Medical device and stent

Abstract

To provide a medical device and a stent that allow medicine that can be discharged over a long period to be indwelled in a blood vessel and allow addition of medicine to be performed easily.SOLUTION: A medical device 10 includes a balloon 20 expandable in a radial direction and a stent 23 arranged outside in the radial direction of the balloon 20 that is expandable in the radial direction accompanying the expansion of the balloon 20. The stent 23 includes a protruding body 51 protruding toward the inside in the radial direction that can pierce the expanded balloon 20. The balloon 20 expands in the radial direction by the injection of fluid containing the medicine.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a medical device having a stent that is placed in a blood vessel, and to a stent. [Background technology]

[0002] In recent years, for example, in the treatment of myocardial infarction and angina pectoris, a procedure has been performed in which a stent is placed in the diseased part (stenosis) of the coronary artery to keep the coronary artery open. This procedure is also sometimes performed to treat stenosis occurring in other blood vessels, bile ducts, tracheas, esophagus, urethra, and other biological lumens.

[0003] A stent may have a drug loaded on its surface, and the drug can be released into the portion of the body lumen in which the stent is placed. An example of a medical device having such a stent is disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-136172 A Summary of the Invention [Problem to be solved by the invention]

[0005] It may be desirable for drugs placed in blood vessels to be released over a long period of time. For example, in the case of coronary microvascular disease, drugs such as low molecular weight drugs, extracellular vesicles, and cells can be placed upstream of the blood vessel at the occlusion site and gradually released over a long period of time, which is expected to provide a high therapeutic effect. In addition, if additional drugs can be replenished after the drug is released, a longer-lasting therapeutic effect can be expected.

[0006] One way to gradually release a drug is to gel it and place it in the blood vessel. However, there is a risk that the drug placed in the blood vessel will be washed away by the blood flow, making it difficult to release the drug over a long period of time. In addition, when loading a drug onto a stent, there is a limit to the amount of drug that can be loaded, making it difficult to release the drug over a long period of time.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical device and stent that can retain a drug that can be released over a long period of time in a blood vessel and also allows easy addition of the drug. [Means for solving the problem]

[0008] The medical device (1) of the present invention, which achieves the above-mentioned object, is a medical device having a radially expandable balloon and a stent arranged radially outside the balloon and radially expandable as the balloon expands, wherein the stent has protrusions that protrude radially inward and can puncture the expanded balloon, and the balloon expands radially when a fluid containing a medicinal agent is injected into the balloon.

[0009] The stent (9) of the present invention, which achieves the above-mentioned object, is a stent that is positioned radially outside a radially expandable balloon and is radially expandable as the balloon is expanded, and has protrusions that protrude radially inward and can puncture the expanded balloon. Effect of the Invention

[0010] The medical device (1) configured as described above can allow a fluid containing a drug to flow out to the area where the stent is placed by expanding the balloon and perforating the balloon with the protrusions of the stent. Therefore, the medical device can apply the drug to the blood vessel wall using the stent as a framework, making it difficult for the drug to flow out with the bloodstream. In addition, after a certain period of time has passed and the drug has been released, the medical device can reinsert the balloon into the stent position and expand it with an expansion fluid containing the drug, allowing the protrusions to perforate the balloon and redeliver the drug to the blood vessel wall.

[0011] (2) In the medical device of (1) above, the protrusions may be formed in a needle shape on the inner surface of the stent, thereby enabling the medical device to reliably puncture the balloon with the protrusions.

[0012] (3) In the medical device of (2) above, the protrusion may be hollow and partially open in the circumferential direction, so that the medical device can spread the drug-containing fluid that has perforated the balloon and flowed out from the opening over a wide area.

[0013] (4) In any of the medical devices (1) to (3) above, the stent may have a flow path portion with a space continuous with a part of the protrusion, whereby the medical device can spread a fluid containing a drug that has perforated the balloon and flowed out over a wide area along the length of the wire.

[0014] (5) In any of the medical devices (1) to (4) above, the stent may have a constricted portion in which the central portion in the axial direction is concave toward the inside in the radial direction, whereby the medical device forms a space between the outer surface of the stent and the blood vessel wall, and the fluid containing the drug that has flowed out from the balloon can be stored in the space, allowing a larger amount of drug to be retained.

