Medical device and expansion method

Abstract

[Problem] To provide a medical device with which it is possible to treat a stricture formed in a part of the blood vessels of the heart when performing thoracotomy in coronary artery bypass graft surgery, etc. [Solution] A medical device 1 has: a conduit 10, 20 that penetrates the wall of the coronary artery (V) and is inserted into the coronary artery; an expandable expansion part 70 that is provided at the distal end of the conduit; and an expansion means 40 that causes the expansion part to expand. A stricture formed in the coronary artery is expanded by the expansion of the expansion part.

Description

Medical Device and Expansion Method

[0001] The present invention relates to a medical device and an expansion method.

[0002] Conventionally, coronary artery bypass grafting (CABG), which connects veins or arteries in other parts of the body to the tip of the occluded part of the coronary artery, is known (for example, Patent Document 1 below). In coronary artery bypass grafting, the purpose is to increase the blood volume to the myocardium by anastomosing a newly separated blood vessel (graft) to the tip of the narrowed part to allow blood to flow into the coronary artery after the narrowed part. Another blood vessel used for bypass is usually taken from the patient's own vein or artery. Usually, the vein in the leg is used, and the internal thoracic artery running under the sternum or the radial artery in the forearm is used as the artery. Generally, arterial grafts often function properly even after 10 years of transplantation.

[0003] On the other hand, as a treatment for coronary artery occlusion, a procedure is also performed in which a catheter is inserted from a blood vessel in the leg or arm, and the occluded part is expanded using a balloon or stent provided at the tip of the catheter.

[0004] Japanese Patent Application Laid-Open No. 2022-167849

[0005] However, there are cases where the coronary artery occlusion is strong and treatment with a catheter is difficult, or where stenosis occurs at multiple locations. In such cases, coronary artery bypass grafting is often selected, but when there are too many stenosis sites, it may be difficult to treat all of them by bypass surgery.

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide a medical device and an expansion method capable of treating some of the stenosis formed in the blood vessel part of the heart when performing open chest surgery such as coronary artery bypass grafting.

[0007] The above object of the present invention is achieved by the following means.

[0008] (1) A medical device comprising a conduit that penetrates the wall of a coronary artery and is inserted into the coronary artery, and an expandable expander provided at the tip of the conduit, wherein the expander expands a stenosis formed in the coronary artery.

[0009] (2) A medical device as described in (1), having a total length of 30 cm or less.

[0010] (3) The medical device according to (1) or (2), wherein a puncture portion is formed at the tip of the conduit.

[0011] (4) The medical device according to any one of (1) to (3), further comprising an expansion means for expanding the expansion portion, wherein the expansion means is a balloon that can be expanded by supplying a pressurized medium, and the expansion portion is a stent that is expanded by the balloon.

[0012] (5) The medical device according to any one of (1) to (3), wherein the expansion portion is a self-expanding stent.

[0013] (6) The medical device according to any one of (1) to (5), wherein the conduit has a scale formed thereon that allows the distance the expanded portion moves to be determined.

[0014] (7) A method for dilating a narrowed portion of a blood vessel during open-chest surgery, comprising: opening the chest of a patient; puncturing the blood vessel near the narrowed portion and inserting a conduit equipped with an expander at its tip into the blood vessel; transporting the expander to the narrowed portion within the blood vessel; and dilating the narrowed portion by expanding the expander.

[0015] (8) The dilation method according to (7), wherein after performing the thoracotomy on the patient, a bypass surgery is performed.

[0016] (9) The dilation method according to (7) or (8), wherein the thoracotomy is performed on the patient while extracorporeal circulation is being performed.

[0017] (10) The medical device according to (1), further comprising a coating layer containing a drug formed on the surface of the expanded portion.

[0018] According to the medical device and expansion method described above, it is possible to treat some narrowing in the blood vessels of the heart when performing open-heart surgery such as coronary artery bypass grafting.

