JP2003250880A - Artificial blood vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an artificial blood vessel and a shunt made of polyurethane with excellent flexibility (kink resistance) without crimping work applied for tubing like bellows and moreover, those which facilitate suturing or punctuating with a sufficient suture strength and excellent adaptability to changes in shape in shrinking and extension thereof and resulting excellent restoration after transplantation along with the self-closing performance of puncture needles. <P>SOLUTION: In the tubular artificial blood vessel, a tubular knitted braid of an alloy wire is arranged and a polyurethane layer on the internal and external surfaces thereof. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial blood vessel in which a braided braid of tubular alloy wires is embedded or sandwiched in a polyurethane layer, and has a flexibility, flexibility, sutureability, kink, and blood flow due to stenosis. It concerns an unobstructed artificial blood vessel.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 61-87563 discloses a tubular or sheet-shaped medical molded article composed of a segment polyurethane and / or a segment polyurethane urea, at least a cross section of which is porous. A molded article for medical use is disclosed.

Japanese Unexamined Patent Publication (Kokai) No. 63-175182 discloses a polyurethane porous structure characterized in that a polyurethane nonwoven fabric or a molded product thereof and a polyurethane porous layer are integrated.

Japanese Unexamined Patent Publication (Kokai) No. 63-305860 discloses an artificial blood vessel in which a layer made of polyurethane and / or polyurethaneurea and a layer made of a fiber assembly are combined, and (i) the inner surface is made of polyurethane and Disclosed is an artificial blood vessel, which is characterized in that (ii) a layer composed of the fiber aggregate has a gap in which cells can grow and is composed of a polyurethane urea and / or (ii) the fiber aggregate.

Japanese Unexamined Patent Publication Nos. 1-64649 and 1
Japanese Patent Publication No.-64650 discloses an artificial blood vessel which is composed of a plurality of layers of polyurethane and / or polyurethaneurea and has a porous wall as a whole.

Japanese Unexamined Patent Publication No. 9-131362 discloses a method for producing an implant that can replace a defective natural tissue portion by using a fiber matrix, which comprises filling the fiber matrix with an organic solvent. And a step in which the organic solvent dissolves a predetermined amount of polyurethane, and by arranging the fiber matrix in a moist atmosphere, the solubility of polyurethane in the organic solvent is reduced to form polyurethane particles. And a step of heating the fiber matrix and the organic solvent to move the polyurethane particles in the organic solvent to form a film on the surface of the fiber matrix.

[0007] As a stent fixed to a tubular membrane or a stent fixed to the outer surface and inner surface of the stent, for example, in Japanese Patent Laid-Open No. 7-24072, the inner and outer surfaces of a tubular structure made of elastic wire are A stent provided with a coating layer made of a porous tetrafluoroethylene resin film is disclosed.

In Japanese Unexamined Patent Publication No. 8-140090, a diameter-reducible stent main body is formed in a substantially cylindrical shape, and a plurality of openings are formed to connect the outer surface and the inner surface of the cylindrical shape, and a heat for covering the main stent body. Disclosed is a stent for in-vivo placement, which comprises a plastic resin layer and a tubular cover that covers the outer circumference and / or the inner circumference of the main stent body, closes the opening, and is fixed to the thermoplastic resin layer. . The main body of the stent is covered with the thermoplastic resin layer, so the stent does not come into direct contact with the living body, but the stent is completely fixed to the tubular cover, so when the stent is left in the living body, There is a case in which a flexible movement cannot be performed with respect to the movement, such as the expansion and contraction in the length direction and the radial direction.

[0009] In JP-A-9-173468, there is a coating layer on the inside of a stent support in the state where there are substantially no pores that allow passage of cells, and on the outside there is a coating layer in which fibers are randomly entangled. There are disclosed coated stents and methods of making the same.

Japanese Unexamined Patent Publication (Kokai) No. 11-42284 discloses that the inner and outer surfaces of a stent formed of an elastic wire having a supporting frame made of a zigzag wire having a top portion and a valley portion have a plain-walled wall thickness of polyester resin fiber. 20 μm
Disclosed is an artificial blood vessel with a stent provided with a tube of -100 μm, characterized in that the inner surface and the outer surface of the tube are partially adhered with a polyester resin.

[0011]

Since polyurethane is excellent in biocompatibility, has elasticity close to that of a living body, and has favorable mechanical properties and operability, many studies have hitherto been made regarding application to artificial blood vessels. ing. In the case of a polyurethane artificial blood vessel, the elasticity of polyurethane makes it easy to close the needle hole after needle puncture, so that hemostasis is easy, and it is used as a self-hemostatic dialysis shunt. Furthermore, the polyurethane shunt has characteristics that it can be used for access from the day of transplantation and has less infiltration of body fluids, so that it has less edema and swelling. However, a polyurethane shunt is required to have an artificial blood vessel or shunt made of polyurethane that is weak in bending and has excellent kink resistance. For the purpose of improving kink resistance, a method of providing a bellows on the tube and a method of winding a polyester fiber around the tube in a coil shape are used. An object of the present invention is to provide a polyurethane artificial blood vessel or shunt that is excellent in flexibility (kink resistance) without performing crimping on the tube like a bellows. An artificial blood vessel that has sufficient suture strength, is easy to suture and puncture, has self-occlusive properties of the puncture hole, and has excellent adaptability to shape changes such as contraction and extension after transplantation and excellent restoration from it. For the purpose of providing shunts.

[0012]

The first invention of the present invention is as follows:
It is intended to provide a tubular artificial blood vessel, characterized in that a braided braid of an alloy wire and a braided braid of the alloy wire are provided with a polyurethane layer on an inner surface and an outer surface thereof.