[0015] (6) In any of the medical devices described above in (1) to (5), the stent may have at least a portion of its surface, including the protrusions, coated with a water-soluble polymer, thereby preventing the protrusions from unintentionally perforating the balloon before the stent is expanded.

[0016] (7) In any of the medical devices (1) to (6) above, the protrusions may protrude from the stent so as to be inclined along the circumferential direction of the balloon. This reduces the risk of unintended balloon perforation in the medical device because the protrusions do not perforate the balloon until the expanded balloon is rotated.

[0017] (8) In any of the medical devices described above in (1) to (7), the fluid injected into the balloon may be a hydrogel, which allows the medical device to gradually release a drug placed in a blood vessel.

[0018] In the stent (9) constructed as described above, when the balloon for expanding the stent is expanded, the protrusions perforate the balloon, allowing the fluid inside the balloon to flow out. The stent can utilize this to allow the drug to flow out. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is an overall front view of the medical device according to the present embodiment. [Diagram 2] FIG. 2 is an enlarged view of the balloon and its surroundings in FIG. [Diagram 3] 13 is a view of the vicinity of the distal end of the medical device with the balloon expanded within the blood vessel. [Figure 4] FIG. 2 is an enlarged cross-sectional view of a portion where a balloon and a stent face each other. [Diagram 5] FIG. 2 is a partially enlarged view of the vicinity of a protrusion of the wire material that constitutes the stent. [Figure 6]1 is an enlarged cross-sectional view of a portion where a balloon and a stent face each other in a state where the balloon is expanded and the stent is pressed against a blood vessel wall. FIG. [Figure 7] FIG. 13 is a view of the vicinity of the distal end of a medical device including a stent according to a first modified example in a state in which a balloon is expanded inside a blood vessel. [Figure 8] FIG. 13 is a diagram showing a state in which a stent according to a first modified example is placed in a blood vessel. [Figure 9] FIG. 11 is an enlarged cross-sectional view of a portion where a balloon and a stent of a second modified example face each other. [Figure 10] FIG. 11 is an enlarged cross-sectional view taken along a plane along the circumferential direction of a portion where a balloon and a stent according to a third modified example face each other. [Figure 11] 11A and 11B are diagrams showing the state in which a balloon is pressed against the inner surface of the stent from the state shown in FIG. 10, where (a) shows the state before the balloon is rotated circumferentially, and (b) shows the state after the balloon has been rotated circumferentially. [Figure 12] 1A and 1B are perspective views of a wire of a stent having protrusions according to a first modified example, in which (a) shows the state before the protrusions are formed, and (b) shows the state after the protrusions have been formed. [Figure 13] 10A and 10B are perspective views of a wire stent having protrusions according to a second modified example, in which (a) shows the state before the protrusions are formed, (b) shows the state after the protrusions are formed, and (c) shows the state after both sides of the protrusions have been bent to form a hollow needle shape. [Figure 14] FIG. 13 is a perspective view of a wire of a stent having protrusions according to a second modified example, in which the wire has a flow path portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for convenience of explanation and may differ from the actual ratios. In addition, in this specification and the drawings, components having substantially the same functional configurations are given the same reference numerals to avoid duplicated explanations. In this specification, the side of the device that is inserted into the living body is referred to as the "distal side" and the side that is operated is referred to as the "base side".

[0021] As shown in Fig. 1, the medical device 10 is a catheter device having a balloon 20 at the tip end of a long, flexible shaft 21, and a hub 22 at the base end of the shaft 21. A stent 23 is disposed on the radially outer side of the balloon 20. The balloon 20 can be radially expanded by injecting an expansion fluid. The stent 23 is a so-called balloon-expandable stent that can be radially expanded by the expansion force of the balloon 20 as the balloon 20 expands radially.

[0022] The shaft 20 includes an outer tube 30 and an inner tube 31 disposed inside the outer tube 30 .

[0023] An expansion lumen 32 through which an expansion fluid for expanding the balloon 20 flows is formed inside the outer tube 30. The distal end of the outer tube 30 is fixed to the proximal end of the balloon 20. The proximal end of the outer tube 30 is fixed to the hub 22.