[0019] This is a schematic diagram showing the application of the medical device according to the first embodiment of the present invention to coronary artery bypass grafting. This is a schematic front view showing the medical device according to the first embodiment. This is a front cross-sectional view of part A in Figure 2. This is a diagram for explaining the method of expanding the medical device. This is a diagram for explaining the method of expanding the medical device. This is a diagram for explaining the method of expanding the medical device. This is a diagram corresponding to Figure 3 showing a medical device according to modification 1 of the first embodiment. This is a diagram corresponding to Figure 3 showing a medical device according to modification 2 of the first embodiment. This is a schematic front view showing the medical device according to the second embodiment. This is a front cross-sectional view along the longitudinal direction of the medical device according to the second embodiment. This is a front cross-sectional view showing the state when the outer tube is moved towards the proximal end relative to the inner tube in the medical device according to the second embodiment. This is a diagram for explaining the method of expanding the medical device according to the second embodiment. This is a diagram corresponding to Figure 8 showing a medical device according to modification 1 of the second embodiment.

[0020] <First Embodiment> Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 4C. Note that the following description does not limit the technical scope or the meaning of terms described in the claims. Also, the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios.

[0021] Figure 1 is a schematic diagram showing the application of the medical device 1 according to the first embodiment of the present invention to coronary artery bypass graft surgery. Figure 2 is a schematic front view showing the medical device 1 according to the first embodiment. Figure 3 is a front cross-sectional view of part A in Figure 2. Figure 4A is a diagram illustrating a method for expanding the medical device 1. Figure 4B is a diagram illustrating a method for expanding the medical device 1. Figure 4C is a diagram illustrating a method for expanding the medical device 1.

[0022] As shown in Figures 1 and 4A, the medical device 1 according to the first embodiment is a device for treating a stenosis N formed in the coronary artery (vascular portion) V of the heart H during coronary artery bypass graft surgery.

[0023] As shown in Figures 2 and 3, the medical device 1 comprises a hollow outer shaft 10, an inner shaft 20 positioned inside the outer shaft 10, a tip 30 positioned at the end of the inner shaft 20, a balloon (corresponding to an expansion mechanism) 40 positioned radially outward from the inner shaft 20, a first contrast member 50 and a second contrast member 60 for confirming the position of the balloon 40, which may be provided as needed, and a stent (corresponding to an expansion portion) 70 positioned on the outer circumference of the balloon 40. In this specification, the side inserted into the body is referred to as the "tip" or "tip side," and the proximal side is referred to as the "proximal end" or "proximal end side." The outer shaft 10 and the inner shaft 20 constitute a conduit. Also, the stent 70 is not shown in Figure 3.

[0024] As shown in Figure 2, the outer tube shaft 10 is configured to extend in the axial direction. The base end of the outer tube shaft 10 has a hub 80.

[0025] As shown in Figure 3, the tip of the outer tube shaft 10 extends to the base end of the balloon 40.

[0026] As shown in Figure 2, a scale 14 is formed on the outer shaft 10. With this configuration, the operator can determine the distance the balloon 40 moves when inserting the medical device 1 into the coronary artery V.

[0027] As constituent materials for the outer tube shaft 10, for example, polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer, thermoplastic resins such as flexible polyvinyl chloride, various elastomers such as polyurethane elastomer, polyamide elastomer, and polyester elastomer, and crystalline plastics such as polyamide, crystalline polyethylene, and crystalline polypropylene can be used.

[0028] Furthermore, the constituent material of the outer tube shaft 10 may be a metal material having relatively high rigidity, such as stainless steel, ductile stainless steel alloy, Ni-Ti alloy, brass, or aluminum. If necessary, a resin material having relatively high rigidity, such as polyimide, polyvinyl chloride, or polycarbonate, can also be used.

[0029] As shown in Figure 3, the inner tube shaft 20 is positioned inside the outer tube shaft 10. As shown in Figure 3, the inner tube shaft 20 extends to the tip of the balloon 40. As shown in Figure 3, the inner tube shaft 20 has a solid shape.

[0030] For example, the same material as that used for the outer shaft 10 can be used for the inner shaft 20.

[0031] As shown in Figure 3, the tip 30 is provided on the tip side of the inner tube shaft 20. The tip 30 has a tapered shape in which the outer diameter decreases towards the tip.

[0032] The tip 30 can be made of, for example, a flexible resin material. However, the material of the tip 30 is not particularly limited as long as it is flexible and can be fixed to the inner tube shaft 20. Note that the tip 30 may not be provided at all.

[0033] As shown in Figure 3, the tip of the balloon 40 is fixed to the inner tube shaft 20, and the base end of the balloon 40 is fixed to the tip of the outer tube shaft 10. The method of fixing the balloon 40 to the inner tube shaft 20 or the outer tube shaft 10 is not particularly limited, but for example, it may be done by bonding with an adhesive.

