JP4338247B2 - Artificial lumen - Google Patents

Description

【０１２０】
実施例３
（in vitro挿入テスト）
臨床においては、ステント型人工血管はシース内に挿入し、そのまま血管内に入れて、プッシャーによって目的とする位置まで押し進め、そこではじめて血管内に放出されて留置される。そこでこのテストをin vitroで行った。まず試作品と対照品Ａを準備し、それぞれを２４フレンチ、長さ６０ｃｍのシース（Ｃｏｏｋ社製）内に挿入した。
【０１２１】
試作品の布は柔軟で、その折り畳みが容易であり、小さく、細く折り畳むことが可能であった。そしてシース内への挿入は容易であった。一方対照品は折り畳み難く、小さくすることに困難をきわめたが、断端をロート状にする事でかろうじて挿入することができた。
【０１２２】
試作品のシース内での移動は容易であり、プッシャーによって抵抗なく６０ｃｍのシース内を通過させることができた。対照品Ａでは抵抗があったが、無理矢理プッシャーを押し込むことで６０ｃｍのシース内を通過させることができた。
【０１２３】
シースを通過した両者は肉眼的には変化を見いだすことはできなかった。しかし両者の布の一部を採取し、走査型電子顕微鏡（倍率：４０倍、１００倍、４００倍、１０００倍、３０００倍）にて観察すると、試作品の表面は３μｍ（ミクロン）程度の超極細ポリエステル繊維が起毛しており、それらの繊維の乱れや損傷は認められなかった。
【０１２４】
一方対照品Ａでは５００倍以下の低倍率では変化を認めなかったが、１０００倍以上で観察すると、ポリエステル繊維の太さは約２０μｍ（ミクロン）であった。それらの繊維を詳細に観察すると、繊維の一部がつぶれて、損傷をうけている繊維が多く見られた。しかし繊維の断裂は認められなかった。
【０１２５】
対照品Ｂを用いて同様にシース内の通過実験を行った。対照品Ｂは小さく細く折り畳むことは試作品と同様に容易であり、シース内への挿入、シース内の通過も容易であった。
【０１２６】
しかしシースを通過し、シース断端から外にでるところの対照品Ｂの表面を肉眼で観察したところ、Ｚ型ステントの金属部分が布を貫通して、布の外面に飛び出している箇所が複数箇所、観察された。
【０１２７】
このような箇所は対照品Ｂがシース内を通り抜けてシース外に出てステントが拡がると、金属部分は人工血管内腔にもどった。しかし金属の貫通部分の布には約２ｍｍの孔が残った。
【０１２８】
シースの通過テスト後の対照品Ｂの一部を取り出し、走査型電子顕微鏡（倍率：１０００倍）で観察すると、繊維は直径役２０μｍ（ミクロン）であり、繊維に損傷は認められなかったが、織り目の乱れが随所に認められ、金属が貫通したと思われる部分では、繊維の断裂は見られないまでも、大きな乱れが織り目に見られ、繊維がばらけて孔が開いていた。
【０１２９】
以上の結果、試作品は取り扱いが容易であり、楽に小さく折り畳むことができ、シース内を損傷を受けることなく通過することが可能であった。これに対して、対照品Ａは無理をせねばシース内に挿入できず、しかもシースを通過させることによって、ポリエステル繊維が損傷を受けることが明らかとなった。
【０１３０】
一方、対照品Ｂは試作品と同様に取り扱いは容易であったが、繊維の織り方が疎であり、ばらけやすく、ステントの金属で繊維構造に乱れが生じ、容易に金属の鈍的な刺激で孔が開くことが判明した。
【０１３１】
更に、対照品Ｃを用いてシース内への挿入を試みたが、小さく畳むことが不可能であって、シース内への挿入はまったく不可能であった。
【０１３２】
実施例４
（各種材料の物性値）
下記表に示す５種類の繊維布既製品について、各種物性を測定した。結果を以下の表に示す。
使用した製品： Ube-graft（宇部興産社製）、トレグラフト（東レ社製）、Micron（Intervascular社製）、Microknit（Goraski社製）、トレーシー（東レ社製）
【０１３３】
【表１】

【０１３４】
実施例５
実際に試作品として報告されている単純な平織り布（宇部興産社製）で、厚さ０．２ｍｍにまで薄くし、起毛部分を押さえて、平滑な表面構造を持った製品を２０ｍｍの口径の製品（管状体）とし、該管状体中に２４ｍｍ用Ｚ型ステント（Ｃｏｏｋ社製、商品名：Ｃｏｏｋ−Ｚ（登録商標）Stent；ステンレス製、線状部材の太さ０．５ｍｍ）を挿入して実験室でステント型人工管腔（人工血管）を作成した。
【０１３５】
上記により得たステント型人工血管を、２４フレンチ（ほぼ成人男性の大腿動脈管に相当する太さ）のシース、長さ５０ｃｍ（材質：テフロン；Ｃｏｏｋ社製；メディコス平田社またはトノクラ社より入手可能）内にゆっくりと約５分間かけてその全体を挿入し、６０分後に該ステント型人工血管を取り出した。取り出した人工血管を観察したところ、「繊維を切る」操作は行わなかったにもかかわらず、ステントの金属部分が布を貫通していたり、布の繊維走行の型くずれが原因で、管状体に孔が開いている部分を複数見出した。
【０１３６】
臨床においてはこの様な現象を実際に観察することは不可能であり、しかも型くずれし易い、薄い布を使用すると、それを防止する事はできない。そのため生じる孔が大きければ出血、すなわちendoleakの原因となりうる。これは布を薄くし、構造を単純化したために繊維の編み、織りの緻密さが低下したことが原因と考えれらる。
【０１３７】
以上、本発明を適応した実施例に付いて説明してきたが、本発明がこれらの実施例に限定されるものではなく、形状、材質等、本発明の要旨を逸脱しない限り変更が可能である。
【０１３８】
【発明の効果】
上述したように本発明によれば、拡張可能部材と、これを囲む多孔性材料の管状体とからなる人工管腔であって；前記多孔性材料のカンチレバー剛軟度試験法による剛軟度をＳａ（ｍｍ）とし、該多孔性材料の重さをＳｂ（ｍｇ／ｃｍ²）とし、そのＡＮＳＩ／ＡＡＭＩ基準の透水率（water permeability）をＳｃ（ｍｌ・ｃｍ^-2・ｍｉｎ^-1）とした際に、これらの積Ｑ₁＝（Ｓａ×Ｓｂ×Ｓｃ）の値が６×１０⁴以下である人工管腔が提供される。
【０１３９】
更に、本発明によれば、拡張可能部材と、これを囲む多孔性材料の管状体とからなる人工管腔であって；前記多孔性材料のカンチレバー剛軟度試験法による剛軟度をＳａ（ｍｍ）とし、該多孔性材料の重さをＳｂ（ｍｇ／ｃｍ²）とし、そのＡＮＳＩ／ＡＡＭＩ基準のsuture retention testによる耐ほつれ強度をＳｄ（ｋｇ）とした際に、これらの組み合わせＱ₂＝（Ｓａ×Ｓｂ÷Ｓｄ）の値が３００以下である人工管腔が提供される。
【０１４０】
更に、本発明によれば、拡張可能部材と、これを囲む布製の管状体とからなる人工管腔であって；前記布が０．０８９ｇ／ｋｍ（０．８デニール）以下の繊維を重量比で１％以上含む人工管腔が提供される。
【０１４１】
上記構成を有する本発明のステント型人工管腔においては、従来におけるようにステント型人工管腔の管状体の厚さを単純に薄くするのではなく、特定の関係を有する物性の組み合わせを満足する布を用いているため、上述したように、生体管腔内への挿入容易性と、管腔挿入後の人工管腔として果たすべき特性とを両立させることが可能となる。すなわち、管状体が薄くても丈夫で、型くずれし難く、小さく折り畳んで細いシース内に挿入可能で、しかも血管内に挿入された後に組織親和性、壁在血栓保持性、細胞親和性等を満足するステント型人工管腔が得られる。
【０１４２】
本発明のステント型人工管腔は、薄くて丈夫な布からなるため、通常の手術で使用するシース内への挿入は容易であり、更に細いシースを用いることも可能となるので、血管壁を損傷する可能性が減少し、患者への不快感を低減し、安全な手術を可能とする。
【０１４３】
本発明のステント型人工管腔は薄くて丈夫な布からなるため、シース内を通過する際の該人工管腔を構成する布の繊維の損傷を防ぐことが可能で、長期的に考えると安全な手術結果を提供することが可能となる。
【０１４４】
更に、超極細繊維が起毛した態様においては、本発明のステント型人工管腔は、血栓を該人工管腔の壁に捉えやすく、人工管腔壁からの血液の漏れを押さえることが可能である。
【０１４５】
また、このような態様においては、本発明のステント型人工管腔は、生体内への植え込み後、生体内の周囲組織を起毛した超極細繊維内に誘導することが可能となるので、人工管腔と周囲組織とのアンカリングが確実となり、graft migrationの危険性を極めて低くすることが可能であり、長期的に見て安全な手術結果を実現させうる。
【０１４６】
更に、このような態様においては、本発明のステント型人工管腔は、布の内面では安定して血栓を捉え、外面では結合組織との一体化が進む事が期待されることから、血管壁を通しての血液の漏れ、いわゆるendoleakを防ぐことが可能となり、安全な術後の状態を実現することが可能である。
【図面の簡単な説明】
【図１】超極細繊維とＺ型金属ステントで構成された、本発明のステント型人工管腔の一態様を示す模式斜視図である。
【図２】超極細繊維４ａ、４ｂ、７および８を有する本発明の人工管腔を構成する布の一例の模式断面図である。
【図３】実施例において、対照品Ａに用いた人工管腔を構成する布の模式断面図である。
【図４】実施例において、対照品Ｂに用いた人工管腔を構成する布の模式断面図である。
【図５】実施例において、対照品Ｃに用いた人工管腔を構成する布の模式断面図である。
【図６】本発明における剛軟度試験法に用いる「カンチレバー形」試験器を示す模式斜視図である。
【符号の説明】
１：人工管腔２：拡張可能部材（ステント）、３：管状体、４ａ：起毛した超極細繊維（布から切断端が出た状態で立ち上がっている）、４ｂ：起毛した超極細繊維（布からループ状態で立ち上がっている）、５：通常の太さの繊維（平織り構造の横糸）、６：通常の太さの繊維（平織り構造の縦糸）、７：超極細繊維（布の内部の縦断面）、８：超極細繊維（布の内部の横断面）、９：対照品Ａの通常の太さの繊維（平織り構造の横糸）、１０：対照品Ａの通常の太さの繊維（平織り構造の縦糸）、１１：対照品Ｂの通常の太さの繊維（平織り構造の横糸）、１２：対照品Ｂの通常の太さの繊維（平織り構造の縦糸）、１３：対照品Ｃの通常の太さの繊維（平織り構造の横糸）、１４：対照品Ｃの通常の太さの繊維（平織り構造の横糸で、ループ状に起毛している繊維）、１５：対照品Ｃの通常の太さの繊維（平織り構造の縦糸）。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an artificial lumen (for example, an artificial blood vessel), and in particular, temporarily or (semi-) permanently placed inside a lumen (for example, a blood vessel) in an animal body such as a human. The present invention relates to a prosthetic lumen of a type including a stent inside, which can replace a part or all of the functions of the lumen.
[0002]
[Prior art]
Many techniques have been developed to produce stents and stent-grafts (or implants) that should be temporarily or (semi-) permanently placed in body lumens (eg, blood vessels) as needed. Yes.
[0003]
  For example, in a small blood vessel region, a stenosis in the coronary artery or peripheral artery of the limb is inserted into the blood vessel, and a stent is inserted along the guide wire.NarrowThere is a method of reaching a stenosis, expanding the stenosis with a balloon, and placing it there. Palmaz US Pat. No. 4,733,665 is a representative technique.
[0004]
As another representative technique, there is a Gianturco type stent in which a zigzag stent is manufactured using a stainless elastic wire, and the stent is inserted in advance in a sheath (a catheter having a large inner diameter). The Gianturco-type stent is inserted into the lumen together with the sheath, and after reaching the target site, the stent is released from the sheath to self-expand the stent.
