion of the stent without a gap, and not bent when the end portion of the stent is exposed is preferable. As a specific example, a balloon is inflated at the end of the stent and covers the end of the stent.

  Next, the manufacturing method of the stent delivery system of this invention is demonstrated. A balloon forming parison is prepared, a first pressure is applied to the parison to expand it radially, and the first pressure is released to prepare a medical balloon. Such a process for producing a medical balloon is known and disclosed in, for example, JP-T-2002-520099.

  On the other hand, a tube for a delivery catheter having an inflation lumen is connected to the medical balloon so that the medical balloon and the inflation lumen can communicate with each other to obtain a stent delivery catheter. This process is also known and disclosed in, for example, JP-T-6-507105.

  In a preferred stent delivery system of the present invention, a layer composed of the prepolymer and the polyol is formed on the medical balloon connected to a stent delivery catheter. As a method for forming the layer, coating is preferable because it can be easily applied to an existing stent delivery catheter. Next, the coated medical balloon is brought into contact with the low molecular weight substance to treat the remaining isocyanate groups, and then the medical balloon is folded. At this time, in order not to leave the isocyanate group, it is preferable to sufficiently contact the low molecular weight substance and react the remaining isocyanate group as much as possible. In some cases, it is more preferable to promote the reaction by heating. .

  Finally, a stent having a stent strut and having a second diameter that can be implanted in the affected area is prepared, and the medical balloon is placed in the lumen of the stent. The stent is then crimped with the balloon to the compressed first diameter.

  In a preferred method of forming the protrusion between the stent struts by the balloon of the present invention and the holding portion of the stent by the balloon, the medical balloon is further folded from the inner diameter of the stent after the medical balloon is folded. It is further equipped with a small inflating. Specifically, the step of covering the medical balloon with a tube having an inner diameter smaller than the inner diameter of the stent, subsequently applying a second pressure to the medical balloon, and then releasing the step, Furthermore, it is the method which has. In the step of crimping the stent together with the balloon to the compressed first diameter, the medical balloon is inflated and flexed so that the protrusion between the stent struts by the balloon and the holding part of the stent by the balloon are Formation becomes easy.

  Specific examples and comparative examples according to the present invention will be described in detail below, but it is obvious that the present invention is not limited to the following examples. The stent retention force shown below was measured based on ASTM: F2394-04 (Standard Guide for Measuring Securement of Balloon Expandable Stent Mounted on Delivery System).

Example 1
(Prepolymer production)
200 g of 4,4′-MDI and 100 g of castor oil were stirred and mixed at 70 ° C. for 5 hours to prepare a prepolymer. From the GPC analysis result of the prepolymer, no peak derived from castor oil was observed, and it was confirmed that castor oil and 4,4′-MDI reacted. Moreover, from the neutralization titration analysis result of the prepolymer, it was confirmed that the isocyanate group contained about 45% of the total weight in terms of 4,4′-MDI in the prepolymer. From the above, it was confirmed that a prepolymer having two or more isocyanate groups in one molecule was produced.

(Formation of high friction layer)
A coating solution comprising 5.4 g of the prepared prepolymer, 6.7 g of castor oil (hydroxyl value: 168), and 68.0 g of tetrahydrofuran (hereinafter referred to as THF) was prepared. A balloon of a stent delivery catheter (φ3.0 mm × 21 mm) was coated with the prepared coating solution, and then immersed in water for 3 minutes to form a high friction layer. After the balloon was dried, the film thickness of the high friction layer was 2.38 ± 0.38 μm.

(Stent crimping)
The coated balloon was folded, a stent (φ1.8 mm × 18 mm) was placed in the balloon straight tube portion, and the stent was reduced in diameter (crimping). As a result of measuring the stent holding force, it was 2.07 ± 0.06N. When the balloon was expanded, it did not break even at the limit balloon pressure.

(Example 2)
The balloon was coated in the same manner as in Example 1. The coated balloon was folded, covered with a sheath having an inner diameter of 1.25 mm, a pressure of 27 atm was applied to the balloon from the inflation lumen, the balloon was expanded for 30 seconds, the pressure in the balloon was released, and the sheath was removed. Thereafter, a stent (φ1.8 mm × 18 mm) was placed in the balloon straight tube, and the stent was reduced in diameter (crimping). The result of measuring the stent holding force was 2.47 ± 0.40 N. When the balloon was expanded, it did not break even at the limit balloon pressure.

(Comparative Example 1)
The stent delivery catheter (φ3.0 mm × 21 mm) used in Example 1 was used without forming a high friction layer on the balloon. A stent (φ1.8 mm × 18 mm) was placed in the straight tube portion of the balloon, and the stent was reduced in diameter (crimping). As a result of measuring the stent holding force, it was 0.95 N. When the balloon was expanded, it did not break even at the limit balloon pressure.

