JPS61103449A - Artificial blood vessel having x-ray contrast property - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention uses polytetrafluoroethylene C or less.

This invention relates to an artificial blood vessel using X-ray contrast properties (referred to as PTFE).

[Conventional technology]

Artificial blood vessels, which are materials used to surgically repair damaged blood vessels (arteries and veins), include autologous veins, biogenic materials, and synthetic materials.
Due to resource issues, synthetic materials are often used. Currently, the main synthetic materials used as artificial blood vessels are tubes made from woven or knitted polyester or polytetrafluoroethylene threads, and expanded porous polytetrafluoroethylene (PTFE).
or FiPTFB (trade name: GOre-'rex■) tube.

In particular, EPTFE artificial blood vessels have antithrombotic properties, which are measures of their performance, patency rate (the rate at which blood flow is maintained in the transplanted artificial blood vessels), adaptability to tissues, ease of handling during surgery, and flexibility. Matsumoto et al.'s “Porou
s Polytetrafluoroethylene
Since 1 Artificial Organs, Volume 1, No. 7 [Published March 13, 1929], it has been described in many medical literature. Inventions related to EPTFE artificial blood vessels include:
Tokuko Sho 5.2-907 Gu and Tokko Sho! 3-3971
No. 9 is known.

FiPT'F' artificial blood vessels have excellent performance as mentioned above! However, because it is radiolucent, its position cannot be confirmed from outside the body by X-ray photography after the transplant surgery. However, EPTFE after implantation
If the position of the artificial blood vessel can be easily confirmed on an X-ray image 3F+ (IC), it will provide vital information regarding the success or failure of the transplant surgery, which is surgically significant.

[Problem that the invention seeks to solve]

In view of the above-mentioned problems with conventional artificial blood vessels, X-ray contrastability! In addition, it has antithrombotic properties, patency rate, compatibility with tissues,
Artificial blood vessel t that is non-inflammatory, easy to handle during surgery, and has excellent flexibility
This has become an issue in our industry.

[Means for solving problems]

The present inventors have solved the above-mentioned problem (as a result of various studies, X-ray contrast agent fine powder with an average particle size of 10 μm or less,
FTFB3 is composed of FTFB3o~g0G0 having a porous microstructure, and a large number of micronodules are connected to each other by fibrils, and a large number of voids are formed between them, and a large number of X-ray contrast agents. An artificial blood vessel whose portion is made of the material contained in the micronodules, or a porous pore in which a large number of micronodules are connected to each other by fibrils and a large number of voids are formed between them on the inside and/or outside of this artificial blood vessel. We have discovered that an artificial blood vessel with a 71JPTFK layer having a unique microstructure can meet the above objectives, and we have invented the invention! It was completed.

First, the production f:yr of the artificial blood vessel of the present invention will be summarized.

(1) Mix a composition of an X-ray contrast agent and PTFB with a liquid lubricant to form a paste-like mixture, extrude it into a tube or sheet shape to make a molded product, and then (with or without removal of the lubricant) at elevated temperatures, and the drawn product, alone or in suitable combinations, is formed into a tubular shape.

Is it heat treated or fired to make an artificial blood vessel? (2) [2]
The desired artificial blood vessel can be obtained by reversing the configuration of (4) (21) and (3).

First, the method [1] will be explained in detail.As an OX-ray contrast agent, inorganic powders conventionally used for this purpose, such as barium sulfate, bismuth oxide, bismuth nitrate,
A fine powder such as bismuth carbonate or nickel powder with an average particle diameter of 108 m or less, preferably 3 μm or less, particularly 1 μm or less is prepared. This is because if the average particle size is 10 μm or more, the workability in the 9th molding process will be significantly inhibited.
In the process of stirring and mixing, add 1Cp to 1Cp and stir and mix.

PTFE microparticles precipitate around the contrast agent microparticles, gel, and precipitate. This process leading to gelation is called co-coagulation.