[0034] The balloon 40 expands radially when a working fluid F (see Figure 4A, etc.) is injected through the lumen 10L of the outer tube shaft 10. The working fluid consists of, for example, a mixture of contrast agent and physiological saline.

[0035] For example, the constituent materials of the balloon 40 can be polyethylene, polypropylene, ethylene-propylene copolymer polyolefin, polyester such as polyethylene terephthalate, polyvinyl chloride, ethylene-vinyl acetate copolymer, cross-linked ethylene-vinyl acetate copolymer, thermoplastic resins such as polyurethane, polyamide, polyamide elastomer, polystyrene elastomer, silicone rubber, latex rubber, etc.

[0036] As shown in Figure 3, the first contrast-enhancing member 50 and the second contrast-enhancing member 60 are provided on the outer circumference of the inner tube shaft 20 and the inner circumference of the balloon 40. The first contrast-enhancing member 50 and the second contrast-enhancing member 60 can be provided to determine the position of the balloon 40.

[0037] The first contrast-enhancing member 50 and the second contrast-enhancing member 60 are radiopaque. Here, "radiopaque" means that in a normal medical setting, the presence of the first contrast-enhancing member 50 and the second contrast-enhancing member 60 can be confirmed (for example, visually recognized) on a radiofluoroscopic image.

[0038] The first contrast-enhancing member 50 and the second contrast-enhancing member 60 can be made of metals such as platinum, gold, silver, iridium, titanium, tungsten, or alloys thereof.

[0039] The stent 70 is a so-called balloon-expandable stent that expands and deforms (plastically deforms) due to the expansion force of the balloon 40.

[0040] The stent 70 is positioned to cover the balloon 40 and is held in place around the outer circumference of the balloon 40 by applying a compressive force.

[0041] The material constituting the stent 70 is preferably a biocompatible metal, such as iron-based alloys like stainless steel, tantalum (tantalum alloy), platinum (platinum alloy), gold (gold alloy), cobalt-based alloys like cobalt-chromium alloy, titanium alloy, niobium alloy, or photoresponsive material. The stent 70 may also be a biodegradable stent mainly composed of polymers, for example, and its material is not particularly limited as long as it is a known balloon-expandable stent. Furthermore, it may be coated with drugs such as sirolimus, paclitaxel, or zotarolimus that have the desired therapeutic effect. In other words, the stent 70 may be configured as a drug-eluting stent (DES) coated with a drug that has the effect of preventing restenosis. Furthermore, the drugs applied to the surface of the stent 70 are not limited to those having a restenosis prevention effect, and may include anticancer drugs, antiviral drugs, antibacterial drugs, anti-neoplastic agents, analgesics and anti-inflammatory drugs, antibiotics, antiepileptic drugs, anxiety relievers, antiparalytics, antagonists, neuron blockers, anticholinergics and cholinergics, antimuscarinic and muscarinic agents, anti-adrenergic agents, antiarrhythmics, antihypertensives, hormones, and nutritional supplements.

[0042] As shown in Figure 2, the hub 80 has a port 81 that can be connected in a liquid-tight and airtight manner to a supply device (not shown) such as an indeflerator for supplying fluid (working fluid). The port 81 of the hub 80 can be made of, for example, a known Luer taper configured to allow connection and disconnection of fluid tubes, etc. The supply device such as an indeflerator can also be defined as an expansion means. In addition to the stent made of the above-mentioned metal material, a stent structure using a photoreactive material whose hardness is changed by irradiation with a light source of a specific wavelength may also be used. The medical device of this embodiment may be appropriately configured with a total length of 30 cm or less, and in this case, the medical device 1 can be suitably accessed to the stenotic portion N of the coronary artery V under thoracotomy. Furthermore, under thoracotomy, the characteristics of the stent 70 can be controlled and set, enabling various treatment methods and the administration of therapeutic drugs that were not possible with conventional methods.

[0043] The constituent material of the hub 80 includes, for example, thermoplastic resins such as polycarbonate, polyamide, polysulfone, polyarylate, and methacrylate-butylene-styrene copolymer.

[0044] The overall length of the medical device 1 is preferably, for example, 30 cm or less. According to this configuration, the medical device 1 can be suitably accessed up to the stenosis N of the coronary artery V under thoracotomy.

