JPS61176353A - Artificial blood vessel similar to actual blood vessel in compliance and stress-strain curve - 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 provides an artificial blood vessel that has a stress-strain curve and compliance similar to that of a biological blood vessel, and that has pores throughout the thickness from the inside to the outside of the vessel wall. Regarding.

[Background Art] In recent years, along with advances in vascular surgery, research on artificial blood vessels has progressed, and a large number of artificial blood vessels have been developed. Currently, artificial blood vessels for medium- or large-diameter arteries with a lumen of approximately 6M or more include, for example, Dobesky artificial blood vessels made of Dacron knitted fabric made by USCI, and expanded polytetrafluoroethylene (hereinafter referred to as EPTFE) made by Boa, USA. Boretex, which consists of

These artificial blood vessels have a hole that communicates from the inside to the outside of the blood vessel, and are quickly covered with pseudoendothelium after being attached to a living body, allowing tissue to enter from the living tissue side through this hole and stably. It has been transformed into an organ and is fulfilling its mission as an artificial blood vessel. Having communicating pores that help organize the artificial blood vessel in this way is hereinafter referred to as having porosity.

However, the compliance of these artificial blood vessels is significantly different from that of biological blood vessels, so after a long period of time after being implanted in a living body,
Various incompatibility problems occur at the anastomotic site, such as pannus hyperplasia. Furthermore, when used as a small-caliber arterial artificial blood vessel with an inner diameter of about 6M or less, a significant difference in compliance appears and patency is poor, making it impossible to use clinically. Therefore, autologous veins are used in reconstructive surgery for arteries below the knee and coronary arteries.

Based on the above, when developing artificial blood vessels, especially artificial blood vessels for small-caliber arteries, it is necessary to improve the porosity of the artificial blood vessel and the blood compatibility of the material of the artificial blood vessel, as well as to improve the compliance of the artificial blood vessel. It is said that it is important to approximate biological blood vessels.

However, the compliance of currently developed artificial blood vessels is limited by the report by Sasabato et al. (Artificial Organs 12 (1), 179-
182.1983), as shown in Table 1.

[Margins below] Table 1 As described above, the compliance of current artificial blood vessels is extremely small compared to the arteries of a living body, and for arteries, they are considered to be steel pipes.

In order to solve this discrepancy in compliance between living blood vessels and artificial blood vessels, US Pat. A method for manufacturing an artificial blood vessel having a compliance with a certain degree of compliance has been disclosed. However, this artificial blood vessel has no porosity. Moreover, the manufactured artificial blood vessel has only very small pores in its wall cross section, and has a relatively dense structure. Although the compliance of artificial blood vessels manufactured in this manner is greater than that of conventional artificial blood vessels, it still tends to be lower than that of biological blood vessels.

The present inventor has solved the problem of such compliance discrepancies, developed an artificial blood vessel with a porous structure made of an elastomer with porosity that is optimal for organization, and has filed a patent application. No. 59-39972, patent application 1982
-44396, patent application No. 1983-44397, patent application No. 1983
9-44398, Japanese Patent Application No. 59-51768, and Japanese Patent Application No. 59-52674).

[Problems to be Solved by the Invention] As shown in FIG. When added, it becomes that of biological blood vessels (l in Figure 4).
and N). Therefore, when abnormally high blood pressure occurs, such as during surgery, there are concerns about rupture or damage, and concerns about maintaining durability over a long period of time.

The present invention has been made in order to eliminate the above-mentioned concerns.

Means for Solving the Problem] The present invention provides a method for suspending an artificial blood vessel that has porosity and compliance similar to that of a living blood vessel, and also has a stress-strain curve similar to that of a living blood vessel. A porous body structure part made of an elastomer and having pores throughout the entire thickness from the inside to the outside of the pipe wall;
The present invention relates to an artificial blood vessel having a compliance and a stress-strain curve similar to that of a living blood vessel, which includes a tubular part made of fibers that is in contact with and/or bonded to at least a portion of the porous structure part.

[Example] The elastomer used in the present invention is a thermoplastic elastomer with excellent blood compatibility, that is, it does not contain low-molecular eluates that cause acute toxicity, inflammation, hemolysis, exothermic reactions, etc., and is compatible with the physiological functions of blood. It is a thermoplastic elastomer that does not cause serious damage to the body and has excellent antithrombotic properties. Examples of such elastomers include polystyrene elastomers,
Examples include polyurethane elastomers, polyolefin elastomers, polyester elastomers, and blends of these elastomers with polymers other than elastomers within a range that maintains the properties of elastomers. These may be used alone or in combination of two or more.