[0024] A guidewire lumen 33 into which a guidewire (not shown) is inserted is formed inside the inner tube 31. The distal end of the inner tube 31 penetrates inside the balloon 20 and opens distally of the balloon 20. The proximal end of the inner tube 31 penetrates the sidewall of the outer tube 30 proximal to the balloon 20 and is fixed to the outer tube 30. A sidewall opening 34 communicating with the guidewire lumen 33 is formed in the sidewall of the outer tube 30 to which the proximal end of the inner tube 31 is fixed.

[0025] The hub 22 has a proximal opening 22a that communicates with the expansion lumen 32 of the outer tube 30. The proximal opening 22a functions as a port for the inflow and outflow of the expansion fluid.

[0026] The balloon 20 is a part that expands the narrowed portion by expanding the narrowed portion, for example. As shown in FIG. 2, the balloon 20 has a cylindrical portion 20b of approximately the same diameter in the axial center portion so that a predetermined range can be efficiently expanded. The stent 23 according to this embodiment is placed on the outside of the cylindrical portion 20b of the contracted balloon 20 in a contracted state. The tip side of the balloon 20 is fixed to the outer wall surface of the inner tube 31. The base end side of the balloon 20 is fixed to the outer wall surface of the tip portion of the outer tube 30. Therefore, the inside of the balloon 20 communicates with the expansion lumen 32 formed in the outer tube 30. Therefore, the inside of the balloon 20 can be filled with an expansion fluid from the base end opening 22a via the expansion lumen 32. The balloon 20 expands due to the inflow of the expansion fluid, and is folded by discharging the inflowed expansion fluid. The balloon 20 is shaped so that, when not inflated, it is folded so as to wrap around the outer circumferential surface of the inner tube 31 in the circumferential direction.

[0027] The balloon 20 is preferably made of a material having a certain degree of flexibility, such as polyolefins, such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these, soft polyvinyl chloride resin, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, thermoplastic resins, such as fluororesin, silicone rubber, latex rubber, etc.

[0028] The expansion fluid for expanding the balloon 20 is a hydrogel containing a drug. In this embodiment, the drug includes a drug having a therapeutic effect, as well as a low molecular weight drug, an extracellular vesicle, a cell, an exosome, a nucleic acid medicine, and the like. The cells include, for example, differentiated cells derived from somatic stem cells, adult stem cells, mesenchymal stem cells, ES cells (embryonic stem cells), or iPS cells (induced pluripotent stem cells). The somatic stem cells are, for example, skeletal myoblasts (myoblast cells). The differentiated cells are, for example, cardiomyocytes, fibroblast cells, and the like.

[0029] Next, the stent 23 will be described. As shown in Figures 2 and 3, the stent 23 includes a plurality of annular portions 40 arranged in the axial direction of the balloon 20, and link portions 42 connecting adjacent annular portions 40 in the axial direction. Each annular portion 40 is formed of a wavy wire material 50 that is repeatedly folded back in a zigzag pattern.

[0030] The annular portions 40 adjacent to each other in the axial direction are integrally connected to each other by a link portion 42. The adjacent annular portions 40 are connected to each other by the link portion 42 at least one location (multiple locations in this embodiment) on the circumference along a circumferential direction intersecting with the axial direction.

[0031] 3, the stent 23 can be expanded in the radial direction by extending the annular portion 40 along the circumferential direction due to the expansion force of the balloon 20. The stent 23 is pressed against the vascular wall 100 by the balloon 20. Even when the balloon 20 is deflated, the stent 23 maintains the expanded state and can be placed in the vascular wall 100 as it is.

[0032] 4, the wire 50 of the stent 23 has a protrusion 51 that protrudes radially inward. At least one protrusion 51 is provided on the stent 23, and in this embodiment, a plurality of protrusions 51 are provided. The protrusion 51 has a needle-like shape and is disposed so as to face the balloon membrane 20a that forms the balloon 20.

[0033] 5, protrusion 51 has a pointed puncture portion 52 at its tip. Protrusion 51 is formed hollow, and a portion of the hollow interior in the circumferential direction is open to form opening 54. Wire 50 has a groove-like flow path portion 55 that is provided with a space continuous with the base portion, which is a part of protrusion 51, and that runs along the length of wire 50.

