WO2014162400A1

WO2014162400A1 - Stent delivery system

Info

Publication number: WO2014162400A1
Application number: PCT/JP2013/059853
Authority: WO
Inventors: 東洋; 宇佐美宏佳; 宮崎郁
Original assignee: テルモ株式会社
Priority date: 2013-04-01
Filing date: 2013-04-01
Publication date: 2014-10-09
Also published as: JPWO2014162400A1; JP6097821B2

Abstract

The purpose of the present invention is to provide a stent delivery system whereby a drug can be effectively applied to a stent. A stent delivery system (10) having a tubular sheath (30) provided with an accommodating part (31) capable of accommodating a contracted self-expandable stent (20) in the inside thereof, an inner tube (40) provided with a stent-pushing protruding part (46) inserted into the sheath (30) and capable of abutting on the stent (20) and pressing the stent (20) in a distal end direction, and a drug containing body (D) including a drug and being capable of adhering to the stent (20), the drug containing body (D) being provided at a position including at least a most-distal-end part of the stent (20) on an inside face of the accommodating part (31) or a position more toward a distal end than the most-distal-end part of the stent (20).

Description

Stent delivery system

The present invention relates to a stent delivery system for maintaining a patency state of a lumen by placing a stent in a stenosis portion or an occlusion portion generated in a living body lumen.

In recent years, for example, in the treatment of myocardial infarction and angina pectoris, a method of securing a space in a coronary artery by placing a stent in a lesion (stenosis) of a coronary artery has been performed, and other blood vessels, bile ducts, trachea, A similar method may be used to improve stenosis in the esophagus, urethra, and other living body lumens. Stents are classified into balloon-expandable stents and self-expandable stents by function and placement method.

The balloon-expandable stent does not have an expansion function in the stent itself, and is inserted into a target site, expanded with a balloon, and is plastically deformed to be closely fixed in the lumen. On the other hand, a self-expanding stent has an expansion function, and is accommodated in a catheter with a reduced diameter in advance, and after reaching the target site, the reduced diameter state is released and expanded. It is tightly fixed in the cavity. For example, in Patent Document 1, a self-expanding stent having a reduced diameter is accommodated inside the outer sheath, and an inner shaft having a stopper capable of coming into contact with the stent is inserted into the outer sheath. A method is described in which the stent is pushed out of the outer sheath and expanded by pulling the outer sheath forward while the movement of the stent is restricted by a stopper at the target site.

JP 11-313893 A

However, even when the stent as described above is placed at the target site and the stenosis is expanded, restenosis may occur at the site where the stent is placed. Since the main cause of restenosis is the growth of the intima, which is a healing reaction of the vessel wall, recently, a drug capable of suppressing the intima growth is coated on the outer surface of the stent, and the stent placement site Development of a drug-eluting stent called DES (Drug Eluting Stents), which elutes the drug and prevents restenosis, has been carried out, and when the stent is released from the outer sheath, There is a possibility that the drug is peeled off due to the friction, and the drug cannot be sufficiently applied to the living body lumen.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a stent delivery system capable of effectively applying a drug to a stent.

A stent delivery system according to the present invention that achieves the above object includes a tubular sheath having a housing portion capable of housing a reduced-diameter self-expanding stent therein, and the sheath is inserted into the sheath. A shaft having a contact portion that can contact the stent and press the stent in the distal direction, and a position on the inner surface of the housing portion that includes at least the most distal end portion of the stent or the distal end side of the most distal end portion of the stent And a drug-containing body that contains a drug and can adhere to the stent.

In the stent delivery system configured as described above, a drug-containing body containing a drug is provided at a position including at least the most distal end portion of the stent or on the distal end side of the most distal end portion of the stent, on the inner surface of the accommodating portion. When the stent is moved in the distal direction relative to the sheath by the contact portion and released from the sheath, the entire portion from the distal end portion to the proximal end portion of the stent comes into contact with the drug-containing body and the drug-containing body is attached. The drug can be effectively applied to the stent.

If the drug-containing body contains a water-swellable polymer material, the water-swellable polymer material absorbs water and swells by contact with physiological saline or blood, so that the stent becomes a gel. When released, it becomes easy to come into contact with the stent and effectively adheres to the stent so that the drug-containing body is entangled.

