JPH0528143B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing an artificial blood vessel formed into a tube of fibers and having excellent fraying resistance, antithrombotic properties, and anastomotic properties.

(Prior Art) Conventional artificial blood vessels made of woven or knitted fabrics are woven or knitted fabrics made of polyester fibers, and are very dense, that is, tightly packed, in order to prevent blood leakage from the walls of the artificial blood vessels. It is made of woven or knitted fabric.

(Problems to be Solved by the Invention) Artificial blood vessels made of textiles in particular have poor needle passability during surgery and are extremely difficult to anastomose with biological blood vessels, placing an excessive burden on the operator. . In addition, since it is a simple tissue consisting of only a simple woven tissue, fraying occurs after passing through a sewing needle or when connected to a biological blood vessel, resulting in anastomosis failure. In the worst case scenario, blood may leak and cause instant death, a fatal flaw. Therefore, the conventional means taken to improve fraying resistance and needle passability has been knitting using a very complicated warp knitting structure, as disclosed in, for example, Japanese Patent Application Laid-Open No. 137599/1983. For this reason, the knitting structure had to be complicated, so the fineness of the yarn used had to be made finer, and the knitting machine needed to be very special and highly precise.

The present inventors have arrived at the present invention as a result of intensive study on the above-mentioned problem, which is a fatal defect in artificial blood vessels.

(Means for solving problems) The present invention has the following configuration.

(1) A method of subjecting a tube-shaped fabric having fluff and/or loop-shaped fibers to high-pressure fluid treatment,
After inserting a spacer inside the tube-like fabric, high-pressure fluid treatment is performed to intertwine at least a portion of the fluff and/or loop-like fibers with fibers constituting basic tissue. Production method.

(2) The method for producing an artificial blood vessel according to claim 1, wherein at least some of the fibers constituting the tissue of the tube-like fabric are ultrafine fibers of 0.5 denier or less.

In the present invention, the tube-like fabric may be any of knitted fabrics, woven fabrics, braided cords, etc., and can be arbitrarily selected regardless of the type of structure. Further, the fiber may be one type of fiber, or two or more types of fiber may be mixed or aligned. Also, although it is acceptable to use one type of thread during the formation of the basic structure, it is more preferable to use two or more types of thread.

Polymers used as fibers include polyether, 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 combination components include polystyrene, polyethylene, water-soluble polyamide, alkaline aqueous solution-soluble polyester, water-soluble polyvinyl alcohol, etc., as appropriate. is possible.

In order to make the present invention more effective, at least some of the fibers constituting the tissue have a single fiber fineness.
It is best to use ultrafine fibers of 1.0 denier or less.
By using ultra-fine fibers, we can enhance the three-dimensional entangling effect caused by high-pressure flow, which will be described later, and also create so-called low porous fibers that are extremely flexible and have low blood leakage.
It becomes an artificial blood vessel.

Furthermore, by using ultrafine fibers, the interfibers are fine and numerous, making it easier for cells and fibers to enter, resulting in extremely thin, uniform, and strong fibrin deposition.

However, on the other hand, there are problems such as strength deterioration of fibers in vivo, and in some cases absorption and disappearance (possibly due to a certain hydrolysis effect in vivo), so the thinner the fiber, the better. .

Therefore, in order to solve these characteristics and problems at the same time, the
Ultrafine fibers (A) of denier or less and fibers of more than 1.0 denier, more preferably more than 1.5 denier
It is preferable that (B) forms the skeleton of the artificial blood vessel. (B) Fibers can suppress in-vivo deterioration, while ultrafine fibers (A) can improve fuzz and/or loop development, biocompatibility, flexibility, entanglement, and needle passability.

The fibers used in the present invention may be filament yarns or staple yarns, but filament yarns have the advantage of being able to be adjusted more freely in terms of the wall thickness of the artificial blood vessel.

Furthermore, if the artificial blood vessel has fluff and/or loops, it has good neointimal formation properties, and it is particularly preferable that the artificial blood vessel has fluff and/or loops of ultrafine fibers. It may also be desirable for the outer wall to have fluff and/or loops to enhance adhesion to surrounding tissue, and the present invention can simultaneously achieve this purpose.

Regarding the above-mentioned ultra-fine fibers, when forming blood vessels, fibers that are already in the form of ultra-fine fibers may be used as they are, but fibers that can be made ultra-fine by chemical or physical means may be used to form tubes. may be formed, and then ultra-fine to form a tube of ultra-fine fibers. Ultrafine fibers can be obtained by using normal spinning methods with due care, but it is also possible to create ultrafine fibers by stretching undrawn yarn under specific conditions, as in the case of polyester. be.