Among the elastomers, the critical surface tension is about 35 d.
Hydrophobic elastomers with a critical surface tension of less than about 30 dyn/i:* are particularly preferred. As the elastomer becomes more hydrophobic, it tends to have less affinity with the biological soft tissues surrounding the outer periphery of the transplanted artificial blood vessel, less interaction with blood components, and better water resistance. If the affinity is strong, the biological soft tissue surrounding the transplanted artificial blood vessel tends to be thick and strongly adhere to the artificial blood vessel, and there is a fear that the artificial blood vessel will contract or deform accordingly.

Among the above-mentioned hydrophobic elastomers, polyether-type segmented polyurethane (including segmented polyurethane urea, hereinafter the same) is more preferable because it has excellent strength, elongation, durability, antithrombotic properties, and the like.

Further preferred are segmented polyurethanes containing fluorine in the hard or soft segments, and segmented polyurethanes containing polydimethylsiloxane in the main chain as disclosed in JP-A-57-211358. Particularly preferred is polydimethylsiloxane as a part of the soft segment. alkylene group, a, e are 0-
30, bld is 0 or 1, C is an integer of 2 or more).

The tube wall of the artificial blood vessel of the present invention is made of the above-mentioned elastomer, and is composed of a porous structure part in which pores are present throughout the entire thickness from the inside to the outside, and a tubular part made of m-fibers.

The porous structure portion made of the elastomer has pores on the inner surface and the outer surface in which a portion of the porous structure portion opens toward the outside, and the eye hole substantially communicates from the inside to the outside; Useful for organizing artificial blood vessels. Although the shape of the eye hole is not particularly limited, it is preferable that the shape present on the inner surface is circular or oval. The maximum diameter of this circular or elliptical system is preferably 1 to 100 mm, and 5 to 5 mm.
0 is more preferred, and 11 to 30 is particularly preferred. When this maximum diameter is larger than 100 mm, blood flow tends to be squeezed out and the antithrombotic property is reduced, and when it is smaller than 1, the organization of the artificial blood vessel tends to be delayed.

The porous structure portion is composed of pore portions that communicate with each other and a continuous elastomer portion that constitutes a partition wall of the pores, and has porosity.

The porous structural portion can contain a required number of pores of a required size in a constant volume, which is advantageous for adjusting porosity and compliance.

Furthermore, it is preferable that the partition wall itself that forms the pores also contains a large number of minute pores or holes therein. Such a partition wall has a sparse structure compared to a solution coating, etc., and is advantageous for obtaining compliance similar to that of a biological blood vessel.

The porous structure part is not particularly limited as long as it has the structure described above, but it is further preferable that it be a network structure in which pores are substantially uniform throughout the entire thickness from the inside to the outside of the tube wall. preferable. The maximum diameter of the cross section of the pore is not particularly limited depending on the relationship with the tubular part made of fibers, but it is usually preferably 1 to 100ρ, more preferably 3 to 75ρ. .

If the maximum diameter of the pores is larger than 100 Js, the strength tends to be poor or the porosity becomes too large, and if it is smaller than 1 Js, the porosity tends to be poor or the strength becomes too large.

The continuous elastomer section does not consist of a combination of fibrous materials such as a woven fabric, knitted fabric, or nonwoven fabric, but refers to a structure in which partition walls forming holes are continuously connected.

The compliance of the porous structure portion may be close to that of a living blood vessel or exhibit a large value. If the compliance value is large, it is possible to adjust the compliance to be similar to that of a living blood vessel by combining it with a tubular material made of fibers. The compliance of such a porous body structure is controlled by the proportion of pores in the porous body structure, the strength of the partition walls forming the pores, the strength of the elastomer used, and the like.

The fibers used in the present invention are used to make threads, ropes, nets, woven fabrics, knitted fabrics, braided fabrics, non-woven fabrics, etc.
It is a slender and long object more than twice as long.

The fibers are not particularly limited, and may be organic or inorganic, as long as they are safe for living organisms, have negligible deterioration in vivo, can withstand sterilization, and can be processed into desired tubular products. Use vine.