[0045] Next, referring to FIGS. 4A to 4C, the method of using the medical device 1 will be described. Here, a procedure for expanding the stenosis N formed in the coronary artery (vascular part) V under thoracotomy during coronary artery bypass graft surgery will be described.

[0046] First, the surgeon performs a bypass graft surgery on the occluded blood vessel that is difficult to treat with a catheter by opening the patient's chest. Next, when observing the coronary artery on the surface of the patient's heart and confirming a relatively mild stenosis N that can be treated with a catheter, a hole is formed in the coronary artery V near the stenosis N using a scalpel or the like.

[0047] Next, the surgeon inserts the medical device 1 into the coronary artery V through the hole formed above, using a sheath for expanding the hole as needed. Then, as shown in FIG. 4A, the balloon 40 of the medical device 1 with the stent 70 mounted is placed at the stenosis N. At this time, if the scale 14 is provided on the outer tube shaft 10, the balloon 40 inserted through the hole can be easily placed at the stenosis N.

[0048] Next, the surgeon supplies the working fluid F to the balloon 40 of the medical device 1 and expands the balloon 40 as shown in FIG. 4B. As a result, by expanding the balloon 40 from the inside of the stent 70, the stent 70 is crimped against the stenosis N.

[0049] Next, as shown in FIG. 4C, after crimping the stent 70 at the stenosis N, the surgeon contracts the balloon 40, removes it outside the body, and ends the procedure.

[0050] Furthermore, the above-described method of use can be performed while performing cardiopulmonary bypass (cardiac arrest coronary artery bypass surgery). Cardiac arrest coronary artery bypass surgery has the advantage of allowing for careful anastomosis over a longer period of time and enabling safe anastomosis of the posterior surface of the heart. It is also possible to perform the above-described method of use without cardiopulmonary bypass (off-pump coronary artery bypass surgery). Off-pump coronary artery bypass surgery is suitable for patients at high risk of complications from cardiopulmonary bypass.

[0051] As described above, the medical device 1 according to the first embodiment includes an outer shaft 10 and an inner shaft 20 that penetrate the wall of the coronary artery V and are inserted into the coronary artery V, an expandable stent 70 provided at the tips of the outer shaft 10 and the inner shaft 20, and a balloon 40 for expanding the stent 70. By expanding the balloon 40, the narrowed portion N formed in the coronary artery V is expanded. With the medical device 1 configured in this way, it is possible to treat a portion of the narrowed portion N formed in the coronary artery V of the heart H when performing open-heart surgery such as coronary artery bypass grafting.

[0052] <Modification 1 of the First Embodiment> Next, the medical device 2 according to Modification 1 of the First Embodiment described above will be explained with reference to Figure 5. The medical device 2 according to Modification 1 of the First Embodiment differs from the medical device 1 according to the First Embodiment in that, as shown in Figure 5, a puncture portion 130 is provided instead of the tip 30.

[0053] In the first embodiment described above, a hole was made in the coronary artery V using a scalpel or the like. However, in the medical device 2 according to Modification 1, a puncture portion 130 is positioned at the tip, so a hole can be made in the coronary artery V using the medical device 2. Therefore, a scalpel is not required, and since the medical device 2 can be used to puncture and then directly inserted into the coronary artery V, work efficiency is improved.

[0054] <Modification 2 of the First Embodiment> Next, the medical device 3 according to Modification 2 of the First Embodiment described above will be explained with reference to Figure 6. The medical device 3 according to Modification 2 of the First Embodiment differs from the medical device 1 according to the First Embodiment in that, as shown in Figure 6, a guide wire lumen L through which a guide wire G can be inserted is formed inside the inner tube shaft 28 and the tip 35.

[0055] In the first embodiment described above, a hole was made in the coronary artery V using a scalpel or the like. However, in the medical device 3 according to the modified example 2, as shown in Figure 6, the tip of the guidewire G is needle-shaped, and a hole may be made in the coronary artery V by puncturing the coronary artery V with the guidewire G. Then, the medical device 3 is inserted into the coronary artery V along this guidewire G.

[0056] <Second Embodiment> Next, the configuration of the medical device 4 according to the second embodiment will be described with reference to Figures 7 to 9. Figure 7 is a schematic front view showing the medical device 4 according to the second embodiment. Figure 8 is a front cross-sectional view along the longitudinal direction of the medical device 4 according to the second embodiment. Figure 9 is a front cross-sectional view showing the state of the medical device 4 according to the second embodiment when the outer tube 330 is moved toward the base end relative to the inner tube 320.