A second aspect of the present invention is to provide a tubular artificial blood vessel, wherein the braided braided tubular alloy wire is embedded in a polyurethane layer.

A third aspect of the present invention is to provide an artificial blood vessel characterized in that the polyurethane layer is in the form of a tubular sheet or film of polyurethane.

A fourth invention of the present invention is to provide an artificial blood vessel characterized in that the hardness of polyurethane is 70 to 100 in Shore A.

In a fifth aspect of the present invention, polyurethane is
An object is to provide an artificial blood vessel characterized by being a segmented polyurethane.

A sixth aspect of the present invention is to provide an artificial blood vessel characterized in that the braid of the alloy wire has a mesh opening of 50 to 3000 μm.

A seventh aspect of the present invention is to provide an artificial blood vessel characterized in that the diameter of the alloy wire is 0.1 μm to less than 100 μm.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The artificial blood vessel of the present invention is a tubular artificial blood vessel, wherein a braided braided alloy wire and a polyurethane layer are provided on the inner and outer surfaces of the braided alloy wire. It is a characteristic artificial blood vessel. In particular, the artificial blood vessel of the present invention is preferably an artificial blood vessel characterized in that a braided braided alloy wire and the inner and outer surfaces of the braided braided alloy wire are directly sandwiched by a polyurethane layer. In the artificial blood vessel of the present invention, the braided braid of the tubular alloy wire is preferably sandwiched between the polyurethane layers and is not exposed to the outside from the inner surface and the outer surface of the artificial blood vessel.

The artificial blood vessel of the present invention is further characterized in that a braided braid of tubular alloy wires is embedded in a polyurethane layer. Furthermore, the artificial blood vessel of the present invention,
An artificial blood vessel characterized by a braided tubular alloy wire directly embedded in a polyurethane layer is preferred.

The artificial blood vessel of the present invention is an artificial blood vessel excellent in flexibility (kink resistance) without crimping like a bellows on the polyurethane layer. The artificial blood vessel of the present invention, by sandwiching or embedding a tubular alloy wire braid with a polyurethane layer, the alloy wire braid does not come into direct contact with blood, and the self-existing needle hole after needle stick is performed. Excellent in occlusivity. Further, since the artificial blood vessel of the present invention has the braided braid of the alloy wire in the form of a tube, it is excellent in shape recovery due to external stress such as external force applied from the direction perpendicular to the axis. Further, the artificial blood vessel of the present invention, by sandwiching or embedding a braided braid of tubular alloy wires with a polyurethane layer, it is possible to suppress fraying and misalignment of the alloy wire of the braided braid, and to achieve good sutureability. You can get it. Further, the artificial blood vessel of the present invention has a small change in diameter when pressed or bent or pulled by an external force, and is excellent in maintaining the opening. Particularly, the artificial blood vessel of the present invention is suitable for a relatively small diameter artificial blood vessel having a diameter of preferably 6 mm or less, more preferably 5.5 mm or less, and particularly preferably 5 mm or less.

The tubular braid of alloy wires may be braided, woven and / or combined with one or more alloy wires to produce a tubular braid. The tubular braid of alloy wire is preferably manufactured by heating at 300 ° C. to 100 ° C. or lower than the melting temperature of the alloy wire, rapidly pouring into cold water, and fixing the shape. The production of the braided tubular alloy wire is not limited by the above production method. It can be manufactured by a method other than the above manufacturing method.

The inner diameter of the braided braided tubular alloy wire is preferably 1 to 8 mm, more preferably 1.5 to 7 m.
m, more preferably 1.5 to 6 mm, particularly preferably 2
It is preferably ~ 5.5 mm. In a braided braid of tubular alloy wire, the braiding, weaving and / or braiding of the brazing alloy wire (mesh aperture) is preferably from 50 to 3000.
μm, more preferably 100 to 2000 μm, more preferably 150 to 1000 μm, particularly preferably 200.
˜500 μm is preferred. In a tubular braided alloy wire, when the braiding, weaving, and / or mesh opening (mesh opening) of the alloy wire is within the above range, the alloy wire has excellent flexibility and also has flexibility (kink resistance). Excellent, excellent self-closing property of the puncture hole, excellent recovery from external stress, and excellent sutureability. Knitting, weaving, and / or mesh opening of an alloy wire means the size or particle size of the particles of the powder that pass through the braid of the alloy wire.

The braided braided alloy wire is one or more alloy wires, preferably 1 to 100 alloy wires, more preferably 2 to 100 alloy wires, more preferably 2 to 75 alloy wires, and particularly preferably. Is knitted, woven and / or braided using 2 to 50 strands.
The alloy wire may be linear or annular.

The diameter of the alloy wire is preferably 0.1 μm
To less than 100 μm, more preferably 3 to 80 μm,
More preferably 5 to 70 μm, particularly preferably 10 to 6
0 μm is preferable. In a braided braid of a tubular alloy wire, when the diameter of the alloy wire is within the above range, the flexibility is excellent,
It also has excellent flexibility (kink resistance), excellent self-closing of the puncture hole, excellent recovery from external stress, and excellent sutureability. The cross section of the alloy wire may be circular or elliptical, such as cylindrical, flat ribbon, or star-shaped.
Any shape can be used. The surface of the alloy wire is preferably smooth. The braided braid of tubular alloy wire has good sutureability and puncture property by controlling the diameter of the alloy wire and the braiding, weaving of the alloy wire and / or the opening of the set (mesh opening). Can be obtained.