By moving the stent relative to the sheath in the distal direction, if the drug-containing body is provided on the distal end side of the innermost surface of the housing portion relative to the most distal portion of the stent, The drug-containing body can be effectively attached to the entire stent. In addition, since the drug-containing body is provided on the distal end side of the most distal end portion of the stent, the drug-containing body is easily accessible from the distal end opening of the sheath and can be easily applied to the sheath.

If the concave portion for accommodating the drug-containing body is formed on the inner surface of the sheath, the drug-containing body can be satisfactorily held, and when the stent moves in the distal direction relative to the sheath, The drug-containing body can be attached to the stent little by little, and the drug-containing body can be uniformly attached to the entire stent.

If the concave portion is formed at the most distal end portion of the sheath, the stent to which the drug-containing body is attached after passing through the concave portion is directly in the sheath without contacting any portion of the stent delivery system. Therefore, the drug-containing body attached to the stent can be effectively maintained. In addition, since the concave portion is formed at the most distal end portion of the sheath, the concave portion can be easily accessed from the opening at the distal end of the sheath, and the drug-containing body can be easily applied to the concave portion of the sheath.

If the drug-containing body has different drug concentrations depending on the site, the amount of drug attached to the stent can be freely adjusted.

If the concave-convex structure is formed on the outer surface of the stent strut, the drug-containing body can be effectively attached to the stent.

It is a top view showing the stent delivery system concerning a 1st embodiment. It is sectional drawing which shows the front-end | tip part of the stent delivery system which concerns on 1st Embodiment. It is a top view when a self-expanding stent is expanded. It is an expanded view when the self-expanding stent is reduced in diameter. It is sectional drawing which shows the time of indwelling a stent in a biological lumen with the stent delivery system which concerns on 1st Embodiment. It is sectional drawing which shows the modification of the stent delivery system which concerns on 1st Embodiment. It is sectional drawing which shows the other modification of the stent delivery system which concerns on 1st Embodiment. It is sectional drawing which shows the front-end | tip part of the stent delivery system which concerns on 2nd Embodiment. It is sectional drawing which shows the time of indwelling a stent in the biological body with the stent delivery system which concerns on 2nd Embodiment. It is sectional drawing which shows the modification of the stent delivery system which concerns on 2nd Embodiment. It is sectional drawing which shows the other modification of the stent delivery system which concerns on 2nd Embodiment. It is sectional drawing which shows the further another modification of the stent delivery system which concerns on 2nd Embodiment. It is sectional drawing which shows the further another modification of the stent delivery system which concerns on 2nd Embodiment. It is a perspective view which shows the modification of a stent.

Embodiments of the present invention will be described below with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.
<First Embodiment>

The stent delivery system 10 according to the first embodiment of the present invention includes a stent 20 placed in a stenosis or occlusion in a blood vessel, bile duct, trachea, esophagus, urethra, or other living body lumen. As shown in FIGS. 1 and 2, the stent 20, the tubular sheath 30 that houses the stent 20, and the slidably inserted through the sheath 30, as shown in FIGS. And an inner tube 40 (shaft) provided with a stent extruding protrusion 46 (contact portion) that can press in the distal direction. In this specification, the side to be inserted into the lumen is referred to as “tip” or “tip side”, and the proximal side to be operated is referred to as “base end” or “base end side”.

As shown in FIGS. 3 and 4, the stent 20 is a so-called self-expanding stent that expands by its own elastic force, and includes a strut 21 that extends thinly and linearly.

The strut 21 arranges a plurality of annular portions 22 formed in an annular shape while the wire rod is folded back in the central axis direction, and a plurality of shared portions 23 shared between the annular portions 22 adjacent to each other. Are integrated into a single cylindrical shape as a whole. The cross-sectional shape orthogonal to the extending direction of the strut 21 is a rectangular shape. Note that the number of the annular portions 22 is not particularly limited.

The stent 20 varies depending on the site to be placed, but generally has an outer diameter of 1.5 to 30 mm, preferably 2.0 to 20 mm, and a wall thickness of 0.04 at the time of expansion (when the diameter is not reduced or restored). The length is from 1.0 to 1.0 mm, preferably from 0.06 to 0.5 mm, and the length is from 5 to 250 mm, preferably from 10 to 200 mm.

The strut 21 is preferably integrally formed in a substantially cylindrical shape with a superelastic metal exhibiting superelasticity before and after insertion into the living body.

