JPH01155860A - Artificial blood vessel - Google Patents

Abstract

PURPOSE:To enhance stretchability and kink resistance and to facilitate suturing operation, by applying spiral crimp processing to a tube and properly determining the relation between the inner diameter of the tube and a crimp height and the relation between the lengths of the tube before and after crimp processing. CONSTITUTION:A tube formed by knitting a thermoplastic resin fiber is subjected to spiral crimp processing. At this time, the relation between the inner diameter Xmm of the tube and a crimp height Ymm (Y>=1) is set to 1/20(X+11)<=Y<=1/8(X+2). Further, the relation between the length L0mm of the tube before crimp processing and the length Lmm thereof after crimp processing is set to 0.15<=L/L0<=0.75.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a method for applying crimping to an artificial blood vessel made of a knitted fabric of thermoplastic resin fibers, particularly a tube knitted and woven from polyester fibers, that is, polyethylene terephthalate spun fibers. This invention relates to artificial blood vessels with improved cord characteristics such as application, rigidity, and sutability.

[Conventional technology]

Historically, knitted fabrics using polyamide or acrylic fibers have also been used for artificial blood vessels. Currently, artificial blood vessels made of polyester or polytetrafluoroethylene are mainly provided.

Current requirements for artificial blood vessels are wide-ranging, such as non-toxicity, no foreign body reaction, durability and no deterioration, appropriate elasticity, antithrombotic properties, and organization. There are many conditions such as good healing, ease of suturing, ability to produce various shapes, little blood leakage, and resistance to infection.

The various thermoplastic resins mentioned above have been used as materials, but among them, polyester synthetic fibers are chemically stable, highly durable, and have little tissue reaction.
They are often used as blood vessel substitutes, and are made of tubular plain weave or stockinette knits.For example, monofilament sheets of 1 to 3 denier (the weight of a thread with a length of 9000 m (unit: g)) are used, and several dozen to several For example, a tube made of 100 bundles of threads woven into a tube shape.Artificial blood vessels made of these tubes have a smooth wall structure, and the inner lumen may become occluded due to bending inside the body or bending due to external pressure (kinking phenomenon). In order to prevent this, the packaging material is made into a product through a process called crimping. (The product becomes a so-called bellows-shaped tube.) Regarding this crimping process, for example, U.S. Patent No.
No. 37673 describes that a cloth tube is fitted onto the surface of a round bar, threads are spirally wound around the tube at equal intervals, the tube is compressed in the axial direction to form pleats, and then heated. A heat setting technique is disclosed.

However, artificial blood vessels that have been subjected to crimping conventionally have a problem in that the finished product has high rigidity (the product is hard), especially when it is made from a woven fabric such as plain weave. If the artificial blood vessel has high rigidity, there will be great resistance when the suture needle used to connect it to the living blood vessel penetrates.
Suturing operation is not easy. In addition, in suturing operations, it is necessary to bend the end of the artificial blood vessel, but the bending force is large, making the surgical technique difficult and applying a large force to the living blood vessel, which can damage the blood vessel wall. Sometimes.

The reason why the conventional crimped artificial blood vessels have high rigidity is that the woven fabric artificial blood vessels are generally applied to large-diameter blood vessels in the chest and abdomen, and to suppress bleeding. In addition to the fine weave, the shape and structure of the crimp part were not appropriate. That is,
The crimp portion of the conventional product is an artificial blood vessel having so-called fine folds, in which the length of one side of the fold is short, the depth is shallow, and the distance between the fold vertices is short. Specifically, for example, regardless of the diameter of the artificial blood vessel, the length of one side of the fold is 0.5 to ls+
It is an artificial blood vessel that has been strongly compressed so that the distance between the apexes is approximately 1.5 mm and the distance between the apexes is extremely small. Therefore, in addition to increased rigidity, it also becomes a cause of elongation and meandering within the body over time after implantation.・ [Means for solving the problems] The present invention has longitudinal extensibility and high kinging resistance, and has excellent caliber recovery property when the load is removed from the flattened state due to load. The present invention also relates to an artificial blood vessel that is highly flexible, easy to suture, and less elongated over time.

That is, the present invention provides a tube formed by knitting and weaving thermoplastic resin fibers, which tube is spirally crimped and has a tube inner diameter X (sa) and a crimp height Y.
(gem) (Y≧1) and 1/20(X+11)≦
There is a relationship of Y≦1/8 (X+2), and the tube length LO (m1m) before crimping and the tube length ++n after crimping are 0.15≦l;/lo≦ The present invention relates to an artificial blood vessel made of a tube having a relationship of 0.75.