As the alloy of the alloy wire, an alloy which does not affect or does not affect the living body or body fluid, particularly a super elastic alloy, can be used, for example, nickel-titanium, nickel-titanium-iron, nickel-titanium-copper, Nickel-
Superelastic alloys such as nickel-titanium alloys such as titanium-chromium and nickel-titanium-copper-chromium can be used, and nickel-titanium is particularly preferable. By using a superelastic alloy wire as the alloy wire, the recoverability due to the stress from the outside of the support structure is excellent, and the self-closing property of the needle hole is improved.

In the artificial blood vessel of the present invention, the polyurethane provided on the inner surface and the outer surface of the braided braided tubular alloy wire may be the same or different. Polyurethane is
Polyurethane for medical use that does not affect or does not affect the living body can be used, random or block copolymerization of a monomer component forming a soft segment and a monomer component forming a hard segment, a block of a soft segment and a hard segment A polymer produced by combining block polymerization with a block or the like can be used. The polyurethane is particularly preferably a segmented polyurethane containing blocks of soft segments and blocks of hard segments. The weight average molecular weight (Mw) of the polyurethane is preferably 200,000.
Approximately 400000 is preferable because relatively long-term transplantation can be carried out. The polyurethane is preferably elastic.

As the monomer component forming the soft segment of polyurethane, a polyether, polyester or polycarbonate having an isocyanate group at both ends and containing no aromatic or cyclic group in the main chain, an aliphatic polyether or a fat Diisocyanate compound selected from group polyester or aliphatic polycarbonate,
Examples thereof include diisocyanate compounds containing a polysiloxane unit having isocyanate groups at both ends. Examples of the monomer component forming the hard segment of polyurethane include an aromatic diisocyanate compound having an isocyanate group at both ends and a segment (structure) containing an aromatic group or a cyclic group in the main chain, and a cyclic alkyl diisocyanate compound. You can A diol and / or a diamine can be used as a chain extender for the diisocyanate compound that is a monomer component. When a diamine is used as the chain extender, the resulting polymer is a polyurea type polyurethane. Polyurethane that is chemically modified can be used.

The soft segment block of polyurethane is selected from polyether, polyester or polycarbonate having no aromatic or cyclic group in the main chain, and segments such as aliphatic polyether, aliphatic polyester and aliphatic polycarbonate. Examples thereof include polyether polyurethane, polyester polyurethane or polycarbonate polyurethane, and silicone-containing polyurethane including silicone. The hard segment block of polyurethane, aromatic polyurethane having a segment containing an aromatic or cyclic group in the main chain,
Examples thereof include cyclic alkyl polyurethane. In particular, a segmented polyurethane using an aliphatic polycarbonate as a soft segment block, a segment containing an aromatic as a hard segment block, and a diol as a chain extender is preferable as the polyurethane.

As the segmented polyurethane, medical segmented polyurethane can be used, and specifically, Pellethan (manufactured by Dow Chemical Japan Co., Ltd.), Tecoflex (Thermedic)
s company), Biospan (The Polymer)
Technology Group) and the like. As the segmented polyurethane, it is preferable to use one having a polycarbonate type soft segment which is excellent in resistance to degradation in vivo, and specifically, a bionate (The Polymer Te)
chnology Group) and the like. As the segmented polyurethane, those obtained as a monomer component of polysiloxane having hydroxyl groups at both ends as a part of the soft segment are preferable, and specifically, Avcothane (manufactured by Avco),
Cardiothane (Avco), Pursi
l (The Polymer Technology G
group product), Carbosil (The Poly)
mer Technology Group), C
ronoflex C (manufactured by Cardiotech)
And so on.

Hardness of polyurethane (durometer)
Is preferably 70 to 100, more preferably 75 to 95, further preferably 76 to 90, and particularly preferably 77 to 85 for Shore A.

The polyurethane layer of the artificial blood vessel of the present invention does not include a braid composed of polyurethane fibers. The polyurethane resin layer preferably has no communication holes from the outer surface to the inner surface and has extremely small water permeability or no water permeability.
The polyurethane resin layer is preferably a sheet or film having a porous or sponge structure.

At least a part of the inner surface and the outer surface of the artificial blood vessel of the present invention preferably has a porous structure. Part or all of the inner surface and / or outer surface of the artificial blood vessel of the present invention is preferably 1 to 1000 μm, more preferably 10 to 500 μm, and more preferably 20 to 400.
It is preferable that the porous structure has a pore size of μm, particularly preferably 30 to 300 μm, and the pore size of the inner surface and the outer surface of the artificial blood vessel may be different. The inner surface and / or outer surface of the artificial blood vessel may partially have a dense portion that is substantially non-porous. The artificial blood vessel of the present invention preferably has a porous structure in which the outer surface has pores, and the inner surface may be non-porous. The polyurethane layer of the artificial blood vessel of the present invention may include a substantially non-porous portion or layer in the layer. The polyurethane layer of the artificial blood vessel of the present invention can include a layer having a sponge structure, and the entire layer preferably has a sponge structure. The pore size can be measured by a scanning electron microscope (SEM).