[0057] As shown in Figures 7 and 8, the medical device 3 includes an inner tube 320 that extends in the axial direction, an outer tube 330 positioned to cover the tip end of the inner tube 320, a stent 400 positioned between the tip end of the inner tube 320 and the tip end of the outer tube 330, which is released from between the inner tube 320 and the outer tube 330 as the outer tube 330 moves and expands and deforms, and a handheld operating section 500 positioned on the proximal end side of the inner tube 320 and configured to be grippable. The inner tube 320 and the outer tube 330 constitute a conduit.

[0058] As shown in Figure 8, the inner tube 320 is composed of a long, tubular body extending in the axial direction. The inner tube 320 also has a solid shape.

[0059] It is preferable to use a flexible material for the material constituting the inner tube 320. For example, polyethylene, polyolefins such as polypropylene, polyamides, polyesters such as polyethylene terephthalate, fluoropolymers such as ETFE, PEEK, polyimide, etc., can be used.

[0060] As shown in Figure 8, the outer tube 330 is made up of a long, tubular body and includes a storage lumen 331 that houses the inner tube 320 and the stent 400, etc. The outer tube 330 is positioned on the outer circumferential side of the inner tube 320 so that it can move relative to the inner tube 320. A scale 14 is formed on the proximal end of the outer tube 330. With this configuration, the operator can grasp the distance the outer tube 330 moves when inserting the medical device 4 into the coronary artery V, and it becomes easy to position the outer tube 330 near the stenosis N.

[0061] A gap 340 for accommodating the stent 400 is formed between the tip of the inner tube 320 and the tip of the outer tube 330.

[0062] Prior to being placed in the stenosis N of the coronary artery V, the stent 400 is housed in the gap 340 in a state of radial compression inward.

[0063] The material used to make up the outer tube 330 can be the same as the material used to make up the inner tube 320.

[0064] The stent stopper 370 is positioned proximal to the stent 400 housed in the gap 340. When moving the outer tube 330 proximal to the inner tube 320, the proximal end of the stent 400 comes into contact with the stent stopper 370. This contact restricts the proximal movement of the stent 400. As the outer tube 330 moves further proximal independently of the stent 400, the stent 400, with its proximal end supported by the stent stopper 370, is pushed out from between the inner tube 320 and the outer tube 330 and released into the stenosis B of the coronary artery V (see Figure 10).

[0065] When the stent 400 is housed in the gap 340, it receives a restraining force from the inner circumferential surface of the outer tube 330, which restricts its radially outward expansion deformation.

[0066] When the outer tube 330 of the stent 400 moves proximal to the inner tube 320, and the gap 340 is exposed to the outside, the constraint of the inner surface of the outer tube 330 is released, and it expands and deforms radially outward, taking on a shape that conforms to the stenosis N of the coronary artery V (see Figure 10).

[0067] In the second embodiment, the stent 400 can be any known stent that possesses biocompatibility, self-expanding properties, and biodegradability. Such a stent 400 can be made of superelastic alloys such as Ni-Ti, or, for example, polymer materials. Examples of such polymer materials include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polytetrafluoroethylene, and fluorine-containing polymers such as tetrafluoroethylene-ethylene copolymers. Biodegradable materials include polylactic acid, polyglycolic acid, and polycaprolactone.

[0068] As shown in Figures 7 and 8, the handheld operating unit 500 includes an outer tube hub 510 to which the base end of the outer tube 330 is attached, a connector 520 connected to the base end of the outer tube hub 510 and provided to be movable together with the outer tube 330, a base shaft 530 that covers the inner tube 320 on the base end side of the connector 520, and an inner tube hub 540 to which the base end of the inner tube 320 is attached.

[0069] As shown in Figure 8, the outer tube hub 510 is liquid-tightly connected to the base end of the outer tube 330. The outer tube hub 510 can be made of, for example, a known resin material or a metal material.

[0070] The connector 520 is detachably connected to the outer tube hub 510. The connector 520 has a main body 521 through which the inner tube 320 is inserted and which communicates with the storage lumen 331 of the outer tube 330, a valve body 523 that is arranged to open and close the lumen of the main body 521, and a cover 524 provided on the base end side of the main body 521.