In the artificial blood vessel of the present invention, the relationship between the tube inner diameter and the crimp height and the ratio of the tube lengths before and after crimping are extremely important. If the crimp height is less than the limited range, a kink phenomenon is likely to occur (or occlusion of the artificial blood vessel).

If it exceeds the limited range, the unevenness of the lumen becomes large, blood stagnates, a large amount of thrombus is formed, and the artificial blood vessel is likely to be occluded. Furthermore, if the ratio of the tube lengths before and after crimping is less than a limited range, the kink phenomenon will be less likely to occur, but the rigidity of the artificial blood vessel will increase, making suturing operations difficult. Furthermore, after transplantation, the elongation within the body increases over time. If it exceeds the limited range, the kink phenomenon tends to occur, leading to occlusion of the artificial blood vessel.The ratio of the tube length before and after crimping (L/Lo) is preferably 0.40 to 0.65. .

Examples of the thermoplastic resin forming the thermoplastic resin fiber include polyolefins such as polyethylene and polypropylene, polyamide, polyurethane, and polyester. In particular, polyester, which is chemically stable, highly durable, and exhibits little tissue reaction, is particularly suitable, especially polyethylene terephthalate.

0 This is obtained by a normal method using a thermoplastic resin.
A tube is formed from a cloth made by knitting and weaving yarns consisting of tens to hundreds of twisted monofilaments of approximately 5 to 5 denier as warp and weft yarns.

For crimping, the tube is fitted onto a threaded rod whose surface has been thoroughly polished, and an appropriate thread is wound along the thread groove.
This is carried out by heating and heat-setting the product as it is. The wrapping is done under sufficient tension so that the tube deforms to approximately conform to the shape of the thread.

The thread to be wrapped around the tube surface is not particularly limited as long as it has heat resistance against heating during heat setting and strength to withstand tension when wrapped, and does not alter the quality of the tube.
It is preferred to use threads made of the same material from which the tube is made.

The material of the threaded rod is not particularly limited, but any material may be used as long as it does not adversely affect the tube into which it is fitted, such as deterioration, and is heat resistant to heating during heat setting. Stainless steel threaded rods are preferred in consideration of availability and price.

The shape of the crimp of the artificial blood vessel of the present invention matches the thread groove of the threaded rod used.

Therefore, the depth and pitch of the thread groove of the threaded rod are extremely important and are selected in accordance with the intended crimp shape.

The present invention will be explained in more detail below with reference to Examples.

Example 1 A 1.0 denier polyethylene terephthalate fiber was twisted to obtain a yarn having a warp of 50 denier and a weft of 100 denier. A plain weave tube was made using this yarn. When this tube was flattened and the weaving width was measured, the tube diameter was 20.2 mm+φ.

After washing this tube with water, the surface was thoroughly polished and the outer diameter was 20 mm.
It was fitted onto a 15O general purpose metric thread made of stainless steel with a diameter of a+mφ, and a polyester thread was wound around it along the thread groove with a tension of 1 kg, and then heated to 170°C.
Heat setting was performed by heating at a temperature of 30 minutes. After heat setting, the tube was removed from the threaded rod, washed with methanol and water, and dried.

The inner diameter of the obtained crimped artificial blood vessel was 18.0III.
IIl, crimp height was 2.0. Further, the ratio of the tube lengths before and after crimping was 0.55.

A length of 15C11 of this artificial blood vessel was taken, and both ends of the artificial blood vessel were held in close contact with a cylinder with a diameter of 4 mm, and the kink phenomenon was observed, but no kink phenomenon occurred.

Further, when a 9-needle 3-0 for blood vessel suturing was inserted at a position 3 mm from the stump of the artificial blood vessel, the needle easily penetrated.

Furthermore, when this artificial blood vessel was made flat and a needle was passed through the overlapped portion of the two layers, the needle still penetrated easily. The operation of folding the residual limb between the bin sets was also easy.

In order to perform an accelerated test for elongation over time, the elongation was measured after high-pressure steam sterilization at 132°C for 15 minutes, and the elongation was extremely small at 3.1% or less.

Example 2 A 1.3 denier polyethylene terephthalate fiber was twisted to obtain a yarn having a warp of 94 denier and a weft of 188 denier. When the weaving width was measured in the same manner as in Example 1, the tube diameter was 14.2 amφ.