A super elastic alloy is preferably used as the super elastic metal. The superelastic alloy here is generally called a shape memory alloy, and exhibits superelasticity at least at a living body temperature (around 37 ° C.). Preferably, a TiNi alloy of 49-54 atomic% Ni, a Cu-Zn alloy of 38.5-41.5 wt% Zn, a Cu-Zn-X alloy of 1-10 wt% X (X = Be, Si, Sn) , Al, Ga), and a superelastic alloy such as a 36-38 atomic% Al Ni—Al alloy. The TiNi alloy is particularly preferable. Further, a Ti—Ni—X alloy (X = Co, Fe, Mn, Cr, V, Al, Nb, W, B, part of Ti—Ni alloy substituted with 0.01 to 10.0 wt% X, Au, Pd, etc.) or a Ti—Ni—X alloy (X = Cu, Pb, Zr) in which a part of the Ti—Ni alloy is substituted with 0.01 to 30.0 atomic%, By selecting the cold working rate or / and the final heat treatment conditions, the mechanical properties can be appropriately changed.

The buckling strength (yield stress during loading) of the superelastic alloy used is 5 to 200 kg / mm ² (22 ° C.), preferably 8 to 150 kg / mm ^2. Restoring stress (yield during unloading) The stress is 3 to 180 kg / mm ² (22 ° C.), preferably 5 to 130 kg / mm ² . Superelasticity here means that even if it is deformed (bending, pulling, compressing) to the region where ordinary metal plastically deforms at the operating temperature, it will recover to its original shape without requiring heating after releasing the load. Means that.

Then, the strut 21 is produced by removing (for example, cutting, melting) the non-strut portion using, for example, a super elastic alloy pipe, thereby forming an integrally formed product. The superelastic metal pipe used for forming the strut 21 is formed by forming an ingot of a superelastic alloy in an inert gas or vacuum atmosphere, mechanically polishing the ingot, and then hot pressing and extruding. By forming a large-diameter pipe, and then successively repeating the die drawing process and heat treatment process, the pipe is reduced to a predetermined thickness and outer diameter, and finally the surface is chemically or physically polished. Can be manufactured. And formation of the strut 21 by this superelastic alloy pipe can be performed by cutting (for example, mechanical polishing, laser cutting), electric discharge machining, chemical etching, etc., and may be performed by using them together.

As shown in FIGS. 1 and 2, the sheath 30 is open at the distal end and the proximal end, and is provided with an accommodating portion 31 that can accommodate the stent 20 inside the distal end side. The distal end opening functions as a discharge port of the stent 20 when the stent 20 is placed in a stenosis in the living body lumen. A drug-containing body D containing a drug and a water-swellable polymer material is applied to the entire surface in contact with the stent 20 on the inner surface of the container 31. The stent 20 is accommodated in the accommodating portion 31 in a state of being reduced in diameter. When the stent 20 is pushed out from the opening at the distal end, the stress load is released, and the stent 20 expands by its own elastic force and restores its shape before compression.

Examples of the drug contained in the drug-containing body D include anticancer drugs, immunosuppressive drugs, antibiotics, anti-rheumatic drugs, antithrombotic drugs, HMG-CoA reductase inhibitors, insulin resistance improvers, ACE inhibitors, calcium antagonists. Agent, antihyperlipidemic agent, integrin inhibitor, antiallergic agent, antioxidant, GP IIb / IIIa antagonist, retinoid, flavonoid, carotenoid, lipid improver, DNA synthesis inhibitor, tyrosine kinase inhibitor, antiplatelet Examples include drugs, anti-inflammatory drugs, biological materials, interferons, and nitric oxide production promoting substances.

Examples of the anticancer agent include vincristine, vinblastine, vindesine, irinotecan, pirarubicin, paclitaxel, docetaxel, and methotrexate. The immunosuppressive agent is, for example, sirolimus derivatives such as sirolimus, everolimus, pimecrolimus, zotarolimus, biolimus, AP23573, CCI-779, tacrolimus, azathioprine, cyclosporine, cyclophosphamide, mycophenolate mofetil, gusperimus, mizoribine, doxorubicin .