[0005]
As described above, a device used for treatment of a blood vessel wall by inserting a sheath into a blood vessel using a sheath, reaching a target vascular lesion, and expanding the device is disclosed in US Pat. No. 5,219,355, No. 5,211,658, No. 5,104,399, No. 5,078,726, No. 4,820,298, No. 4,787,899, No. 4,617,932, No. 4, No. 562,596, No. 4,577,631, No. 4,140,126, and European Patent Nos. 508473, 466518, and 461791.
[0006]
On the other hand, self-expanding vascular stents that can expand themselves after being released from the sheath are disclosed in US Pat. Nos. 5,147,370, 4,994,071, 4,776,337 and These are described in European Patent Nos. 575719, 556850, 540290, 536610, 4813654, German Patent DE 42119949, and the like.
[0007]
More recently, a technique for initially obtaining a target shape by using a shape memory alloy to obtain the same temperature as the body temperature after being released from the sheath has been used in the medical field. The use of such shape memory alloys is described in the specifications of US Pat. Nos. 4,665,906 and 4,505,767.
[0008]
As a clinical application of these stents and other technologies, in the aortic region, for the purpose of treating aortic aneurysms, Argentina's Parodi et al. Covered a polyester cloth on a stent that can be inflated with a balloon made by Palmaz, An insertion procedure was reported in 1991 (see Parodi JC, Palmaz JC, Baeone D, et al. Transfemoraointraluminal graft implantation for abdominal aortic aneurysms. Ann VascSurg 1991; 5: 491-5). Chuter et al. Also produced bifurcated stents and grafts for abdominal aortic aneurysms and reported clinical applications in 1994 (Chuter TAM, DonayreC, Wendt G, Bifurcated stent-grafts for endovascular repair of abdominalaortic aneurysm : preliminary case reports. See Surg Endosc 1994; 8: 800-2).
[0009]
These techniques have been applied to several aneurysm treatments that have been regarded as difficult in practice in clinical applications, and have shown excellent results. In these techniques, a method of incising or puncturing the femoral artery or iliac artery, inserting a catheter or sheath into the body from the incision or puncture site, and reaching the pathological site of the blood vessel is employed.
[0010]
In particular, in the treatment of an abdominal aortic aneurysm or thoracic aortic aneurysm, an incision is made in the femoral artery or iliac artery, and the aneurysm portion is passed through the incised portion. ) And a stent graft through a thick sheath.
[0011]
Such a treatment using a catheter or a sheath can be performed even in cases where laparotomy or thoracotomy is difficult, and thus a new treatment method that has not been considered in the past has been provided. Based on these results, a new treatment called Endovascular Surgery has been established.
[0012]
However, these new Endovascular Surgery treatments may still be incomplete. One cause is the patient's side and the patient's condition may not be suitable for this procedure (eg, the arterial wall is fragile and cannot withstand stent fixation).
[0013]
One other cause is that there is still room for improvement in the devices used for this treatment. Since patient-side problems are case-by-case, considering the increase in vascular diseases accompanying the aging of society as a whole, improvement of the device side (stents or stent-grafts) is urgently needed today Needless to say.
[0014]
Problems with conventional stents or stent-grafts are as follows.
(1) The size of the stent / graft is relatively large, and even when folded, the stent / graft must be thick. Therefore, a thick sheath is required to insert the stent / graft into the body.
(2) The stent / graft (expansion member + tubular body as a whole) is relatively hard and therefore cannot sufficiently follow the patient's bent and cured pathological blood vessel wall.
(3) Since the adhesion between the blood vessel wall and the stent / graft is low, the Endoleak problem, which is a phenomenon in which blood leaks from the gap between them, is likely to occur.
(4) “Slipping” may occur in the stent / graft position during or after insertion into the blood vessel.
(5) The stent itself may block an opening of a “side branch” (a branching portion of a lumen) in the vicinity of the site where the stent is placed due to the “displacement” or the like.
[0015]
An example of instrument imperfection is that in the prior art, the stent and implant are passed through the pathological portion of the sheath and implant to the position to be secured in the lumen, and more centrally. And an instrument in the case where it is necessary to fix the stent or the like. In this case, if the lesioned part is bent, it is necessary to bend the stent along the lesioned part accordingly. At this time, if the sheath into which the stent and the “folded graft” are inserted is thick and hard, there is a risk of damaging the pathological part.
[0016]
For example, in the thoracic aorta, there is a tendency for aortic dissection to occur frequently in the vicinity of a site about 2 cm away from the left subclavian artery (side branch) from the aorta, but this part is greatly curved, In order to secure stents and grafts using conventional techniques in this part, a flexible and bendable stent-graft is required. Furthermore, in this case, it is necessary to take care not to occlude the left subclavian artery (side branch), and it is required to fix the stent accurately and reliably in a short blood vessel section.
[0017]
In addition, as described above, the part where the aortic dissection occurs frequently is the site of the tightest curve in the aorta, and the manufacture of stents and grafts that follow this curve, and safe insertion and fixation have been required. It was. However, stents or implants that can fully meet these requirements have not yet been developed.