After washing this tube with water, the outer diameter 14
Insert it into a stainless steel l5O-general metric thread of a+mφ, fix it with both ends pulled so that L/Lo is 0.70, and then thread a polyester thread over it along the thread groove. After wrapping with a tension of 1 kg,
Heat setting was performed by heating at a temperature of 170° C. for 40 minutes.

After heat setting, the tube was removed from the threaded rod, washed with methanol and water, and dried.

The inner diameter of the obtained crimped artificial blood vessel was 12.2II1
11 crimp height was 1.3.

This artificial blood vessel was taken to have a length of 15 am, and its two ends were brought together to form an arc shape, and the kink phenomenon was observed, but no kink phenomenon occurred.

Further, when a nine-needle 3-0 for blood vessel suturing was inserted at a position 3Il1m from the stump of the artificial blood vessel, the needle easily penetrated. Furthermore, when this artificial blood vessel was made flat and a needle was passed through the overlapped portion of the two layers, the needle still penetrated easily. It was also easy to pinch the residual limb with tweezers and fold it back.

In order to conduct an accelerated test for elongation over time, the elongation was measured after high-pressure steam sterilization at 132°C for 15 minutes, and the elongation was 0.5% or less, which was extremely small.

Comparative Example 1 A tube was molded in the same manner as in Example 2, and after washing the tube with water, it was fitted into a stainless steel rod with a smooth surface and an outer diameter of 14 mm, whose surface was sufficiently polished, and the tube was molded into a tube with a diameter of 0.5 mm.
A polyester thread of 0.5 mm was wound helically at intervals of 0.5+nn+.The tube was then compressed from both ends to form pleats. Heat setting was performed by heating at 170° C. for 40 minutes while strongly compressing the tube until folds were formed throughout the tube. After heat setting, the tube was removed from the threaded rod, washed with methanol and water, and dried.

The inner diameter of the obtained crimped artificial blood vessel was 12.0 mm. Also, the crimp height is 0. ．． The length of the tube was 25 mm, and the ratio of the tube lengths before and after crimping was 0.13, both of which were extremely small.

A length of 15C11 of this artificial blood vessel was taken, and the two ends were brought together to form an arc shape, and the kink phenomenon was observed, but no kink phenomenon occurred.

However, due to the dense presence of fine folds, when a 3-0 round needle for blood vessel suture was inserted at a position 3IIIm from the stump of the artificial blood vessel, an extremely large amount of force was required to penetrate the needle. . Furthermore, when this artificial blood vessel was flattened and a needle was passed through the overlapped portion of the two layers, the needle did not penetrate.

In order to perform an accelerated test for elongation over time, the elongation after 15 minutes of high-pressure steam sterilization at 132°C was measured, and the elongation was 22%, which was extremely large.

Comparative Example 2 A crimped tube was formed using the same tube as in Example 1, using the same threaded rod as in Example 1, and performing the same heat setting.

This tube was fitted into a round bar with an outer diameter of 18 cm and a smooth surface, and the tube length ratio before and after crimping (L/Lo) was determined.
Press down and fix from both ends so that the value is 0.77,
A heat set was performed at a temperature of 170°C for 40 minutes. The crimp height of the obtained crimped artificial blood vessel was 1.3 se
It was a.

This artificial blood vessel was taken to have a length of 15C11, held at both ends, brought into close contact with a cylinder with a diameter of 4C11, and bent. When the kink resistance was observed, the inner lumen of the artificial blood vessel was almost completely collapsed, leaving no residue.

〔Effect of the invention〕

The artificial blood vessel of the present invention is a crimped artificial blood vessel made of cloth made of thermoplastic resin fibers, and has a specific crimp shape that makes it flexible and easy to pass through with a suture needle.
This is an artificial blood vessel that stretches less over time.

Claims (2)

[Claims] (1) A tube made by knitting and weaving thermoplastic resin fibers, the tube is spirally crimped, and the tube inner diameter X (mm) and crimp height Y (mm) (Y≧
1) has a relationship of 1/20 (X+11)≦Y≦1/8 (X+2), and the tube length before crimping L_0 (m
m) and the tube length L (mm) after crimping process have a relationship of 0.15≦L/L_0≦0.75. (2) The artificial blood vessel according to claim (1), wherein the thermoplastic resin is polyethylene terephthalate.