JPH0369543B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a bioprosthesis represented by an artificial blood vessel, a patch, etc., and a method for manufacturing the same.

[Prior Art] Conventional bioprosthetics made of woven or knitted fabrics have problems in properties such as sutureability, fraying resistance, and flexibility, and also have many problems in terms of biocompatibility.

In order to fundamentally improve the above-mentioned problems, the inventors of the present invention have carried out intensive studies and have dramatically improved the above-mentioned problems by using ultra-fine fibers and by further performing high-pressure fluid treatment. 60−77764
It has been disclosed in Japanese Patent Application Laid-open No. 61-92666.

[Problem that the invention seeks to solve]

However, by pursuing these series of studies more deeply, it was discovered that there were various new problems.

The first problem is a problem that arises because the woven structure consisting of multiple tissues is complex. In other words, the thickness of the bioprosthesis becomes thicker than necessary, resulting in problems with the compatibility of the prosthesis, such as difficulty in suturing, failure of anastomosis, or crimping of small-diameter artificial blood vessels that do not enter the sharp shape, resulting in poor shape retention. For example, it cannot be granted. In addition, complex and highly sophisticated woven and knitted fabrics are essential, and various problems occur during weaving, such as warp breakage occurring due to the extremely large number of reeds during weaving, and in some cases, weaving becomes impossible. .

The second problem is that in order to keep fraying to a very high level, it is usually necessary to increase the pressure or increase the number of times of high-pressure fluid treatment, which causes fibers, especially microfibers, to fibrillate and break. There were problems such as falling off and a decrease in strength.

The present inventors have finally arrived at the present invention as a result of intensive studies on the above-mentioned problems.

[Means for solving problems]

That is, the present invention has the following configuration.

(1) A bioprosthesis composed of covering yarn containing ultrafine fibers of 0.9 denier or less, where at least a portion of the microfibers constituting the bioprosthesis are intertwined between the yarns. A bioprosthesis characterized by:

(2) A method for manufacturing a bioprosthesis, which includes at least the following steps and sequentially performed in the production of the bioprosthesis.

Process of forming covering yarn.

A step of forming a sheet-like object or a tube-like object by weaving, knitting, or braiding the covering yarn.

A step of subjecting the sheet-like material or tube-like material to high-pressure fluid treatment.

(3) Shrinkage rate of core thread of covering yarn in boiling water
The method for producing a bioprosthesis according to claim 2, wherein the bioprosthesis is made of high shrinkage fibers having a content of 10% or more.

The present invention will be explained in detail below.

The bioprosthesis referred to in the present invention includes, for example, a patch for intermediate defect prosthesis in thoracic vascular surgery, a patch for abdominal cell tissue prosthesis, a patch for arterial and venous blood vessel prosthesis, a patch for cardiac prosthesis, a heart valve prosthesis, and a patch for prosthesis of abdominal tissue. There are various types of patches such as patches for hernia prosthesis, patches for prosthesis of tracheal defects, artificial blood vessels, artificial skin, and sheets for artificial skin, but the effectiveness of the present invention is limited by these, The term is not limited, and covers all members or materials for prosthetizing a defective part of living tissue.

The most characteristic feature of the present invention is that firstly, a covering yarn consisting of a core yarn and a cover yarn spirally wound around the core yarn is formed using ultrafine fibers of 0.9 denier or less, and is woven or The point is that various deformed objects including sheet-like objects and tube-like objects are formed by knitting or braiding.
In other words, by composing microfibers with covering yarns, even if sheet-like objects, tube-like objects, or other structures are formed using extremely simple structures, both sides of the bioprosthesis will remain virtually intact. Since it is made of ultrafine fibers, the biocompatibility of the bioprosthesis can be extremely effectively improved. Moreover, the thickness of the bioprosthesis can be made extremely thin.

Of course, by applying the covering yarn to at least a portion of the multilayer structure, it is possible to provide a bioprosthesis that requires a relatively large thickness.

The second reason is that the high-pressure fluid treatment pressure used to stop fraying can be lowered, and this low-pressure treatment eliminates the occurrence of fuzz and strength deterioration. . This effect was unexpected even with the rich experience and knowledge of the present inventor. The reason for this is not clear, but it is thought to be at least due to the fact that ultrafine fibers are used as the covering yarn of the covering yarn.

That is, when a tube is formed by a weaving or knitting structure or a braided structure using the covering yarn referred to in the present invention, the fiber bundles made of adjacent covering yarns are directly connected to each other's ultrafine fibers existing on the outside. As a result of having an arrangement in which the ultrafine fibers are in contact with each other and are arranged in such a manner that they are easily interlocked as if they overlap each other rather than in a parallel arrangement, the entanglement of the ultrafine fibers is promoted by high-pressure fluid treatment at a relatively low pressure, resulting in sufficient It seems that it has become possible to impart fraying resistance. Furthermore, in order to enhance this entanglement effect, if high shrinkage fibers are used as the core yarn and are shrunk after forming the tube, the pitch of the spiral of the ultrafine fibers in the sheath will shrink, resulting in substantial sagging of the fibers, resulting in significant tangles due to high-pressure fluid treatment. A mating effect occurs, and fraying resistance is further improved. In this case, the shrinkage of the core yarn is preferably 10% or more. More preferably
15% or more.