At the end of this co-coagulation process, adding a small amount of acid or alkali will accelerate precipitation. 0 Once precipitation is complete, supernatant liquid!
Decant and dry the resulting mixture of FTFB and X-ray contrast agent. By this co-coagulation method, 20% by weight C
The X-ray contrast agent in the following 1% (all percentages by weight) can be mixed into FTFB, and a molded product with no major problems in appearance can be obtained even after the next molding process. The content of contrast agent is 20-20% of the total weight of the mixture
, preferably 0 to 60%. If it is less than 20%, sufficient X-ray contrast performance cannot be obtained, and if it is more than 70%, moldability decreases and problems such as the X-ray contrast agent separating from the molded product occur. The resulting mixture is a mixture of the conventional 1=2:Ninimuni WiJI' a-IJ k-=Seenininny--2111, i.e., a mixture of an X-ray contrast agent and PTFE. , liquid hydrocarbons such as white oil, petroleum ether, etc.) in a weight ratio of about 80 parts to 0 parts, and from the mixture a preform is produced (the preform is made into a tubular or It is extruded into a sheet.Although the sheet-shaped molded product has a certain degree of strength, it cannot be used in the stretching process as it is, so the thickness of the sheet-shaped product is about 1/2 ~ / / /
OK When rolled in this way, the strength increases. The liquid lubricant is removed from the tube-shaped or sheet-shaped molded product thus obtained by extraction or heating and volatilization. Note that molded products without removing the liquid lubricant can also be used in the next stretching process, but the results are not good.

The tube-shaped or sheet-shaped PTFE molded product containing the X-ray contrast agent obtained as described above is used.

b. While heating to a temperature below C, preferably at a temperature below the melting point of FTFB, the film is stretched a little (both in one direction).

The stretching ratio is approximately 1.2 to -0 times. This stretching does not significantly reduce the cross-sectional area of the material, but increases its dimension in the stretching direction, so the resulting product inevitably has voids and becomes porous. is a stretched molded product.

Although it is fired to a lesser extent, it is unfired if the temperature is below the melting point of PTFE. The incompletely fired or unfired expanded PTFE tube or sheet thus obtained is maintained in the stretched state and heated to a temperature above the melting point of 41 PTFE to further increase the degree of firing, resulting in improved dimensional stability and strength. The degree of firing is proportional to the firing temperature and time, so depending on the purpose, that is, when the product itself is a finished product, it can be completely fired.

In the case of an intermediate product (to be further processed), it is fired to the extent that it is easier to process. The wall thickness of the tube thus obtained is approximately 0. ""-'2mm, the outer diameter can be adjusted within a maximum range of about 30mm, and the sheet thickness is approximately "-""~4"
``・Width can be adjusted within the range of thickness -J[4J17'' to about 1''/5''.

The open-pore porous PTFE containing the X-ray contrast agent stretched in this way has a large number of micronodules connected to each other by a large number of fibrils, and there is a continuity between the micronodules and the fibrils. Porous microstructure with voids (micropores) formed! I have it. Surprisingly, most of the X-ray contrast agent is contained in the micronodule portion, and almost no X-ray contrast agent is contained in the fibril portion.

Therefore, the mechanical properties of this material are not significantly different from open-cell, porous PTFE that does not contain an X-ray contrast agent.

For example, the fibril length is Q, j ~ 300μ, the porosity is 2j
~90%, the tensile strength is weaker as the content of X-ray contrast agent increases (but only decreases by about 10%), and the flexibility, flexibility, elasticity and elastic recovery are rich.

Stretched porous PT containing the above calcined X-ray contrast agent
FFi (hereinafter expanded porous PTFE is referred to as BPTFE) tube can be used as it is as an artificial blood vessel, but
If it is necessary to increase the durability against tearing caused by suture needles or dilatation caused by blood pressure, EP containing an unfired or incompletely fired X-ray contrast agent as seen above may be used.
An unfired or incompletely fired EPTFFli tape obtained in the same manner is wrapped around the TFE tube, or an unfired or incompletely fired EPTF Li tape containing an X-ray contrast agent obtained as described above is wrapped around the TFE tube. A tape made by slitting an incompletely fired EPTFE sheet is evenly wrapped around a metal rod of the desired outer diameter and fixed, then heated to a temperature higher than the melting point of PTFln to integrate it, and then the metal rod is Pulling out (
manufactured by

In addition, it is durable and anti-thrombotic! Increase or decrease adhesion with one tissue (
or eliminate the possibility of detachment of the X-ray contrast agent, a large number of micronodules are connected to each other by fibrils on the inside and/or outside of the EPTFE tube containing the X-ray contrast agent, B, which does not contain an X-ray contrast agent, has a porous microstructure with many voids formed between them
It is preferable to provide a PTFE layer.

The method for manufacturing EPTFK sheets and tubes that do not contain an X-ray contrast agent and have the above-mentioned porous microstructure used here is described in 1, for example, Japanese Patent Publication No. Sho YG Tag No. 66, Japanese Patent Publication No. Sho Glow 7.2 G. Publication No. 1, or Japanese Unexamined Patent Application Publication No. 1963
It is carried out according to the method described in -22gg No. 1 and the like. That is, PTFE powder (or PTFE dispersion agglomerate') is mixed with the addition of a liquid lubricant (for example, solvent naphtha, hydrocarbon oil such as white oil, 1 petroleum ether, etc.) [Mixing ratio PTFE:liquid lubricant=80
:, 2o) and extrude the preform from the mixture into a sheet or tube using a ram extruder, and roll the sheet as necessary to form a molded product. Remove the liquid lubricant from this molded product (you may not remove it, but the result is not good). .20
Stretch it approximately twice as much. next.