Antibiotics are, for example, mitomycin, actinomycin, daunorubicin, idarubicin, pirarubicin, aclarubicin, epirubicin, peplomycin, dinostatin styramer, vancomycin. Anti-rheumatic agents are, for example, methotrexate, sodium thiomalate, penicillamine, lobenzarit. Antithrombotic agents are, for example, heparin, aspirin, antithrompine preparations, ticlopidine, hirudin.

Examples of the HMG-CoA reductase inhibitor include cerivastatin, cerivastatin sodium, atorvastatin, atorvastatin calcium, rosuvastatin, rosuvastatin calcium, pitavastatin, pitavastatin calcium, fluvastatin, fluvastatin sodium, simvastatin, lovastatin, pravastatin, pravastatin sodium.

The insulin resistance improving agent is, for example, a thiazolidine derivative such as troglitazone, rosiglitazone, or pioglitazone. Examples of the ACE inhibitor include quinapril, perindopril erbumine, trandolapril, cilazapril, temocapril, delapril, enalapril maleate, ricinopril, and captopril. Calcium antagonists are, for example, nifedipine, nilvadipine, diltiazem, benidipine, nisoldipine.

Antihyperlipidemic agents are, for example, bezafibrate, fenofibrate, ezetimibe, torcetrapib, pactimib, K-604, imputapide, probucol.

The integrin inhibitor is, for example, AJM300. The antiallergic agent is, for example, tranilast. Antioxidants are, for example, α-tocopherol, catechin, dibutylhydroxytoluene, butylhydroxyanisole. The GP IIb / IIIa antagonist is, for example, abciximab. The retinoid is, for example, all-trans retinoic acid. Flavonoids are, for example, epigallocatechin, anthocyanins, proanthocyanidins. Examples of carotenoids are β-carotene and lycopene.

The lipid improving agent is, for example, eicosapentaenoic acid. An example of the DNA synthesis inhibitor is 5-FU. Tyrosine kinase inhibitors are, for example, genistein, tyrphostin, arbustatin, staurosporine. Antiplatelet drugs are, for example, ticlopidine, cilostazol, clopidogrel. The anti-inflammatory agent is, for example, a steroid such as dexamethasone or prednisolone.

The biological material is, for example, EGF (Epidmal Growth Factor), VEGF (Vascular Endower Growth Factor), HGF (Hepatocyte Growth Factor, PDGF (Plateletgratebetter). The interferon is, for example, interferon-γ1a. The nitric oxide production promoting substance is, for example, L-arginine.

In addition, paclitaxel, docetaxel, sirolimus, and everolimus are preferable, and sirolimus and paclitaxel are particularly preferable from the viewpoint that they are generally used for stenosis treatment and can be efficiently transferred into cells in a short time.

The water-swellable polymer material contained in the drug-containing body D plays a role of supporting the drug, swells when contacted with physiological saline or blood, swells, becomes a gel, and adheres to the stent 20 It plays a role in improving sex. Examples of the water-swellable polymer material include polyvinyl alcohol, polyethylene glycol, sodium polyacrylate, topological gel, and the like.

Further, a sheath hub 50 is fixed to the proximal end portion of the sheath 30. The sheath hub 50 includes a sheath hub main body 51 and a valve body (not shown) that is accommodated in the sheath hub main body 51 and that holds the inner tube 40 in a fluid-tight manner. In addition, the sheath hub 50 includes a side port 52 that branches obliquely rearward from the vicinity of the center of the sheath hub body 51. Moreover, it is preferable that the sheath hub 50 includes an inner tube lock mechanism that restricts movement of the inner tube 40.

The inner tube 40 is provided at the shaft-shaped inner tube main body portion 41, the inner tube main body portion 41 at the distal end, and protrudes from the distal end of the sheath 30. And a fixed inner pipe hub 43.

The inner tube tip 42 is formed in a taper shape that protrudes from the tip of the sheath 30 and gradually decreases in diameter toward the tip. By forming in this way, the insertion into the constricted portion becomes easy. Further, the inner tube distal end portion 42 has a proximal end capable of contacting the distal end of the sheath 30 and functions as a stopper that prevents the sheath 30 from moving in the distal end direction.

