JPH0724072A - Stent and its manufacturing method - Google Patents
Stent and its manufacturing methodInfo
- Publication number
- JPH0724072A JPH0724072A JP28574993A JP28574993A JPH0724072A JP H0724072 A JPH0724072 A JP H0724072A JP 28574993 A JP28574993 A JP 28574993A JP 28574993 A JP28574993 A JP 28574993A JP H0724072 A JPH0724072 A JP H0724072A
- Authority
- JP
- Japan
- Prior art keywords
- stent
- tetrafluoroethylene resin
- porous
- tubular structure
- tubular
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Media Introduction/Drainage Providing Device (AREA)
- Materials For Medical Uses (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、生体適合性に優れたス
テント及びステントの製造方法に関する。TECHNICAL FIELD The present invention relates to a stent having excellent biocompatibility and a method for manufacturing the stent.
【０００２】[0002]
【従来の技術】ステントは、収縮した管腔部分を拡張し
たり、管腔内に解放通路を設けるための装置であり、疾
病等によって狭窄した血管、尿管、消化管、気管等の管
腔状器官・組織の流路再開、例えば動脈硬化性閉塞症に
おける血流再開を目的として、臨床的に使用されてい
る。2. Description of the Related Art A stent is a device for expanding a contracted lumen portion or providing a release passage in the lumen, and is a lumen of a blood vessel, a ureter, a digestive tract, a trachea, etc. narrowed by a disease or the like. It is clinically used for the purpose of reopening the flow path of organs and tissues, for example, reopening the blood flow in arteriosclerotic obstruction.
【０００３】従来、ステントとして、弾性線材で構成さ
れた管状構造のもの（管状ステントまたはワイヤステン
ト）が知られている。ステントの材質としては、ステン
レス鋼ワイヤ等の金属線が好適に用いられ、これをコイ
ル状またはジグザグ状等に屈９曲及び接続して管状構造
を形成している。このような構造の管状ステントは、圧
縮して細長い形状にすることが可能である。Conventionally, as a stent, one having a tubular structure composed of an elastic wire (a tubular stent or a wire stent) is known. As a material of the stent, a metal wire such as a stainless steel wire is preferably used, and the metal wire is bent and connected in a coil shape or a zigzag shape to form a tubular structure. The tubular stent having such a structure can be compressed into an elongated shape.
【０００４】このようなステントとしては、例えば、多
数の直線部分が互いに屈曲部により接続されてジグザグ
構造の閉ループに形成されたワイヤからなるステント
（特公平４−３２６６２号公報）、一連の直線部分及び
複数の屈曲部を含む円筒形状のヘビ状形態に形成された
ワイヤからなるステント（特開昭６３−２３０１５８号
公報）、複数個のワイヤの各端部を互いに溶接してなる
管状ステント２個以上を柔軟なヒンジ部で接合した間接
接合型ステント（特開平３−１５１９８３号公報）、ウ
ズ巻バネからなるステント（米国特許第４，５５３，５
４５号明細書）、コイル状に形成した熱記憶合金からな
るステントなどが提案されている。As such a stent, for example, a stent (Japanese Patent Publication No. 4-32662) consisting of a wire formed by forming a closed loop having a zigzag structure in which a large number of linear portions are connected to each other by bending portions, a series of linear portions. And a stent composed of a wire formed in a cylindrical snake shape including a plurality of bent portions (JP-A-63-230158), and two tubular stents formed by welding the ends of the plurality of wires to each other. An indirect joint type stent (JP-A-3-151983) in which the above is joined by a flexible hinge portion, and a stent composed of a wound coil spring (US Pat. No. 4,553,5)
No. 45), a stent made of a heat storage alloy formed in a coil shape has been proposed.
【０００５】ステントの適用方法としては、例えば、ス
テントを圧縮した状態でカテーテル先端に取り付け、経
皮的に血管などの管腔内に挿入して患部付近に運搬し、
次いで、カテーテル先端から管腔内の狭窄部位に遊離さ
せ、ステント自身の弾性的復元力によって形状を復元
し、それによって狭窄部位の内径を拡張して、流路再開
を行う方法、あるいは、カテーテル先端にステントと共
に取り付けたバルーンを膨張させ、それによって圧縮さ
れたステントを拡張させる方法がある。As a method of applying the stent, for example, the stent is attached to a catheter tip in a compressed state, percutaneously inserted into a lumen such as a blood vessel, and transported to the vicinity of an affected area,
Then, it is released from the catheter tip to the stricture site in the lumen and the shape is restored by the elastic restoring force of the stent itself, thereby expanding the inner diameter of the stricture site and restarting the flow path, or the catheter tip There is a method of expanding a balloon attached to the stent together with the stent, thereby expanding the compressed stent.
【０００６】ステントによる治療法は、同様の症例で施
行される代替管の移植外科手術のような外科的切開手術
が不要で、簡易な非侵襲的治療法である。また、ステン
トによる治療法は、バルーン、ナイフまたはカッター等
をカテーテル先端に取り付けて行う経皮的管形成術に比
して、効果が確実で、しかも安全性に問題がない。そこ
で、近年、特に血管系において、ステントの使用例が多
く報告されている。[0006] The treatment method using a stent is a simple non-invasive treatment method that does not require surgical incision such as a surgical operation for transplanting an alternative tube which is performed in the same case. Further, the treatment method using a stent is more effective than the percutaneous angioplasty performed by attaching a balloon, a knife, a cutter or the like to the tip of the catheter, and there is no problem in safety. Therefore, in recent years, many examples of the use of the stent have been reported especially in the vascular system.
【０００７】ところで、従来のステントは、弾性的復元
力または拡張後の形状維持力が必要なことから、ステン
レス鋼ワイヤ等の金属線をコイル状またはジグザグ状に
屈曲加工したもの、あるいはこれらの金属線と接続用プ
ラスチック糸で構成されたものであるため、生体適合性
に乏しいという問題がある。このような構造のステント
を、例えば、血管系で使用する際には、折角確保した血
流路が金属の高い血栓性によって血栓閉塞を引き起こ
し、ごく初期の開存しか得られないか、あるいは血栓性
の低い部位での使用に適用範囲が限られるなどの問題が
あった。また、元々治療対象となる管腔状器官は、ガン
や動脈硬化などの原因でその管腔組織が異常に内腔側に
増殖・膨張する症状を持っている。したがって、ステン
トにより管腔を拡張しても、ステントを構成する金属線
の隙間から管腔組織が増殖・膨張して再び閉塞してしま
うという問題があった。By the way, since the conventional stent requires elastic restoring force or shape retaining force after expansion, a metal wire such as a stainless steel wire is bent into a coil shape or a zigzag shape, or these metals are used. Since it is composed of a wire and a plastic thread for connection, it has a problem of poor biocompatibility. When a stent having such a structure is used, for example, in the vascular system, the blood flow path secured at certain angles causes thrombus occlusion due to the high thromboticity of the metal, and only a very early patency is obtained, or a thrombus is obtained. There was a problem that the application range was limited to the use in the site with low property. Further, the luminal organ to be treated originally has a symptom that the luminal tissue abnormally proliferates and expands toward the luminal side due to cancer and arteriosclerosis. Therefore, even if the lumen is expanded by the stent, there is a problem in that the lumen tissue proliferates and expands from the gap between the metal wires forming the stent and occludes again.
【０００８】[0008]
【発明が解決しようとする課題】本発明の目的は、生体
適合性、特に抗血栓性に優れ、再狭窄の危険の少ないス
テントを提供することにある。本発明者は、前記従来技
術の問題点を克服するために鋭意研究した結果、弾性線
材で構成された管状構造物の内面及び外面に、四弗化エ
チレン樹脂多孔質体膜からなる被覆層を設けることによ
り、抗血栓性に優れ、しかも管腔組織の増殖・膨張によ
る管腔の再閉塞が抑制されるなど、優れた特性を有する
ステントの得られることを見出した。SUMMARY OF THE INVENTION An object of the present invention is to provide a stent having excellent biocompatibility, particularly antithrombogenicity, and less risk of restenosis. The present inventor has conducted extensive studies to overcome the above-mentioned problems of the prior art, and as a result, formed a coating layer composed of a tetrafluoroethylene resin porous body film on the inner surface and the outer surface of a tubular structure composed of an elastic wire. It was found that by providing the stent, a stent having excellent properties such as excellent antithrombotic property and suppressing re-occlusion of the lumen due to proliferation and expansion of the lumen tissue can be obtained.
【０００９】四弗化エチレン樹脂多孔質体は、その優れ
た生体適合性から、人工血管等の医療材料として使用さ
れている。本発明では、これを金属線等の弾性線材で構
成された管状構造物の内外面に配置することにより、弾
性線材を生体より遮断し、従来得られなかった抗血栓性
等の生体適合性をステントに付与し、しかも再狭窄の危
険を少なくすることに成功した。Porous tetrafluoroethylene resin is used as a medical material for artificial blood vessels and the like because of its excellent biocompatibility. In the present invention, by arranging this on the inner and outer surfaces of a tubular structure composed of an elastic wire such as a metal wire, the elastic wire is shielded from the living body, and biocompatibility such as antithrombogenicity which has not been obtained hitherto. It was successfully applied to a stent and the risk of restenosis was reduced.