In the stretched state, the stretched product is heated at a temperature of 2'2" or slightly lower than the melting point of the pentagonal cloth, preferably from 00 to 3907:
：Heated with ＼suru ζ上ao）Todai Sai ξ１１云♂ｑEveryone 7）o
'1%, contains a porous microstructure with many voids formed between them, and has flexibility, flexibility, heat resistance, chemical resistance,
It is rich in water repellency, non-adhesiveness, slipperiness, stretchability, elastic recovery power, etc., and usually has a wall thickness of 0.03 to 3-6 mm.
, especially D-3-~2, DHlm.

Porosity: 30-9j%, especially 60-90%, average pore size: 0.
O1~ko0μ, especially l~jμ, Gurley number (6,
Cross section of goo t cnt 'f' Under a pressure of 2.7 mmHg / OD QQ time required for air to permeate) 0+
O1~5000 seconds, water leak pressure O+~1-sKy/c
m is 0 These properties can be varied over a wide range by adjusting the manufacturing conditions, so it is possible to obtain a material suitable for the purpose.

In addition, by the method (2), M
- To provide the above-mentioned X-ray contrast agent-free EPTFE on the outside of an unfired or incompletely-fired EPTFE tube, the tube is passed through a metal rod and the above-mentioned X-ray contrast agent-free IEPTFE is placed on the outside of the unfired or incompletely fired EPTFE tube. This can be achieved by uniformly wrapping and fixing the tape, heating it to a temperature higher than the melting point of PT'FE, baking it into one piece, and pulling out the metal rod.

In addition, by the method (3), the EPTFE layer not containing the above-mentioned X-ray contrast agent is replaced with the EPTFE layer containing the above-mentioned X-ray contrast agent.
To install it inside the TFE tube, attach the above X to the metal rod.
Linear contrast agent! Contains no unfired or incompletely fired EPTF
Cover with E-tube or similar EPTFE tape! Unfired or incompletely fired EPTFE tape wrapped uniformly and containing the above-mentioned X-ray contrast agent on top! The metal rod may be wound and fixed in a uniform overlapping state or in a spiral or ring shape with intervals, heated to a temperature higher than the melting point of the whole VPTFE to integrate, and then the metal rod is pulled out.

In addition, by the method [4], the EPTFE layer not containing the above-mentioned X-ray contrast agent is replaced with the above-mentioned EPTFE layer containing the above-mentioned X-ray contrast agent.
For installation on the inside and outside of the PTFE tube, [2
) and (3) may be combined as appropriate.

Note that when installing the BPTFEj layer that does not contain the above-mentioned X-ray contrast agent on the FiPTFE tube that contains the above-mentioned X-ray contrast agent, it is not limited to the methods (2) to (4) above, and tape! Of course, changes such as alternating winding (or configuring three or more layers) can be made as appropriate depending on requirements 1 for the artificial blood vessel, such as strong X-ray contrast, flexibility, and expansion resistance.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these.

Example 1 Barium sulfate (manufactured by Kishida Chemical Co., Ltd.) with an average particle size of 7 μm was added to water. After dispersing the FTFE dispersion in an amount equal to the solid content 6, the barium sulfate and FTPK are co-coagulated by stirring and mixing. After the coagulation is completed, the supernatant liquid Y is poured out and the resulting precipitate is Precipitate k1.2oC for λ days,
Heat and dry to obtain barium sulfate O%, PTFE Ao%
A granular mixed powder was obtained.

100 parts by weight of this mixed powder was mixed with 25 parts by weight of petroleum naphtha, extruded into a tube shape with an inner diameter of mm and a wall thickness of 1.9 mm in the same manner as the usual PTFB paste extrusion molding method, and heated to form a tube containing petroleum naphtha. After removing the An artificial blood vessel containing a weight factor was obtained.

The thus obtained artificial blood vessel was flexible and did not collapse even when curved at 6R-f, and no wrinkles were generated. Also.

When an X-ray photograph of this artificial blood vessel y was taken, it appeared gray and the X-ray contrast property was confirmed. ! / After dispersing the PTFE dispersion in an amount with a solid content of A Ky, the PTFE dispersion was stirred and mixed to co-coagulate barium sulfate and PTFE. The coagulum was dried by heating to obtain a dry mixed powder containing 0% barium sulfate and PTFE 60.