[0034] As shown in Fig. 6, the protrusions 51 can perforate the expanded balloon 20 by pressing the balloon membrane 20a against them. When the balloon 20 is perforated, the expansion fluid 120, which is a hydrogel containing a drug, flows out of the balloon 20. Since the protrusions 51 are hollow and have openings 54, the expansion fluid 120 can easily flow out through the openings 54 when the balloon 20 is perforated. In addition, the wire 50 has a flow path 55 along its length, so that the flowed-out expansion fluid 120 can be spread along the length of the wire 50, allowing the expansion fluid 120 to reach a wide area.

[0035] When the balloon 20 is expanding the stent 23, the balloon 20 is pressed against the stent 23 with a force such that the protrusions 51 do not puncture the balloon membrane 20a. When the stent 23 is expanded and pressed against the blood vessel wall 100, the balloon 20 is pressed against the stent 23 with a force such that the protrusions 51 puncture the balloon membrane 20a due to the reaction force from the blood vessel wall 100. As a result, the balloon 20 is not punctured during the expansion of the stent 23, and when the stent 23 is expanded in the blood vessel, the balloon 20 is punctured and the expansion fluid 120 flows out.

[0036] In this manner, the medical device 10 of the present embodiment is provided with a protrusion 51 protruding radially inward on the stent 23, and the protrusion 51 pierces the balloon 20 when the stent 23 is in an expanded state, allowing the drug-containing expansion fluid 120 to flow out. This allows the stent 23 to be used as a framework to apply a gel-like drug to the vascular wall 100, making it difficult for the drug to flow out with the bloodstream. The drug to be placed is a hydrogel, and is gradually released over time. After a certain period of time has passed and the drug has been released, the balloon 20 is reinserted at the position of the stent 23 and expanded with the drug-containing expansion fluid 120, so that the protrusion 51 pierces the balloon 20 and the drug can be redelivered to the vascular wall 100. In addition, the protrusion 51 of the stent 23 is prevented from piercing the balloon 20 during the expansion of the stent 23, thereby preventing it from affecting the expansion force of the balloon 20.

[0037] In this embodiment, the protrusion 51 is hollow, but may be solid and needle-shaped. The protrusion 51 may have a shape other than needle-shaped as long as it can pierce the balloon 20. The stent 23 is formed by laser cutting a tubular metal member. At this time, an uneven shape may occur on the edge of the wire 50, and the protrusion 51 can be formed by leaving at least a part of this uneven shape without polishing or the like.

[0038] The stent 23 may not have a flow path portion 55. Also, the wire 50 of the stent 23 may be thinner in the vicinity of the protrusion 51 than in other portions. This makes it difficult for the expansion fluid 120 that flows out when the balloon 20 is perforated to interfere with the wire 50 of the stent 23, making it easier to spread the expansion fluid 120 around.

[0039] The balloon 20 may have a double structure of an outer balloon membrane and an inner balloon membrane. In this case, a hydrogel containing a drug is stored in advance in the space between the outer balloon membrane and the inner balloon membrane, and the inflation fluid 120 can flow in and out of the inner balloon membrane. This allows the balloon 20 to be reliably inflated, since even if the protrusion 51 pierces the outer balloon membrane, it does not affect the inflation of the inner balloon membrane.

[0040] Next, a modified example of the stent will be described. As shown in FIG. 7, the stent 60 may have a constricted portion 64 in which the central portion in the axial direction is concave toward the radial inside. In this case, the annular portion 61 in the central portion in the axial direction has a smaller maximum expansion diameter than the annular portions 61 at both ends in the axial direction, and thus a space can be formed between the outer surface of the stent 60 and the vascular wall 100. The stent 60 has a protrusion protruding toward the radial inside, and can pierce the expanded balloon 20. As shown in FIG. 8, the expansion fluid 120 containing the drug that flows out from the balloon 20 is stored in the space between the outer surface of the stent 60 and the vascular wall 100. The expansion fluid 120 stored in the space between the outer surface of the stent 60 and the vascular wall 100 is held down by the stent 60 against the vascular wall 100. In this way, by providing the constricted portion 64 in the stent 60, the expansion fluid 120 can be stored more between the stent 60 and the vascular wall 100, and the effect of the drug can be sustained for a longer period.