【００１０】また、内面側及び外面側の四弗化エチレン
樹脂多孔質体膜の相互間を部分的に熱融着させることに
より、弾性線材で構成された管状構造物の圧縮折り畳み
の自由度を保持することができる。多孔質体膜相互間
を、四弗化エチレン樹脂よりも低融点の熱可塑性樹脂を
用いて接着してもよい。本発明は、これらの知見に基づ
いて完成するに至ったものである。Further, by partially heat-sealing the inner surface side and the outer surface side of the porous membranes of tetrafluoroethylene resin, the degree of freedom in compression folding of the tubular structure composed of the elastic wire is increased. Can be held. The porous films may be bonded to each other using a thermoplastic resin having a melting point lower than that of the tetrafluoroethylene resin. The present invention has been completed based on these findings.
【００１１】[0011]
【課題を解決するための手段】かくして、本発明によれ
ば、弾性線材で構成された管状構造物の内面及び外面
に、四弗化エチレン樹脂多孔質体膜からなる被覆層が設
けられていることを特徴とするステントが提供される。Thus, according to the present invention, a coating layer made of a tetrafluoroethylene resin porous material film is provided on the inner surface and the outer surface of a tubular structure made of an elastic wire. A stent is provided which is characterized by the following.
【００１２】また、本発明によれば、弾性線材で構成さ
れた管状構造物の内面及び外面に、四弗化エチレン樹脂
多孔質体の管状膜を配置し、内面側及び外面側の管状膜
相互間を部分的に熱融着させることを特徴とするステン
トの製造方法が提供される。さらに、本発明によれば、
弾性線材で構成された管状構造物の内面及び外面に、四
弗化エチレン樹脂多孔質体の管状膜を配置すると共に、
これら管状膜間に四弗化エチレン樹脂よりも低融点の熱
可塑性樹脂を配置し、四弗化エチレン樹脂の融点未満で
熱可塑性樹脂の融点以上に加温した状態で、内面側及び
外面側の管状膜相互間を部分的に加圧接着させることを
特徴とするステントの製造方法が提供される。Further, according to the present invention, the tubular membrane of the porous tetrafluoroethylene resin is disposed on the inner surface and the outer surface of the tubular structure made of the elastic wire, and the tubular membranes on the inner surface side and the outer surface side are provided with each other. There is provided a method of manufacturing a stent, which is characterized by partially heat-sealing the gaps. Further according to the invention,
A tubular membrane of a tetrafluoroethylene resin porous body is arranged on the inner and outer surfaces of a tubular structure made of elastic wire,
A thermoplastic resin having a melting point lower than that of the tetrafluoroethylene resin is placed between these tubular membranes, and the inner surface side and the outer surface side of the thermoplastic resin are heated to a temperature lower than the melting point of the tetrafluoroethylene resin and higher than the melting point of the thermoplastic resin. A method for manufacturing a stent is provided, which comprises partially pressure-bonding tubular membranes to each other.
【００１３】以下、本発明について詳述する。本発明で
使用する弾性線材で構成された管状構造物としては、特
に限定されず、例えば、従来から知られている金属線を
主とした管状ステントを使用することができる。弾性線
材で構成された管状構造物は、弾性線材を屈曲及び接続
して構成されたものであって、弾性的に圧縮した時、当
初の内径より細径の通路に挿入可能で、かつ、弾性的復
元力を解放した時、当初形状に復元可能なものであるこ
とが好ましい。The present invention will be described in detail below. The tubular structure composed of the elastic wire used in the present invention is not particularly limited, and for example, a conventionally known tubular stent mainly composed of a metal wire can be used. A tubular structure made of elastic wire is formed by bending and connecting elastic wires, and when elastically compressed, it can be inserted into a passage having a diameter smaller than the initial inner diameter, and is elastic. It is preferable that the initial shape can be restored when the dynamic restoring force is released.
【００１４】このような管状構造物は、弾性線材をコイ
ル状またはジグザグ状等に屈曲及び接続して、管状構造
を形成することにより作成することができる。その具体
例としては、図２に示すような構造のものを挙げること
ができる。即ち、ステンレス線（９）をジグザグに折り
曲げて円筒状にし、円筒状の両端の各折り曲げ部分に輪
（１０）を形成して、その輪の中にステンレスコイル管
（８）を円状に配置して管状構造物を作成する。図１
は、図２の管状構造物（３）を四弗化エチレン樹脂多孔
質体膜（１）及び（２）で被覆した構造のステントの模
式図である。図５に示すように、ステンレス線（４）を
コイル状に巻いて管状構造を形成してもよい。このよう
な構造の管状構造物は、変形させ、当初内径よりも細径
の通路に挿入することができる。Such a tubular structure can be produced by bending and connecting an elastic wire into a coil shape or a zigzag shape to form a tubular structure. As a specific example thereof, a structure shown in FIG. 2 can be mentioned. That is, a stainless wire (9) is bent in a zigzag shape to form a cylinder, and a ring (10) is formed at each bent portion at both ends of the cylinder, and a stainless coil tube (8) is arranged in a circle in the ring. To form a tubular structure. Figure 1
FIG. 3 is a schematic view of a stent having a structure in which the tubular structure (3) of FIG. 2 is coated with porous films of tetrafluoroethylene resin (1) and (2). As shown in FIG. 5, the stainless wire (4) may be wound into a coil to form a tubular structure. The tubular structure having such a structure can be deformed and inserted into a passage having a diameter smaller than the initial inner diameter.
【００１５】弾性線材の材質としては、本発明品の製造
工程において、四弗化エチレン樹脂多孔質体をその融点
以上に加熱融着させることから、四弗化エチレン樹脂の
融点付近の温度において溶融切断等の起こらない材質の
ものが好ましい。また、ステントには、弾性的復元力及
び形状維持力が必要である。したがって、弾性線材とし
ては、ステンレス鋼、タングステン、プラチナ等の金属
線、炭素繊維複合線を主として、これらを管状に構成す
る目的で使用されうる接続線も、金属線及び四弗化エチ
レン樹脂糸を使用することが望ましい。As the material of the elastic wire, since the tetrafluoroethylene resin porous body is heated and fused to its melting point or higher in the manufacturing process of the product of the present invention, it is melted at a temperature near the melting point of the tetrafluoroethylene resin. It is preferable to use a material that does not cause cutting. Further, the stent needs elastic restoring force and shape maintaining force. Therefore, as the elastic wire, a metal wire such as stainless steel, tungsten, platinum, etc., a carbon fiber composite wire is mainly used, and a connecting wire that can be used for the purpose of forming these into a tubular shape is also a metal wire and a tetrafluoroethylene resin thread. It is desirable to use.
【００１６】本発明で使用される四弗化エチレン樹脂多
孔質体膜は、例えば、特公昭４２−１３５６０号公報に
記載の方法により製造することができる。即ち、先ず、
四弗化エチレンの未燒結粉末に液状潤滑剤を混和し、押
出・圧延によりチューブ状またはシート状に予備成形す
る。この成形体から液状潤滑剤を除去し、または除去す
ることなく、少なくとも一軸方向に延伸すると未燒結の
多孔質体が膜状で得られる。この多孔質体を収縮しない
ように固定した状態で、四弗化エチレン樹脂の融点であ
る３２７℃以上に加熱して、延伸した構造を燒結・固定
すると、強度の向上した燒結品が得られる。The porous tetrafluoroethylene resin membrane used in the present invention can be produced, for example, by the method described in Japanese Patent Publication No. 42-13560. That is, first,
A liquid lubricant is mixed with an unsintered powder of ethylene tetrafluoride, and extruded and rolled to be preformed into a tube or sheet. If the liquid lubricant is removed from this molded body or if it is stretched in at least uniaxial direction without removing it, an unsintered porous body in a film form is obtained. When this porous body is fixed so as not to shrink, it is heated to 327 ° C. or higher, which is the melting point of the tetrafluoroethylene resin, and the stretched structure is sintered and fixed, whereby a sintered product with improved strength can be obtained.