In terms of processability, ease of availability, flexibility, uniformity, etc., recycled artificial fibers, semi-synthetic fibers, and synthetic fibers are preferred. Specific examples of these include cellulose-based, protein-based, polyamide-based, polyester-based, polyurethane-based, polyethylene-based, polystyrene-based, polyvinyl chloride-based, polyvinylidene chloride-based, polyfluoroethylene-based,
Examples include polyacrylic fibers and polyvinyl alcohol fibers. Among these, stretchable fibers are generally preferred. Specific examples of this include fibers in which the m-fibers themselves are stretchable, such as rubber-based, polyurethane elastic-based, and polyester elastic-based fibers, as well as highly processed elastic threads such as woolly nylon and woolly tetron. Examples include covered yarn, which is a yarn made by stretching rubber or spandex filaments and wrapping them around other spun yarns or filaments.

The tubular article made of fibers used in the present invention includes the above-mentioned fibers, yarns spun from at least one kind of the above-mentioned fibers, multifilaments made from at least one kind of the above-mentioned fibers, woven fabrics using threads combining these; knitted fabrics, plaited fabrics, non-woven fabrics,
Or a combination of these. The tubular material is not particularly limited as long as it has compliance and stress-strain curves similar to those of biological blood vessels when combined with the porous structure made of elastomer. The tubular material may be formed into a tubular structure by itself as a fiber or a material made from fibers, or may form a tubular structure when combined with a porous structure part made of an elastomer to form an artificial blood vessel. It's okay. The role and properties of the tubular material and the method for measuring the stress-strain curve will be explained in detail later, but the basically necessary properties are such that the stress-strain curve of the tubular material is 0.
It is to have a point where the elastic modulus changes from a small elastic modulus to a large elastic modulus between 2 and 1.0.

Preferably, the small modulus is less than an average of 0.111/sr2, more preferably less than about 0.01 K9/ax2. In addition, it is preferable that the large elastic modulus is 0.2h/tag' or more on average,
More preferably, it is about 0.3 to 10θ/jlII2.

The stress in the present invention is the value obtained by dividing the load during the tensile test by the cross-sectional area of the test piece before loading. However, since the tubular material is a loose combination of fibers, its cross-sectional area cannot be quantitatively measured. The cross-sectional area of the pipe wall shall be used.

Such properties of the tubular article can be achieved by the following two methods alone or in combination. The first method is to adjust the way the fibers are combined and the density of the combination points.

The second method is to use stretchable fibers. From the viewpoint of processability, workability, and obtaining a stress-strain curve similar to that of biological blood vessels, it is more preferable to use a tubular product made of woven fibers, and use a weft knitted material made of stretchable fibers with loose stitches. A tubular object is particularly preferred.

The tubular object only needs to be present at least partially in contact with and/or bonded to the porous structure made of elastomer. For example, as shown in FIG. 2, the tubular object (2) may be located outside the porous body structure part (1) made of elastomer, and a part of the tubular object may be exposed on the outer surface of the porous body structure part (1).
As shown in the figure, the tubular object (a) is located inside the porous structure part (1) of the artificial blood vessel, and a part of the tubular object ('2J) is exposed on the inner surface of the porous structure part (1). Further, as shown in Fig. 1, a tubular object ('2J
may be completely incorporated into the porous structure portion (1), and this case is preferable from the viewpoint of preventing fraying of the fibers constituting the tubular object and maintaining antithrombotic properties of the blood contact surface.

The preferred compliance for an artificial blood vessel varies depending on the thickness of the artificial blood vessel, the site of use, etc. - Although it cannot be determined generally, the compliance of a living blood vessel in which normal revascularization surgery is performed is about 0.1 to 0.8. Therefore, it is considered preferable to set it within this range. The compliance of the artificial blood vessel of the present invention can be adjusted as described above, and any compliance can be manufactured within the range of 0.1 to 0.8. Compliance is 0.1-0
, 8 artificial blood vessels are used for applications such as arterial blood vessels, and have inner diameters of 1 to 6III, depending on their thickness. and
Those with a compliance of 0.1 to 0.5 can be suitably used as artificial blood vessels for small-caliber arteries.

The compliance referred to in this specification is the formula (1): % formula % [11 (where C is compliance, Vo is internal pressure 50avt
The internal volume of the measured blood vessel at lo, ΔP is the internal pressure of 50 imH
g force IB internal pressure 150m+Hgt Te0) 100n+
mHg, ΔV is from internal pressure 50ml1g to internal pressure 150mHg
It is defined as the internal volume of the measured blood vessel that increases during In actual measurement, a measurement blood vessel is inserted into a closed circuit, a liquid is injected into this circuit using a micrometer metering pump, the amount of injected liquid and the change in pressure in the circuit are measured, and the compliance is calculated from equation (1). be able to.