On the other hand, as fibers that can be made ultra-fine by post-processing, fibrils can be made by 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 thinner or ultra-fine. In the case of such fibers, during tube processing, even if the fiber is of normal thickness, it can be made extremely fine after processing, resulting in processing problems such as weaving, knitting, stringing, and various thread processing methods before weaving or knitting. This is preferable because it can minimize thread breakage, fuzz generation, etc. when threading.

The most distinctive feature of the present invention is that high-pressure fluid treatment is applied to a tubular fabric such as an artificial blood vessel. Although high-pressure fluid treatment is commonly performed on sheet-like objects, it is unthinkable to perform high-pressure fluid treatment on tube-like objects, especially artificial blood vessels. This is because if a tube-shaped object is folded flat and processed, the inner surfaces will intertwine and become integrated, and if high-pressure fluid is prevented from penetrating to prevent integration, there will be a place where a large amount of water can escape. disappears.

This is because not only does entanglement not occur, but also the shape of the tube-like object cannot be maintained. Further, in order for the fibers to intertwine, movement of the fibers is essential, and for this purpose, it is thought that the insert must be considerably smaller than the inner diameter of the tube-like object.

However, as a result of extensive research, the inventors of the present invention have found that by inserting a spacer such as a cylindrical object, a rod-like object, or a plate-like object inside the tube-like object, the tube can be prevented from being pinched by the inner walls during high-pressure fluid treatment. ,
It has been unexpectedly discovered that the initial objective of the present invention can be achieved by taking care to prevent the tube-like material from twisting or wrinkling.

In the present invention, based on the above-mentioned technical concept, it is necessary that at least a portion of the fluff and/or loop-like fibers be intertwined with the fibers constituting the basic structure. With such a configuration, an artificial blood vessel with excellent fraying resistance, antithrombotic properties, and anastomotic properties can be obtained.

In particular, regarding fraying resistance, in the past, the sutured parts of living blood vessels and artificial blood vessels were easily frayed during or after suturing, resulting in blood leakage and, in the worst case, instant death, which was a fatal flaw. The fraying resistance of the artificial blood vessel obtained by the invention is significantly improved.

The method of manufacturing the artificial blood vessel according to the present invention is a method that uses high-pressure flow, and it is particularly preferable to form fuzz and/or loops on the fabric before injecting the high-pressure flow. Fluff and/or
Alternatively, the loops can be formed by a method used when forming the basic structure, such as pile or cut pile woven or knitted fabrics, but satin structures may also be used, and heat treatment or chemical treatment may be applied. It may be a loop due to a yarn length difference caused by a difference in yarn length, or a yarn length difference caused by a combination of tissues that have been given a contraction difference, for example. In addition, typical methods include raising treatment after weaving or knitting, such as a method using a raising machine, a method using a shearing machine, and a method of rubbing with sandpaper in some cases, but the present invention is not limited to these methods. Not something to be held back by,
It is important that fluff and/or loops are formed before the high pressure jet treatment.
In some cases, it may be better to treat both the inner wall surface and the outer wall surface to form fuzz/loop.

Although various methods for the entanglement treatment using high-pressure flow can be considered, a method using a liquid is more efficient, and among them, a method using a water jet flow is the most preferable from the viewpoints of safety and economy. i.e. 5-200
Kg/cm ² waterjet punch is used to spray water from a small hole onto the surface having fluff and/or loops (in some cases, both sides may have fluff and/or loops) and/or the back surface thereof. good. If the injection pressure is too low, the fibers will not become tangled, but if the injection pressure is too high, the fibers will be cut, which is not good. Within this range, the strength of the fiber, the fineness at that time, the thickness of the bundle,
In addition, it can be appropriately determined depending on the flexibility of the artificial blood vessel.

In addition, high-pressure flow treatment can be performed by injecting high-pressure flow from a nozzle with many small holes that can be sprayed toward the artificial blood vessel from a part larger than the thickness of the artificial blood vessel, or by flattening a tube-shaped object. This can also be done by folding it into a shape and injecting a high-pressure stream through a number of small holes located parallel to it. In this case, a spacer such as a cylindrical net, plastic, metal, glass, or in some cases foam, which may or may not pass through water, is placed inside the tube. By inserting the tube and performing high-pressure fluid treatment, the tube does not get stuck between the inner walls, making subsequent treatment easier, and in some cases, it can be used as a method to control the diameter of the tube. Can be used.

Further, it is preferable that the waterjet punch be oscillated from side to side or cyclically so as not to match the period of the basic tissue. Thereby, punch lines and moire phenomena can be reduced.

Furthermore, if the tube-shaped article is turned over and subjected to high-pressure flow treatment, the fraying resistance can be further improved, but this is not always necessary.

In addition, in the production of artificial blood vessels, it is necessary to form a fabric into a tube, and the method for forming a tube is to cut the fabric, then create a tube-like object by sewing, gluing, or fusing. However, when forming the basic structure, it is more preferable to form it into a tube shape, since there is no seam. In the former case, that is, when first forming a sheet-like object and then forming a tube-like object, the above-mentioned napping treatment etc. may be performed at the sheet-like stage or after forming the tube-like object. Of course.