【００１７】四弗化エチレン樹脂多孔質体膜は、その材
質に由来する無毒性、生体内非分解性、抗血栓性等の生
体適合性に加え、微小な結節とそれを連結する細い繊維
からなる微細な多孔質体構造によって、十分な強度と可
撓性を有している。したがって、四弗化エチレン樹脂多
孔質体膜は、ステントによる治療において、カテーテル
内腔へのステント圧縮挿入の際に、弾性線材からなる管
状構造物の形状変化に追随し、しかも、その弾性的復元
力を妨げない。The porous membrane of tetrafluoroethylene resin has a biocompatibility such as nontoxicity, non-degradability in vivo, antithrombotic property, etc., which is derived from its material, and is composed of minute nodules and fine fibers connecting them. It has sufficient strength and flexibility due to the fine porous body structure. Therefore, in the treatment with a stent, the tetrafluoroethylene resin porous membrane follows the shape change of the tubular structure made of an elastic wire when the stent is compressed and inserted into the lumen of the catheter, and its elastic restoration is achieved. Does not interfere with power.
【００１８】カテーテル内腔へのステント圧縮挿入を考
慮すると、本発明品を構成する四弗化エチレン樹脂多孔
質体膜は、力学的特性を満足する範囲内で、十分に薄く
する必要がある。あまり厚い多孔質体膜を被覆すると、
ステントをカテーテル内腔へ圧縮挿入することが困難に
なる。本発明者の検討では、弾性線材による管状構造物
の形状・径によっても異なるが、内外面ともに膜厚５０
μｍ以下とすることが好ましく、さらに膜厚３０μｍ以
下とすることがより好ましい。しかし、一般に膜厚２０
μｍ以下となると製造上困難な上、力学的強度が低く圧
縮拡張に耐えられなくなるため、実質上、膜厚は２５〜
５０μｍの範囲が最適となる。Considering the compression and insertion of the stent into the lumen of the catheter, the tetrafluoroethylene resin porous membrane that constitutes the product of the present invention must be sufficiently thin within the range that satisfies the mechanical characteristics. If you coat a too thick porous film,
Compressing the stent into the catheter lumen becomes difficult. According to a study by the present inventor, the film thickness is 50
The thickness is preferably less than or equal to μm, and more preferably 30 μm or less. However, in general, a film thickness of 20
If it is less than μm, it is difficult to manufacture, and the mechanical strength is low and it cannot withstand compression expansion.
The optimum range is 50 μm.
【００１９】四弗化エチレン樹脂多孔質体の多孔質構造
は、前述のように可撓性の点で重要である。延伸倍率が
小さく、気孔率の低過ぎる多孔質体は、固くて使用し難
い。しかし、逆に、延伸倍率が大きく、気孔率の高過ぎ
る多孔質体は、強度が十分ではなく、弾性線材を生体か
ら遮断することが困難となる。本発明者の検討では、孔
径が０．２μｍ〜１μｍの範囲で、バブルポイントが
０．０３〜３．０ｋｇ／ｃｍ2の範囲の四弗化エチレン
樹脂多孔質体が好ましい。The porous structure of the tetrafluoroethylene resin porous body is important in terms of flexibility as described above. A porous body having a low draw ratio and too low porosity is hard and difficult to use. However, conversely, a porous body having a large draw ratio and too high porosity does not have sufficient strength, and it becomes difficult to shield the elastic wire from the living body. According to the study by the present inventors, a tetrafluoroethylene resin porous body having a pore diameter in the range of 0.2 μm to 1 μm and a bubble point in the range of 0.03 to 3.0 kg / cm 2 is preferable.
【００２０】従来の金属線で構成された管状ステントを
用いて、例えば、狭窄した血管内面を押し広げると、強
度の低下した患部や柔軟な血栓では、金属線が血管壁に
食い込んで破ったり、血栓中に潜り込んでしまい、血流
路を回復できない場合があった。これに対して、本発明
のステントでは、外面の四弗化エチレン樹脂多孔質体膜
によって、面状に狭窄部位を押し広げるため、このよう
な問題が生じない。また、金属線のみのステントでは、
患部に存在した血栓が回復した流路の内面に必ず残る
が、本発明のステントでは、外面の四弗化エチレン樹脂
多孔質体膜によって、血栓が周辺に押し付けられて流路
から完全になくなってしまう。Using a conventional tubular stent composed of a metal wire, for example, when the inner surface of a stenotic blood vessel is expanded, the metal wire bites into the blood vessel wall and breaks in the affected area with weakened strength or a flexible thrombus, In some cases, the blood flow path could not be recovered because it had sunk into the thrombus. On the other hand, in the stent of the present invention, such a problem does not occur because the outer surface of the porous tetrafluoroethylene resin film spreads the narrowed portion in a planar manner. Also, in the case of a stent with only metal wires,
Although the thrombus existing in the affected area always remains on the inner surface of the recovered channel, in the stent of the present invention, the outer surface of the tetrafluoroethylene resin porous body film causes the thrombus to be completely removed from the channel by being pressed to the periphery. I will end up.
【００２１】弾性線材からなる管状構造の内外面を多孔
質体膜で遮断した本発明のステントは、生体内において
血流や細胞の浸潤を防止することも可能である。例え
ば、悪性新生物、癌の治療において、患部に対する血管
分岐部に本発明品を挿入することで血流を遮断し、癌の
壊死・発育の抑制を図ったり、癌細胞の流出を阻害して
転移を防止する等の治療に使用することが可能である。The stent of the present invention in which the inner and outer surfaces of a tubular structure made of an elastic wire are blocked by a porous membrane can prevent blood flow and infiltration of cells in a living body. For example, in the treatment of malignant neoplasms and cancers, the product of the present invention is inserted into the vascular bifurcation to the affected area to block the blood flow, to prevent the necrosis / growth of cancer, or to prevent the outflow of cancer cells. It can be used for treatment such as prevention of metastasis.
【００２２】本発明で使用する四弗化エチレン樹脂多孔
質体膜の多孔質構造は、生体細胞の通過を遮断する孔径
とすることが好ましい。本発明者の検討では、繊維長で
平均１５μｍ以下、バブルポイントで０．３ｋｇ／ｃｍ
2以上の多孔質体膜を使用することにより、細胞浸潤を
遮断することが可能であり、このような遮断を目的とす
るステント治療においては、このような物性を有する四
弗化エチレン樹脂多孔質体膜を使用することが好まし
い。The porous structure of the tetrafluoroethylene resin porous material membrane used in the present invention preferably has a pore size that blocks passage of living cells. According to the study by the present inventors, the average fiber length is 15 μm or less, and the bubble point is 0.3 kg / cm.
By using two or more porous membranes, it is possible to block cell infiltration, and in the stent treatment aiming at such blocking, the tetrafluoroethylene resin porous material having such physical properties is used. Preference is given to using body membranes.
【００２３】四弗化エチレン樹脂の抗血栓性をより有効
に発揮させるために、ステントの内面は、血流の乱れを
生じる皺や弛みのない滑らかな面にすることが望まし
い。このため、四弗化エチレン樹脂多孔質体膜は、管状
構造物と一体化する際に、形状に応じて伸びてフィット
し易い二軸延伸された未燒結品あるいは半燒結品を使用
することが望ましい。二軸延伸された半燒結品は、例え
ば、配管等のシール材として利用されているグレードの
ものである。四弗化エチレン樹脂ファインパウダーは、
３４７℃に融点ピークを持ち、これを燒結体とすると３
２７℃に融点ピークをもつ。したがって、半燒結品は、
特性として原料である四弗化エチレン樹脂ファインパウ
ダーの３４７℃の融点ピークを部分的に持つ点で、完全
燒結体と区別される。In order to more effectively exhibit the antithrombogenicity of the tetrafluoroethylene resin, it is desirable that the inner surface of the stent be a smooth surface without wrinkles or slack that causes disturbance of blood flow. For this reason, it is possible to use a biaxially stretched unsintered product or a semi-sintered product for the porous tetrafluoroethylene resin membrane, which is easy to stretch and fit according to the shape when integrated with the tubular structure. desirable. The biaxially stretched semi-sintered product is, for example, of a grade used as a sealing material for pipes and the like. Fine powder of tetrafluoroethylene resin
It has a melting point peak at 347 ° C and is 3 when it is used as a sintered body.
It has a melting point peak at 27 ° C. Therefore, the semi-sintered product is
As a characteristic, it is distinguished from a completely sintered product in that it partially has a melting point peak at 347 ° C. of the raw material tetrafluoroethylene resin fine powder.
【００２４】本発明のステントを製造するには、弾性線
材で構成された管状構造物の内面及び外面に、チューブ
状に成形した四弗化エチレン樹脂多孔質体膜（管状膜）
を配置する。次に、四弗化エチレン樹脂の融点より高い
温度に加熱した金属体にて、内外面の四弗化エチエン樹
脂多孔質体膜を挟み込み、熱融着させる。この場合、ス
テントの内径によっては、加熱した金属体を内腔に挿入
することが困難な場合があるが、そのような場合には、
管状構造物の内径と同径の金属棒を挿入し、外側から加
熱した金属体を押しつけることで、内面の金属棒と外面
の加熱金属体の間で内外面の四弗化エチレン樹脂多孔質
体膜を挟み込み、熱融着させることが可能である。In order to manufacture the stent of the present invention, a porous tetrafluoroethylene resin membrane (tubular membrane) formed into a tubular shape is formed on the inner and outer surfaces of a tubular structure made of an elastic wire.