[0071] The main body 521 is provided so as to be movable relative to the inner tube 320, and by moving the main body 521 toward the proximal end of the inner tube 320, the outer tube 330 can be moved toward the proximal end of the inner tube 320. This operation allows the stent 400 to be expanded and deformed.

[0072] As shown in Figure 8, the valve body 523 is positioned within the lumen of the main body 521 so as to surround the outer circumference of the base shaft 530, and is provided to allow the gap between the main body 521 and the base shaft 530 to be opened and closed. The opening and closing operation of the valve body 523 is performed by a cover 524, which will be described later.

[0073] The material constituting the valve body 523 is not particularly limited as long as it is flexible and liquid-tight, and various elastic materials such as natural rubber, synthetic rubber, polyamide-based and polyester-based thermoplastic elastomers can be used. Among these, silicone rubber, which has excellent resilience to compression and deformation over a wide temperature range, can be suitably used.

[0074] When the valve body 523 is open, the connector 520 becomes movable relative to the base shaft 530. This allows the outer tube 330 to be moved relative to the inner tube 320.

[0075] When the valve body 523 is completely closed, the outer circumference of the base shaft 530 is pressed against (tightened) the valve body 523, thereby restricting the relative movement of the outer tube 330 relative to the inner tube 320. This prevents the relative positions of the outer tube 330 and the inner tube 320 from shifting when introducing the medical device 3 into the coronary artery, thus improving operability.

[0076] The cover 524 has a female threaded portion 524b that screws into a male threaded portion 524a formed on the outer surface of the base end of the main body portion 521. The female threaded portion 524b rotates relative to the male threaded portion 524a, and these threaded portions screw into each other, thereby enabling the valve body 523 to be opened and closed radially inward.

[0077] The materials constituting the main body 521 and the lid 524 are not particularly limited, and for example, polyvinyl chloride, polyethylene, polypropylene, cyclic polyolefin, polystyrene, poly-(4-methylpentene-1), polycarbonate, acrylic resin, polyester such as acrylonitrile-butadiene-styrene copolymer, polyethylene terephthalate, polyethylene naphthalate, butadiene-styrene copolymer, polyamide (e.g., nylon 6, nylon 6.6, nylon 6.10, nylon 12), etc. can be used.

[0078] The base shaft 530 has a hollow pipe shape through which the inner tube 320 can be inserted. The base shaft 530 can be made of, for example, stainless steel, nitinol, or the like.

[0079] The inner tube 320 is inserted into the inner tube hub 540 together with the base shaft 530. The inner tube hub 540 is connected to the base ends of the base shaft 530 and the inner tube 320.

[0080] Examples of materials that make up the inner tube hub 540 include thermoplastic resins such as polycarbonate, polyamide, polysulfone, polyarylate, and methacrylate styrene copolymer.

[0081] A gripping portion 550 is provided on the outer circumference of the part where the base shaft 530 and the inner tube hub 540 are connected. The gripping portion 550 is the part that the operator grips when operating the hand-operated unit 500, and its outer surface may be treated with knurling or the like for anti-slip purposes.

[0082] The total length of the medical device 4 according to the second embodiment is preferably 30 cm or less. With this configuration, the medical device 4 can be suitably accessed up to the stenotic portion N of the coronary artery V under thoracotomy.

[0083] Next, with reference to Figures 9 and 10, the method of using the medical device 4 according to the second embodiment will be described. Here, a procedure for dilating a stenosis N formed in the coronary artery (blood vessel) V under open chest surgery will be described.

[0084] First, the surgeon creates a hole in coronary artery V using a scalpel or similar instrument.

[0085] Next, the surgeon inserts the medical device 4 into the coronary artery V, expanding the hole created above with a sheath or the like as needed. At this time, the medical device 4 is inserted until the stent 400 is positioned near the stenosis N. If the outer tube 330 has markings, the outer tube 330 inserted through the hole can be easily positioned near the stenosis N.

[0086] Next, as shown in Figure 9, the surgeon moves the outer tube 330 toward the proximal end relative to the inner tube 320. As a result, as shown in Figure 10, the stent 400 expands and deforms radially outward, and compresses against the stenotic portion N.

[0087] <Modification 1 of the Second Embodiment> Next, the medical device 5 according to Modification 1 of the Second Embodiment described above will be explained with reference to Figure 11. The medical device 5 according to Modification 1 of the Second Embodiment differs from the medical device 4 according to the Second Embodiment in that, as shown in Figure 11, a puncture portion 337 is formed at the tip of the outer tube 335.