(Examples) Next, the present invention will be explained more clearly using examples, but the validity and scope of rights of the present invention are not limited or restricted thereby.

Example 1 The warp yarn and the weft yarn (back yarn) were made of polyethylene terephthalate 50 denier 24 filament temporarily twisted yarn, and the weft surface yarn was a polymer array composite fiber containing 78 parts of island component polyethylene terephthalate and sea component polystyrene 22. Using 245 denier 40 filament yarn with 36 islands, it is woven into a tube shape with a so-called weft double weave structure, inner diameter 19 mmφ, length 100 cm.
A tube was formed, washed with hot water, and after drying, the polystyrene was removed with perchlorethylene. Next, a napping treatment agent was applied to this tube, and then the tube was napped using a napping machine.

The diameter of the tube obtained was 8.5 mmφ.
Next, after inserting a polyester film (spacer) with a width of 24 mm and a thickness of 0.12 mm into the tube, the discharge hole diameter was 0.25 mmφ, the discharge hole interval was 2.5 mm, and the pressure was 70 Kg/cm ²
Water jet punch treatment was performed under these conditions.

The basic structure of the obtained artificial blood vessel was a double-layer structure, but it was observed that a large number of ultrafine fibers were mainly entangled between single fibers, between weaves, and between fiber bundles. The fraying resistance of the artificial blood vessel and the one before water jet was examined. The fraying resistance was determined by cutting the artificial blood vessel at an angle of 45 degrees to the axis with scissors, passing a suture through the 2 mm stump, and measuring the fraying strength using a tensile tester. As a result, those who do not perform water jet punch. The weight of the artificial blood vessel was 1.7Kg, whereas the weight of the artificial blood vessel was 1.7Kg. There were also fuzz and loops on both the inner and outer walls of the tube.

Example 2 When the artificial blood vessel obtained in Example 1 was turned over and waterjet punched again under the same conditions, the fluff and/or loops and fiber bundles of the ultrafine fibers were found to be more entangled than in Example 1. It was observed that there were.

Example 3 Using polyester fibers of 50 denier 18 filament and 50 denier 72 filament, a tube with a diameter of 20 mmφ was formed with a half structure using a 2-needle type, 30G double lash knitting machine, washed with boiling water, and then dried. A post-raising treatment was performed. When observing the condition after raising, it was found that the fine-grained fibers formed more raised fluff and loops than the thick-fiber fibers. Furthermore, after inserting a stainless steel rod (spacer) of 16 mm in diameter into the tube, waterjet punching was performed under the conditions of a discharge port of 0.3 mm in diameter, a discharge hole interval of 2.5 mm, and a pressure of 75 kg/cm ² .

When we observed the obtained artificial blood vessel, we found that fine fibers were entwined with thick fibers.
It was found that it reached between the fibers, between the stitches, and between the fiber bundles. Although relatively rare, it was also observed that large fineness was intertwined with fineness. It was also observed that the fibers were present in the form of fuzz or loops, and that some fibers of the fuzz or loops penetrated between or within the fiber bundles and reached the inner wall of the tube. When the fraying resistance of this artificial blood vessel was investigated, it was found that not only was the fraying resistance improved compared to one that was not subjected to waterjet punch treatment, but there was also extremely little drop-off of floating threads that occurred at the stump. In particular, the fraying resistance from the end of the stitch was much improved.

(Effect of the invention) The effects of the present invention are enumerated as follows.

(1) The fraying resistance, antithrombotic properties, and anastomosis properties have been dramatically improved.

(2) Fuzz and/or loops can be easily formed on both sides at the same time.

(3) Since it is a means for post-processing, the basic structure can be made simple or complex depending on the purpose.

(4) Loss of hair or floating hair caused by hair raising treatment etc. can be substantially eliminated by washing or re-entangling.

As mentioned above, we have solved all the problems that were impossible with conventional technology at once, and developed a method for producing an artificial blood vessel that is extremely flexible, has excellent needle passability and fraying resistance, and has excellent neointimal formation. I was able to find out.

Claims (1)

[Scope of Claims] 1. A method of subjecting a tubular fabric having fluff and/or looped fibers to high-pressure fluid treatment, the method comprising: inserting a spacer inside the tubular fabric, and then subjecting the tubular fabric to high-pressure fluid treatment; A method for manufacturing an artificial blood vessel, comprising intertwining at least a portion of the fluff and/or loop-like fibers with fibers constituting basic tissue. 2. The method for manufacturing an artificial blood vessel according to claim 1, wherein at least some of the fibers constituting the structure of the tube-like fabric are ultrafine fibers of 0.5 denier or less.