In the artificial blood vessel of the present invention, at least a part of the inner surface of the inner polyurethane layer and / or the outer surface of the outer polyurethane layer preferably has a porous structure.
In the artificial blood vessel of the present invention, a part or all of the inner surface of the inner polyurethane layer and / or the outer surface of the outer polyurethane layer is preferably 1 to 1000 μm, more preferably 10 to 500 μm, and more preferably 20 to 400 μm.
A porous structure having a pore size of 30 to 300 μm is particularly preferred, and the inner surface of the inner polyurethane layer and the outer surface of the outer polyurethane layer may have different pore sizes. The inner surface of the inner polyurethane layer and / or the outer surface of the outer polyurethane layer may have a dense portion which is substantially non-porous in whole or in part. The polyurethane layer may include a substantially non-porous portion or layer in the layer. The polyurethane layer may include a layer having a sponge structure, and the entire layer preferably has a sponge structure.
In the artificial blood vessel of the present invention, the outer surface of the outer layer polyurethane layer preferably has a pore structure, and the inner surface of the inner layer polyurethane layer may be non-porous.

The porosity of the polyurethane layer is preferably 0.1 to 99.9%, more preferably 30 to 99%,
More preferably 70 to 95%, particularly preferably 80 to 9
0% is preferable. The porosity of the polyurethane layer may be the same or different between the inner layer and the outer layer. The polyurethane layer may partially include a dense portion that is substantially non-porous. The porosity can be calculated by the following formula (1).

[Equation 1]

The polyurethane layer can be obtained by a method of coagulating a solution in which polyurethane is dissolved by contact or immersion in a solution capable of coagulating polyurethane by a wet method or a dry-wet method. Method of solidifying by dry and wet method, then removing pore forming agent, method of removing solvent from solution in which polyurethane is dissolved, adding pore forming agent to solution in which polyurethane is dissolved, and removing solvent and pore forming agent Known methods such as a method, a method of extruding polyurethane in a molten state, a method of adding a pore-forming agent to polyurethane, extruding in a molten state and removing the pore-forming agent, a method of punching a polyurethane membrane or film with a laser, etc. The methods can be manufactured alone or in combination. The polyurethane layer may be molded at once or may be molded at a plurality of times.

An example of the method for producing the polyurethane layer will be shown.
The production of the polyurethane layer is not limited by these production methods. It can be manufactured by a method other than these manufacturing methods. 1. A pore-forming agent is added to polyurethane and this is dissolved in a solvent to obtain a polyurethane solution. Using a stainless steel rod as a core material, a polyurethane solution is uniformly applied to this rod and dried to obtain a tubular structure. A method for producing a polyurethane porous tubular structure by extracting a tubular structure from a core material, immersing the tubular structure in an extract of a pore-forming agent, and eluting the pore-forming agent. 2. Polyurethane is dissolved in a solvent to obtain a polyurethane solution. This polyurethane solution is uniformly applied to a stainless steel core material, dried, or rapidly immersed in a coagulation solution. A method for producing a polyurethane porous tubular structure by wet coagulation by this. 3. Polyurethane is dissolved in a solvent to obtain a polyurethane solution. A method for producing a polyurethane porous tubular structure by uniformly applying this polyurethane solution to a stainless steel core material, rapidly freezing it using a freezing agent, and drying this under reduced pressure. 4. Polyurethane is dissolved in a solvent to obtain a polyurethane solution. A poor solvent is gradually added to this polyurethane solution to partially coagulate and precipitate the polyurethane to prepare a suspension. A method for producing a polyurethane porous tubular structure by applying this suspension to a core material and then drying it. 5. Polyurethane is dissolved in a solvent to obtain a polyurethane solution. A poor solvent is gradually added to this polyurethane solution to partially coagulate and precipitate the polyurethane to prepare a suspension. A method for producing a polyurethane porous tubular structure by applying this suspension to a core material, drying or immediately contacting or dipping in a coagulating liquid. In the method of 5, the porosity and the pore size can be controlled by the kind of poor solvent added to the polyurethane solution, the concentration of the suspension, the composition, the stirring strength, the drying method, and the like.

In the above production method, the type of polyurethane used, polyurethane soluble solvent, polyurethane concentration, pore former, solvent drying conditions, polyurethane coagulation conditions,
Forming polyurethane layers with various thicknesses, surface structures, and cross-sectional structures by changing the conditions for extracting the pore-forming agent, freezing conditions, reduced-pressure drying conditions, coating thickness of the polyurethane solution on the mandrel, jigs for the mandrel, etc. can do. Further, the porosity can be controlled by the content ratio of the pore forming agent, and the pore diameter can be controlled by adjusting the particle diameter of the pore forming agent.

As the pore-forming agent, other inorganic salt such as potassium chloride or water-soluble organic polymer such as starch, polyvinyl alcohol or polyethylene glycol can be used instead of salt. As the extractant of the pore forming agent, not the water but polyurethane insoluble, and an organic solvent or an organic aqueous solution which dissolves the pore forming agent may be used. The extraction temperature of the pore-forming agent may be any temperature as long as it does not affect the polyurethane layer, and water may be cold water, hot water or hot water.

The polyurethane can be used by being dissolved or suspended in a solvent which is dissolved or suspended. Polyurethane is dissolved or suspended in a solvent, preferably 1 to
It is preferably used by dissolving or suspending in the range of 50% by weight, more preferably 2 to 25% by weight, more preferably 2 to 20% by weight, and particularly 3 to 15% by weight. Examples of the solvent include cyclic ether solvents, amide solvents, sulfoxide solvents and halogen solvents. These solvents can be used alone or as a mixture. Tetrahydrofuran, dioxane, etc. can be mentioned as a cyclic ether solvent. Examples of the amide solvent include dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like. Examples of the sulfoxide solvent include dimethyl sulfoxide and sulfolane. Examples of the halogen solvent include hexafluoroisopropanol, chloroform, dichloromethane and the like.