To place. Next, the tetrafluoroetheneene resin porous material film on the inner and outer surfaces is sandwiched by a metal body heated to a temperature higher than the melting point of the tetrafluoroethylene resin and heat-sealed. In this case, depending on the inner diameter of the stent, it may be difficult to insert the heated metal body into the lumen, but in such a case,
Insert a metal rod with the same diameter as the inner diameter of the tubular structure and press the heated metal body from the outside, so that the tetrafluoroethylene resin porous body on the inner and outer surfaces is inserted between the metal rod on the inner surface and the heated metal body on the outer surface. It is possible to sandwich the film and heat-bond it.
【００２５】この熱融着による一体化は、内外両面の四
弗化エチレン樹脂多孔質体膜の全面に行ってもよいが、
熱融着により多孔質構造が無孔化し、四弗化エチレン樹
脂多孔質体膜の可撓性が減少する。また、全面融着は、
管状構造物の圧縮折り畳みの自由度を減少させ、ステン
トのカテーテルへの圧縮挿入性を低下させる。The integration by heat fusion may be carried out on the entire surface of the porous tetrafluoroethylene resin membrane on both inner and outer surfaces.
The heat fusion makes the porous structure non-porous and reduces the flexibility of the tetrafluoroethylene resin porous membrane. Also, the whole surface fusion is
It reduces the degree of compression folding freedom of the tubular structure and reduces the compression insertability of the stent into the catheter.
【００２６】このため、内外面の四弗化エチレン樹脂多
孔質体膜の熱融着は、部分的に行うことが望ましい。具
体的には、例えば、水玉模様状あるいは何本かの線状に
熱融着部分を設けると、上記のような問題を回避するこ
とができる。また、管状構造物の変形に対する自由度を
保持するためには、管状構造物が四弗化エチレン樹脂多
孔質体膜間にない部分で、これらの部分接着を行う方が
より有効である。熱融着では、完全に燒結された多孔質
体膜よりも、未燒結品を用いた方が、高い接着力を得る
ことができる。この点でも、本発明に使用される四弗化
エチレン樹脂多孔質体膜は、半燒結品または未燒結品が
好ましい。For this reason, it is desirable to partially heat-bond the porous tetrafluoroethylene resin film on the inner and outer surfaces. Specifically, for example, if the heat-sealed portion is provided in a polka dot pattern or some linear shapes, the above problems can be avoided. Further, in order to maintain the degree of freedom of the deformation of the tubular structure, it is more effective to partially bond the tubular structure at a portion which is not between the porous membranes of tetrafluoroethylene resin. In heat fusion, higher adhesive strength can be obtained by using an unsintered product than by using a completely sintered porous film. Also in this respect, the semi-fluorinated ethylene resin porous body membrane used in the present invention is preferably a semi-sintered product or an unsintered product.
【００２７】本発明のステントを製造する他の方法とし
ては、内外面の四弗化エチレン樹脂多孔質体膜を、接着
剤として熱可塑性樹脂を用い、加熱・加圧して接着させ
る方法がある。具体的には、弾性線材で構成された管状
構造物の内面及び外面に、四弗化エチレン樹脂多孔質体
の管状膜を配置すると共に、これら２つの管状膜間に四
弗化エチレン樹脂よりも低融点の熱可塑性樹脂を配置
し、四弗化エチレン樹脂の融点未満で熱可塑性樹脂の融
点以上に加温した状態で、内面側及び外面側の管状膜相
互間を部分的に加圧接着させる。As another method for producing the stent of the present invention, there is a method in which the porous tetrafluoroethylene resin film on the inner and outer surfaces is adhered by heating and pressing using a thermoplastic resin as an adhesive. Specifically, a tubular membrane of a tetrafluoroethylene resin porous body is arranged on the inner surface and the outer surface of a tubular structure made of an elastic wire, and the ethylene tetrafluoride resin is placed between these two tubular membranes. A thermoplastic resin having a low melting point is arranged, and the tubular membranes on the inner surface and the outer surface are partially pressure-bonded to each other while being heated below the melting point of the tetrafluoroethylene resin and above the melting point of the thermoplastic resin. .
【００２８】熱可塑性樹脂としては、ポリプロピレン、
ポリエチレン、エチレン−酢酸ビニル共重合体、アイオ
ノマーなどのヒートシール型の接着剤（シーラント）等
があり、通常、フィルムや不織布などの層状のものを弾
性線材で構成された管状構造物の所要箇所に巻き付け
て、２つの管状膜の間に配置することが好ましい。例え
ば、金属線管状構造物の所要箇所にポリプロピレン不織
布を帯状に巻き付け、その内外面に四弗化エチレン樹脂
多孔質体の管状膜を配置する。As the thermoplastic resin, polypropylene,
There are heat-seal type adhesives (sealants) such as polyethylene, ethylene-vinyl acetate copolymer, ionomer, etc. Normally, layered ones such as films and non-woven fabrics are applied to the required locations of tubular structures composed of elastic wire rods. It is preferably wrapped and placed between two tubular membranes. For example, a polypropylene non-woven fabric is wound around a required portion of a metal wire tubular structure in a band shape, and a tubular membrane of a porous tetrafluoroethylene resin body is arranged on the inner and outer surfaces thereof.
【００２９】この熱可塑性樹脂を用いた接着法によれ
ば、四弗化エチレン樹脂の融点よりも低い温度で管状膜
相互間を接着させることができるため、内外面の四弗化
エチレン樹脂多孔質体膜相互間を部分的に熱融着させる
方法と比較して、四弗化エチレン樹脂多孔質体膜の変形
やピンホール発生などのおそれがない。また、四弗化エ
チレン樹脂多孔質体は、完全焼成物よりも半焼成物の方
が細胞等に対するバリヤ性に優れているが、この接着法
によれば、接着部分の四弗化エチレン樹脂多孔質体膜が
焼成されることがない。さらに、架橋型の接着剤は、生
体適合性に難があるが、ポリオレフィン等の熱可塑性樹
脂を用いると、そのような問題はない。According to the bonding method using this thermoplastic resin, since the tubular membranes can be bonded to each other at a temperature lower than the melting point of the tetrafluoroethylene resin, the porous tetrafluoroethylene resin on the inner and outer surfaces can be bonded. Compared with the method of partially heat-sealing the body membranes, there is no risk of deformation of the porous tetrafluoroethylene resin membrane or pinholes. Further, in the tetrafluoroethylene resin porous body, the semi-calcined product has a better barrier property against cells etc. than the completely calcined product. The body film is not baked. Further, the cross-linking type adhesive has difficulty in biocompatibility, but when a thermoplastic resin such as polyolefin is used, such a problem does not occur.
【００３０】本発明のステントは、次のような特徴を有
している。 （１）無毒性、生体内非分解性、抗血栓性等の生体適合
性に優れる。 （２）管腔内面を四弗化エチレン樹脂多孔質体膜により
面状で押し広げるため、血栓が、再開通した血流路内に
残らない。 （３）癌治療など、血流・細胞の遮断目的に使用でき
る。 （４）四弗化エチレン樹脂多孔質体の低摩擦性により、
カテーテルへの挿入が容易である。 これらの特徴により、本発明品は、生体適合性、適用範
囲、作業性が著しく改善されたものであり、ステントに
よる治療の有効性をさらに高めることができ、血管など
の狭窄内腔の良好な再開通を実現することができる。The stent of the present invention has the following features. (1) Excellent biocompatibility such as nontoxicity, non-degradability in vivo, antithrombotic property, etc. (2) Since the inner surface of the lumen is expanded in a planar manner by the tetrafluoroethylene resin porous film, thrombus does not remain in the reopened blood channel. (3) It can be used for the purpose of blocking blood flow and cells such as cancer treatment. (4) Due to the low friction property of the tetrafluoroethylene resin porous body,
Easy to insert into catheter. Due to these characteristics, the product of the present invention has remarkably improved biocompatibility, application range, and workability, can further enhance the effectiveness of treatment with a stent, and has good stenosis lumens such as blood vessels. Recanalization can be realized.