25 parts by weight per 100 parts by weight of this mixed powder
Mix petroleum naphtha to 5 normal -FTFB<-,X)
A sheet with a thickness of 100 μm and a width of 20 mm was obtained by extrusion molding. This sheet was further stretched 9 times in the longitudinal direction under ISO'C heating to obtain a porosity of 92.
% of the porous microstructure was obtained. From this sheet, I made a chief with a width of 20 mm.In addition to this, I made a sheet with an inner diameter of g mm and a wall thickness of 4 mm.
An EPTFE tube having a porous structure in which a large number of micronodules obtained by the method described in Publication No. After inserting the core, the tape containing barium sulfate was wound (3 wraps) and heated at about 35JC for about 10 minutes.
The stainless steel core was removed to obtain a contrast-enabled artificial blood vessel.

When an X-ray photograph was taken of this, the tube appeared from gray to black and white, confirming the contrast effect. Example 3 'jldtif! l:III″l ')a ICL,”
-'ja e ′"'J')""゛ 1PTF
Made of EA6%, width = 2mm, porosity 35%, thickness 0
．． A 3mm tape was made.

This tape was prepared using iiEPTF similar to that described in Example 2.
It is spirally wound on the B tube with a pitch of 1 cm, and then JP-A No. 411. Porous microstructure obtained by the method described in -72g¥ publication! Wrap a tape obtained from a PTFE sheet with a wall thickness of 160 μm, a width of 2 g, and a length of jmm C2.
rap). Next, after heating at about 35 °C for 10 minutes, the stainless steel core was removed in the same manner as described in Example 2 to obtain a contrast-enabled artificial blood vessel. When this was taken on an X-ray, a spiral black line was seen on the tube part, and the contrast effect was confirmed.0 Example 4 Same as Example 1, barium sulfate 23% 1PTFE7
A 7% blend was prepared and dried to obtain a mixed powder. 20 parts by weight of petroleum naphtha was mixed with 100 parts by weight of this mixed powder, and the inner diameter smm, wall thickness /
A Y mm tube was formed. After removing petroleum naphtha from this molded product by heating, it was stretched twice under heat (ujOC) to create an EPTFE tube.

After inserting g, a stainless steel core with a diameter of 7 mm into this tube, the same wall thickness ljfDlt as used in Example 3
m, wrap a tape with a width of 2 smm (2 wraps), and
After heating for AoC,/17 minutes, the core was removed to create an artificial blood vessel.

When this was taken on an X-ray, the tube appeared gray.

〔Effect of the invention〕

The Lf1 artificial blood vessel of the present invention with high X-ray contrast properties has a continuous porous PTFE containing an X-ray contrast agent, which is the main part, between a large number of micronodules and fibrils that are three-dimensionally connected to each other. The tensile strength of the X-ray contrast agent Z As high as the stretched FTFB without (
, flexibility.

It has elasticity and is easy to handle during surgery. Furthermore, the above-mentioned microstructure allows a single tissue to grow into the wall of the artificial blood vessel after transplantation, has good formation of pseudointima on the inner wall surface, has antithrombotic properties, and has a high patency rate.

Regarding X-ray contrast properties, the strength of contrast properties can be changed to a desired degree by adjusting the content of the X-ray contrast agent or the thickness of the layer containing the contrast agent.
It can also be provided in a spiral or band shape. Further, in the artificial blood vessel of the present invention, the artificial blood vessel wall can be formed in layers, particularly in such a manner that the fibrils have crossed directions, thereby preventing holes and cracks caused by suture needles and suture threads.

Also, the durability against expansion due to blood pressure is 74%.

Claims (2)

[Claims] (1) X-ray contrast agent fine powder with an average particle size of 10 μm or less 20~
70% by weight polytetrafluoroethylene 30-8, which has a porous microstructure in which a large number of micronodules are bonded to each other by fibrils and a large number of voids are formed between them.
0% by weight, and most of the X-ray contrast agent is contained in the micronodules. (2) X-ray contrast agent fine powder with an average particle size of 10 μm or less 20~
70% by weight polytetrafluoroethylene 30-8, which has a porous microstructure in which a large number of micronodules are bonded to each other by fibrils and a large number of voids are formed between them.
A large number of micronodules are formed by fibrils on the inside and/or outside of the flexible tube with X-ray contrast properties, which consists of 0% by weight and most of the X-ray contrast agent is contained in the micronodules. An artificial blood vessel having X-ray contrast characteristics, characterized in that polytetrafluoroethylene layers are bonded to each other and have a porous microstructure in which a large number of voids are formed between the polytetrafluoroethylene layers.