Further, as the poor solvent which can be obtained by adding a poor solvent to the above solvent system, water,
Alternatively, low molecular weight alcohols such as methanol, ethanol and propanol, ketones such as acetone, aromatics such as toluene and halogen solvents such as dichloromethane and chloroform can be used.

Specific examples of the method for manufacturing the braided braid of the tubular alloy wire include: 34 nitinol wires having a diameter of 50 μm are knitted together to obtain a tubular knitted fabric having a diameter of 3.5 mm. The mesh size is about 330 μm. The tubular knitted fabric can be produced by heating it at 530 ° C., holding it for 10 minutes, and then rapidly putting it in cold water to fix its shape.

An example of the method for producing an artificial blood vessel of the present invention will be shown. The production of the artificial blood vessel of the present invention is not limited by these production methods. It can be manufactured by a method other than these manufacturing methods. 1. On the inner polyurethane layer supported by the core rod,
A braid of tubular alloy wire is coated. Further, a polyurethane solution is coated thereon by a method such as coating, dipping or spraying, and an outer polyurethane layer is formed by the method described above. In this method, an artificial blood vessel in which a braided braid of alloy wires is embedded in an inner polyurethane layer and an outer polyurethane layer can be prepared. 2. On the inner polyurethane layer supported by the core rod,
A braid of tubular alloy wire is coated. Furthermore, a method of coating an outer polyurethane layer from the above to create an artificial blood vessel.

The thickness of the artificial blood vessel is preferably in the range of 12 to 1000 μm, more preferably 50 to 800 μm, and particularly preferably 100 to 750 μm.

In the artificial blood vessel of the present invention, the thickness of the polyurethane layer is preferably in the range of 5 μm to 1000 μm. The total thickness of the inner polyurethane layer and the outer polyurethane layer is preferably in the range of 5 μm to 1000 μm.

The alloy wire, the braid of the alloy wire, the polyurethane layer and / or the artificial blood vessel is coated with a known biocompatible material such as collagen or gelatin, heparin, urokinase, dipyridamole, cilostazoline, acetyl. Those treated with antithrombotic agents such as salicylic acid, anticancer agents such as paclitaxel, or derivatives thereof can be used.

Embodiments of the present invention will be described below in more detail with reference to the drawings. The present invention is not limited to only these embodiments. FIG. 1 is a perspective view showing an example of an artificial blood vessel 1 according to the present invention, which includes an outer polyurethane layer 3
It shows a shape in which a part of is cut out. Artificial blood vessel 1
A braid 4 of alloy wires is provided between the inner polyurethane layer 2 and the outer polyurethane layer 3. In the artificial blood vessel 1, the braided braid 4 of alloy wires is embedded in the polyurethane layer including the inner polyurethane layer 2 and the outer polyurethane layer 3. In the artificial blood vessel 1, the inner polyurethane layer 2 and the outer polyurethane layer 3 are integrated, and it is difficult or impossible to cut off or peel off a part of the inner polyurethane layer or the outer polyurethane layer.

FIG. 2 is a partial development view of the braided alloy wire 10. In the knitted alloy wire 10, the wire knitting interval between the alloy wire 11 and the alloy wire 12 is a
And the wire knitting interval between the alloy wire 13 and the alloy wire 14 is shown as b. Depending on the knitting, the wire knitting interval a
And b may be a ≧ b or b> a. The diameter (diameter) of the particles 15 passing through the stitches of the alloy wire knitted fabric 10 is shown as a mesh size.

[0049]

The present invention will be described in more detail based on the following examples. However, the present invention is not limited to the following examples.

Example 1 Polycarbonate type polyurethane (Bionate 80A, Shore A hardness: 80) 1
To 10 parts by weight, 10 parts by weight of sodium chloride powder was added, and this was dissolved in 9 parts by weight of tetrahydrofuran to obtain a 5% by weight polyurethane solution (A). The salt powder used was one that had been classified so as to have a particle size of 100 μm or less. A stainless steel core rod having a diameter of 2.5 mm was immersed in the polyurethane solution (A). Then, the core rod was pulled up while passing through a hole of a jig having an inner diameter of 3.0 mm and a circular hole, and dried at room temperature in dry air. The core rod was turned upside down, and the core rod was again immersed in the polyurethane solution (A) and quickly pulled up while passing through the hole of the jig having the circular hole, and dried at room temperature in dry air. . The operations of inverting the core rod upside down, dipping, pulling up, passing through a jig, and drying were further performed twice, a total of four times, to obtain a tubular porous polyurethane layer having a wall thickness of 0.1 mm. This was used as the inner polyurethane layer. Diameter 45μ
A tubular braid having an inner diameter of 2.5 mm was prepared by using 34 linear alloy wires made of nickel-titanium and having a diameter of 230 μm and a wire weaving interval of 330 μm, and was coated on the inner polyurethane layer. Furthermore, the polyurethane solution (A) is applied and coated on the tubular knitted fabric,
The tubular knit was covered with a layer of polyurethane. The core rod coated with the coated polyurethane solution (A) was passed through a jig hole having an appropriately increased inner diameter to adjust the coating thickness. further,
The core rod was turned upside down, the polyurethane solution (A) was applied and coated, and the jig was passed through the hole once to perform a total of two coating operations. After drying the core rod, the core rod was pulled out. A structure having a wall thickness of 0.1 mm was obtained by covering the tubular knitted fabric with a polyurethane layer. Furthermore, after immersing this structure in a sufficient amount of warm water at 40 ° C. and exchanging the water for another 24 hours, and then changing the water 5 times every 2 hours, it was confirmed that the salt could be sufficiently removed Then, it was taken out and dried under reduced pressure at 40 ° C. for 48 hours. An artificial blood vessel was obtained in which the inner and outer surfaces of the braided alloy wire were covered with a porous polyurethane layer. The artificial blood vessel has an inner diameter of 2.5 mm, an outer diameter of 2.7 mm, a length of 40 cm, a porosity of 90%, and a surface pore size of the outer polyurethane layer of 100 μm.
Met. The artificial blood vessel could be easily sutured with a surgical suture. The artificial blood vessel was immersed in physiological saline and evaluated. The minimum kink radius (inner diameter) of the artificial blood vessel was 2.8 mm.
In the leak test, a water pressure of 120 mmHg was applied to the inside of the artificial blood vessel after piercing the artificial blood vessel with a 16 G needle and withdrawing the needle, but no leak was observed from the needle hole or the surface of the polyurethane layer. In addition, the artificial blood vessel was pulled so that the length in the axial direction was 150%, and the outer diameter was 2.2 mm in that state, which was 81.5% of the outer diameter before pulling, and the opening remained even after stretching. It was confirmed that it was maintained. 3 and 4 are scanning electron micrographs (S
EM) is shown. FIG. 5 shows a scanning electron micrograph (SEM) of a part of the cross section of the artificial blood vessel. FIG. 6 shows a scanning electron micrograph (SEM) of the outer surface of the outer polyurethane layer of the artificial blood vessel, and FIG. 7 shows a scanning electron micrograph (SEM) of the inner surface of the inner polyurethane layer of the artificial blood vessel. From FIG. 5, the tubular knitted fabric is covered with the polyurethane layer, the polyurethane layer has a sponge structure, and the holes on the outer surface do not communicate with the inner surface. 6 and 7, the outer surface and the inner surface of the polyurethane layer have a porous structure.