[0088] In the second embodiment described above, a hole was made in the coronary artery V using a scalpel or the like. However, in the medical device 5 according to Modification 1 of the second embodiment, a puncture portion 337 is formed at the tip, so a hole can be made in the coronary artery V with the medical device 5. Therefore, a scalpel is not required, and the medical device 5 can be used to puncture and then inserted directly into the coronary artery V, improving work efficiency.

[0089] Although the medical device and method of use according to the present invention have been described above through embodiments and modifications, the present invention is not limited to the configurations described in the embodiments and modifications, and can be modified as appropriate based on the claims.

[0090] In the second embodiment described above, the inner tube 320 was made of solid material, but the inner tube may be made of hollow material. In this case, the medical device may be inserted into the coronary artery along a guide wire that has been previously inserted into the coronary artery. Furthermore, the dilator may be inserted into the coronary artery V with the overall rigidity increased while the dilator is inserted into the medical device, and then the dilator may be removed.

[0091] <Third Embodiment> Next, a third embodiment will be described. The medical device shown in this embodiment differs from the medical device 1 of the first embodiment in that it does not have a stent 70 corresponding to an expansion portion on the outer circumference of the balloon 40. Other common parts may be configured in the same way as the medical devices 1, 3, and 4 shown in the embodiments described above, and the balloon is fixed to the inner diameter shaft and configured to receive the working fluid F inside the balloon. After the medical device is appropriately positioned in the coronary artery, when the working fluid F is supplied, the balloon expands and the inner surface of the coronary artery comes into contact with the balloon and is pressed, and the stenosis N is expanded. The balloon expands by injecting fluid using an injection device such as an indeflater (not shown). In this embodiment, the balloon corresponds to the expansion portion, and the injection device corresponds to the expansion means.

[0092] The balloon in this embodiment may be configured as a drug-coated balloon (DCB) with a coating layer containing a drug on its outer surface. When the balloon expands within the coronary artery, the inner surface of the coronary artery wall is pressed against it, and as the stenosis N expands, the coating layer follows the balloon surface and comes into contact with the inner surface of the coronary artery wall, and the drug in the coating layer is applied to the contact area. The stenosis N carries a risk of restenosis with balloon expansion alone, but by including a drug with a restenosis-preventing effect in the coating layer, the risk of restenosis can be reduced. The drug-coated balloon may be designed to have both sufficient hardness to press against the stenosis N and sufficient flexibility to allow the drug in the coating layer to be applied, but this can be appropriately adjusted depending on the composition of the coating layer and the drug used.

[0093] The drugs contained in the drug layer include immunosuppressants, such as cyclosporines including cyclosporine; immunostimulants such as rapamycin; anticancer drugs such as paclitaxel; antiviral or antibacterial agents; anti-neoplastic agents; analgesics and anti-inflammatory agents; antibiotics; antiepileptic agents; anxiety relievers; antiparalytic agents; antagonists; neuron blockers; anticholinergic agents and cholinergic agents; antimuscarinic agents and muscarinic agents; anti-adrenergic agents; antiarrhythmic agents; antihypertensive agents; hormones; and nutritional supplements. The balloon surface and the coating layer can have various shapes, but when the outer surface of the balloon is made smooth and the coating layer is formed by crystallization on a non-porous surface, the outer surface of the balloon may be made smooth and the coating layer may be formed on minute pores that do not penetrate the surface. The minute pores may have an outer diameter of 0.1 to 5 μm and a depth of 0.1 to 10 μm, for example, and are formed as appropriate depending on the drug and treatment. The drug used in this case may be a water-insoluble drug and may be selected from the group consisting of rapamycin, paclitaxel, docetaxel, everolimus, etc.