A stent holding projection 45 is provided on the proximal end side of the inner tube distal end portion 42 of the inner tube 40. A stent push-out protrusion 46 is provided on the proximal end side from the stent holding protrusion 45 by a predetermined distance. The stent 20 is disposed between the two

protrusions

45 and 46. The

protrusions

45 and 46 are preferably annular protrusions. The outer diameters of these

protrusions

45 and 46 are large enough to contact the compressed stent 20. For this reason, the movement of the stent 20 toward the distal end side is restricted by the stent holding protrusion 45 and the movement toward the proximal end is restricted by the stent push-out protrusion 46. When the sheath 30 is moved to the proximal side while the position of the inner tube 40 is maintained, the movement of the stent 20 to the proximal side is regulated by the stent push-out projection 46, and the stent 20 is moved to the inner surface of the sheath 30. And is discharged from the distal end opening of the sheath 30. Furthermore, it is preferable that the proximal end side of the stent push-out protrusion 46 is a tapered portion 46A that gradually decreases in diameter toward the proximal end side. Similarly, the proximal end side of the stent holding protrusion 45 is preferably a tapered portion 45A that gradually decreases in diameter toward the proximal end side. By doing so, the sheath 30 is moved to the proximal end side with respect to the inner tube 40, and after the stent 20 is released from the sheath 30, the sheath 30 is moved to the distal end side to move the inner tube 40 into the sheath 30. When re-accommodating, the

protrusions

45 and 46 can be prevented from being caught by the tip of the sheath 30. Moreover, the two

protrusions

45 and 46 may be formed of separate members made of an X-ray contrast material. Thereby, the position of the stent 20 can be accurately grasped under X-ray contrast, and the procedure becomes easier.

The inner tube 40 penetrates through the sheath 30 and protrudes from the proximal end opening of the sheath 30. An inner tube hub 43 is fixed to the proximal end portion of the inner tube 40. The inner tube 40 is formed with a lumen 44 through which a guide wire is inserted extending from the distal end to the proximal end. The lumen 44 may be formed so as to open from the tip of the inner tube 40 to the side in the middle of the inner tube 40.

The sheath 30 is preferably formed of a material having a certain degree of flexibility. Examples of such a material include polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, Polyolefins such as ionomers or a mixture of two or more of these, soft polyvinyl chloride resins, polyamides, polyamide elastomers, polyesters, polyester elastomers, polyurethanes, polytetrafluoroethylene and other fluororesins, silicone rubbers, latex rubbers, etc. can be used .

The inner tube 40 can be made of the same material as the sheath 30 or a metal material. The metal material is, for example, stainless steel or Ni—Ti alloy.

The sheath hub 50 and the inner tube hub 43 can be made of, for example, a resin material such as polycarbonate, polyolefin, styrene resin, or polyester, or a metal material such as stainless steel, aluminum, or an aluminum alloy.

Next, a method for placing the stent 20 in a living body lumen (for example, a blood vessel) using the stent delivery system 10 will be described.

First, the stent 20 having a diameter reduced toward the central axis is accommodated in the accommodating portion 31 on the distal end side of the sheath 30, and the stent extruding protrusion 46 of the inner tube 40 is positioned on the proximal end side of the stent 20. The inside of the sheath 30 and the inside of the inner tube 40 are filled with physiological saline. In particular, by filling the inside of the sheath 30 (the inner surface of the accommodating portion 31) with physiological saline, a drug-containing body D described later becomes a gel.

Next, a sheath introducer is placed in the patient's blood vessel by, for example, the Seldinger method, and the guide wire and the stent delivery system 10 are inserted into the blood vessel from the inside of the sheath introducer while the guide wire is inserted into the guide wire lumen 44. Insert inside. Subsequently, the stent delivery system 10 is advanced while the guide wire is advanced, and the distal end of the sheath 30 reaches the stenosis.

Thereafter, while holding the inner tube hub 43 by hand and holding the stent extruding protrusion 46 from moving to the proximal end side, the sheath hub 50 is pulled and moved to the proximal end side to move toward the proximal end. The stent 20 is released from the 30 tip opening so as to be pushed out by the stent extruding protrusion 46. As a result, as shown in FIG. 5, the stent 20 is released from the stress load, expands by its own elastic force, and is restored to the shape before compression. Thereby, the stenosis part S can be favorably maintained in a state where the stent 20 is expanded by the stent 20.