[0018]
The situation regarding the stent or the graft as described above is completely the same even in a stent-type artificial lumen, which is a member that includes a tubular body that encloses a stent, and that allows the tubular body to replace a part or all of the functions of the lumen. It is the same.
[0019]
In order to solve such difficulties, the shape, properties, expansion method, material, etc. of the expandable stent have been improved, and development of a new stent-type artificial lumen has been promoted. In particular, when inserting into a blood vessel, etc., the stent-type artificial device is designed so that it can be inserted from as thin a blood vessel as possible so that it becomes thinner when folded and the stent and cloth are made flexible. To the lumen.
[0020]
[Problems to be solved by the invention]
As a contrivance for this, some progress is seen in the “stent portion” constituting the stent type artificial lumen. However, no significant progress has been made in improving tubular bodies to be combined with stents (usually parts made of fabric).
[0021]
As an improvement in the above-mentioned “cloth portion”, the conventional cloth is made thinner today. For example, a product having a smooth surface structure in which a plain plain woven fabric is thinned to a thickness of about 0.2 mm and a raised portion is pressed has been reported.
[0022]
However, when the cloth is thinned, the diameter of the multifilament yarn constituting the cloth is also reduced, so the strength of the cloth may be lowered, and the water permeability as the cloth is also increased (therefore, blood is passed through the cloth). Serious leakage) may occur. In order to prevent such a decrease in the strength of the fabric (in order to avoid a decrease in the diameter of the multifilament yarn itself), the number of multifilament yarns used is reduced, a simple knitted structure, a woven structure, and a smooth surface without raising I have to become a cloth. However, the “new” defects caused by the improvement of the cloth portion have not been pointed out so far.
[0023]
An object of the present invention is to provide a stent-type artificial lumen that eliminates the above-mentioned drawbacks of the prior art.
[0024]
Another object of the present invention is to provide a stent-type artificial lumen that achieves both ease of insertion into a living body lumen and characteristics to be achieved as an artificial lumen after insertion of the lumen.
[0025]
Still another object of the present invention is that the tubular body is thin and strong, hardly deformed, can be folded into a small sheath and inserted into a thin sheath. Another object of the present invention is to provide a stent-type artificial lumen that satisfies cell affinity and the like.
[0026]
[Means for Solving the Problems]
As a result of diligent research, the present inventor did not simply reduce the thickness of the tubular body of the stent-type artificial lumen as in the past, but a porous material (cloth, cloth) satisfying a combination of physical properties having specific relationships. Etc.) was found to be extremely effective for achieving the above-mentioned purpose.
[0027]
The artificial lumen of the present invention is based on the above findings, and more specifically, an artificial lumen comprising an expandable member and a tubular body of a porous material surrounding the expandable member; The bending resistance by the softness test method is Sa (mm), and the weight of the porous material is Sb (mg / cm²) And the ANSI / AAMI standard water permeability is Sc (ml · cm^-2・ Min^-1), The product Q of these₁= (Sa × Sb × Sc) is 6 × 10^FourIt is characterized by the following.
[0028]
According to the present invention, there is further provided an artificial lumen including an expandable member and a tubular body of a porous material surrounding the expandable member; the bending resistance of the porous material according to the cantilever bending resistance test method is Sa ( mm) and the weight of the porous material is Sb (mg / cm²) And the fraying resistance according to the ANSI / AAMI standard retention test is Sd (kg).₂= Prosthetic lumen with a value of (Sa × Sb ÷ Sd) of 300 or less is provided.
[0029]
  According to the present invention, there is further provided an artificial lumen comprising an expandable member and a cloth tubular body surrounding the expandable member;0.089 g / km (0.8 denier)An artificial lumen containing 1% or more by weight of the following fibers is provided.
[0030]
The above-described artificial lumen of the present invention is based on the results obtained by the inventor's earnest study on problems that have not been studied at all with regard to the artificial lumen.
[0031]
That is, as a result of the prediction of the defects of the artificial lumen based on the knowledge about the conventional artificial lumen, the present inventor has obtained a stent-type artificial lumen simply made of a thin and smooth cloth as a porous material. It has been discovered that a serious problem can occur when it is actually inserted into a lumen in a living body such as a blood vessel and after a long period of time has elapsed after insertion.
[0032]
That is, when the number of fibers constituting the tubular body is reduced, the cloth is thinned, and a simple woven structure or knitted structure is formed, there is a disadvantage that the mesh or the woven pattern is likely to be deformed. In order to make the cloth thinner, the number of fibers constituting the cloth must be reduced, and the three-dimensional thickness must be reduced by simplifying the mesh and the weave. However, if the knitting structure and the weaving structure are simplified, the fabric is likely to be disturbed by a slight stimulus, i.e., easily out of shape.
[0033]
At first glance, it is unlikely to be inconvenient in a stent-type artificial lumen that it is easily deformed. However, if any stimulus is applied, the fiber is not cut and the mesh or weave of the fabric is likely to change. For example, when a stent-type artificial lumen using a thin cloth that is easily deformed is inserted into a blood vessel through a thin sheath, if the metal portion of the stent may hit the cloth (it may always occur) However, when such a situation occurs, even though the metal part is dull bite, the mesh and texture structure are shifted without cutting the fibers of the thin cloth, and the metal gradually becomes clothed. This can cause the mesh or weave to spread out, resulting in the metal part penetrating the fabric.
[0034]
Such a phenomenon may occur during the passage of the artificial lumen through the sheath in order to insert the stent-type artificial lumen into the lumen in the living body. After passing through the sheath, the expandable part of the artificial lumen expands in the blood vessel, and the metal part returns to its original position (before the sheath is inserted), so that the metal penetrates the fabric. I can't see you. However, the fabric still has holes that are pushed out and fiber running disturbance. In reality, even if such a phenomenon occurs, since the stent-type artificial lumen is already in the blood vessel in clinical practice, it is impossible to recognize the expanded hole by observing it with the naked eye. .
[0035]
Therefore, many manufacturers now tend to make the fabric as thin as possible to facilitate passage through the sheath and have a smooth structure with a simple structure and no brushing. It is considered that there is a major defect in the structure in terms of strength against general stimulation.
[0036]
In other words, when the cloth is simply thinned by the conventional technique, the above-described defects (penetration of the cloth by the metal portion) cannot be avoided. If you make it thin and smooth, you will get a seemingly improved impression, but even if it looks good when you insert a stent-type artificial lumen, it is a dangerous act in the long run, There is a great possibility that it is not an essential improvement.
[0037]
In addition, if the fabric is further thinned and the mesh and weave are kept fine, the surface structure of the fabric becomes smooth and the fibers become a scaffolding for cells to adhere to the fibers. Etc., and the inner and outer surfaces of the lively cloth tend to be extremely flat. Such a configuration may be different from a conventional artificial lumen (ie, an undesirable state) in relation to cells, tissues, blood, thrombus, etc. after the stent-type artificial lumen is inserted. This inventor was able to find out based on the knowledge which has observed the healing process after implantation of the artificial lumen so far.
[0038]
In other words, in such a state that the “metal part protrudes through the cloth”, when the stent-type artificial lumen is pushed and fixed to the blood vessel wall toward the outside in the blood vessel lumen, the compressed blood vessel Cells on the wall fall into compression necrosis, or generational changes of cells and tissues are performed at positions retreated by compression, and connective tissues that can only receive the fixing force due to compression more slowly are formed at those positions. The Rukoto. In this case, if the outer surface of the cloth constituting the artificial lumen is a smooth surface, the cells cannot enter the inside of the cloth. Things can't be done.
[0039]
The stent-type artificial lumen is constantly stimulated by pulsation over a long period of time, and the position is gradually shifted due to pressure from surrounding tissues and pulling by scar tissue. The possibility of migration has been pointed out, but if anchoring is weak, it becomes difficult to prevent it.
[0040]
On the other hand, on the inner surface of the cloth, under the circumstances where the phenomenon described above is occurring on the outer surface, if the inner surface of the cloth is smooth and has low water permeability, the thrombus tissue attached to the inner surface of the cloth is It cannot be rooted in the fiber gap of the fabric, and it becomes difficult to continue to exist stably. As a result, the thrombotic tissue is in an unstable state in which it adheres and falls off and newly attaches and falls off. Therefore, even if cells invade into the thrombus tissue and fortunately an organized tissue is also formed, it is placed in an unstable state due to insufficient anchoring, so there are tissue fragments and thrombus around the periphery. It is easily peeled off and easily complications such as embolism in peripheral blood vessels. That is, the inner surface continues to be unstable as with the outer surface.
[0041]
As mentioned above, the improvement of the fabric part of the artificial lumen has been extremely delayed, and many products still have an endovascular surgery that should be used for general open surgery. However, the current situation is that it must be diverted. Therefore, in today's clinical setting, since a device for open surgery is used, it is inherently difficult to narrow the entire device and insert a stent-type artificial lumen using a thin sheath. I was in a dilemma.