[0094] Furthermore, the coating layer may be a gelled layer, composed of an amphiphilic polymer compound, from which the drug is released. An amphiphilic polymer compound is a polymer compound that possesses both hydrophilic and hydrophobic parts, and is characterized by its solubility in many organic solvents in addition to water. Examples of such amphiphilic polymer compounds include homopolymers or copolymers of alkylacrylamides such as N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-dimethylaminopropylacrylamide, and acryloylmorpholine; copolymers of vinyl methyl ether and maleic anhydride derivatives; random, graft, or block copolymers of hydrophilic monomers and hydrophobic monomers, for example, copolymers of N-vinylpyrrolidone, (meth)acrylic acid, N,N-dimethylaminoethyl acrylate, and styrene sulfonic acid as hydrophilic monomers, and copolymers of (meth)acrylic acid esters as hydrophobic monomers; and block copolymers of polyethylene glycol and polypropylene glycol. The thickness of the gelled layer is preferably 1 μm or more when dry in order to maintain strength. The drugs used in this embodiment are not particularly limited, as long as they are used for the treatment or prevention of lesions. For example, in the case of vascular stenosis as mentioned above, thrombolytic agents such as urokinase, prourokinase, streptokinase, and plasminogen activator are commonly used, as well as heparin, warfarin, and aspirin. Drugs that suppress the proliferation of smooth muscle cells and vectors for gene therapy can also be administered. Furthermore, the outer surface of the balloon may be porous, and the coating layer may be in the form of a drug infiltrating the porous surface. Alternatively, a photoreactive drug whose properties can be controlled by irradiation with light of a specific wavelength may be applied, allowing for suitable drug control.

[0095] As described above, the total length of the medical device in this embodiment may be set to 30 cm or less as appropriate. With this configuration, the medical device 1 can be suitably accessed to the stenosis N of the coronary artery V under open-chest surgery. In other words, according to this embodiment, the access time to the stenosis N of the coronary artery V is shortened, and the balloon can be positioned more precisely than in conventional treatment methods. Therefore, even in cases where it was difficult to access the stenosis N with conventional techniques, it becomes possible to appropriately position the medical device and apply drugs via the balloon surface. Specifically, drugs that were difficult to adhere to the balloon surface with conventional techniques and were difficult to deliver due to the time and resistance to reach the stenosis N can now be easily and reliably applied to the inner surface of the coronary artery wall requiring treatment. Furthermore, misplacement, misadministration, and unnecessary drug scattering to other parts other than the stenosis N can be prevented, thus enabling safe treatment with reduced risk of side effects. Although this device and the treatment method using this device are described as being suitable for the treatment of coronary artery stenosis, the drugs contained in the coating layer are not limited to those that have an effect of preventing restenosis, and may be used for other diseases and treatment methods by adjusting them as appropriate.

[0096] This application is based on Japanese Patent Application No. 2024-169880, filed on 30 September 2024, the disclosures of which are cited in their entirety by reference.

[0097] 1, 2, 3, 4, 5 Medical device, 10 Outer shaft (conduit), 14 Graduation, 20 Inner shaft (conduit), 40 Balloon (expansion means), 70 Stent (expansion part), 130, 337 Puncture site, 320 Inner tube (conduit), 330, 335 Outer tube (conduit), 400 Stent (expansion part), H Heart, V Coronary artery, N Stenosis.

Claims

1. A medical device comprising a conduit that penetrates the wall of a coronary artery and is inserted into the coronary artery, and an expandable expander provided at the tip of the conduit, wherein the expander expands a stenosis formed in the coronary artery.

2. The medical device according to claim 1, wherein the total length is 30 cm or less.

3. The medical device according to claim 1 or 2, wherein a puncture portion is formed at the tip of the conduit.

4. The medical device according to claim 1 or 2, further comprising an expansion means for expanding the expansion portion, wherein the expansion means is a balloon that can be expanded by supplying a pressurized medium, and the expansion portion is a stent that is expanded by the balloon.

5. The medical device according to claim 1 or 2, wherein the expansion portion is a self-expanding stent.

6. The medical device according to claim 1 or 2, wherein the conduit has a scale formed thereon that allows for the determination of the distance traveled by the expanded portion.

7. A method for dilating a narrowed portion of a blood vessel during open-chest surgery, comprising: opening the chest of a patient; puncturing the blood vessel near the narrowed portion; inserting a conduit equipped with an expander at its tip into the blood vessel; transporting the expander to the narrowed portion within the blood vessel; and dilating the narrowed portion by expanding the expander.

8. The dilation method according to claim 7, wherein a bypass surgery is performed after the thoracotomy is performed on the patient.

9. The dilation method according to claim 7 or 8, wherein the thoracotomy is performed on the patient while extracorporeal circulation is being performed.

10. The medical device according to claim 1, further comprising a coating layer containing a drug formed on the surface of the extended portion.

Images