JPS6158190B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an artificial blood vessel with excellent anastomotic properties, antithrombotic properties, and shape retention properties.

(Prior art) The main properties required for an artificial blood vessel are, needless to say, non-toxicity to the living body and no deterioration in the living body due to intense fatigue; That's what I'm doing.

(2) Excellent anastomosis with biological blood vessels.

(3) Excellent shape retention.

Examples include. In the present invention, antithrombotic properties mean that vascular endothelial cells (new blood vessel walls) are formed immediately after transplantation.

Conventional artificial blood vessels are woven or knitted fabrics made of polyester fibers with a single yarn fineness of normal thickness.In addition, they are made of extremely high-density polyester fibers to prevent blood leakage from the artificial blood vessel walls and to maintain their shape. It is made of tightly woven and knitted fabric. For this reason, even though softening measures such as crimping have been taken, the material is extremely hard, making it difficult to pass through the needle during surgical sutures, and the blood vessels of the living body are hardened due to arteriosclerosis. If there is a problem, it can be a major cause of anastomosis failure between the biological blood vessel and the artificial blood vessel, leading to risks such as massive bleeding. Moreover, if the texture of the woven or knitted fabric is made coarse to improve anastomotic properties, blood leakage cannot be prevented.
This was an even more important problem especially when anticoagulants were administered.

Furthermore, a serious problem with conventional artificial blood vessels is that the formation of vascular endothelial cells is slow and non-uniform. In other words, because it is a woven fabric made of thick fibers and tightly packed, there is no scaffold for vascular endothelial cells to form, and even if cells once adhere to them, they are easily washed away by blood flow. This causes serious problems such as not only endothelial cells not being formed but also the blood clots that flow out occluding the narrow blood vessels on the peripheral side.

As a means to simply provide a scaffold for vascular endothelial cell formation, published patent publications 117287-1987 and 52-
94699, 52-113094, and 53-137599, methods of forming loops on the surface of knitted fabrics are disclosed. However, since all of these are made of fibers of normal thickness, they are insufficiently effective in forming scaffolds, and they also lack other properties required for artificial blood vessels, such as needle-passability and anastomotic properties. It has not been possible to obtain an artificial blood vessel that fully satisfies the characteristics necessary for easier operation, shape retention, appropriate blood leakage, and compatibility with living organisms.

In particular, if emphasis is placed on preventing blood leakage and shape retention, problems will arise with anastomotic properties and needle passability, and if emphasis is placed on anastomotic properties and needle passability, problems with blood leakage and shape preservation will occur. It was impossible to satisfy all the factors.

(Objective of the present invention) The present invention aims to improve the drawbacks of the conventional artificial blood vessels, and the purpose is to form vascular endothelial cells (new blood vessel walls) extremely early and uniformly, resulting in low blood leakage. The present invention relates to an unprecedented high-performance artificial blood vessel that has excellent shape retention, such as virtually no flattening or bending during or after surgery, is flexible, and has excellent anastomotic properties with living blood vessels.

(Structure of the present invention) That is, the present invention provides: (1) A woven or knitted fabric consisting of multiple structures, having at least a portion of ultrafine fibers (A) of 0.5 denier or less on the inner wall and/or outer wall, and having a base structure. The constituent threads are mainly fibers of 1.0 denier or more (B)
An artificial blood vessel characterized by comprising:

(2) An artificial blood vessel characterized by further comprising piloere formed on the inner and/or outer walls of the artificial blood vessel.

(3) An artificial blood vessel further characterized in that a bulky textured thread is used as the ground thread.

(4) An artificial blood vessel further characterized in that the ultrafine fibers (A) and the fibers (B) are formed from any one of polyester, polyamide, polyolefin, and polytetrafluoroethylene.

(5) Furthermore, an artificial blood vessel characterized by a water permeability of 2000 ml/min or less.

It is related to.

The most characteristic feature of the present invention is that ultra-fine fibers (A) are used, and the weaving and knitting structure is devised to make more effective use of the ultra-fine fibers by using a multiple weaving and knitting structure. By using ultra-fine fibers (A), the tube does not become hard and flexible even when the weaving density is reduced, and it has excellent needle passability, and surprisingly, vascular endothelial cells (new blood vessel walls) form quickly and uniformly. is formed. Although the latter effect cannot be fully explained, the state of fibrin deposition is thought to have a very important meaning in the formation of vascular endothelial cells. It is not inconceivable that this is because fibrin is deposited extremely thinly, uniformly, and firmly because the fibrin is formed in large numbers and minutely, making it easier for cells and fibers to enter. In addition, by using ultrafine fibers (A) not only on the inner wall but also on the outer wall of the blood vessel, it blends well with the surrounding tissue of the blood vessel and has the effect of improving adhesion of the surrounding tissue, but it is not necessary for the outer wall. It may not be.