[0042]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings as necessary. In the following description, “parts” and “%” representing the quantity ratio are based on weight unless otherwise specified.
[0043]
(Artificial lumen)
The artificial lumen of the present invention comprises an expandable member and a tubular body of a porous material surrounding the expandable member.
[0044]
FIG. 1 is a schematic perspective view showing one basic aspect of the artificial lumen of the present invention. Referring to FIG. 1, the artificial lumen in such an embodiment includes an expandable member 2 (only a part of which is shown) and a tubular body 3 of a porous material surrounding the expandable member 2.
[0045]
(Expandable member)
The expandable member 2 can be appropriately selected from conventionally known members that can be expanded in a lumen (for example, a “stent” -shaped member).
[0046]
As long as the expandable member 2 described above can be formed, the characteristics, material, thickness, etc. of the linear member constituting the expandable member are not particularly limited, and can be appropriately selected from known materials and used. It is. Usually, the material constituting the expandable member is often made of a metal (used to include an alloy), but is not limited thereto.
[0047]
In view of facilitating taking a desired shape at a predetermined temperature when the stent is inserted into a lumen, a material having a shape memory function (for example, shape memory) is used. Alloy) or a superelastic material (for example, a superelastic alloy).
[0048]
  Furthermore, the linear member may be any one of known shapes / structures such as monofilaments, multifilaments, tapes, etc.OneA combination of the above structures) can also be taken. This makes it possible to select and adjust the flexibility, restoring force, etc. of the linear member, and it is easy to make an expandable member having a curved surface adapted to the curved surface of the inner wall of a soft lumen (for example, a blood vessel). Become.
[0049]
(size)
As long as the insertion into the lumen is possible, the size of the expandable member 2 is not particularly limited.
[0050]
(Production method)
As long as it is possible to give the above-mentioned predetermined shape, the production method of the expandable member 2 of the present invention is not particularly limited, and can be appropriately selected from known material (metal etc.) processing methods (if necessary) (In combination of two or more).
[0051]
As a method for expanding the expandable member, any of a self-expandable type and a type expanded by another device such as a balloon can be used.
[0052]
(Tubular body)
From the viewpoint of achieving both ease of insertion into a living body lumen and characteristics as an artificial lumen after the insertion of the lumen (suppressing penetration and deformation of the tubular body of the expandable member), the tubular body 3 Is made of Sa (mm) according to the 45 degree cantilever stiffness test method described in JIS (L1096-1990, General Textile Test Method), and the weight of the porous material is Sb ( mg / cm²) And the ANSI / AAMI standard water permeability is Sc (ml · cm^-2・ Min^-1), The product Q of these₁= (Sa × Sb × Sc) is 6 × 10^FourOr less, more preferably 5 × 10^FourThe following (especially 4 × 10^FourOr less).
[0053]
In the present invention, the porous material constituting the tubular body 3 is made of the above-mentioned bending resistance from the viewpoint of achieving both the ease of insertion into a living body lumen and the characteristics of an artificial lumen after insertion of the lumen. Sa (mm) and the weight of the porous material is Sb (mg / cm²) And fraying resistance Sd (kg) according to ANSI / AAMI standard retention test, these combinations Q₂= (Sa × Sb ÷ Sd) may be 300 or less. This Q₂The value of is preferably 250 or less (particularly 200 or less).
[0054]
Each of the physical properties, the bending resistance Sa, the weight Sb of the porous material, the water permeability Sc and the fraying resistance Sd can be measured as follows.
[0055]
<Measurement method of bending resistance Sa>
Measured by “45 ° cantilever method”. Five or more test pieces each having a width of about 2 cm and a length of about 15 cm are sampled from a sample (a porous material such as a cloth) whose bending resistance Sa is to be measured. A short side is placed on the scale base line on a smooth surface with a 45-degree slope at one end. The test piece is gently slid in the direction of the slope by an appropriate method, and the position of the other end when the center point of one end of the test piece is in contact with the slope A is read on the scale. The bending resistance is indicated by the length (mm) that the test piece has moved, and the average value of the front and back surfaces of the test piece (up to an integer).
[0056]
<Measurement method of weight Sb of porous material>
An electronic scale (for example, manufactured by Sartorius) that can measure the weight of a porous material (cloth, etc.) 2 cm wide x 15 cm long dried (about 25 ° C., about 10% RH for about 24 hours or more) to 0.1 mg , Trade name: BP210S electronic balance or manufactured by Chyo Balance, trade name: JL-200)²The weight per hit.
[0057]
<Measurement method of water permeability Sc>
Water having a water pressure corresponding to 120 mmHg pressure (16.0 kPa) is 0.5 to 1.0 cm.²The amount of water passing through the sample surface is measured for 60 seconds, and the measured amount of water is 1.00 cm.²Convert to per porous material.
[0058]
<Measurement method of fray resistance Sd>
The fray resistance Sd (kg) is measured by a suture retention test based on ANSI / AAMI (American National Standards Institute / Association for the Advancement of Medical Instrumentation) standard.
[0059]
(Material of tubular body)
The material and form of the tubular body 3 are not particularly limited. The tubular body 3 is preferably made of a flexible material and form from the viewpoint that the tubular body 3 can be easily bent following a lumen such as a bent blood vessel. For example, when the tubular body 3 is made of cloth or film, it is preferable to impart flexibility to these materials by performing bellows processing or the like. For example, in the case where the tubular body 3 is made of a fibrous material (for example, e-PTFE), it is preferable to appropriately take the fibril length and impart flexibility. Here, “e-PTFE” means expanded polytetrafluoroethylene, that is, a polytetrafluoroethylene (Teflon) tube is rapidly stretched to form a myriad of cracks to form a porous state and further to have flexibility. As this e-PTFE, for example, what is generally sold under the product name “Gore-Tex” (Gore, USA) can be used.
[0060]
(Extra fine fiber)
In the present invention, the above-described Q₁≦ 6 × 10^FourOr Q₂As long as at least one of ≦ 300 is satisfied, the material, thickness, thickness, and the like of various porous materials or fibers that can form the tubular body 3 are not particularly limited. As a result of earnest research on the compatibility of the porous material or fiber with the ease of insertion into the living body lumen and the characteristics of the artificial lumen after the insertion of the lumen, the present inventor has made such Q₁Or Q₂It has been found that this relationship can be easily realized, for example, by using a specific amount of specific ultrafine fibers.
[0061]
  That is, in the embodiment of the present invention using such ultrafine fibers, the tubular body 3 is0.089 g / km (0.8 denier)It is preferable that the following (thin) fibers contain 1% or more by weight. this0.089 g / km (0.8 denier)The content of the following fibers is preferably 2% or more, and more preferably 3% or more. From the point that a raised structure is easily obtained, the tubular body 3 is:0.056 g / km (0.5 denier)It is preferable that the following extremely fine fibers are contained in an amount of 1% or more, further 3% or more, particularly 5% or more.
[0062]
In such an aspect of the present invention, as was done in the prior art, the porous material is not simply thinned, but a predetermined amount of predetermined thin fibers are mixed in the fibers constituting the cloth, and cells and The structure is devised to induce an excellent anchoring state of the thrombus.
[0063]
The fiber diameter (denier) constituting the tubular body 3 and the weight ratio of the fibers can be confirmed, for example, by the following method.
[0064]
<Method for confirming fiber diameter>
The sample cloth was embedded in epoxy resin, methyl methacrylate resin, or hydrophilic PHEMA (polyhydroxyethyl methacrylate), and this was sliced into a thickness of 1 to 2 μm with a glass knife, and the sliced sample was optical microscope (magnification: 40). Observe under ~ 200 times). Take the numerical value of 10 of the smallest diameters of the fiber diameter cross section and take the average value.
[0065]
  <Method for confirming fiber weight ratio> A sliced sample is observed under an optical microscope in the same manner as described above. Extra fine fibers (for example,0.089 g / km (0.8 denier)Below), and the number of fibers having other normal thicknesses is arbitrarily selected 10 mm²Measure at 10 locations.
[0066]
Next, the average value of the thickness of each fiber is calculated, thereby calculating the total amount of ultrafine fibers and other fibers, and calculating the weight ratio. In this case, if the types (raw materials) of the ultrafine fiber and the normal thickness fiber are the same, the calculation is performed assuming that the mass per unit is the same.
[0067]
  As described above, the cloth constituting the tubular body 3 in the present invention is, for example,0.089 g / km (0.8 denier)This can be realized by mixing 1% or more of the following thin fibers. Normal (non-fine) fibers are0.133 g / km (1.2 denier)Or0.222 g / km (2.0 denier)The cross-sectional diameter of the fiber is 16μmTo 20μmMet.