(Comparative Example 2)
In the same manner as in Comparative Example 1, the balloon catheter (φ3.0 mm × 21 mm) was folded, covered with a sheath with an inner diameter of 1.25 mm, and a pressure of 27 atm was applied to the balloon from the inflation lumen, and the balloon was expanded for 30 seconds. The pressure in the balloon was released and the sheath was removed. Thereafter, a stent (φ1.8 mm × 18 mm) was placed in the balloon straight tube, and the stent was reduced in diameter (crimping). As a result of measuring the stent holding force, it was 1.25 N. When the balloon was expanded, it did not break even at the limit balloon pressure.

It is the schematic at the time of folding a balloon and arrange | positioning a stent.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Balloon 1A Straight pipe part 1B Tip side taper part 1C Rear end side taper part
2 Outer tube 3 Inner tube 4 X-ray opaque marker 5 Guide wire lumen 6 Inflation lumen 10 Stent 12 Holding part

Claims (15)

A medical balloon comprising a high friction layer on a balloon surface, wherein the high friction layer comprises at least (A) a polyurethane prepolymer having two or more isocyanate groups in one molecule, and (B) a lower diamine, a lower After reacting with at least one substance selected from the group consisting of diol and polyol,
(C) A medical balloon formed by treatment with a low molecular weight substance having a hydroxyl group.   (A) The total number of isocyanate groups in the polyurethane prepolymer is not less than the total number of amine groups and hydroxyl groups in at least one substance selected from the group consisting of (B) lower diamine, lower diol and polyol, and 4 The medical balloon according to claim 1, wherein the medical balloon is twice or less.   The medical balloon according to claim 1 or 2, wherein the high friction layer has a thickness of 5 µm or less.   The medical balloon according to any one of claims 1 to 3, wherein at least one substance selected from the group consisting of (B) a lower diamine, a lower diol, and a polyol is castor oil.   The medical balloon according to any one of claims 1 to 4, wherein the low molecular weight substance having a hydroxyl group (C) is composed of at least one substance selected from the group consisting of water and lower alcohols.   The medical balloon according to any one of claims 1 to 5, wherein (A) the polyurethane prepolymer is a composition of castor oil and 4,4'-diphenylmethane diisocyanate (hereinafter 4,4'-MDI).   The medical balloon according to claim 1, wherein when the balloon is folded, a protrusion is provided on the surface.   The medical balloon according to claim 7, wherein the balloon forms at least one wing on a surface when the balloon is folded, and the protrusion is located on the surface of the wing.   A stent delivery system comprising a stent that is expandable from a compressed first diameter to a second diameter that can be implanted in an affected area, and a balloon catheter, wherein the balloon catheter is any one of claims 1 to 6. A stent delivery system comprising: the medical balloon described above; and an inflation lumen connected to the balloon so as to be in fluid communication.   A stent delivery catheter comprising a stent having a strut that is a linear element and expandable from a compressed first diameter to a second diameter that can be implanted in an affected area, and a balloon catheter, the balloon catheter Comprising a medical balloon according to claim 7 and an inflation lumen connected in fluid communication with the balloon, wherein at least one of the stent struts in the folded state of the balloon. A stent delivery system characterized in that the protruding portion of the balloon is sandwiched.   The stent delivery system according to claim 9 or 10, further comprising at least one holding portion of the stent formed on at least one of a distal end and a proximal end of the balloon.   The stent delivery system according to claim 11, further comprising the holding portion formed by the balloon. A method for producing a stent delivery system according to any one of claims 9 to 12,
(A) preparing a balloon forming parison;
(B) applying a first pressure to the parison to expand it radially, releasing the first pressure and preparing a medical balloon;
(C) connecting a tube for a delivery catheter having an inflation lumen to the medical balloon so that the medical balloon and the inflation lumen are in fluid communication with each other to obtain a stent delivery catheter;
(D) forming a layer composed of (A) and (B) on the medical balloon; and (e) folding the coated medical balloon after contacting with (C). Steps,
(F) preparing a medical stent having a stent strut that is a linear element and implantable in an affected area;
(G) placing the medical balloon in the lumen of the stent and crimping the stent to the compressed first diameter;
A method for manufacturing a stent delivery system.   14. The method for manufacturing a stent delivery system according to claim 13, wherein in the step (d), the method for forming a layer is a coating. 15. The method of manufacturing a stent delivery system according to claim 13 or 14, wherein in the step (e), the medical balloon is further disposed in a lumen of a tube having an inner diameter smaller than the inner diameter of the stent, Applying a second pressure to the balloon and then releasing to remove the tube;
And (g) crimping the stent to the compressed first diameter such that at least one protrusion of the balloon is sandwiched by the stent struts.