The stress-strain curve of the artificial blood vessel of the present invention will be explained based on FIG. 4.

In FIG. 4, (Il is a porous structure made of elastomer, (1) is the artificial blood vessel of the present invention, l is the thoracic aorta which is a biological blood vessel, and (I) is the stress-strain of the carotid artery which is a biological blood vessel. This is an example of a line.The stress-strain curve of living blood vessels is difficult to quantify because it varies depending on the artery, vein, caliber of the blood vessel, age, individual differences, etc., but the common thing is that As shown in Figure l, (to), the stress-strain curve has a small elastic modulus in the normal blood pressure range, but when stress exceeding the normal blood pressure range is applied, the elastic modulus suddenly becomes large. As can be seen from FIG. 4, the artificial blood vessel (11) of the present invention has a stress-strain curve similar to such a biological blood vessel.

In this specification, the stress-strain curve is similar to a biological blood vessel if it is similar to the curve shown in FIG. In other words, there is a point where the strain (and) O changes from a small elastic modulus to a large elastic modulus between about 0.2 and 1.0, and the small elastic modulus is on average 0.1k.
g/a2 or less, with a large elastic modulus of 0.2 kg on average
/m2 or more. Furthermore, there is a point where the strain changes from a small elastic modulus to a large elastic modulus between about 0.3 and 0.8, and the small elastic modulus is on average 0.07 to 0.007 to 9/am2,
It is preferred to have a stress-strain curve with a large elastic modulus of about 0.3-10 Kg/tm2.

The stress-strain curve was measured in the axial direction of the artificial blood vessel using a tensile testing machine commonly used in the field of polymer materials (for example, Autograph 152000 manufactured by Shimadzu Corporation). It is preferable to use an artificial blood vessel as it is as a sample for stress-strain curve measurement. When an artificial blood vessel is cut in the axial direction, for example into a strip, and measured, the strength of the tubular material made of fibers changes and tends to show different stress-strain curves. Although there is no particular limitation on the stress-strain curve in the circumferential direction of the artificial blood vessel, it is preferable that the stress-strain curve in the axial direction also approximates that of a biological blood vessel.

Note that stress in the present invention is the value obtained by dividing the load during the tensile test by the cross-sectional area of the test piece before loading, and strain is the value obtained by dividing the elongation during the tensile test by the length of the test piece before loading.

Moreover, the elastic modulus in the present invention is the slope of a tangent line at an arbitrary position on a stress-strain curve, so-called tangential elastic modulus. The average of a small elastic modulus or a large elastic modulus as used herein means the average elastic modulus of the stress-strain curve portion corresponding to both, and the average tangent that can be drawn on the corresponding stress-strain curve. It may be obtained by differentiating the stress-strain curve. However, the elastic modulus where the strain is close to 0 and the elastic modulus just before the artificial blood vessel ruptures tend to change depending on the measurement conditions, so there is no need to take them into consideration.

The region of small elastic modulus in the stress-strain curve roughly matches the normal blood pressure range in which compliance is measured, so if the compliance approximates that of a biological blood vessel, the stress-strain curve in this region also approximates that of a biological blood vessel. . On the other hand, the main role of regions with high elastic modulus is to prevent rupture and damage in the event of abnormally high blood pressure such as during surgery, and to maintain long-term durability. The approximation can be made within a range that satisfies the role of .

In the artificial blood vessel of the present invention, the compliance and small elastic modulus values measured in the normal blood pressure range are mainly determined by the strength of the porous structure made of elastomer, and the values of the compliance and small elastic modulus measured in the normal blood pressure range are determined mainly by the strength of the porous structure made of elastomer. A large elastic modulus value is determined primarily by the strength of the tubular material made of fibers. Therefore, by combining the two, it is possible to approximate the stress-strain curve of an artificial blood vessel.

Since the artificial blood vessel of the present invention has a stress-strain curve similar to that of a biological blood vessel, it is unlikely to rupture or be damaged even if an abnormal increase in blood pressure occurs during surgery.
It is also excellent in maintaining durability long after transplantation. .

Since the artificial blood vessel of the present invention is composed of an elastomer with excellent blood compatibility, its inner side, that is, the blood contact surface, has good blood compatibility, but the antithrombotic property at the initial stage of implantation into a living body can be further improved. For this purpose, the surface may be coated with albumin, gelatin, chondroitin sulfate, heparinized material, etc.