[0068]
  In the present invention, for example,0.089 g / km (0.8 denier)In the embodiment using the following thin fibers, the fiber diameter is 5μmLess than(0.056 g / km (0.5 denier)For the following thin fibers, the fiber diameter is 4μmHowever, even if it is only 1% by weight, the number of thin fibers accounts for 3% or more of the total number of fibers,0.011 g / km (0.1 denier)The content of 5% by weight ratio of the following ultrafine fibers is that the number of ultrafine fibers far exceeds the number of other fibers in terms of the number of fibers, that is, the tubular body 3 is an ultrafine fiber having a number of 50% or more. It will be composed of.
[0069]
(Material of cloth)
From the viewpoint of non-carcinogenicity, non-foreign substance reactivity, non-degradability, non-degradability, non-swellability, non-deformability, etc. in the living body, the tubular body 3 is made of polyester, polyamide (in the case where this is made of cloth). It is preferable to include a fiber made of any one of polyolefins.
[0070]
(Form of cloth)
In the present invention, as long as predetermined physical properties are satisfied, the thickness, material, weaving, and the like of the fibers constituting the cloth are not particularly limited. That is, for example, any of knitted fabric, woven fabric, and non-woven fabric can be used in the present invention. Nonwoven fabrics are preferred from the standpoint that the cut ends of the fabric are more difficult to fray.
[0071]
  Among nonwoven fabrics, those in which fine fibers are randomly entangled (by a high-pressure water jet or the like) are particularly preferable. In the fabric of this aspect, the cut end is particularly difficult to fray, and it is easier to prevent the deformation of the shape as the fabric structure. Such entanglement of fibers (particularly extremely complicated entanglement)0.089 g / km (0.8 denier)By including 1% or more of the following extremely fine fibers, it becomes easier.
[0072]
Japanese Patent No. 906347 (Japanese Patent Publication No. 4-59899), US Pat. No. 4,695,280 and European Patent No. 128,741 are conventional arts of artificial lumens using ultrafine fibers. When fine fibers are used by these techniques, it becomes possible to impart flexibility, intimal healing promotion effect, etc. to the artificial lumen. Therefore, although superfine fiber is used also in patent No. 906347 (Japanese Patent Publication No. 4-59899), U.S. Pat. No. 4,695,280 and European Patent No. 128,741, the purpose of use and the effect by use are different from those of the present invention. These publications are completely different, and these publications do not consider the limitation on the thickness of the artificial lumen.
[0073]
That is, in the stent-type artificial lumen of the present invention, a new effect of increasing the anchoring of surrounding tissues and thrombi can be obtained by reducing the thickness while maintaining the mechanical strength of the fabric constituting the stent-type artificial lumen.
[0074]
(Constant load gauge determination of wall thickness)
The cloth constituting the tubular body 3 is preferably as thin as possible when compressed so that it can be easily inserted into the sheath. For that purpose, it is preferable to make it as thin as possible during compression. More specifically, it is preferable to suppress the thickness to C = 0.2 mm or less (further 0.15 mm or less) by the ISO 5084 constant load gauge determination of wall thickness measurement method.
[0075]
On the other hand, after the artificial lumen of the present invention is placed in a blood vessel or the like, it is preferable to exert an anchoring effect so as to give a place for invasion of cells and not release a thrombus. In order to satisfy the structure for obtaining such a state, it is necessary to maintain a state in which a thickness of M = 0.4 mm or more (more than 0.5 mm or more) is maintained by the ISO 5081 microscopic determination of wall thickness measurement method. Is preferred.
[0076]
  The ratio of the two types of wall thickness (M / C) is preferably about 1.1 to 6, more preferably about 2 to 5 (particularly about 2 to 4).
[0077]
In view of the fact that these two conflicting demands can be easily realized, the cloth constituting the tubular body preferably contains 1% by weight or more of ultrafine fibers (0.8 denier or less). Although ultrafine fibers can be easily squeezed, the fiber gaps tend to expand when the squeezing is released. This phenomenon can be easily observed when a fabric made of thick fibers is generally difficult to fold. The phenomenon is also obvious. As a result, it becomes easy for the ultrafine fibers having a wide fiber gap to retain cells and blood clots and exert an anchoring effect. In order to further enhance this effect, it is advantageous to keep the ultrafine fiber in a raised state, as will be described later, but even if it is in a high raised state, it can be easily flattened by compression. And the thickness of the whole cloth at the time of compression is not increased substantially.
[0078]
  To satisfy the above conflicting conditions, ultra-fine fibers (0.089 g / km (0.8 denier)It is most preferred to use The thickness of conventional polyester fiber, polyolefin fiber, and polyamide fiber is about0.133 g / km (1.2 denier)Or0.222 g / km (2.0 denier)It is. In such a conventional fiber, the thinning of the fiber due to compression is limited, and the restoration of the thickness of the cloth by releasing the pressure is limited even if a raised state is provided, and the raised structure is easily crushed by the compression. Even so, some thickness remains. However, when a cloth is made of ultra-fine fibers, the thickness can be suppressed during compression, and the thickness may return when the compression is released. As a result of examining the thickness of the ultra-fine fiber that does not significantly affect the increase in thickness from such a way of thinking, it is also affected by the thickness of the ultra-fine fiber, the total number of fibers,0.089 g / km (0.8 denier)Below, further0.056 g / km (0.5 denier)The following (especially0.044 g / km (0.4 denier)The following fiber) is mixed at a weight ratio of at least 1% or more, further 3% or more (particularly 5% or more), so that both of the conflicting conditions can be easily satisfied.
[0079]
  The ultrafine fiber has an extremely fine fiber diameter compared to a normal fiber. For example, normal polyester fiber is about0.133 g / km (1.2 denier)Or0.222 g / km (2.0 denier)It is. The fiber has a cross-sectional diameter of 16 to 20μmIt is. In contrast, with ultra-fine polyester fiber,0.022 g / km (0.2 denier)Then, the cross-sectional diameter of the fiber is about 3μmIt is.
[0080]
As a general idea, there is room for the possibility that if the cross-sectional diameter of the ultrafine fiber is reduced, the tensile strength is reduced in proportion thereto.
[0081]
However, as a characteristic of the fiber, the thinner the fiber, the more strongly the fiber is pulled in the manufacturing process. Therefore, a special phenomenon in which each polymer in the fiber begins to be regularly oriented along the long axis of the yarn. Can be utilized. In such a case, it is known that the strength of the fiber increases dramatically.
[0082]
Therefore, even when ultra-fine fibers are used in the present invention, it is substantially inferior in strength even when thinned compared to ordinary fibers, and it is substantially impossible to substitute ordinary fibers. I don't get it. Therefore, the flexibility is improved as compared with the fineness, but the strength is not lowered. It can be said that the aspect using the ultrafine fiber of the present invention makes use of the characteristic of the fiber that the fiber is made thin and the strength is not lowered while the fiber is supple.
[0083]
(Foldability)
When the tubular body 3 used in the present invention is formed into a tubular body having an inner diameter of 20 mm, the tubular body 3 is equal to or more than a cloth that can be folded and inserted into a 12F (French; 1 French = 1/3 mm) catheter. It is preferably made of a cloth having a characteristic that can be folded into a small size.
[0084]
(Strength of cloth)
The tubular body 3 is preferably such that at least a part of the fabric constituting the tubular body 3 has a strength of 6 g / d or more (for details of the strength, see Toshihiko Ota et al., “High-strength / high-modulus fiber” polymer). (Academic Society, Kyoritsu Shuppan, 1988)). Examples of such fibers include aromatic fibers (trade name: Kevlar) such as Aramid of DuPont, USA.
[0085]
(Brushed)
In terms of facilitating the compatibility between the ease of insertion into a living body lumen and the characteristics of an artificial lumen after insertion of the lumen, the cloth constituting the tubular body in the present invention has been “raised”. It is preferable.
[0086]
The method of performing such “raising” treatment is not particularly limited, and can be appropriately selected from known raising methods, or two or more kinds can be used in combination.
[0087]
As described above, the stent-type artificial lumen is a phenomenon in which the position is gradually shifted by the stimulation from the pulsation, the compression from the surrounding tissue, the tension by the scar tissue, etc. So-called graft migration may occur. If anchoring by the artificial lumen is weak, it becomes difficult to prevent graft migration.
[0088]
The phenomenon of weak anchoring is a result that often occurs when the fabric with low permeability does not have a raised state. In general artificial lumens (not including expandable members) Since it is not necessary to make it thin, it is possible to create a raised state sufficiently, or to increase the water permeability so that cells can also penetrate into the mesh of the cloth on the blood vessel wall. Should be integrated and the anchoring of the fabric should be good. However, since the conventional stent-type artificial lumen cloth has to have a smooth surface on the outside as described above, there is a drawback that the anchoring described above is weakened.