[Example 2] Alicyclic polyether polyurethane (Tecoflex 100A, Shore A hardness 10)
0) 1 part of salt powder was added with 10 parts of salt powder, and this was dissolved in 9 parts of tetrahydrofuran to obtain a 5 wt% polyurethane solution (B). The salt powder used was one that had been classified so as to have a particle size of 100 μm or less. A stainless steel core rod having a diameter of 4.0 mm was immersed in the polyurethane solution (B). Then, the core rod was pulled up while passing through a hole of a jig having an inner diameter of 4.5 mm and a circular hole, and dried at room temperature in dry air. The core rod was turned upside down, and the core rod was immersed again in the polyurethane solution (B) and quickly pulled up while passing through the hole of the jig having the circular hole, and dried at room temperature in dry air. . Upside down core rod,
The operations of dipping, passing through a jig, pulling up, and drying were further performed twice, a total of four times, to obtain a tubular porous polyurethane layer having a wall thickness of 0.1 mm. This was used as the inner polyurethane layer. Nickel titanium alloy wire 3 with a linear diameter of 45 μm
Using 4 wires, wire weaving interval 330 μm, opening 230
A tubular knit having a diameter of 4 μm and an inner diameter of 4 mm was prepared and coated on the inner polyurethane layer. Further, from above the tubular knit, alicyclic polyether polyurethane (Tecofl
Ex100A, Shore A hardness 100) 1 part was dissolved in tetrahydrofuran 9 parts, 10 weight% of polyurethane solution (C) was applied and coated, and the tubular knitted fabric was covered with the polyurethane layer. The core rod coated with the coated polyurethane solution is
The coating thickness was adjusted by passing it through a hole of a jig having an appropriately increased inner diameter. Further, a polyurethane solution (B) was coated thereon, and the core rod coated with the coated polyurethane solution (B) was passed through a hole of a jig having an appropriately increased inner diameter to adjust the coating thickness. The core rod was turned upside down, the polyurethane solution (B) was applied and coated, and the jig was passed through the hole once, and the coating operation was performed twice in total. After drying the core rod, the core rod was pulled out. Wall thickness of tubular knitted fabric covered with polyurethane layer
A 3 mm structure was obtained. Furthermore, after immersing this structure in a sufficient amount of warm water at 40 ° C. and exchanging the water after 24 hours, and then changing the water every 2 hours 5 times, it was confirmed that the salt could be sufficiently removed. Then, it was taken out and dried under reduced pressure at 40 ° C. for 48 hours. An artificial blood vessel was obtained in which the inner and outer surfaces of the braided alloy wire were covered with a porous polyurethane layer. The artificial blood vessel has an inner diameter of 4.0 mm, an outer diameter of 4.3 mm, and a length of 40 c.
m, the porosity was 90%, and the pore size on the surface of the outer polyurethane layer was 120 μm. The artificial blood vessel could be easily sutured with a surgical suture. The artificial blood vessel was immersed in physiological saline and evaluated. The minimum kink radius (inner diameter) of the artificial blood vessel is 4.2 m
It was m. In the leakage test, a water pressure of 120 mmHg was applied to the inside of the artificial blood vessel after piercing the artificial blood vessel with a 16G needle and withdrawing the needle, but no leakage was observed from the needle hole or the polyurethane layer. Also, the artificial blood vessel has an axial length of 150%.
The outer diameter is 4.
It was 1 mm, which was 97.6% of the outer diameter before stretching, and it was confirmed that the opening was maintained even after stretching.