The covering yarn referred to in the present invention can be formed, for example, by a covering machine (for example, model SR, manufactured by Kataoka Kikai Kogyo Co., Ltd.). Although the single yarn fineness of the core yarn and cover yarn is not particularly important, better results can often be obtained by making the core yarn thicker and the cover yarn thinner.

Specifically, it is preferable to use fibers with a single filament fineness of 0.5 denier or more, more preferably 1.0 denier or more, but 0.5 denier or less may be preferable in some cases.
For example, when a fiber of 0.05 denier or less is used as the cover yarn for the ultrafine fiber (A), it may be preferable to use a core yarn of about 0.3 denier.

Further, it is most preferable to use ultrafine fibers as described below for the cover yarn, but depending on the purpose of use and the case, good results can be obtained even if the cover yarn is thicker than the fiber of the core yarn.

That is, depending on the intended bioprosthesis and its shape, better results may be obtained by intentionally using ultrafine fibers for the core yarn and ultrafine fibers for the cover yarn.
In addition, the form of the covering may be one of S twist or Z twist, or a method in which Z or S twist is added after S or Z twist,
Furthermore, a method in which cover threads are alternately wound on top of the threads may also be used.

In the present invention, the polymer used as the material fiber is
It refers to polyester, polyamide, polytetrafluoroethylene, polyolefin, collagen fiber, etc., and the type is not particularly important as long as its properties against living organisms are not different from these polymers.
Among these, polyester is particularly preferred. Of course, in some cases, good results may be obtained by using two or more types of polymers, and in some cases, this may even be more preferable.

Further, the ultrafine fibers used in the present invention refer to ultrafine fibers whose single fiber fineness is 0.9 denier or less, preferably 0.5 denier or less, and more preferably 0.2 denier or less.

In forming the covering yarn, a covering yarn is formed using fibers that can be made ultra-fine by chemical or physical means, and then a tube is formed that does not become ultra-fine, or a tube is formed after ultra-fine. However, in the case where the tube is formed without making it ultra-fine, it may be made ultra-fine next, so that the tube may be formed with a covering yarn using the ultra-fine fiber as the covering yarn.

Alternatively, the covering yarn may be formed by using fibers that are already in the form of ultrafine fibers as they are. In this case, it goes without saying that the subsequent ultra-fine processing is omitted.

Ultra-fine fibers can be obtained by using normal spinning methods with due care, but it is also possible to create ultra-fine fibers by drawing the end-drawn yarn under specific conditions, as in the case of polyester. be. On the other hand, fibers that can be made ultrafine by post-processing means fibers that can be fibrillated or made ultrafine by removing or exfoliating one component of a multicomponent fiber.

In addition, 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, hot water-soluble polyester, and water-soluble polyester. It is possible to appropriately combine polyvinyl alcohol and the like.
The combination of such polymers is determined depending on the case, taking into consideration thread-spinning properties, processability, functionality, removability of impurities and residues, etc.

Further, in order to form a structure having gaps between ultrafine fibers and/or between thick fibers, it is more preferable to use sea-island type polymer array fibers. Multi-component blend type fibers are also considered, but there is some concern that the fibers may fall off. However, similar effects can be obtained in other respects. That is, by forming the material with the gap, the fraying resistance is made more effective due to the flexibility and the entanglement imparted by the high-pressure liquid flow treatment.

In addition, in the case of fibers that can be made ultra-fine by post-processing,
During the formation of covering yarn and tube processing, even if the fiber is of normal thickness, it can be made extremely fine after processing, so there are problems during processing, such as during weaving, knitting, stringing, before weaving, knitting, or core yarn formation. This is preferable because yarn breakage, fuzz generation, etc. can be minimized when various yarn processing methods are applied to the cover yarn. In addition, in order to enhance the effect of high-pressure liquid fluid treatment, high-pressure jets are applied after weaving or knitting, such as by using a raising machine, by using a shearing machine, or in some cases by rubbing with sandpaper. In some cases, it may be advantageous to form fluff and/or loops before processing.

Preferable results can also be obtained by using fibers with fine crimp as the cover yarn.

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.

Also, if the spray pressure is too low, the fibers will not get tangled, but if the spray pressure is too high, the fibers will be cut, which is not good. Within this range, it can be appropriately determined depending on the strength of the fiber, the fineness and thickness of the bundle, the flexibility of the bioprosthesis, etc.