The ultrafine fibers (A) of the present invention refer to ultrafine fibers of 0.5 denier or less, preferably 0.2 denier or less, and for blood vessel formation, fibers that are already in the form of ultrafine fibers are used as they are. However, it is also possible to form tubes using fibers that can be made ultra-fine by chemical or physical means, and then ultra-fine the tubes so that the tubes are formed from ultra-fine fibers as a result. good. Ultra-fine fibers can be obtained by using normal spinning methods with due care, but it is also possible to make ultra-fine fibers by stretching undrawn yarn under specific conditions, as in the case of polyester. It is.

On the other hand, fibers that can be made ultra-fine by post-processing include removing or exfoliating one component of multicomponent fibers, as seen in Japanese Patent Publication No. 48-22126, Japanese Patent Publication No. 53-22593, etc. It means a type of fiber that becomes fibrillated or ultra-fine. In the case of such fibers, during tube processing, even if the fiber is of normal thickness, it can be made ultra-fine after processing, resulting in processing problems such as when weaving or knitting, or by taking various yarn processing methods before weaving or knitting. This is preferable because it can minimize the occurrence of thread breakage and fuzz generation.

Polymers used as fibers include polyester, polyamide, polytetrafluoroethylene,
Although it does not matter what kind it is, such as polyolefin,
Particularly preferred is polyester. When using multi-component fibers, the final polymer remaining is the above-mentioned polymer, but other combined components include polystyrene, polyethylene, water-soluble polyamide, alkaline aqueous solution-soluble polyester, water-soluble polyvinyl alcohol, etc., as appropriate. is possible.
The combination of such polymers is determined depending on the case, taking into account spinning properties, processability, and functionality.

Further, the ultrafine fiber (A) may be a so-called filament yarn or a staple yarn, but filament yarn is often preferable from the viewpoint of fluff removal. On the other hand, the fiber (B) is preferably a multifilament yarn or staple yarn of 1.3 denier or more than 1.0 denier obtained by a normal spinning method. In some cases, monofilament yarn is preferable, but multifilament yarn is preferable. Filament yarn is preferred in many cases, and it is more preferable to use textured yarn that has been subjected to a bulking process such as a temporary twisting process, since needle passability and flexibility can be further improved.

Woven and knitted fabrics having multiple textures as referred to in the present invention include, for example, double weft texture, double warp texture, double warp texture, texture with three or more layers in each side, texture with three or more layers in warp, weft pile texture, warp pile texture, etc. Specific examples include woven fabrics with applied structures, cut piles, and combinations of these structures; I can do it.

In addition, the yarn used in the multi-layer structure uses ultra-fine fibers (A) and/or aligned or mixed fibers of ultra-fine fibers (A) and fibers (B) to form the surface structure. The fibers used are fibers (B) and/or aligned or mixed fibers of ultrafine fibers (A) and fibers (B). In the present invention, the inner wall and/or outer wall of the artificial blood vessel is made of superficial tissue, and the outer wall and/or the so-called intermediate wall between the inner wall and the outer wall is made of ground tissue. The threads that make up the ground weave are called base threads, core threads, core threads, etc., and the ground weave is sometimes called back weave. By selecting these multiple tissues and threads, we can coat the inner wall of the blood vessel and/or the ultra-fine fiber (A) of 0.5 denier or less with excellent endothelial cell forming properties.
Alternatively, by actively forming fibers (B) on the outer wall and/or actively forming the fibers (B) on the so-called intermediate wall between the inner wall and the outer wall, it is possible to simultaneously enhance shape retention. . In addition, the presence of ultra-fine fibers (A) and fibers (B) in appropriate amounts in the inner wall and/or outer wall, and/or in the so-called intermediate portion between the inner and outer walls provides needle passability and flexibility at the same time. It became possible to do so. Therefore, by appropriately selecting the weaving/knitting structure and thread usage, it is possible to improve the endothelial cell forming property of the artificial blood vessel and its compatibility with the living body, while at the same time imparting needle passability, flexibility, and shape retention. In addition, it has become possible to create an artificial blood vessel that matches the site and purpose of use.

As a means of forming a tube, it is possible to make a woven or knitted fabric, then cut it, and then make it into a tube-like object by sewing, gluing, or fusing. More preferred.

In order to make the present invention even more effective, it is preferable to form raised pili of ultrafine fibers (A) on the inner and/or outer walls of blood vessels. However, the fibers that are napped are not limited to only the ultrafine fibers (A), but the fibers (B) may coexist, and all of the fibers (B) do not need to be napped.