As explained above, the artificial blood vessel of the present invention includes a porous structure portion made of an elastomer in which pores exist throughout the thickness from the inside to the outside of the vessel wall, and at least a portion of the porous structure portion and (or ) and a tubular part made up of fibers that are bonded to each other, so that an artificial blood vessel whose compliance and stress-strain curve approximate those of a living blood vessel can be obtained.

Next, the method for manufacturing an artificial blood vessel of the present invention will be explained based on one embodiment.

After coating the mandrel with an elastomer solution containing a pore-forming agent, the mandrel is immersed in a coagulation solution to precipitate the elastomer.This repeated operation is repeated when hanging a tubular structure made of elastomer. At any stage, by covering the mandrel with a tubular material made of fibers, or by winding fibers or a strip made of fibers in a helical shape, a composite tubular structure is obtained, and the desired pipe wall is formed. Once the thickness has been changed, the mandrel is removed and the pore-forming agent is removed from the tubular structure, thereby allowing the artificial blood vessel of the present invention to be used.

The elasmer solution consists of an elastomer, a good solvent, and a pore-forming agent, and may contain a small amount of a poor solvent if necessary.

The good solvent is a solvent that dissolves the elastomer, and may be a single solvent or a mixed solvent.

The above-mentioned pore-forming agent is unnecessary for a good solvent and can be removed during or after molding of the artificial blood vessel, and includes, for example, inorganic salts such as common salt and calcium carbonate, water-soluble sugars such as glucose and starch, and proteins. etc. can be used.

The poor solvent is a solvent that does not dissolve the elastomer but is miscible with a good solvent, such as water, lower alcohols, ethylene glycol, propylene glycol,
．． 4-butanediol, glycerin, etc. may be used alone or in combination of two or more.

The coagulating liquid is a poor solvent or a mixture of a poor solvent and a good solvent, and serves to coagulate the elastomer solution.

The artificial blood vessel of the present invention thus obtained has the following excellent properties.

■Has porosity that helps organize artificial blood vessels.

■Compliance approximates that of biological blood vessels.

■Liquor strain curve approximates biological blood vessels.

■Blood contact surface has excellent blood compatibility.

Furthermore, since the tube wall of the artificial blood vessel of the present invention is a structure in which at least a portion of a tubular material made of fibers is in contact with and/or bonded to a substantially continuous porous structure of an elastomer, It also has the following useful properties:

■The suture needle has good penetration and suturing is easy.

■No fraying occurs at the cut end even when cut to any length.

Moreover, the suture thread does not become frayed from the sutured portion.

■The suture needle's through hole self-closes.

■It is difficult to form nodules under actual conditions of use where blood pressure is applied.

The artificial blood vessel of the present invention having such properties has excellent patency when transplanted into a living body, and does not cause problems such as hyperplasia of the vanus at the anastomotic site. In addition, there is no fear of rupture or damage in the event of abnormally high blood pressure during surgery, etc., and it maintains excellent durability over a long period of time. Furthermore, it has excellent workability during revascularization surgery.

Therefore, the artificial blood vessel of the present invention can be used as an artificial blood vessel, a bypass artificial blood vessel,
It can be used as a patch material and also for blood access. Roughly 0.1-0.8
It is preferable to use it as an arterial artificial blood vessel having a compliance of In particular, the compliance and stress-strain curves are similar to those of biological blood vessels, and the blood contact surface has excellent blood compatibility, so it has a compliance of 0.1 to 0.5, which currently does not exist in clinically used artificial blood vessels. It can also be used as an artificial blood vessel for small-caliber arteries with an internal diameter of 1 to 6M. Therefore, it can be suitably used for revascularization of arteries below the knee or as an artificial blood vessel for aorta-coronary artery bypass.

Furthermore, the artificial blood vessel of the present invention can also be used as a substitute for a soft tubular body such as a ureter.

Next, the artificial blood vessel of the present invention will be explained using Examples.

Example 1 Casein 22.59 with a particle size of 30 mm or less was mixed with dioxane 5
0ae and N,N-dimethylacetamide 30ai! were stirred and dispersed in a mixed solvent using a homogenizer. 15 g of the polyurethane described in Example 1 of JP-A-58-188458 was added to this dispersion and dissolved with stirring.

A glass rod with a diameter of 3 mm was immersed in this dispersion solution and then taken out, and the dispersion solution was evenly coated onto the glass rod. This mandrel was immersed in ethylene glycol to precipitate the elastomer.