And since the medicine containing body D currently apply | coated to the inner surface of the accommodating part 31 contains the water-swellable polymeric material, when it contacts with physiological saline and blood, it absorbs water and swells and becomes gel form. . For this reason, when the stent 20 is released, the drug-containing body D easily comes into contact with the stent 20 and adheres to the stent 20 so as to be entangled. At this time, since the drug-containing body D is applied to the entire surface in contact with the stent 20 on the inner surface of the housing portion 31, the drug-containing body D can be effectively attached to the entire stent 20. Then, the stent 20 to which the drug-containing body D containing the drug is attached is placed in the living body lumen, so that the occurrence of restenosis and delayed stent thrombosis after the placement of the stent 20 can be effectively suppressed.

After the stent 20 is placed in the living body lumen, the guide wire and the stent delivery system 10 are removed from the blood vessel via the sheath introducer, and the procedure is completed.

As described above, the stent delivery system 10 according to the first embodiment includes the tubular sheath 30 including the accommodating portion 31 that can accommodate the reduced-diameter self-expanding stent 20 therein, and the sheath 30. Of the inner tube 40 (shaft) having a stent extruding protrusion 46 (contact portion) that is inserted and can contact the stent 20 and press the stent 20 in the distal direction, and the inner surface of the accommodating portion 31, the stent 20 and a drug-containing body D that is provided at a position including at least the most distal end portion and contains a drug and can be attached to the stent 20. For this reason, when the stent 20 is released from the sheath 30, the stent extruding protrusion 46 moves the stent relative to the sheath 30 in the distal direction, so that the drug-containing body D is transferred to the entire stent 20. It can be attached effectively. Then, the stent 20 to which the drug-containing body D containing the drug is attached is placed in the living body lumen, so that the occurrence of restenosis and delayed stent thrombosis after the placement of the stent 20 can be effectively suppressed.

In addition, since the drug-containing body D contains a water-swellable polymer material and swells and gels by absorbing water in contact with physiological saline or blood, the stent 20 is released when the stent 20 is released. It becomes easy to contact 20 and adheres effectively to the stent 20 so that the drug-containing body D is entangled.

Note that the drug-containing body D does not have to be applied to the entire inner surface of the housing portion 31, and at least the most distal portion of the stent 20 on the inner surface of the housing portion 31, for example, as in the modification shown in FIG. 6. What is necessary is just to apply | coat to the position containing. In this way, even when the drug-containing body D is not applied to the entire surface of the accommodating portion 31, the stent 20 moves in the distal direction relative to the sheath 30 when the stent 20 is released from the sheath 30. Thus, the entire stent 20 inevitably passes through the site where the drug-containing body D is applied. For this reason, the drug-containing body D can be adhered to the entire outer surface of the stent 20 without applying the drug-containing body D to the entire surface of the housing portion 31.

Further, for example, as in another modification shown in FIG. 7, an annular recess 62 capable of accommodating the drug-containing body D may be formed in the accommodating portion 61 of the sheath 60. If the concave portion 62 is formed, the drug-containing body D can be satisfactorily held in the sheath 60, and the drug-containing body D can be attached to the stent 20 little by little when the stent 20 moves in the housing portion 61. The drug-containing body D can be more uniformly attached to the entire stent 20. In addition, by providing the recess 62, peeling of the drug-containing body D can be suppressed when the stent 20 whose diameter has been reduced after the drug-containing body D is applied to the recess 62 is stored in the storage section 61. Note that the drug-containing body D can be applied to the inner surface of the sheath 60 from the gap between the struts 21 of the stent 20 after the stent 20 is accommodated in the accommodating portion 61.
Second Embodiment

The stent delivery system 70 according to the second embodiment of the present invention is different from the stent delivery system 10 according to the first embodiment in the site where the drug-containing body D of the sheath 80 is provided. In addition, in order to avoid duplication, the description which abbreviate | omits duplication is attached | subjected to the site | part which has the same function as 1st Embodiment.

As shown in FIG. 8, the sheath 80 of the stent delivery system 70 is provided with an accommodating portion 81 that can accommodate the stent 20 inside the distal end side, and an annular concave portion 82 is provided on the inner surface at the distal end side of the accommodating portion 81. . The concave portion 82 is provided from the distal end side to the most distal end surface 83 of the sheath 80 from the most distal end portion of the stent 20 when the stent 20 is accommodated in the accommodating portion 81, and is formed in a stepped shape. Then, a drug-containing body D containing a drug and a water-swellable polymer material is applied to the recess 82.