[0089]
The state of low water permeability without raising can cause inconvenience even on the inner surface. That is, when the implant is successfully received and the cloth is inserted into the blood vessel cavity, in general, a thrombus adheres to the inner surface of the cloth portion, and it is organized to form a film made of stable self tissue. Is expected. Since the inner surface of this membrane is rarely coated with endothelial cells, in many cases it remains as a thrombotic tissue or as a connective tissue attached without endothelial cell coating. It is a reality.
[0090]
  In the present invention, as is done in the prior art, instead of simply thinning the cloth, for example, in the fibers constituting the cloth0.089 g / km (0.8 denier)By mixing the following extremely thin fibers, the structure is devised so as to realize predetermined physical properties as a cloth and induce an excellent anchoring state of cells and thrombus.
[0091]
Furthermore, as another effect of entanglement of thin fibers in a disordered manner by brushing, it prevents the shape of the fabric and prevents complications that may occur after implantation such as endoleak. Can avoid disadvantages.
[0092]
(Suture retention test)
Furthermore, as a countermeasure against deformation, it has a strength equal to or higher than the resistance to fraying of 0.5 kg or more in the ANSI / AAMI standard suture retention test of the porous material artificial lumen used for normal open surgery. preferable. As described above, this condition is a thin cloth artificial lumen and cannot be satisfied with a simple structure.
[0093]
In the present invention, such a condition can be easily satisfied by causing the ultrafine fibers to be entangled in a disorderly and complex manner inside and on the surface of the cloth constituting the artificial lumen. As described above, thin fibers are strong in strength even if they are thin. If the thin fibers are randomly and intricately entangled, no matter what direction the force is applied, they become tightly entangled, and the stronger the stimulus, the closer the entanglement between the fibers, the innumerable The present inventors have also found a phenomenon in which a knot is formed, and as a result, is difficult to fray, even in a thin cloth.
[0094]
  Furthermore, the entanglement of such fine fibers can be entangled more randomly and more complexly as the fiber thickness becomes thinner. As a result of the examination of the thickness of the fiber according to the present invention,0.089 g / km (0.8 denier)Below, further0.056 g / km (0.5 denier)The following (especially0.044 g / km (0.4 denier)When the tubular body 3 containing 1% or more of the following fiber is used, such a complicated and disordered fiber entanglement state can be easily obtained, and 0.5 kg in the ANSI / AAMI standard suture retention test. It has been found that the above fraying resistance can be obtained.
[0095]
Although it is not easy to quantitatively express the ease with which the cloth is deformed, other methods can be used as an index indicating the ease with which the fibers are scattered. It is expressed as fraying ease at the cut end of the fabric. Therefore, it is also possible to express the ease of deformation of the cloth with the resistance to fraying at the site 2 mm away from the cut end by cutting the artificial lumen in the oblique direction with the suture thread at the cut end.
[0096]
That is, if the resistance to fraying at the cut end is high, it is estimated that the cloth is not easily deformed even in a flat state. From this point of view, when the resistance to fraying at the cut end is measured, a general artificial tube for open surgery shows a resistance value of about 0.5 kg. It has been found by the present inventor that it is 0.3 kg or less at about 0.4 mm).
[0097]
  When measuring the strength of the thin cloth entangled with the ultrafine fibers created in this way,0.089 g / km (0.8 denier)Below, further0.056 g / km (0.5 denier)The following (especially0.044 g / km (0.4 denier)It was found that the following fiber) was required to be contained in a weight ratio of at least 1%. Such a state uses the method of entanglement of ultrafine fibers by water jet described in US Pat. No. 4,695,280 and European Patent No. 128,741. It has been found by the inventor's examination that it can be easily obtained. Furthermore, it has been found by the inventor's examination that the fabric having such a method can easily obtain a pressure strength of 20 kg or more by the burst test based on ANSI / AAMI.
[0098]
In order to create a fabric in such a state of “ultrafine fiber entanglement”, it is convenient if the fiber is any one of polyester, polyamide, and polyolefin, but is not necessarily limited thereto. The present technology for obtaining the entanglement of ultrafine fibers can be implemented as long as it is a substance that can be implanted in a living body.
[0099]
The state in which the ultrafine fibers are entangled can be created by, for example, two methods.
[0100]
One is a technique of forming ultrafine fibers from the beginning into a tubular fabric as described in Japanese Patent No. 906347 (Japanese Patent Publication No. 4-59899), US Pat. No. 4,695,280 and European Patent No. 128,741. After the weaving or knitting, the cloth is formed, the raising process is performed such that the fibers are scattered by the raising technique. As a result, it is possible to obtain a state in which countless ultrafine fibers stand up on the surface of the cloth. And by applying a water jet treatment with high-pressure water to entangle these fibers in a disorderly and strong manner, the ultrafine fibers are flexible and easily raised, and the raised ultrafine fibers are looped, One piece is cut and the cut end is raised, and the mixed raised state is seen on both sides of the cloth.
[0101]
In another method, a fabric having a simple woven structure or knitted structure is first made, and then a nonwoven fabric made of ultra-fine fibers is overlapped on the fabric, and a water jet treatment with high-pressure water is performed in that state. By this operation, the non-woven fabric of ultrafine fibers is entangled and integrated with each fiber gap of the substrate, and as a result, a raised state in which the ultrafine fibers rise from the substrate can be obtained. Any method can obtain a state in which the ultrafine fibers are raised on both sides of the cloth.
[0102]
Such a cloth has a tubular shape, but the tubular product tends to kink when bent, and therefore, a crimping process is applied to prevent the kink. Useful. In a stent-type artificial lumen limited to use in a straight portion of a lumen, this crimp structure is less useful than in the case of an artificial lumen for a bent portion.
[0103]
(Water permeability)
The water permeability (or water permeability) based on ANSI / AAMI of the tubular body 3 is 1000 ml · cm.^-2・ Min^-1The following is preferable, and further 500 ml · cm^-2・ Min^-1Below, especially 200ml · cm^-2・ Min^-1The following is preferred. However, since ultra-fine fibers are entangled in the fabric, the leakage of blood from the mesh space of the actual fabric or the fiber gap of the fabric is extremely small compared to a normal porous material artificial lumen having the same water permeability Things can be considered.
[0104]
In the present invention, when a water pressure corresponding to a pressure of 120 mmHg is applied, 500 ml · cm per square centimeter.^-2・ Min^-1In the case of the following water permeability, when formed into a tubular body having an inner diameter of 20 mm, the tubular body 3 having a cloth thickness that can be inserted into a thin catheter of 12 F or less can be suitably used.
[0105]
The ultra-fine fibers that are entangled in this way are completely scattered by the water jet treatment, and as a result, very thin fibers are entangled in the form of spider webs without any corners. For this reason, even if water is passed, thrombus easily adheres, and the thrombus retention ability is exhibited. Therefore, there is a characteristic that blood leakage is extremely reduced. It is described in Japanese Patent Application Laid-Open No. 63-115555 that such characteristics can be obtained when ultrafine fibers are used.
[0106]
(size)
When the artificial lumen of the present invention is actually used in a human living body, the thickness to be used is usually an area having an inner diameter of 3 mm or more and 40 mm or less. However, depending on the application, it is not necessarily limited to this range.
[0107]
(Fixing of tubular body and expandable member)
The tubular body 3 and the expandable member 2 described above may be fixed or connected to each other as necessary.
[0108]
In the artificial lumen of the present invention, the means for connecting or fixing the tubular body 3 and the expandable member 2 is not particularly limited. More specifically, as means for connection or fixation, for example, direct stitching or “hanging” with a polymer (eg, synthetic polymer) material such as polypropylene monofilament yarn or polyester multifilament yarn, The entanglement by a metal thread | yarn etc. can be used. From the viewpoint of adhesion, it is preferable to perform the connection or fixation by direct stitching using a polyester multifilament yarn.
[0109]
Hereinafter, the present invention will be described more specifically with reference to examples.
[0110]
【Example】
  Example 1(Preparation of various artificial lumens) FIG. 1 shows one embodiment (artificial blood vessel) of the configuration of the stent type artificial lumen of the present invention. For example, a cloth tube with bellows0.133 g / km (1.2 denier) denierOf normal thickness polyester fiber (50 wt%) and0.022 g / km (0.2 denier)(Prototype) was made using a super-fine polyester fiber (50% by weight). The inner diameter was 30 mm and the length was 10 cm. A Z-shaped stent for forming a trachea that can be expanded to 40 mm was inserted as an example of the stent, and it was sutured and fixed with 2-0 polyester multifilament yarn. The water permeability of this cloth is about 150ml · cm²・ Min^-1Met.