[0041] 9, the stent 70 may be covered with a coating 76 made of a water-soluble polymer. The coating 76 covers at least a portion of the surface of the wire 73, including the protrusions 75. The coating 76 made of a water-soluble polymer has elasticity and protects the protrusions 75 from perforating the balloon 20. This makes it possible to prevent the protrusions 75 from unintentionally perforating the balloon 20 at a stage before the stent 70 is expanded, such as when the medical device 10 is transported.

[0042] In Fig. 9, the coating 76 covers the entire inner and outer surfaces of the stent 70. Since the stent 70 is housed in a sheath device (not shown) until it is delivered to the lesion, the coating 76 does not come into contact with blood and does not dissolve. Therefore, the coating 76 can protect the protrusions 75. When the stent 70 is exposed from the sheath device at the lesion and expanded by the balloon 20, the coating 76 dissolves in the blood and the protrusions 75 are exposed, perforating the balloon 20 and allowing the expansion fluid 120 to flow out from the balloon 20.

[0043] As shown in FIG. 10, the protrusions 85 of the stent 80 may protrude from the wire 83 so as to be inclined along the circumferential direction of the balloon 20. As shown in FIG. 11(a), the protrusions 85 are inclined with respect to the radial direction of the stent 80, so that even if the balloon 20 expands and contacts the inner surface of the stent 80, the tip of the protrusions 85 does not perforate the balloon membrane 20a. When the balloon 20 is rotated in the circumferential direction from this state, as shown in FIG. 11(b), the protrusions 85 perforate the balloon membrane 20a, allowing the expansion fluid 120 to flow out of the balloon 20. In this way, by making the protrusions 85 inclined, the protrusions 85 can perforate the balloon 20 at the timing intended by the surgeon, thereby reducing the risk of perforation of the balloon 20 occurring in an unintended situation.

[0044] Next, modified examples of the protrusion and the flow path will be described. As shown in Fig. 12(a), the protrusion 152 can be formed by forming a lateral protrusion 151 that protrudes laterally from the wire 150, and bending the lateral protrusion 151 as shown in Fig. 12(b), so that the protrusion protrudes toward the radially inner side of the stent 90. In this way, the protrusion 152 can also be formed by forming a protruding portion on a part of the wire 150 and bending it.

[0045] As shown in Fig. 13(a), the protrusion 162 can be formed by forming a cut portion 161 in the wire 150 and, as shown in Fig. 13(b), by lifting the inner portion of the cut portion 161, so that the protrusion 162 can protrude toward the radially inner side of the stent 95. Also, as shown in Fig. 13(c), both side portions of the raised protrusion 162 can be folded to form a tube to form a hollow needle-like hollow protrusion 163.

[0046] As shown in FIG. 14, the wire 160 can have a flow path 164 having a space continuous with a base portion, which is a part of the protrusion 162, formed on the surface opposite to the side from which the protrusion 162 protrudes. In this way, the flow path 164 only needs to have a space continuous with a part of the protrusion 162, and may be formed on a surface other than the inner surface of the wire 160. When the balloon 20 expands, the protrusion 162 of the stent 95 perforates the balloon 20, causing the expansion fluid 120 to flow out. The flowed-out expansion fluid 120 is transmitted to the flow path 164 along the length of the wire 160 through a groove portion formed on the wire 160 when the protrusion 162 is raised and formed, and the expansion fluid 120 can reach a wide range of the vascular wall 100.

[0047] As described above, the medical device 10 (1) according to this embodiment includes a radially expandable balloon 20 and a stent 23 disposed radially outside the balloon 20 and radially expandable with the expansion of the balloon 20, and the stent 23 has a protrusion 51 that protrudes radially inward and can perforate the expanded balloon 20, and the balloon 20 expands radially when a fluid containing a drug is injected. The medical device 10 thus configured can allow the fluid containing a drug to flow out to the area where the stent 23 is disposed by perforating the balloon 20 with the protrusion 51 of the stent 23 as the balloon 20 expands. Therefore, the medical device 10 can apply a drug to the blood vessel wall using the stent 23 as a framework, making it difficult for the drug to flow out with the blood flow. In addition, after a certain period of time has passed and the drug has been released, the medical device 10 can reinsert the balloon 20 into the position of the stent 23 and expand it with an expansion fluid containing the drug, causing the protrusions 51 to puncture the balloon 20 and redeploy the drug to the blood vessel wall.