When the stent 20 is indwelled in the living body lumen using the stent delivery system 70, the sheath 80 is moved to the proximal side while holding the inner tube 40 so that the stent extruding protrusion 46 does not move to the proximal side. The stent 20 is ejected from the distal end opening of the sheath 30 so as to be pushed out by the protrusion 46 for pushing out the stent. As shown in FIG. 9, the stent 20 is released from the stress load, expands by its own elastic force, and restores the shape before compression. Thereby, the stenosis part S can be favorably maintained in a state where the stent 20 is expanded by the stent 20.

Since the drug-containing body D applied to the recess 82 contains a water-swellable polymer material, the drug-containing body D swells by absorbing water when it comes into contact with physiological saline or blood, and becomes a gel. For this reason, when the stent 20 is released, the drug-containing body D easily comes into contact with the stent 20 and adheres to the stent 20 so that the drug-containing body D is entangled. Note that the drug-containing body D is provided in the recess 82 on the distal end side relative to the housing portion 81, and the stent 20 is not in contact with the drug-containing body D in a state where the stent 20 is housed in the housing portion. However, since the stent 20 passes through the recess 82 as the stent 20 moves in the distal direction relative to the sheath 30, the drug-containing body D is effectively attached to the entire stent 20. Can do. Then, the stent 20 to which the drug-containing body D containing the drug is attached is placed in the living body lumen, so that the occurrence of restenosis and delayed stent thrombosis after the placement of the stent 20 can be effectively suppressed.

And since the recessed part 82 is provided in the front end side (frontmost part of the sheath 80) rather than the accommodating part 81, it is easy to access the recessed part 82 from the front-end | tip opening of the sheath 80, and makes the chemical | medical agent containing body D apply | coat to the recessed part 82 easily. be able to. In addition, by providing the recess 82, peeling of the drug-containing body D can be suppressed when the stent 20 whose diameter has been reduced after the drug-containing body D is applied to the recess 82 is stored in the storage portion 61. The drug-containing body D can be applied to the recess 82 after the stent 20 is accommodated in the accommodating portion 81.

Moreover, since the recessed part 82 which accommodates the chemical | medical agent containing body D is formed in the inner surface of the sheath 80, while being able to hold | maintain the chemical | medical agent containing body D favorably in the sheath 80, when the stent 20 moves in the sheath 80, the chemical | medical agent is contained. The inclusion body D can be attached to the stent 20 little by little, and the drug-containing body D can be uniformly attached to the entire stent 20.

Further, since the concave portion 82 is formed at the most distal end portion of the sheath 80, the stent 20 to which the drug-containing body D is attached through the concave portion 82 does not come into contact with any portion of the stent delivery system 70. Since it is released as it is from the distal end opening of the sheath 80 into the living body lumen, the drug-containing body D attached to the stent 20 can be effectively maintained. Moreover, since the recessed part 82 is formed in the most distal part of the sheath 80, it is easy to access the recessed part 82 from the front-end | tip opening of the sheath 80, and the chemical | medical agent containing body D can be easily apply | coated to the recessed part 82. Therefore, for example, it is possible to apply the drug-containing body D to the recess 82 immediately before the operator uses the stent delivery system 70.

The drug-containing body D may be provided on the most distal surface 83 of the sheath 80, for example, as in the modification shown in FIG. Even in this case, since the stent 20 to which the drug-containing body D is attached after passing through the most distal surface 83 is released as it is from the distal end opening of the sheath 80 into the living body lumen, the drug-containing substance attached to the stent 20 is contained. The body D can be effectively maintained.