【００３１】[0031]
【実施例】以下、本発明について、実施例及び比較例を
挙げて具体的に説明するが、本発明は、これらの実施例
のみに限定されるものではない。EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
【００３２】なお、物性の測定方法は以下の通りであ
る。 〈バブルポイント〉四弗化エチレン樹脂多孔質体膜をイ
ソプロピルアルコールに含浸し、膜の孔内をイソプロピ
ルアルコールで充満した後、膜の一方の面より徐々に空
気圧を負荷したときに、初めて反対面から気泡が出てく
るときの圧力。 〈開存率〉ステントを動物の血管内に配置し、ある一定
期間生かした後の、その時点で血流が認められたステン
トの本数の、配置したステント全数に対する比率。 〈形成血栓厚み〉ステントを動物に移植し、ある一定期
間生かした後に取り出したステントをホルマリン固定
後、臨界点乾燥を施し、走査型電子顕微鏡で、長軸方向
に切断した断面の内面に付着した血栓層を測定した平均
値。 〈焼成度〉四弗化エチレン樹脂多孔質体膜を示差走査熱
量計にて１０℃／分の昇温速度にて融点解析し、３４７
℃の時点で吸熱ピークのないものを完全焼成、あるもの
を半焼成、半焼成のうち、融点ピークが３４５℃以下の
ものを未焼成とした。The measuring methods of the physical properties are as follows. <Bubble point> After impregnating a porous tetrafluoroethylene resin membrane with isopropyl alcohol and filling the pores of the membrane with isopropyl alcohol, air pressure is gradually applied from one side of the membrane to the opposite side for the first time. Pressure when bubbles come out from the. <Patent rate> The ratio of the number of stents in which blood flow was observed at the time after the stent was placed in the blood vessel of an animal and kept alive for a certain period to the total number of the placed stents. <Thickness of formed thrombus> The stent was transplanted to an animal, fixed for formalin after alive for a certain period of time, fixed with formalin, subjected to critical point drying, and attached to the inner surface of the cross section cut in the longitudinal direction with a scanning electron microscope. The average value of the measured thrombus layer. <Firing degree> The melting point of the porous tetrafluoroethylene resin film was analyzed by a differential scanning calorimeter at a temperature rising rate of 10 ° C./min, and was analyzed at 347
Those having no endothermic peak at the time of ° C were completely calcined, some were semi-calcined, and among the semi-calcined, those having a melting point peak of 345 ° C or less were uncalcined.
【００３３】［実施例１］０．３５ｍｍφのステンレス
線（９）の両端をつないで円状にし、その接続部に内外
径０．３５ｍｍ、０．４ｍｍφのステンレス管で被覆し
補強したものを、２．５ｃｍ間隔でジグザグに１６回折
り曲げて、両端に各８ケの折り曲げ部分が並ぶ図２に示
すような円筒状にした。折り曲げ部は、図２のように
０．２ｍｍφほどの円（１０）を形成するように曲げ、
この円内を通って、両端それぞれの折り曲げ部先端をつ
なぐ円状にステンレスコイル管（８）を配置した。ステ
ンレスコイル管としては、８０μｍ線を隙間なくコイル
状に巻き、０．４ｍｍφの円筒状にしたものを用い、全
体として、長さ１ｃｍ、内径１０ｍｍφの金属線からな
る管状構造物（３）を作製した。[Example 1] A stainless wire (9) having a diameter of 0.35 mm was connected at both ends to form a circular shape, and its connecting portion was covered with a stainless pipe having an inner and outer diameters of 0.35 mm and 0.4 mm and was reinforced. It was bent 16 times in a zigzag pattern at 2.5 cm intervals to form a cylindrical shape as shown in FIG. 2 in which eight bent portions were arranged at both ends. The bent portion is bent so as to form a circle (10) of about 0.2 mmφ as shown in FIG.
A stainless steel coil tube (8) was arranged in a circular shape connecting the ends of the bent portions at both ends through the circle. As the stainless steel coiled tube, a tube having 80 μm wire wound in a coil shape without a gap to form a cylindrical shape of 0.4 mmφ is used, and as a whole, a tubular structure (3) made of a metal wire having a length of 1 cm and an inner diameter of 10 mmφ is produced. did.
【００３４】四弗化エチレン樹脂多孔質体膜として、バ
ブルポイント１．３ｋｇ／ｃｍ2、厚み３０μｍの未燒
結品シート（住友電工社製ポアフロン・メンブレンフィ
ルターＵＰ−０２０−４０）を使用し、折り返した端部
を熱融着させた後、熱融着による接着代が内面になるよ
うに内外面を反転させて、９ｍｍφのチューブ状にし
た。As a porous film of tetrafluoroethylene resin, an unsintered sheet (Poreflon Membrane Filter UP-020-40 manufactured by Sumitomo Electric Industries, Ltd.) having a bubble point of 1.3 kg / cm 2 and a thickness of 30 μm was used and folded back. After the end portions were heat-sealed, the inner and outer surfaces were inverted so that the adhesion margin by heat-sealing was the inner surface, and a tube shape of 9 mmφ was formed.
【００３５】次に、金属線管状構造物を、内径５ｍｍ
φ、外径７ｍｍφの管の内腔に圧縮挿入しておき、この
管の外に、用意した四弗化エチレン樹脂多孔質体チュー
ブを配置し、ここから金属線管状構造物を挿入した管の
みを抜き去ることで、金属線管状構造物の外面に四弗化
エチレン樹脂多孔質体膜を被覆した。四弗化エチレン樹
脂多孔質体チューブは、金属線管状構造物より十分長く
しておいて、図３に示すように、この余分な部分を金属
線管状構造物の内腔に折り込んで反対の端部より出し
（７）、その端部（６）で金属線管状構造物の内外面の
四弗化エチレン樹脂多孔質体を熱融着した。Next, the metal wire tubular structure is set to have an inner diameter of 5 mm.
Compressed and inserted into the inner diameter of a pipe with φ and an outer diameter of 7 mmφ, arrange the prepared tetrafluoroethylene resin porous body tube outside this pipe, and insert the metal wire tubular structure from here Was removed to coat the outer surface of the metal wire tubular structure with a porous membrane of tetrafluoroethylene resin. The tetrafluoroethylene resin porous body tube is made sufficiently longer than the metal wire tubular structure, and as shown in FIG. 3, this extra portion is folded into the lumen of the metal wire tubular structure and the opposite end is inserted. (7) was taken out from the portion, and the tetrafluoroethylene resin porous body on the inner and outer surfaces of the metal wire tubular structure was heat-sealed at the end (6).
【００３６】このようにして得られた四弗化エチレン樹
脂多孔質体膜（１、２）で内外面を被覆した金属線管状
構造物（３）の内腔に、外径１０ｍｍφのステンレス丸
棒を挿入し、図４のように金属線管状構造物の２本の支
柱（４）とステンレスコイル管で成す１６個の三角形の
各重心付近に、５００℃に加熱した１ｍｍφの円柱の端
部を押し付け、内外の四弗化エチレン樹脂多孔質体膜を
点接着（５）して、長さ２ｃｍ、内径１０ｍφのステン
トを作製した。A stainless steel rod having an outer diameter of 10 mmφ is provided in the inner cavity of the metal wire tubular structure (3) whose inner and outer surfaces are coated with the thus obtained porous tetrafluoroethylene resin membrane (1, 2). As shown in FIG. 4, the end of a 1 mmφ cylinder heated to 500 ° C. was inserted near the center of gravity of each of the 16 triangles formed by the two columns (4) of the metal wire tubular structure and the stainless steel coiled tube as shown in FIG. By pressing, the inner and outer porous films of tetrafluoroethylene resin were point-bonded (5) to produce a stent having a length of 2 cm and an inner diameter of 10 mφ.
【００３７】［実施例２］実施例１と同じステンレス線
を、１．５ｍｍピッチで内径２ｍｍ、長さ１ｃｍのコイ
ル状に巻いたものを金属線管状構造物とし、実施例１と
同じ四弗化エチレン樹脂多孔質体未燒結品シートを内径
１．８ｍｍφのチューブ状に成形したものを四弗化エチ
レン樹脂多孔質体管状膜として、実施例１同様にして金
属線管状構造物に被覆した。次いで、２ｍｍφのステン
レス丸棒を挿入して、金属線管状構造物のコイルと同じ
ピッチで、金属線と重ならないように０．３５ｍｍφの
ステンレス線を外周に巻き付けた後に、３５０℃に加熱
した３５ｍｍφガラス管円筒加熱炉に炉内滞在時間２分
間の条件で加熱した。外周に巻いたステンレス線及び内
腔のステンレス丸棒を除去し、図５に示すような長さ１
ｃｍ、内径２ｍφのステントを作製した。[Embodiment 2] The same stainless steel wire as in Embodiment 1 is wound in a coil shape having an inner diameter of 2 mm and a length of 1 cm at a pitch of 1.5 mm to form a metal wire tubular structure. A sheet of unsintered porous ethylene resin porous body was formed into a tubular shape having an inner diameter of 1.8 mmφ to form a tetrafluoroethylene resin porous body tubular membrane, which was coated on a metal wire tubular structure in the same manner as in Example 1. Then, a 2 mmφ stainless round bar was inserted, and a 0.35 mmφ stainless wire was wound around the outer periphery at the same pitch as the coil of the metal wire tubular structure so as not to overlap with the metal wire, and then heated to 350 ° C. to 35 mmφ. The glass tube was heated in a cylindrical heating furnace under the condition that the residence time in the furnace was 2 minutes. Remove the stainless wire wound around the outer circumference and the stainless round bar of the inner cavity, and set the length 1 as shown in Fig. 5.