[Example 3] Polyether polyurethane (Pellethan 80AE, Shore A hardness 80)
10 parts was dissolved in 90 parts of dimethylacetamide to obtain 10 parts.
A weight% polyurethane solution (D) was obtained. A stainless steel core rod having a diameter of 6.5 mm was immersed in the polyurethane solution (D), and the core rod was quickly pulled up while passing through a hole of a jig having a circular hole having an inner diameter of 6.6 mm, and was immediately cooled in cold water. Was immersed in and solidified to obtain a tubular porous polyurethane layer. This was dried and then used as an inner polyurethane layer. Using 34 linear nickel-titanium alloy wires having a diameter of 45 μm, a tubular knit having a wire weaving interval of 330 μm, an opening of 230 μm, and an inner diameter of 6.5 mm was prepared, and was coated on the inner polyurethane layer. Furthermore, the core rod coated with the polyurethane solution (D) by dip-coating the tubular braid onto the tubular braid was coated with the polyurethane solution (D). Was quickly passed through and rapidly immersed in cold water for solidification to obtain a structure in which a tubular knitted fabric was covered with a polyurethane layer. After this structure was dried, it was pulled out from the core rod to obtain an artificial blood vessel. An artificial blood vessel was obtained in which the inner and outer surfaces of the braided alloy wire were covered with a porous polyurethane layer. The artificial blood vessel has an inner diameter of 6.5 mm, an outer diameter of 6.9 mm, a length of 40 cm,
The porosity is 65% and the surface pore size of the outer polyurethane layer is 2
It was 0 μm, and pores of about 150 μm were recognized in the cross section. The artificial blood vessel could be easily sutured with a surgical suture. The artificial blood vessel was immersed in physiological saline and evaluated. The minimum kink radius (inner diameter) of the artificial blood vessel was 25.7 mm. In the leak test, a water pressure of 120 mmHg was applied to the inside of the artificial blood vessel after piercing the artificial blood vessel with a 16 G needle and withdrawing it, but no leak was observed from the needle hole or the surface of the polyurethane layer. In addition, the artificial blood vessel was pulled so that the length in the axial direction was 150%, and the outer diameter was 6.4 in that state.
mm, which corresponds to 92.8% of the outer diameter before pulling,
It was confirmed that the opening was maintained even after stretching.

[Example 4] 10 parts by weight of polycarbonate type polyurethane (Bionate 80A, Shore A hardness 80) was dissolved in 90 parts of tetrahydrofuran.
A polyurethane solution (E) was obtained. While strongly stirring this polyurethane solution (E), 50 parts of methanol was added dropwise little by little to prepare a suspension solution. Immerse a stainless steel rod with an inner diameter of 4 mm in this suspension solution to give an inner diameter of 4.5 m.
After passing through the jig of m and pulled up, it was naturally dried at room temperature to obtain a tubular polyurethane layer. Using 34 linear nickel-titanium alloy wires having a diameter of 45 μm, a tubular knit having a wire weaving interval of 330 μm, a mesh opening of 230 μm, and an inner diameter of 4.0 mm was prepared and coated on the polyurethane layer. Further, the stainless rod was immersed in the suspension solution, passed through a jig having an inner diameter of 4.7 mm and pulled up, and then naturally dried at room temperature to obtain a tubular structure. The tubular structure was pulled out from the mandrel and then dried under reduced pressure at 40 ° C. for 24 hours to obtain an artificial blood vessel in which the inner and outer surfaces of the braided alloy wire were covered with a porous polyurethane layer. The artificial blood vessel has an inner diameter of 4.0 mm, an outer diameter of 4.3 mm, a length of 40 cm, a porosity of 58%, and a pore size of 100 to 100 on the entire surface of the outer polyurethane layer.
Many holes of about 300 μm were recognized. The artificial blood vessel could be easily sutured with a surgical suture. The artificial blood vessel was immersed in physiological saline and evaluated. The minimum kink radius (inner diameter) of the artificial blood vessel was 9.4 mm. In the leak test, a water pressure of 120 mmHg was applied to the inside of the artificial blood vessel after piercing the artificial blood vessel with a 16 G needle and withdrawing it, but no leak was observed from the needle hole or the surface of the polyurethane layer. In addition, the artificial blood vessel was pulled so that the length in the axial direction was 150%, and the outer diameter was 4.1 mm in the state as it was, which was 95.3% of the outer diameter before pulling, and the opening remained after stretching. It was confirmed that it was maintained.

[Comparative Example 1] The same operation as in Example 1 was carried out except that the tubular knitted fabric was not coated to prepare a tubular structure made of a polyurethane layer. Since this tubular structure is easily broken, the minimum kink radius cannot be measured. When the tubular structure was pierced with a 16 G needle and removed, and then water pressure of 120 mmHg was applied, leakage was recognized. In addition, the artificial blood vessel is pulled so that the axial length becomes 150%, and the tube becomes flat in that state,
The outer diameter could not be measured.

[Comparative Example 2] An artificial blood vessel was prepared in the same manner as in Example 1 except that 34 nickel-titanium alloy wires each having a linear diameter of 45 μm were used and a tubular knitted fabric with a mesh opening of 30 μm was used. Got An artificial blood vessel has a high resistance of a puncture needle during suturing, which makes it difficult to suture. Also, the needle hole was not blocked after the needle was removed. The artificial blood vessel was immersed in physiological saline and evaluated. Minimum kink radius (inner diameter) of artificial blood vessel
Was 23.1 mm. In the leak test, the artificial blood vessel was pierced with a 16G needle, and after removing it, the water pressure inside the artificial blood vessel 1
Although 20 mmHg was applied, the needle hole remained open and did not recover, and leakage was recognized from the needle hole. Further, when the artificial blood vessel was pulled so that the length in the axial direction was 150%, some peeling of the polyurethane layer was observed.