[0111]
In this prototype, as shown in the schematic perspective view of FIG. 1, the tubular body 3 made of cloth mixed with ultrafine fibers has a crimp structure by heat treatment. Inside the tubular body 3, a Z-shaped metal stent as the expandable member 2 is placed and fixed.
[0112]
Furthermore, as shown in the schematic cross-sectional view of FIG. 2, the tubular body 3 has a plain weave structure with fibers 5 (weft) and 6 (warp) of normal thickness. Ultrafine fibers 7 (longitudinal section) and 8 (transverse section; shown as dots because they are extremely thin) are mixed in the fiber gaps of the cloth. The ultra-fine fibers 4a and 4b are raised on the surface of the cloth. A part of the raised ultra-fine fibers has a loop-like structure 4b, and a part thereof is raised in a state 4a with a cut end protruding. These raised pieces are easily crushed when the cloth is pressed, and the overall thickness of the cloth is not increased extremely.
[0113]
  On the other hand, as a control having a water permeability close to that of the above-mentioned “prototype”, cloth artificial blood vessels of the same thickness and the same length (UBE Industries, UBE-graft) are similarly prepared, and Z is similarly placed inside thereof. A mold stent was inserted and secured. The water permeability of this cloth is about 120ml · cm²・ Min^-1(Control A). In this control product A, as shown in the schematic cross-sectional view of FIG.μm) Fibers are observed in a plain weave state. The weft yarns 9 and the warp yarns 10 intersect in an orderly manner and are closely woven, and there are almost no gaps.
[0114]
  Separately from this, a cloth artificial blood vessel (manufactured by Ube Industries Co., Ltd.), which was prototyped as a cloth that can be easily inserted into the sheath, was obtained, and another control product B having the same thickness and the same length was prepared. The water permeability of this cloth is about 250ml · cm²・ Min^-1(Control product B). In this control product B, as shown in the schematic cross-sectional view of FIG.μm) Fibers are observed in a plain weave state. The weft 11 and the warp 12 intersect in an orderly manner and are closely woven, and there are almost no gaps, but the thickness of the entire fabric is thin, and there is a possibility that water will leak at the intersection of the warp and the weft.
[0115]
As another control product, a commercially available artificial blood vessel having a raised structure was obtained. This is composed only of fibers having a normal fiber thickness, and the normal fiber has a raised structure. With this artificial blood vessel, another control product C having the same thickness and the same length was prepared. The water permeability of this cloth is about 1200ml · cm^-2・ Min^-1(Control product C). In this control product C, as shown in the schematic perspective view of FIG. 5, normal fibers (thickness, about 20 microns) are observed in a plain weave state. The weft yarns 13 and the warp yarns 15 are arranged in an orderly manner, but each fiber is not densely woven and a fiber gap is observed. The warp 15 part is remarkable. A part of the weft 13 is greatly raised to form a large loop 14 from the cloth. This state is a cross section of a cloth having a raised structure made of a cloth having a general thickness.
[0116]
  Each end of the prototype and the control product A are bound, and a vinyl chloride tube is inserted into the other end.didLater, fresh blood collected from the dog was injected into the 50 ml lumen. As a result, both blood vessels were stained red, and blood seemed to leak at first glance, but even if the pressure was increased to 120 mmHg, blood did not leak from the artificial blood vessel wall. Therefore, the water permeability of both is 150 ml · cm²・ Min^-1And 120ml · cm²・ Min^-1However, it was found that both leakages to blood can be prevented and that there is virtually no difference in water permeability.
[0117]
When the same test was performed on the control product B, the blood continued to leak from the artificial blood vessel wall and did not stop until 50 ml of blood had been injected.
[0118]
When the same test was performed on the control product C, blood continued to leak from the artificial blood vessel wall as in the control product B, and did not stop until 50 ml of blood had been injected.
[0119]
Example 2
Cantilever bending resistance Sa (mm) and weight Sb (mg / cm) of various artificial lumens prepared in Example 1²), Water permeability Sc (ml · cm^-2・ Min^-1) And resistance to fraying strength Sd (kg), and based on the measurement results, the product Q₁= (Sa × Sb × Sc), and their combination Q₂= The value of (Sa × Sb ÷ Sd) was calculated. The obtained results are shown below.

[0120]
Example 3
(In vitro insertion test)
In clinical practice, a stent-type artificial blood vessel is inserted into a sheath, is inserted into the blood vessel as it is, is pushed to a target position by a pusher, and is first released and placed in the blood vessel there. Therefore, this test was performed in vitro. First, a prototype and a control product A were prepared, and each was inserted into a sheath (manufactured by Cook) having a length of 24 French and a length of 60 cm.
[0121]
The prototype fabric was flexible, easy to fold, small and thin. And it was easy to insert into the sheath. On the other hand, the control product was difficult to fold, and it was difficult to make it small, but it was barely possible to insert it by making the stump into a funnel shape.
[0122]
The movement of the prototype in the sheath was easy and the pusher could pass through the 60 cm sheath without resistance. In the control product A, there was resistance, but it was possible to pass through the 60 cm sheath by pushing the pusher.
[0123]
  Both who passed through the sheath could not find any changes macroscopically. However, when a part of both cloths are collected and observed with a scanning electron microscope (magnification: 40 times, 100 times, 400 times, 1000 times, 3000 times), the surface of the prototype is 3μmAbout ultra-fine polyester fibers were raised, and no disturbance or damage was found in these fibers.
[0124]
  On the other hand, in the control product A, no change was observed at a low magnification of 500 times or less, but when observed at 1000 times or more, the thickness of the polyester fiber was about 20 times.μmMet. When these fibers were observed in detail, some of the fibers were crushed and damaged. However, no fiber tear was observed.
[0125]
Using the control product B, a passage experiment in the sheath was similarly performed. It was easy to fold the control product B small and thin like the prototype, and it was easy to insert into the sheath and pass through the sheath.
[0126]
However, when the surface of the control product B passing through the sheath and coming out of the sheath stump was observed with the naked eye, there were a plurality of portions where the metal portion of the Z-shaped stent penetrated the fabric and protruded to the outer surface of the fabric. The place was observed.
[0127]
When the control product B passed through the inside of the sheath and went out of the sheath to expand the stent, the metal portion returned to the artificial blood vessel lumen. However, a hole of about 2 mm remained in the cloth of the metal penetration portion.
[0128]
  A part of the control product B after the sheath passage test was taken out and observed with a scanning electron microscope (magnification: 1000 times).μmThere was no damage to the fiber, but weaving of the texture was observed everywhere, and in the part where the metal seems to have penetrated, even if no fiber breakage was seen, a large disturbance was seen in the texture, The fibers were scattered and the holes were open.
[0129]
As a result, the prototype was easy to handle, could easily be folded small, and could pass through the sheath without being damaged. On the other hand, it was revealed that the control product A could not be inserted into the sheath unless forced, and that the polyester fiber was damaged by passing through the sheath.
[0130]
On the other hand, the control product B was easy to handle in the same way as the prototype, but the weave of the fibers was sparse and easy to disperse, and the fiber structure was disturbed by the metal of the stent. It was found that a hole was opened by stimulation.
[0131]
Furthermore, although it tried to insert in a sheath using the control article C, it was impossible to fold small and insertion into the sheath was impossible at all.
[0132]
Example 4
(Physical properties of various materials)
Various physical properties of the five types of ready-made fiber cloth products shown in the following table were measured. The results are shown in the table below.
Products used: Ube-graft (manufactured by Ube Industries), Tregraf (manufactured by Toray), Micron (manufactured by Intervascular), Microknit (manufactured by Goraski), Tracy (manufactured by Toray)
[0133]
[Table 1]

[0134]
Example 5
A simple plain weave cloth (manufactured by Ube Industries Co., Ltd.), which has been reported as a prototype, is thinned to a thickness of 0.2mm, raised parts are pressed, and a product with a smooth surface structure has a caliber of 20mm. As a product (tubular body), a Z-type stent for 24 mm (manufactured by Cook, trade name: Cook-Z (registered trademark) Stent; stainless steel, thickness of linear member 0.5 mm) is inserted into the tubular body. In the laboratory, a stent-type artificial lumen (artificial blood vessel) was created.
[0135]
The stent-type vascular prosthesis obtained above is a 24 French sheath (thickness approximately equivalent to that of an adult male femoral artery), and a length of 50 cm (material: Teflon; manufactured by Cook; Medicos Hirata or Tonokura) The whole was slowly inserted into the tube for about 5 minutes, and the stent-type artificial blood vessel was taken out after 60 minutes. Observation of the removed artificial blood vessel revealed that although the “cut fiber” operation was not performed, the metal part of the stent penetrated the fabric, or the fabric fiber was deformed. Found multiple open parts.