A cm-sized stent having an inner diameter of 2 mφ was produced.
【００３８】［実施例３］四弗化エチレン樹脂多孔質体
膜として、バブルポイント１．３ｋｇ／ｃｍ2、厚み８
０μｍの四弗化エチレン樹脂多孔質体未燒結品シート
（住友電工社製ポアフロンメンブレンフィルタ−ＵＰ−
０２０−８０）を使用したこと以外は、実施例１と同様
にしてステントを作成した。Example 3 As a tetrafluoroethylene resin porous material membrane, bubble point 1.3 kg / cm 2 , thickness 8
0 μm sheet of tetrafluoroethylene resin porous material unsintered (Sumitomo Electric's Pore Freon Membrane Filter-UP-
A stent was produced in the same manner as in Example 1 except that 020-80) was used.
【００３９】［実施例４］四弗化エチレン樹脂多孔質体
膜として、バブルポイント０．３３ｋｇ／ｃｍ2、厚み
５０μｍの四弗化エチレン樹脂多孔質体完全燒結品シー
ト（住友電工社製ポアフロンメンブレンフィルタ−ＷＰ
−１００−５０）を使用したこと以外は、実施例１と同
様にしてステントを作成した。[Example 4] As a porous film of a tetrafluoroethylene resin porous material, a sheet of completely sintered tetrafluoroethylene resin porous material having a bubble point of 0.33 kg / cm 2 and a thickness of 50 µm (POREFLON manufactured by Sumitomo Electric Industries, Ltd. Membrane Filter-WP
A stent was produced in the same manner as in Example 1 except that -100-50) was used.
【００４０】［実施例５］四弗化エチレン樹脂多孔質体
膜として、バブルポイント０．１８ｋｇ／ｃｍ2、厚み
５０μｍの四弗化エチレン樹脂多孔質体完全燒結品シー
ト（住友電工社製ポアフロンメンブレンフィルタ−ＷＰ
−３００−５０）を使用したこと以外は、実施例２と同
様にしてステントを作成した。[Embodiment 5] As a tetrafluoroethylene resin porous material film, a sheet of completely sintered tetrafluoroethylene resin porous material having a bubble point of 0.18 kg / cm 2 and a thickness of 50 μm (Sumitomo Electric Co., Ltd. Membrane Filter-WP
A stent was produced in the same manner as in Example 2 except that -300-50) was used.
【００４１】［実施例６］実施例１と同様に金属線管状
構造物の周囲に、図４の内外の四弗化エチレン樹脂多孔
質体膜の接着部分を含む円筒帯状にポリプロピレン不織
布（三井石油化学工業社製シンテックスＰＳ−１０８）
を巻き付け、その内外面に四弗化エチレン樹脂多孔質体
膜を配置して、１ｍｍφの円柱の端部を２００℃に加熱
したこと以外は、実施例１と同様にして、ポリプロピレ
ン不織布を介して内外面の四弗化エチレン樹脂多孔質体
膜を接着した構造のステントを作成した。[Embodiment 6] Similar to Embodiment 1, a polypropylene nonwoven fabric in the form of a cylindrical band (Mitsui Oil & Oil Co., Ltd.) is formed around the metal wire tubular structure and includes the adhering portions of the inner and outer porous films of tetrafluoroethylene resin shown in FIG. Syntex PS-108 manufactured by Chemical Industry Co., Ltd.)
Was wound, a tetrafluoroethylene resin porous material membrane was placed on the inner and outer surfaces thereof, and the end of a 1 mmφ cylinder was heated to 200 ° C. A stent having a structure in which porous membranes of ethylene tetrafluoride resin on the inner and outer surfaces were adhered was prepared.
【００４２】［比較例１］実施例１で使用した金属線管
状構造物を管状ステントとした。 ［比較例２］実施例２で使用した金属線管状構造物を管
状ステントとした。[Comparative Example 1] The metal wire tubular structure used in Example 1 was used as a tubular stent. Comparative Example 2 The metal wire tubular structure used in Example 2 was used as a tubular stent.
【００４３】［比較例３］実施例１で作製した四弗化エ
チレン樹脂多孔質体膜で内外面を被覆した金属線管状構
造物の内腔に、外径１０ｍｍφのステンレス丸棒を挿入
し、３５０℃恒温槽に１０分間入れることで、四弗化エ
チレン樹脂多孔質体膜を完全燒結したものを比較例３と
した。[Comparative Example 3] A stainless round bar having an outer diameter of 10 mmφ was inserted into the inner cavity of a metal wire tubular structure whose inner and outer surfaces were coated with the porous tetrafluoroethylene resin membrane prepared in Example 1. Comparative Example 3 was obtained by completely sintering the tetrafluoroethylene resin porous film by placing it in a 350 ° C. thermostat for 10 minutes.
【００４４】［比較例４］実施例１で金属線管状構造物
の外側に四弗化エチレン樹脂多孔質体膜を被覆した状態
で両端の長さをそろえ、金属線管状構造物の外面にのみ
四弗化エチレン樹脂多孔質体を被覆したものを比較例４
とした。[Comparative Example 4] In Example 1, the lengths of both ends of the metal wire tubular structure were made uniform while the outside of the metal wire tubular structure was covered with a porous film of tetrafluoroethylene resin, and only the outer surface of the metal wire tubular structure was prepared. Comparative Example 4 with a coating of a tetrafluoroethylene resin porous body
And
【００４５】［比較例５］実施例２で金属線管状構造物
の外側に四弗化エチレン樹脂多孔質体膜を被覆した状態
で両端の長さを切りそろえ、金属線管状構造物の外面に
のみ四弗化エチレン樹脂多孔質体を被覆したものを比較
例５とした。[Comparative Example 5] In Example 2, the outer ends of the metal wire tubular structure were covered with a porous film of tetrafluoroethylene resin, and both ends were trimmed so that only the outer surface of the metal wire tubular structure was covered. Comparative Example 5 was prepared by coating a porous tetrafluoroethylene resin body.
【００４６】〈圧縮挿入性評価〉各実施例及び比較例で
得られたステントについて、圧縮挿入性を比較した。具
体的には、ステントを径の違うＦＥＰチューブ内腔に挿
入して行き、挿入可能な最小内径を求めた。<Evaluation of compressive insertability> The compressive insertability of the stents obtained in each Example and Comparative Example was compared. Specifically, the stent was inserted into the FEP tube lumens having different diameters, and the minimum insertable inner diameter was determined.
【００４７】同じ金属線管状構造物を用いた実施例１、
３、４及び６と比較例１、３及び４のステントうち、実
施例１及び６と比較例１及び４のものは、内径２ｍｍφ
と同じで、四弗化エチレン樹脂多孔質体層による圧縮性
の低下はなかった。実施例３のステントは、４ｍｍφ、
実施例４は、３ｍｍφと若干圧縮挿入性が低下したが、
ステントとしての使用において問題はないと考えられ
る。比較例３のステントは、内外面の四弗化エチレン樹
脂多孔質体膜と金属線管状構造物が強固に固定されてお
り、５ｍｍφが限度で多少圧縮挿入性に難があった。Example 1 using the same metal wire tubular structure,
Among the stents of Examples 3, 4 and 6 and Comparative Examples 1, 3 and 4, those of Examples 1 and 6 and Comparative Examples 1 and 4 had an inner diameter of 2 mmφ.
As with the above, there was no reduction in compressibility due to the tetrafluoroethylene resin porous material layer. The stent of Example 3 has a diameter of 4 mm
In Example 4, the compression insertability was slightly reduced to 3 mmφ,
It is considered that there is no problem in use as a stent. In the stent of Comparative Example 3, the porous membrane of tetrafluoroethylene resin on the inner and outer surfaces and the metal wire tubular structure were firmly fixed, and there was some difficulty in compression insertability within 5 mmφ.
【００４８】また、元の内径が２ｍｍφの実施例２と比
較例２及び５のステントは、内径１．２ｍｍφまでと差
はなかったが、実施例５のものについては、１．５ｍｍ
φと若干圧縮挿入性が低下した。The stents of Example 2 and Comparative Examples 2 and 5 having the original inner diameter of 2 mmφ did not differ from the inner diameter of 1.2 mmφ, but the stent of Example 5 had a diameter of 1.5 mm.
With φ, the compression insertability was slightly degraded.
【００４９】挿入可能な最小径の管に対する挿入・離脱
後の形状復帰性（形状回復性）については、実施例１、
２及び６と比較例１及び２のステントについては、２０
回挿入・離脱を繰り返しても全く元と変化はなかった
が、実施例３及び４のものでは、挿入１０回を越えるく
らいから、四弗化エチレン樹脂多孔質体膜と金属線管状
構造物の位置関係が微妙にずれだして、部分的に微小な
皺が発生したが、構造が破壊することはなかった。Regarding the shape recoverability (shape recoverability) after insertion / removal with respect to a pipe having the smallest diameter that can be inserted, Example 1,
For the stents of Nos. 2 and 6 and Comparative Examples 1 and 2, 20
Although there was no change from the original even after repeated insertions / removals, in the case of Examples 3 and 4, the tetrafluoroethylene resin porous body membrane and the metal wire tubular structure were formed after about 10 insertions. The positional relationship began to deviate slightly, and small wrinkles partially occurred, but the structure was not destroyed.