Next, using covered yarn made of 70 denier nylon Il fiber wrapped around 20 denier spandex,
Approximately 3 tons in diameter, knitted using a ribbon knitting machine with a 12-needle head.
A ns tube was placed over a glass rod on which the elastomer was deposited.

The glass rod was immersed in the dispersion solution and then taken out, the surface of the glass rod was coated with the dispersion solution, and then immersed in the coagulation solution. After the elastomer was sufficiently deposited, the mandrel was taken out and the coagulated liquid on the surface was removed. After the dispersion solution was deposited on the mandrel in the same manner as described above, the elastomer was precipitated in the coagulation solution. After that, the glass rod was thoroughly washed with water and the glass rod was removed to obtain a composite tubular product. This composite tubular article was immersed in an aqueous sodium hydroxide solution having a pH of 13.5 to extract and remove casein, and finally thoroughly washed with water to obtain an artificial blood vessel according to the present invention.

The obtained artificial blood vessel had an inner diameter of about 3 mm and an outer diameter of about 4.5 m. When this artificial blood vessel was observed with a scanning electron microscope, it was found that there were about 20 to 30 circular to oval pores on the inner surface, and circular to irregularly shaped pores of about 1 to 10 ρ on the outer surface. Were present. A tubular material made of fibers was incorporated into the center of the cross section of the tube wall, and the remaining elastomer part had a network structure.

Next, when water was passed through this artificial blood vessel at a water pressure of 120 s + eHg, the inner surface 1a of the artificial blood vessel! Approximately 501 d of water per minute penetrated the outer surface of the vascular graft, which was found to be porous.

Next, this artificial blood vessel was pre-clotted with fresh blood, cut to a length of 8α, inserted into a closed circuit, and a metering pump that pumped 0.05 d per stroke was used to pump ACD blood from a cow into the closed circuit. Changes in internal pressure were measured. Compliance was measured from equation (1) based on the stroke number of the metering pump and changes in internal pressure, and was found to be 0.30.

The stress-strain curve of this artificial blood vessel was calculated using Shimadzu Autograph 132.
When measured using 000, it was shown as the fourth factor ([1
A graph similar to that of biological blood vessels was obtained.

Next, when this artificial blood vessel was transplanted into the femoral artery of a mongrel adult with a length of about 7ax, it showed a patency of more than 2 months.

Furthermore, even if this artificial blood vessel was cut at any point, the cut portion did not fray, and the sutureability was excellent, and the through hole of the suture needle self-occluded when the thread was removed. In addition, artificial blood vessels tended to be less likely to form knots when the internal pressure was 50 to 150 U+Hg.

From the above, it can be seen that this artificial blood vessel is excellent as an artificial blood vessel for small-caliber arteries.

[Effects of the Invention] The artificial blood vessel of the present invention is porous and has a compliance and stress-strain curve similar to that of a living blood vessel, so it has excellent patency when implanted in a living body, and has excellent patency at the anastomosis site. Problems such as pannus hyperplasia do not occur. Furthermore, there is little fear of rupture or damage in the event of abnormally high blood pressure during surgery, etc., and it has excellent long-term durability.

[Brief explanation of the drawing]

Figures 1 to 3 are explanatory diagrams of different embodiments of the positions of tubular objects made of fibers on the wall of an artificial blood vessel, and Figure 4 is an artificial blood vessel having a porous structure (graph (I)). , the artificial blood vessel obtained in Example 1 (graph (1)
), thoracic aorta (graph circle) and carotid artery (graph ■)
It is a graph showing each stress-strain curve. (Drawing codes) (1): Porous structure part (z: Tubular object 1: Porous structure part No. 14909 Approximate artificial blood vessel and 1 person 5 Subject of amendment (1) Contents of 6 amendments to ``Detailed Description of the Invention J'' in the specification (1) ``Structure'' on page 3, line 6 of Mei 1111 has been changed to `` (2) Correct the word ``coating,'' which is missing on page 10, to read ``a molded article obtained by drying a coated product or a molded article manufactured from a molten state.'' (3) Page 15, 14 of the same article. Correct “fabric” in the line to “knitted fabric”. (5) Correct “artificial blood vessel” in line 13 of page 21 to “biological blood vessels in various parts”.

Claims (1)

[Claims] 1 Made of an elastomer, it is composed of a porous structural part in which pores exist throughout the thickness from the inside to the outside of the tube wall, and fibers that are present in contact with and/or bonded to at least a portion of the porous structural part. An artificial blood vessel whose compliance and stress-strain curves are similar to those of a living blood vessel.