Furthermore, the term "napped" as used in the present invention refers to something that has loops and/or fluff, and the means for creating the napped includes means for creating loops during weaving or knitting;
For example, typical methods include pile woven and knitted fabrics, their cut and pile methods, processing after forming woven and knitted fabrics, such as raising with a napping machine, methods using a shearing machine, and in some cases, buffing with sandpaper. However, the present invention is not limited to these means only. In addition, although the napping state can be adjusted depending on the purpose, an unexpected effect of the present invention is that since ultra-fine fibers are used, even if the napping state varies somewhat, the performance is relatively small and stable performance is exhibited. . On the other hand, determining the fiber density when forming an artificial blood vessel is a very important issue, and the requirements vary depending on the case, making it difficult, but it is practical and convenient to look at the water permeability as a reference. be. The water permeability referred to here is 120
It refers to the amount of water (ml) that passes ^per minute per cm2 of fabric under mmHg pressure. In the present invention, this value is 2000ml/min.
It is more effective in the case of an artificial blood vessel with a low water permeability, preferably 1000 ml/min or less, more preferably 500 ml/min or less.

However, this value is just a guideline and should not necessarily be used as a guideline.
Even products with a water permeability of around 300ml/min or 5000ml/min show superior properties in terms of vascular endothelial cell formation and anastomosis compared to conventional products. However, the overall effect is particularly exhibited under low water permeability. Normally, it is extremely difficult to form endothelial cells under such low water permeability, but when ultrafine fibers are used as in the present invention, this formation becomes easy, probably because the fibers and cells are well compatible. In addition, the artificial blood vessel of the present invention can sufficiently achieve its purpose without crimping, so crimping is not necessary, but it may be effective in cases where more flexibility and higher shape retention are required. There is also.

(Effects of the present invention) The present invention has been described in detail above, and the artificial blood vessel of the present invention using ultrafine fibers is highly flexible despite its extremely low leakage, and has significantly improved anastomotic properties. Not only that, but because they are ultra-fine fibers, the number of scaffolds suitable for biological cell attachment increases significantly, increasing compatibility with the fibers, exhibiting excellent antithrombotic properties, and forming endothelial cells at an extremely early stage. This process was carried out successfully and successfully, resulting in an unprecedented artificial blood vessel.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 A 50-denier 24-filament polyethylene terephthalate yarn with temporary twisted texture was used for the warp yarn and the weft yarn (back yarn), and the weft surface yarn was made of Japanese Patent Publication No. 48-22126.
Composite fiber defined by 78 parts of island component polyethylene terephthalate, 22 parts of sea component polystyrene, number of islands
Using 36 island fibers of 245 denier and 40 filament, weave them into a tube with a so-called double warp, weft, and quadruple weave structure to form a tube with an inner diameter of 17 mmφ and a length of 100 cm, which was then washed with hot water, dried, and perchlorethylene. The polystyrene was removed. Next, this tube was brushed using a napping machine. The tube was washed with hot water, dried, turned over, sterilized with ethylene oxide gas, and then transplanted into the descending thoracic aorta of a dog. The water permeability of this fabric was 295 ml/min.

When transplanting into the aorta of a dog, suturing with the living blood vessel was extremely easy and successful. In particular, it had good needle passability and was soft, so it had excellent suturing and anastomosis properties. Pre-clotting immediately before transplantation was not performed due to low water permeability, but almost no blood leakage was observed. However, blood seeped all over the cloth, turning it red.
Afterwards, the results of observing the excised specimen of the artificial blood vessel showed that on the second day, the red color immediately after transplantation faded to pale red, and on the 20th day, blood seepage had decreased and neointimal formation was marked. It was observed that this was occurring, and after 2 months, granulation-like swelling was observed, which indicates that the formation of neointima is very active. After about 3 months, the neointima on the inner wall of the blood vessel was almost completed and had become a shiny grayish white color. This result shows that the healing time is significantly shortened compared to conventional artificial blood vessels.

Claims (1)

[Scope of Claims] 1. A woven or knitted fabric consisting of multiple structures, and having ultrafine fibers of 0.5 denier or less on the inner and/or outer walls.
What is claimed is: 1. An artificial blood vessel comprising (A) at least in part, and wherein the base threads constituting the base tissue mainly consist of fibers (B) of 1.0 denier or more. 2. The artificial blood vessel according to claim 1, characterized in that the inner wall and/or the outer wall are formed with standing piloere. 3. The artificial blood vessel according to claim 1 or 2, characterized in that a bulky textured yarn is used as the ground yarn. 4. Claims 1 to 3, characterized in that the ultrafine fibers (A) and/or the fibers (B) are made of polyester, polyamide, polyolefin, or polytetrafluoroethylene. Artificial blood vessel described in. 5. The artificial blood vessel according to claims 1 to 4, which has a water permeability of 2000 ml/min or less.