Also, the drug-containing body D may have different drug concentrations depending on the site. By varying the concentration of the drug according to the site, the amount of the drug attached to the stent 20 can be freely adjusted. In particular, since the amount of the drug-containing body D attached to the distal end side and the proximal end side of the stent 20 is likely to be different, the stent 20 is released by changing the concentration of the drug according to the site of the drug-containing body D. The amount of drug applied to the stent 20 can be made uniform. For example, in the modification shown in FIG. 11, the first drug-containing body D1, the second drug-containing body D2, the third drug-containing body D3, and the fourth drug-containing body from the bottom side (radially outer side) of the recess 82. D4 is provided, and the concentration of the drug can be gradually lowered from the drug-containing body D1 toward the drug-containing body D4. In this way, the low-concentration drug-containing body D4 is attached to the distal end portion of the stent 20 that first contacts with the drug-containing body and entangles many drug-containing bodies, and then contacts the drug-containing body and contains the drug. At the proximal end portion of the stent 20 where a large amount of body cannot be entangled, a high-concentration drug-containing body D1 is attached, and the amount of drug applied to the stent 20 can be made uniform. For example, in another modification shown in FIG. 12, the first drug-containing body D5, the second drug-containing body D6, the third drug-containing body D7, and the fourth drug-containing body from the proximal end side of the recess 82. D8 is provided, and the concentration of the drug can be gradually decreased from D5 to D8. In this way, a large amount of the drug-containing body D8 having a low concentration is attached to the distal end portion of the stent 20 that first contacts with the drug-containing body and entangles the drug-containing body in a large amount. At the proximal end portion of the stent 20 where a large amount of inclusions cannot be entangled, a large amount of the high-concentration drug-containing body D5 is attached, and the amount of the drug applied to the stent 20 can be made uniform. The number of parts having different concentrations is not limited. Further, the concentration of the drug-containing body may gradually change in an inclined manner.

Further, as shown in FIG. 13, a drug-containing body D is provided by providing a sponge-like porous body 84 made of a resin having open cells and flexibility in the recess 82, and containing the drug in the porous body 84. May be formed. Accordingly, the drug can be adhered to the stent 20 while being favorably held by the porous body 84. In this case, the porous body 84 may or may not contain a water-swellable polymer material. Further, a fiber assembly such as a non-woven fabric may be used instead of the sponge-like porous body.

Note that 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 idea of the present invention. For example, as shown in FIG. 14, a concavo-convex structure 93 may be formed on the outer surface 92 in contact with the living body lumen of the strut 91 of the stent 90. In the example shown in FIG. 14, the concavo-convex structure 93 includes a concave portion 94 and a surface 95 (convex portion) on which the concave portion 94 is formed. By forming the concavo-convex structure 93 on the outer surface 92, the drug-containing body D can be effectively attached to the outer surface 92 of the strut 91 of the stent 90. Moreover, the concavo-convex structure may be constituted by a convex portion and a surface (concave portion) on which the convex portion is formed. Moreover, you may make the surface roughness of the outer surface of a strut higher than another surface as an uneven | corrugated structure. The surface ancestry can be specified by the maximum height, ten-point average roughness, centerline average roughness, or the like shown in JIS standards.

Further, the stent may be a drug eluting stent in which a strut surface is coated with a drug-containing layer in advance.

Also, the various configurations described above can be applied in appropriate combination. Therefore, for example, the drug-containing body D of the stent delivery system 10 according to the first embodiment may have a different drug concentration depending on the site, and may be included in a porous body or a fiber assembly.

10,70 stent delivery system,
20,90 stent,
21,91 struts,
30, 60, 80 sheath,
31, 61, 81 accommodating part,
40 inner pipe,
46 Protrusion for stent extrusion (contact part),
62, 82 recess,
83 Cutting edge,
93 Uneven structure,
D, D1-D8 Drug-containing body.

Claims

A tubular sheath having a housing portion capable of housing a reduced-diameter self-expanding stent therein;
A shaft provided with a contact portion that is inserted into the sheath and is capable of pressing the stent in the distal direction in contact with the stent;
Of the inner surface of the housing portion, a position including at least the most distal end portion of the stent or a distal end side of the most distal end portion of the stent, and a drug-containing body that contains a drug and can be attached to the stent. Having a stent delivery system.
The stent delivery system according to claim 1, wherein the drug-containing body includes a water-swellable polymer material.
The stent delivery system according to claim 1 or 2, wherein the drug-containing body is provided on the distal end side of the innermost surface of the accommodating portion with respect to the most distal end portion of the stent.
The stent delivery system according to any one of claims 1 to 3, wherein a concave portion for accommodating the drug-containing body is formed on an inner surface of the sheath.
The stent delivery system according to claim 4, wherein the concave portion is formed at a most distal end portion of the sheath.
The stent delivery system according to any one of claims 1 to 5, wherein the drug-containing body has a different drug concentration depending on a site.
The stent delivery system according to any one of claims 1 to 6, wherein an uneven structure is formed on an outer surface of the strut of the stent.