[0048] (2) In the medical device 10 described above in (1), the protrusions 51 may be formed in a needle shape on the inner surface of the stent 23. This allows the medical device 10 to reliably puncture the balloon 20 with the protrusions 51.

[0049] (3) In the medical device 10 described in (2) above, the protrusion 51 may be hollow and partially open in the circumferential direction. This allows the medical device 10 to spread the drug-containing fluid that has perforated the balloon 20 and flowed out from the opening 54 over a wide area.

[0050] (4) In any of the medical devices 10 described above in (1) to (3), the stent 23 may have a flow path portion 55 having a space continuous with a part of the protrusion 51. This allows the medical device 10 to spread the drug-containing fluid that has perforated the balloon 20 and flowed out over a wide area along the length of the wire.

[0051] (5) In any of the medical devices 10 described above in (1) to (4), the stent 60 may have a constricted portion 64 in which the central portion in the axial direction is concave toward the inside in the radial direction. This allows the medical device 10 to form a space between the outer surface of the stent 60 and the blood vessel wall, and to store the drug-containing fluid that has flowed out of the balloon 20 in the space, allowing a larger amount of drug to be placed.

[0052] (6) In any of the medical devices 10 described above in (1) to (5), the stent 70 may have at least a portion of its surface, including the protrusions 75, coated with a water-soluble polymer. This makes it possible for the medical device 10 to prevent the protrusions 75 from unintentionally perforating the balloon 20 before the stent 70 is expanded.

[0053] (7) In any of the medical devices 10 described above in (1) to (6), the protrusions 85 may protrude from the stent 80 so as to be inclined along the circumferential direction of the balloon 20. This prevents the protrusions 85 from perforating the balloon 20 until the expanded balloon 20 is rotated, thereby reducing the risk of perforation of the balloon 20 in unintended circumstances.

[0054] (8) In the medical device 10 of any of the above (1) to (7), the fluid injected into the balloon 20 may be a hydrogel. This allows the medical device 10 to gradually release a drug placed in a blood vessel.

[0055] The stent 23 (9) according to this embodiment is a stent 23 that is disposed radially outside the radially expandable balloon 20 and is radially expandable as the balloon 20 expands, and has protrusions 51 that protrude radially inward and can pierce the expanded balloon 20. When the balloon 20 for expanding the stent 23 expands, the protrusions 51 of the stent 23 thus configured can pierce the balloon 20 and allow the fluid inside the balloon 20 to flow out. The stent 23 can utilize this to allow a drug to flow out.

[0056] The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical concept of the present invention. [Explanation of symbols]

[0057] 10 Medical Devices 20 Balloon 21 Shaft 22 Hub 23 Stent 40 Annular section 42 Link section 50 wire rod 51 Projection 52 Puncture site 54 Opening 55 Flow path 56 Projection body 60 Stents 64 Waist 70 Stents 73 Wire rod 75 Projection 76 Covering 80 Stents 83 Wire rod 85 Projection 100 Blood vessel wall 120 Expansion Fluid

Claims

1. A medical device having a radially expandable balloon and a stent disposed radially outside the balloon and radially expandable in response to the expansion of the balloon, The stent has a protrusion that protrudes radially inward and can pierce the expanded balloon, The balloon is a medical device that expands radially when a fluid containing a drug is injected into it.

2. The medical device according to claim 1 , wherein the protrusions are needle-shaped and formed on the inner surface of the stent.

3. The medical device according to claim 2 , wherein the protrusion is hollow and has an opening in a circumferential direction.

4. The medical device according to any one of claims 1 to 3, wherein the stent has a flow path portion having a space continuous with a part of the protrusion.

5. The medical device according to any one of claims 1 to 3, wherein the stent has a narrowed portion in an axial center portion that is concave radially inward.

6. The medical device according to any one of claims 1 to 3, wherein at least a portion of the surface of the stent, including the protrusions, is coated with a water-soluble polymer.

7. The medical device according to any one of claims 1 to 3, wherein the protrusion protrudes from the stent so as to be inclined along the circumferential direction of the balloon.

8. The medical device according to any one of claims 1 to 3, wherein the fluid injected into the balloon is a hydrogel.

9. A stent is disposed radially outside a radially expandable balloon and is radially expandable in response to the expansion of the balloon, A stent having protrusions that protrude radially inward and can pierce the expanded balloon.

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