【００５０】これらに対して、比較例３のステントは、
１回の挿入で形状がいびつになり、また、一部の四弗化
エチレン樹脂多孔質体膜が破れた部分、金属線が四弗化
エチレン樹脂多孔質体より露出した部分ができた。比較
例４及び５のステントは、３〜５回の挿入で両端部の四
弗化エチレン樹脂多孔質体膜が皺になり、金属端が露出
して被覆しない部分ができた。On the other hand, the stent of Comparative Example 3 had
The shape was distorted by one insertion, and a part of the porous tetrafluoroethylene resin porous film was broken, and a part where the metal wire was exposed from the porous tetrafluoroethylene resin porous material was formed. In the stents of Comparative Examples 4 and 5, the tetrafluoroethylene resin porous material film at both ends was wrinkled after the insertion of 3 to 5 times, and the metal ends were exposed and some portions were not covered.
【００５１】〈移植評価〉実施例２及び５と比較例２及
び５のステントをそれぞれ、体重１３〜１５ｋｇのウサ
ギの頚動脈内に挿入移植を行った。先端にステントを予
め内腔に挿入した外径１．５ｍｍφ、内径１．２ｍｍφ
のＦＥＰチューブを、頚動脈の移植部位の１ｃｍ下流よ
り血管内に挿入し、ＦＥＰチューブ内腔の他端より棒を
挿入してステントを血管内に放出した。移植後５分、１
時間、２４時間、及び２週間後、生育後屠殺して、該ス
テントを取り出し、開存率を調査した後に、ホルマリン
固定し、次いで臨界点乾燥を行い、走査型電子顕微鏡
で、ステント内面の血栓形成状態、形成血栓厚みを観察
・測定した。また、２週後のサンプルについては、病理
組織標本を作製し、治癒状態について観察した。<Evaluation of Transplantation> The stents of Examples 2 and 5 and Comparative Examples 2 and 5 were inserted and transplanted into the carotid artery of rabbits weighing 13 to 15 kg, respectively. 1.5mmφ outer diameter and 1.2mmφ inner diameter with a stent inserted into the lumen in advance
The FEP tube of 1 was inserted into the blood vessel 1 cm downstream from the implantation site of the carotid artery, and a rod was inserted from the other end of the lumen of the FEP tube to release the stent into the blood vessel. 5 minutes after transplantation, 1
After 24 hours and 2 weeks, they were sacrificed after growth, the stents were taken out, the patency rate was investigated, fixed with formalin, and then dried at a critical point, and the thrombus on the inner surface of the stent was observed with a scanning electron microscope. The formation state and the thickness of the formed thrombus were observed and measured. Further, for the sample after 2 weeks, a pathological tissue specimen was prepared and observed for the healing state.
【００５２】移植評価の結果、比較例２及び５のステン
トは、移植後５分後にすでに金属線周辺に活性化し偽足
を伸ばす血小板の集積が見られ、１時間後には、形成血
栓層の厚みが不均一で赤血球を含む赤色血栓が形成され
たところも多数散見された。移植後１日でも血小板を含
む安定しない血栓が部分的に観察され、開存率が示すよ
うに、閉塞するものもあった。移植２週後でもまだ赤色
血栓は残存し、開存率は低下していた。病理組織標本の
観察では、形成された血栓層も３０〜５０μｍと厚く、
器質化していない血栓層が多く見られた。特に、比較例
２のものでは、ステンレス線のすぐ外側の血管内膜及び
中膜に圧迫による壊死変性部が認められた。As a result of the transplantation evaluation, the stents of Comparative Examples 2 and 5 showed accumulation of platelets which had been activated around the metal wire and extended pseudolegs 5 minutes after the transplantation, and 1 hour later, the thickness of the formed thrombus layer. A large number of red thrombi were formed which were heterogeneous and formed with red blood cells. Unstable thrombi containing platelets were partially observed even one day after transplantation, and as shown by the patency rate, some were occluded. The red blood clot still remained 2 weeks after the transplantation, and the patency rate was decreased. In the observation of the pathological tissue specimen, the formed thrombus layer was as thick as 30 to 50 μm,
Many non-organized thrombus layers were seen. Particularly, in Comparative Example 2, a necrotic degeneration part due to compression was observed in the intima and media of the immediate outer side of the stainless wire.
【００５３】それに対して、実施例２及び５のステント
は、開存率は良好で、全般的に形成血栓厚みは薄く均一
であった。移植後５分では少量の血小板の付着が見られ
る程度で、１時間後には、血栓層の増加および活性状態
が見られたが、１日後には既に血小板の少ないフィブリ
ン様物質に覆われた安定な血栓層となっていた。２週後
には、血栓層はほぼ器質化され、ステント両端部で血管
内皮細胞の伸展が見られ、良好な治癒が行われていた。
また、実施例５のものでは、四弗化エチレン樹脂多孔質
体の多孔質内にステント外壁からの組織細胞の侵入が見
られた。On the other hand, in the stents of Examples 2 and 5, the patency rate was good, and the thickness of the formed thrombus was generally thin and uniform. At 5 minutes after transplantation, a small amount of platelets were found to adhere, and after 1 hour, an increase in the thrombus layer and an active state were observed, but 1 day later, it was stable because it was already covered with fibrin-like substances with low platelets. It was a clot layer. Two weeks later, the thrombus layer was almost organically formed, vascular endothelial cells were spread at both ends of the stent, and good healing was achieved.
Further, in Example 5, invasion of tissue cells from the outer wall of the stent was observed in the porous tetrafluoroethylene resin porous body.
【００５４】〈埋植評価〉四弗化エチレン樹脂多孔質体
膜膜で被覆しない比較例１及び２を除く各実施例及び比
較例のステントの両端に栓をした状態で、ウサギの背皮
下に埋植試験を行った。埋植後３週間で各ステントを取
り出し、病理組織標本として組織の侵入性を観察した。<Evaluation of Implantation> Under the condition that both ends of the stents of Examples and Comparative Examples except Comparative Examples 1 and 2 which were not covered with the tetrafluoroethylene resin porous body membrane film were plugged under the dorsal skin of rabbits. An implant test was performed. Three weeks after the implantation, each stent was taken out and the tissue invasion was observed as a pathological tissue specimen.
【００５５】四弗化エチレン樹脂多孔質体膜のバブルポ
イントが１．３ｋｇ／ｃｍ2の実施例１〜３、６及び比
較例３〜５、及び被覆した四弗化エチレン樹脂多孔質体
膜のバブルポイントが０．３３ｋｇ／ｃｍ2の実施例４
のステントでは、ステント内腔への組織侵入は全く認め
られなかったが、比較例４及び５のものについては、四
弗化エチレン樹脂多孔質体が若干収縮して、一部に膜が
被覆しない部分が生じ、その隙間より内腔への組織侵入
が起こっているサンプルもあった。Examples 1 to 3 and 6 and Comparative Examples 3 to 5 in which the bubble point of the tetrafluoroethylene resin porous material membrane was 1.3 kg / cm 2 , and the coated tetrafluoroethylene resin porous material membrane. Example 4 with a bubble point of 0.33 kg / cm 2.
In the stent of No. 4, no tissue invasion into the lumen of the stent was observed, but in the cases of Comparative Examples 4 and 5, the tetrafluoroethylene resin porous body slightly contracted and the membrane was not partially covered. In some samples, a part was generated and tissue invasion into the lumen occurred through the gap.
【００５６】これに対して、四弗化エチレン樹脂多孔質
体膜のバブルポイントが０．１８ｋｇ／ｃｍ2の実施例
５のステントでは、好中球を主とする細胞がステントの
内腔及び四弗化エチレン樹脂多孔質体膜の多孔質内に散
見され、一部に繊維芽細胞を中心とする組織の侵入が認
められ、細胞の遮断性においては、実施例１〜３、４及
び６が優れている。以上の実施例及び比較例のステント
の構造、圧縮挿入性評価、及び移植評価の結果を表１及
び表２に一括して示す。On the other hand, in the stent of Example 5 in which the bubble point of the tetrafluoroethylene resin porous material membrane was 0.18 kg / cm 2 , cells mainly containing neutrophils were formed in the lumen of the stent and the stent. It was found scattered in the porosity of the fluorinated ethylene resin porous material membrane, and invasion of the tissue centering on the fibroblasts was observed in part, and in the cell blocking property, Examples 1-3, 4 and 6 were used. Are better. Tables 1 and 2 collectively show the results of the structures of the stents of the above Examples and Comparative Examples, the evaluation of compression insertability, and the evaluation of implantation.