[Comparative Example 3] Four nickel-titanium alloy wires having a diameter of 200 μm were used, and the braid spacing 3 was used.
An artificial blood vessel was obtained in the same manner as in Example 1, except that a tubular knitted fabric having a mesh size of 30 μm and a mesh size of 230 μm was used. In the artificial blood vessel, the suture needle may hit the metal fiber depending on the location, and the puncture was impossible. Moreover, cutting of the artificial blood vessel has been difficult. The artificial blood vessel was immersed in physiological saline and evaluated. The minimum kink radius (inner diameter) of the artificial blood vessel could not be measured, and it was difficult to bend it to a radius of 50 mm or less. In the leak test, 16G was added to the artificial blood vessel.
120m of water pressure inside the artificial blood vessel after piercing and removing the needle
Although mHg was applied, no leak was observed from the needle hole. In addition, the artificial blood vessel is pulled so that the length in the axial direction is 150%, and the outer diameter is 1.1 mm in that state, which is 40.7% of the outer diameter before pulling, and the opening diameter after stretching. It was confirmed that was not maintained.

[Comparative Example 4] An artificial blood vessel was obtained in the same manner as in Example 1, except that a linear steel wire having a low elasticity was used. The artificial blood vessel was punctured with a 16 G needle, and the needle hole was not closed after the needle was removed. The artificial blood vessel was immersed in physiological saline and evaluated. Minimum kink radius (inner diameter) of artificial blood vessel
Was 16.2 mm. However, the artificial blood vessel did not return to its original shape after the kink evaluation. In the leak test,
A water pressure of 120 mmHg was applied to the inside of the artificial blood vessel after puncturing the artificial blood vessel with a 16 G needle and removing the needle, but leakage was recognized from the needle hole. In addition, the artificial blood vessel was pulled so that the length in the axial direction was 150%, and the outer diameter was 2.2 as it was.
mm, which corresponds to 81.5% of the outer diameter before pulling,
It was confirmed that the opening was maintained even after stretching. However, after stretching, the film remains stretched in the length direction and does not return to the length before stretching.

[Comparative Example 5] A diameter of 4 was obtained in the same manner as in Example 1.
An inner diameter of 2.5 mm woven with 34 5 μm nickel-titanium alloy wires and braided at a wire weaving interval of 330 μm
Of tubular knitting. When this tubular knitted fabric was stretched by 200% in the axial direction and the diameter in a stretched state was measured, the inner diameter was 1.2 mm, which was 48.0% of the outer diameter before stretching, and the inner diameter after stretching. It was confirmed that it was difficult to maintain.

[0059]

INDUSTRIAL APPLICABILITY The artificial blood vessel of the present invention is an artificial blood vessel which is excellent in flexibility (kink resistance) without subjecting the polyurethane layer to crimping like a bellows. INDUSTRIAL APPLICABILITY The artificial blood vessel of the present invention is excellent in self-closing property of the needle hole because the braided braid of the alloy wire is sandwiched between the polyurethane layers so that the braided braid of the alloy wire does not come into direct contact with blood. Further, since the artificial blood vessel of the present invention has the braided braid of tubular alloy wires, it is excellent in recoverability due to external stress. Further, in the artificial blood vessel of the present invention, by braiding the braided braid of the alloy wire between the polyurethane layers, it is possible to prevent the alloy wire from being frayed or displaced, and to obtain good sutureability.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of an artificial blood vessel of the present invention, which is a shape in which a part of an outer polyurethane layer is cut off.

FIG. 2 is a partial development view of a knitted alloy wire.

FIG. 3 shows a scanning electron micrograph (SEM) of a part of the tubular knitted fabric of Example 1.

FIG. 4 shows a scanning electron micrograph (SEM) of a part of the tubular knitted fabric of Example 1.

5 shows a scanning electron micrograph (SEM) of a part of the cross section of the artificial blood vessel of Example 1. FIG.

6 shows a scanning electron micrograph (SEM) of the outer surface of the outer polyurethane layer of the artificial blood vessel of Example 1. FIG.

7 shows a scanning electron micrograph (SEM) of the inner surface of the inner polyurethane layer of the artificial blood vessel of Example 1. FIG.

[Explanation of symbols]

1: Artificial blood vessel, 2: Inner layer polyurethane layer, 3: Outer layer polyurethane layer, 4, 10: Knitted wire of alloy wire, 5: Inner surface of artificial vessel or inner surface of inner layer polyurethane layer, 6: Outer surface or outer layer of artificial vessel Outer surface of polyurethane layer, 11, 12, 13, 14: Alloy wire, 15: Particles passing through braid of alloy wire.

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Claims (7)

[Claims] 1. A tubular artificial blood vessel, wherein a tubular braided alloy wire and a braided braid of the alloy wire are provided with a polyurethane layer on the inner and outer surfaces thereof. 2. A tubular artificial blood vessel, wherein a braided braid of tubular alloy wires is embedded in a polyurethane layer. 3. The polyurethane layer is in the form of a tubular sheet or film of polyurethane.
Alternatively, the artificial blood vessel according to claim 2. 4. The hardness of polyurethane is 70 to shore A.
It is 100, The artificial blood vessel of any one of Claim 1 or Claim 2 characterized by the above-mentioned. 5. The artificial blood vessel according to any one of claims 1 to 4, wherein the polyurethane is a segmented polyurethane. 6. An alloy wire braid has a mesh opening of 50 to 50.
It is 3000 micrometers, The artificial blood vessel of Claim 1 or Claim 2 characterized by the above-mentioned. 7. The diameter of the alloy wire is from 0.1 μm to 100.
The artificial blood vessel according to claim 1, wherein the artificial blood vessel has a thickness of less than μm.