[0136]
In clinical practice, it is impossible to actually observe such a phenomenon, and if a thin cloth that is easily deformed is used, it cannot be prevented. Therefore, if the resulting hole is large, it can cause bleeding, ie endoleak. This is thought to be due to the fact that the density of the knitting and weaving of the fibers has decreased due to the thin cloth and the simplified structure.
[0137]
As described above, the embodiments to which the present invention is applied have been described, but the present invention is not limited to these embodiments, and the shape, material, and the like can be changed without departing from the gist of the present invention. .
[0138]
【The invention's effect】
As described above, according to the present invention, an artificial lumen including an expandable member and a tubular body of a porous material surrounding the expandable member; the bending resistance of the porous material according to the cantilever bending resistance test method is obtained. Sa (mm) and the weight of the porous material is Sb (mg / cm²) And the ANSI / AAMI standard water permeability is Sc (ml · cm^-2・ Min^-1), The product Q of these₁= (Sa × Sb × Sc) is 6 × 10^FourAn artificial lumen is provided that is:
[0139]
Furthermore, according to the present invention, there is provided an artificial lumen comprising an expandable member and a tubular body of a porous material surrounding the expandable member; the bending resistance of the porous material according to the cantilever bending resistance test method is Sa ( mm) and the weight of the porous material is Sb (mg / cm²) And the fraying resistance according to the ANSI / AAMI standard retention test is Sd (kg).₂= Prosthetic lumen with a value of (Sa × Sb ÷ Sd) of 300 or less is provided.
[0140]
  Furthermore, according to the present invention, there is provided an artificial lumen comprising an expandable member and a cloth tubular body surrounding the expandable member;0.089 g / km (0.8 denier)An artificial lumen containing 1% or more by weight of the following fibers is provided.
[0141]
In the stent-type artificial lumen of the present invention having the above-described configuration, the thickness of the tubular body of the stent-type artificial lumen is not simply reduced as in the conventional case, but a combination of physical properties having a specific relationship is satisfied. Since the cloth is used, as described above, it is possible to achieve both the ease of insertion into a living body lumen and the characteristics to be achieved as an artificial lumen after insertion of the lumen. That is, even if the tubular body is thin, it is hard to lose its shape, can be folded and inserted into a thin sheath, and after being inserted into a blood vessel, it satisfies tissue affinity, mural thrombus retention, cell affinity, etc. A stent-type artificial lumen is obtained.
[0142]
Since the stent-type artificial lumen of the present invention is made of a thin and strong cloth, it can be easily inserted into a sheath used in normal surgery, and a thinner sheath can be used. The possibility of injury is reduced, patient discomfort is reduced, and safe surgery is possible.
[0143]
Since the stent-type artificial lumen of the present invention is made of a thin and strong cloth, it is possible to prevent the fiber of the cloth constituting the artificial lumen from being damaged when passing through the sheath. It is possible to provide an appropriate surgical result.
[0144]
Furthermore, in a mode in which ultrafine fibers are raised, the stent-type artificial lumen of the present invention can easily catch a thrombus on the wall of the artificial lumen, and can suppress blood leakage from the artificial lumen wall. .
[0145]
Further, in such an embodiment, the stent-type artificial lumen of the present invention can be guided into the ultrafine fiber raised from the surrounding tissue in the living body after being implanted in the living body. Anchoring between the cavity and surrounding tissue is ensured, the risk of graft migration can be extremely low, and a long-term safe surgical result can be realized.
[0146]
Further, in such an embodiment, the stent-type artificial lumen of the present invention is expected to stably capture the thrombus on the inner surface of the cloth and progress to integration with the connective tissue on the outer surface. It is possible to prevent blood leakage through the blood vessel, so-called endoleak, and to realize a safe postoperative condition.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an embodiment of a stent-type artificial lumen of the present invention, which is composed of ultrafine fibers and a Z-type metal stent.
FIG. 2 is a schematic cross-sectional view of an example of a fabric constituting an artificial lumen of the present invention having ultrafine fibers 4a, 4b, 7 and 8.
FIG. 3 is a schematic cross-sectional view of a cloth constituting an artificial lumen used for a control product A in Examples.
4 is a schematic cross-sectional view of a cloth constituting an artificial lumen used for a control product B in Examples. FIG.
FIG. 5 is a schematic cross-sectional view of a cloth constituting an artificial lumen used for a control product C in Examples.
FIG. 6 is a schematic perspective view showing a “cantilever type” tester used in the bending resistance test method of the present invention.
[Explanation of symbols]
1: Artificial lumen 2: Expandable member (stent), 3: Tubular body, 4a: Brushed ultrafine fiber (rises with a cut end protruding from the cloth), 4b: Brushed ultrafine fiber (cloth) 5: Normal thickness fiber (plain weave yarn), 6: Normal thickness fiber (plain weft warp), 7: Superfine fiber (longitudinal section inside the fabric) Surface), 8: extra-fine fibers (cross section inside the fabric), 9: fibers of normal thickness of the control product A (wefts of plain weave structure), 10: fibers of normal thickness of the control product A (plain weave) Warp of structure), 11: fiber of normal thickness of reference product B (weft of plain weave structure), 12: fiber of normal thickness of control product B (warp of plain weave structure), 13: normal of control product C 14 (fiber weft with a plain weave structure), 14: fiber of normal thickness of the control product C (weft with a plain weave structure, Fibers are brushed-loop shape), 15: warp normal thickness of the fibers (plain weave structure of control product C).

Claims (19)

An artificial lumen comprising an expandable member and a tubular body of a porous cloth surrounding the expandable member; the bending resistance of the porous cloth by a cantilever bending resistance test method is Sa (mm), and the porous cloth When the weight of Sb is mg (cm / cm ² ) and the ANSI / AAMI standard water permeability is Sc (ml · cm ² · min ⁻¹ ), the product Q ₁ = (Sa × Sb × Sc) is 6 × 10 ⁴ or less, and
The artificial lumen, wherein the cloth includes fibers made of any one of polyester, polyamide, polyolefin, and polytetrafluoroethylene. An artificial lumen comprising an expandable member and a tubular body of a porous cloth surrounding the expandable member; the bending resistance of the porous cloth by a cantilever bending resistance test method is Sa (mm), and the porous cloth The weight of Sb (mg / cm ² ) and the anti-fraying strength according to the ANSI / AAMI standard suture retention test as Sd (kg), these combinations Q ₂ = (Sa × Sb ÷ Sd) The value is 300 or less, and
The artificial lumen, wherein the cloth includes fibers made of any one of polyester, polyamide, polyolefin, and polytetrafluoroethylene. An artificial lumen comprising an expandable member and a fabric tubular body surrounding the expandable member; wherein the fabric comprises at least 1% by weight of fibers of 0.089 g / km (0.8 denier) or less; and The artificial lumen according to claim 1 or 2, wherein the fabric includes fibers made of any one of polyester, polyamide, polyolefin, and polytetrafluoroethylene.   The artificial lumen according to any one of claims 1 to 3, wherein the cloth includes fibers of 0.089 g / km (0.8 denier) or less.   The artificial lumen according to claim 1, wherein at least a part of the cloth has a raised structure.   The artificial lumen according to any one of claims 1 to 5, wherein at least a part of fibers constituting the cloth has a strength of 6 g / d or more.   The artificial lumen according to any one of claims 1 to 6, wherein the cloth has a compressive strength of 20 kg or more according to an ANSI / AAMI standard burst test.   The artificial lumen according to any one of claims 1 to 7, wherein at least a part of the fibers constituting the cloth is in a disorderly entangled state.   The artificial lumen according to any one of claims 1 to 8, wherein the cloth has a knitted fabric, a woven fabric, a nonwoven fabric, or a structure in which two or more of these are mixed.   The artificial lumen according to claim 1, wherein the cloth is crimped. The artificial lumen according to any one of claims 1 to 10, wherein the water permeability of the cloth is 2000 ml · cm ² · min ^-1 or less.   The artificial lumen according to any one of claims 1 to 11, wherein an inner diameter of the cloth is 3 mm or more and 40 mm or less.   The artificial lumen according to claim 1, wherein at least a part of the expandable member is made of a shape memory alloy.   The artificial lumen according to claim 1, wherein at least a part of the expandable member is made of a superelastic metal.   The artificial lumen according to claim 1, wherein the expandable member has a multifilament structure.   The artificial lumen according to claim 1, wherein the expandable member has a belt-like structure.   The artificial lumen according to claim 1, wherein the expandable member is made of a synthetic polymer material.   The artificial lumen according to claim 1, wherein the expandable member has a self-expanding function.   The artificial lumen according to claim 1, wherein the expandable member has a function capable of being expanded by a balloon.

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