【００５７】[0057]
【表１】 [Table 1]
【００５８】[0058]
【表２】 [Table 2]
【００５９】なお、表１〜２中で示した構造・特性につ
いての略語は、以下のことを示す。 ・内径：ステントの内径。 ・内層ＰＴＦＥ厚：ステントの金属線管状構造物内面に
被覆した四弗化エチレン樹脂多孔質体膜の厚み。 ・外層ＰＴＦＥ厚：ステントの金属線管状構造物外面に
被覆した四弗化エチレン樹脂多孔質体膜の厚み。 ・ＢＰ：使用した四弗化エチレン樹脂多孔質体膜のバブ
ルポイント。 ・接着量：内外面に被覆した四弗化エチレン樹脂多孔質
体膜の全接触面積に対する、これらを接着した部分の面
積の割合（百分率）。 ・焼成度：ステントの四弗化エチレン樹脂多孔質体膜の
焼成度。 ・形状復帰挿入回数：元の状態に復帰可能な平均挿入回
数。 ・挿入による変形：挿入可能最小径に対する２０回以内
の挿入で発生するステントの形状及び形態の変化。The abbreviations for the structures and properties shown in Tables 1 and 2 indicate the following. -Inner diameter: The inner diameter of the stent. -Inner layer PTFE thickness: The thickness of the tetrafluoroethylene resin porous material film coated on the inner surface of the metal wire tubular structure of the stent. Outer layer PTFE thickness: The thickness of the tetrafluoroethylene resin porous body film coated on the outer surface of the metal wire tubular structure of the stent. -BP: Bubble point of the used tetrafluoroethylene resin porous material film. -Adhesion amount: The ratio (percentage) of the area of the part where these are adhered to the total contact area of the tetrafluoroethylene resin porous material film coated on the inner and outer surfaces. -Firing degree: The degree of firing of the tetrafluoroethylene resin porous material film of the stent. -Number of shape-return insertions: Average number of insertions that can return to the original state. -Deformation due to insertion: A change in the shape and form of the stent that occurs within 20 insertions with respect to the minimum insertable diameter.
【００６０】[0060]
【発明の効果】本発明のステントは、ステントのもつ手
術の簡易性、確実な開存性に加え、四弗化エチレン樹脂
多孔質体の材質がもつ抗血栓性を合わせ持つ。したがっ
て、本発明のステントは、血管系における閉鎖性血管疾
患や動脈瘤などにおける血管の再建に特に有効である。
また、本発明のステントは、バブルポイント０．３ｋｇ
／ｃｍ2以上の四弗化エチレン樹脂多孔質体膜を使用す
ることにより、生体細胞の遮断が可能となり、癌による
圧迫閉塞などの各種生体管に対する再建にも有効であ
る。EFFECTS OF THE INVENTION The stent of the present invention has the anti-thrombogenic property of the material of the tetrafluoroethylene resin porous body, in addition to the simple operation and reliable patency of the stent. Therefore, the stent of the present invention is particularly effective for reconstructing blood vessels in obstructive vascular diseases in the vascular system, aneurysms and the like.
The stent of the present invention has a bubble point of 0.3 kg.
By using a tetrafluoroethylene resin porous material membrane of not less than / cm 2 , living cells can be blocked, and it is also effective for reconstruction of various living vessels such as pressure obstruction due to cancer.
【図１】本発明のステントの一例を示す模式図で、外面
の四弗化エチレン樹脂多孔質体膜層の一部を切りとった
形状を示す。FIG. 1 is a schematic view showing an example of a stent of the present invention, showing a shape in which a part of a porous tetrafluoroethylene resin membrane layer on the outer surface is cut off.
【図２】本発明で使用する弾性線材からなる管状構造物
の１例を示す模式図である。FIG. 2 is a schematic diagram showing an example of a tubular structure made of an elastic wire used in the present invention.
【図３】本発明の製造方法の１例を示す模式図で、金属
線管状構造物に四弗化エチレン樹脂多孔質体膜を被覆す
る工程を断面図で示す。FIG. 3 is a schematic view showing an example of the production method of the present invention, and a cross-sectional view showing the step of coating a metal wire tubular structure with a porous film of tetrafluoroethylene resin.
【図４】本発明の製造方法の１例を示す模式図で、最終
段階を示す。FIG. 4 is a schematic diagram showing an example of the manufacturing method of the present invention, showing the final step.
【図５】本発明のステントの１例を示す模式図で、その
一部を切り取った形状を示す。FIG. 5 is a schematic view showing an example of the stent of the present invention, showing a shape obtained by cutting a part thereof.
１：管状構造物内面の四弗化エチレン樹脂多孔質体膜層 ２：管状構造物外面の四弗化エチレン樹脂多孔質体膜層 ３：弾性線材からなる管状構造物 ４：金属線管状構造物が膜に内包された部分（破線） ５：内外の四弗化エチレン樹脂多孔質体層の接着部分
（斜線部） ６：加熱接着する部位（円内） ７：四弗化エチレン樹脂多孔質体チューブの反転して内
側に折り込まれた部分 ８：金属線の折り曲げ部に設けた輪をつなぐコイル状金
属線（点線） ９：金属線 １０：金属線の折り曲げ部に設けた輪1: Tetrafluoroethylene resin porous body membrane layer on the inner surface of the tubular structure 2: Tetrafluoride ethylene resin porous body membrane layer on the outer surface of the tubular structure 3: Tubular structure made of elastic wire 4: Metal wire tubular structure Is enclosed in the film (dashed line) 5: Adhesive part of inner and outer tetrafluoroethylene resin porous material layer (shaded area) 6: Heat-adhesive part (in circle) 7: Ethylene tetrafluoride resin porous material Inverted part of the tube and folded inside 8: Coil-shaped metal wire (dotted line) connecting the loops provided at the bent portion of the metal wire 9: Metal wire 10: Wheel provided at the bent portion of the metal wire
Claims (4)
及び外面に、四弗化エチレン樹脂多孔質体膜からなる被
覆層が設けられていることを特徴とするステント。1. A stent characterized in that a coating layer made of a porous tetrafluoroethylene resin film is provided on the inner and outer surfaces of a tubular structure made of an elastic wire.
性線材を屈曲及び接続して構成されたものであって、弾
性的に圧縮した時、当初の内径より細径の通路に挿入可
能で、かつ、弾性的復元力を解放した時、当初形状に復
元可能なものである請求項１記載のステント。2. A tubular structure made of an elastic wire is formed by bending and connecting the elastic wire, and when elastically compressed, can be inserted into a passage having a diameter smaller than an initial inner diameter. The stent according to claim 1, which is capable of returning to its initial shape when the elastic restoring force is released.
及び外面に、四弗化エチレン樹脂多孔質体の管状膜を配
置し、内面側及び外面側の管状膜相互間を部分的に熱融
着させることを特徴とするステントの製造方法。3. A tubular membrane made of a porous tetrafluoroethylene resin is disposed on the inner and outer surfaces of a tubular structure made of elastic wire, and the tubular membranes on the inner and outer surfaces are partially heated. A method for manufacturing a stent, which comprises fusing.
及び外面に、四弗化エチレン樹脂多孔質体の管状膜を配
置すると共に、これら管状膜間に四弗化エチレン樹脂よ
りも低融点の熱可塑性樹脂を配置し、四弗化エチレン樹
脂の融点未満で熱可塑性樹脂の融点以上に加温した状態
で、内面側及び外面側の管状膜相互間を部分的に加圧接
着させることを特徴とするステントの製造方法。4. A tubular membrane of a porous tetrafluoroethylene resin body is arranged on the inner and outer surfaces of a tubular structure made of an elastic wire, and the melting point between these tubular membranes is lower than that of the ethylene tetrafluoride resin. The thermoplastic resin is placed, and it is possible to partially press-bond the tubular membranes on the inner surface side and the outer surface side with each other in a state of being heated below the melting point of the tetrafluoroethylene resin and above the melting point of the thermoplastic resin. A method for manufacturing a characteristic stent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28574993A JP3570434B2 (en) | 1993-05-10 | 1993-10-20 | Stent and method for manufacturing the same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13269793 | 1993-05-10 | ||
| JP5-132697 | 1993-05-10 | ||
| JP28574993A JP3570434B2 (en) | 1993-05-10 | 1993-10-20 | Stent and method for manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0724072A true JPH0724072A (en) | 1995-01-27 |
| JP3570434B2 JP3570434B2 (en) | 2004-09-29 |
Family
ID=26467215
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28574993A Expired - Fee Related JP3570434B2 (en) | 1993-05-10 | 1993-10-20 | Stent and method for manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3570434B2 (en) |
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| US6514282B1 (en) | 1999-10-04 | 2003-02-04 | Kanji Inoue | Method of folding transplanting instrument and transplanting instrument |
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