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. This not only makes it possible to reduce punch streaks and moiré phenomena, but also makes it possible to intertwine the entire fabric and even every nook and cranny.

Furthermore, if the sheet-like material or tube-like material 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 case of the manufacturing method of artificial blood vessels, it is necessary to form the fabric into tubes, and the method for forming the tubes is to cut the fabric after it is made into a fabric, and then to make the tube shape by sewing, gluing, fusing, etc. Although it can be formed into a solid object, it is preferable to form the basic structure into a tube shape, since this eliminates seams.

On the other hand, when forming a sheet-like object or a tube-like object, it may be formed using only the covering yarn, but depending on the intended bioprosthesis,
The covering yarn and other microfibers and/or
Alternatively, it is also preferable to form a tube in combination with a thick fiber or the like, and this may produce better effects.

〔Example〕

Next, the present invention will be explained more clearly with reference to Examples, but the validity and scope of rights of the present invention are not limited or restricted thereby.

Example 1 Polyethylene terephthalate 50 denier core yarn
24 filament, cover yarn has an island component of 50 parts polyethylene terephthalate, and a sea component of 50 parts polystyrene.
Covering machine (Kataoka Machine Industry Co., Ltd.) using 75 denier 18 filament with 16 islands.
A covering yarn was formed using the following method: The conditions were a yarn speed of 5.3 m/min, a cover yarn spindle rotation speed of 8000 T/min, and covering was performed in both the S direction and the Z direction.

Then, the resulting covering yarn is glued,
It was warped and a plain weave tube was formed using a narrow cloth name loom. The covering yarn was also used for the weft yarn. The tube has a woven inner diameter of 13
mmφ, length 100cm, weaving density vertical x horizontal = 17
It was 15 books/cm x 15 books/cm.

Next, this tube was washed with hot water, dried, and the polystyrene was removed with trichlorethylene to make it ultra-fine.

The obtained artificial blood vessel had both inner and outer walls covered with ultrafine fibers, and had a supple and extremely smooth texture. Looking more closely, the thick fibers used for the core yarn were visible here and there, but were essentially covered by ultra-fine fibers. Furthermore, when I checked the needle passage performance, I found that the needle moved very smoothly. This tube has a discharge hole of 0.25mmφ, a discharge hole interval of 2.5mm,
Waterjet punching was carried out at a pressure of 20 kg/cm ² .

The resulting artificial blood vessel had far superior "fray resistance" compared to those not treated with waterjet, and was more flexible. However, in order to further impart "fray resistance", only pressure is applied under the same conditions.
When water jet punching was carried out at 40 kg/cm ² , the "fray resistance" was further improved.

Moreover, the inner and outer walls of the artificial blood vessel are covered with ultrafine fibers,
It was very touchy. When the artificial blood vessel was observed in more detail under a microscope, it was observed that the ultrafine fibers were intertwined so as to overlap each other in large numbers between single fibers, between textures, and between fiber bundles.
Upon closer examination, some thick fibers were visible here and there, but mainly ultrafine fibers were present on both sides of the artificial blood vessel wall. Also, on the side opposite to the waterjet punched side,
Some short fuzz was present.

Example 2 Completely the same as Example 1 except that the sea component in Example 1 was changed to a hot water soluble polymer made from terephthalic acid, isophthalic acid, sodium sulfone isophthalic acid, and ethylene glycol, and the sea removal component was changed to hot water. Similar results were obtained in the same manner.

〔Effect of the invention〕

The effects of the present invention are enumerated as follows.

(1) Ultrafine fibers with excellent biocompatibility are used as covering yarns, so they can be placed on both sides of a bioprosthesis, and have excellent fibril deposition in the fine fiber gaps.

(2) Since sufficient performance can be achieved with a simple woven or braided structure, the thickness of the bioprosthesis can be made extremely thin, and it has excellent usability as a medical component or material.

(3) Because it uses ultra-fine fiber covering yarn, it has excellent entangling properties even when treated with high-pressure fluid at low pressure.Furthermore, it can be done without fraying without needing a napping treatment, so it prevents hair loss and fiber waste from falling off and fibers. There is no decrease in strength.

Claims (1)

[Scope of Claims] 1. A bioprosthesis composed of a covering yarn containing ultrafine fibers of 0.9 denier or less,
A bioprosthesis characterized in that at least a portion of the ultrafine fibers constituting the bioprosthesis are intertwined between the yarns. 2. A method for manufacturing a bioprosthesis, which includes at least the following steps and is performed in order. Process of forming covering yarn. A step of forming a sheet-like object or a tube-like object by weaving, knitting or braiding the covering yarn. A step of subjecting the sheet-like material or tube-like material to high-pressure fluid treatment. 3. Shrinkage rate of core thread of covering yarn in boiling water
The method for producing a bioprosthesis according to claim 2, wherein the bioprosthesis is made of high shrinkage fibers having a content of 10% or more.