JPH0817808B2 - Antithrombotic indwelling catheter - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antithrombotic vascular indwelling catheter for clinical treatment or examination.

<< Prior Art and its Problems >> Various types of indwelling catheters are used for clinical treatment or various examinations.

For example, nutrition supplementation by an intravenous indwelling catheter, or an angiography catheter, etc.

Since these catheters are inserted into a blood vessel for use, they are made of a flexible material such as polyurethane or soft silicone resin so as not to damage the inner wall of the blood vessel.

However, although these materials have relatively excellent antithrombotic properties, they do not produce thrombus at all, so thrombus is generated at the surface that comes into contact with blood, and the generated thrombus peels off inside the blood vessel. When it reaches the peripheral microvessels, it may clog the blood vessels, causing cerebral infarction and impaired limb circulation.

Furthermore, conventionally, in order to obtain better antithrombotic properties, anticoagulants such as heparin and fibrinolytic enzymes such as urokinase,
Many methods have been proposed for immobilizing on the surface of the material surface in contact with blood, or impregnating the material for sustained release.
However, these methods reduce the effect of release and release,
There are some problems such as a decrease in enzyme activity due to denaturation of the enzyme upon immobilization, lack of storage stability, and a decrease in enzyme activity due to sterilization, and they have not been sufficiently solved.

The present invention has been made in view of such conventional problems, the surface of the intravascular catheter (the surface in contact with blood), by imparting excellent antithrombotic properties, eliminates the formation of thrombus, It is an object of the present invention to provide a catheter for indwelling a blood vessel in which a side effect such as blood circulation disorder in the peripheral portion is novel.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention provides an antithrombotic indwelling catheter, a hollow tubular catheter body made of a flexible synthetic resin, and an outer periphery of the catheter body. And a hydrogel-forming layer made of polyvinyl alcohol, which is anchor-bonded to the pores of the porous polyurethane layer and surrounds and covers the outer periphery of the porous polyurethane layer.

The antithrombogenic vascular indwelling catheter having the above-described configuration will be described in detail. As the synthetic resin for forming the hollow tubular catheter main body, there is a flexible polyurethane that can be adhered to the porous polyurethane layer on the outer periphery, or a soft resin. Polyvinyl chloride or the like is recommended, and hollow tubing is formed by a method such as melt extrusion of these resins.

The porous polyurethane layer that surrounds and surrounds the outer periphery of the hollow tubular material is made of polyurethane dissolved in a solvent, calcium carbonate,
Inorganic salts such as magnesium oxide and magnesium hydroxide were mixed to form a slurry, which was extruded from an annular die to coat the outer periphery of the tubular article, or the surface of the tubular article was coated with the slurry. After that, the solvent is removed and the inorganic salts are further eluted to form a porous layer.

In this case, the thickness of the porous urethane layer may be such that the polyvinyl alcohol layer as the hydrogel forming layer can be anchor-bonded.

When it is necessary to withstand the injection pressure of a contrast agent such as an angiography catheter, it is preferable to embed a reinforcing agent braided in a braided shape with a stainless steel wire in the middle portion of the catheter body.

The hydrogel layer, polyvinyl alcohol, particularly those having a degree of polymerization of 500 or more, a degree of saponification of 80% or more, and ethylene / vinyl alcohol copolymers having a high vinyl alcohol content such as antithrombotic performance, durability, etc. From the viewpoint, it is preferable that these form a layer having a thickness of about 1 to 100 μm.

<< Operation >> Since the present invention has the hydrogel-forming layer made of polyvinyl alcohol on the porous polyurethane layer provided on the outer periphery of the hollow tubular catheter body, when it is used as a catheter in a blood vessel, it is physiologically used in advance. The outermost layer, polyvinyl alcohol, becomes a hydrogel layer by moistening it with saline or by using water in the blood during use, and develops antithrombogenicity, and this hydrogel layer is anchored to the porous polyurethane layer. Since it does not fall off, the antithrombotic performance can be stably maintained for a long period of time.

<< Example >> * Example 1 (intravenous indwelling catheter) 100 parts of polyether segmented polyurethane was dissolved in tetrahydrofuran, and light calcium carbonate 39 was added thereto.
0 parts and 110 parts of magnesium oxide are added and the solvent is volatilized while kneading with stirring to obtain a viscous slurry-like raw material for forming the porous layer.

Using polyether segmented polyurethane as a raw material, a hollow tubular catheter body 1 having a small diameter is prepared by a method such as melt extrusion molding, and the slurry-like raw material is applied to the outer periphery thereof.

Next, this is desolvated with water, and the inorganic material is extracted and removed with hydrochloric acid to make it porous, thereby forming the porous polyurethane layer 2 surrounding and covering the outer periphery of the hollow tubular material.

Then, after sufficiently washing with water, it is dried by a freeze-drying method while maintaining its porous shape.

Here, the method for forming the porous polyurethane layer 2 is not limited to the one in which the inorganic salts added to the above-mentioned slurry are extracted and removed by an acid such as hydrochloric acid, but may be one dissolved in water such as salt, for example. Absent. In this case, the solvent is removed by air-drying instead of water, and after drying, it is made porous again by water.

Further, the outer circumference of the porous polyurethane layer 2 is impregnated with an aqueous solution of polyvinyl alcohol (hereinafter, abbreviated as PVA) having an average molecular weight of 1700 and a saponification degree of 99% or more, dried, and then the inside of the pores of the porous polyurethane layer 2 Part of the circumference is anchor-bonded, and the hydrogel forming layer 3 that surrounds and covers the outer circumference
To form.

The cross-sectional shape of the catheter obtained by the above processing is shown in FIG.

In the catheter shown in the figure, the hydrogel forming layer 3
The heat treatment of PVA improves the crystallinity and the antithrombotic property.

* Example 2 (Angiographic catheter) An angiographic catheter is a method in which a catheter is inserted from a relatively peripheral blood vessel such as a thigh to a target site (coronary artery or the like), and then a contrast agent is injected. Used in. Therefore, it must have a waist strength that can withstand insertion, a pressure resistance that can withstand the injection pressure of the contrast agent, and a softness that does not damage the inner wall of the blood vessel. For this reason, the catheter needs to be reinforced with a steel wire in order to provide pressure resistance and waist strength. In this embodiment, the reinforcing member 4 was embedded in the catheter body 1 as follows.

A thin hollow tube was prepared by melt extrusion of polyether segmented polyurethane, and a reinforcing material 4 braided in a braided shape with a very thin stainless steel wire was attached to the outer periphery of the thin hollow tube. Thereafter, the polyether segmented polyurethane is again melt-extruded on the outer periphery thereof, the reinforcing material 4 is completely covered, and it is covered so as to adhere to the lower layer polyurethane,
A catheter body 1'was formed.

Then, the same slurry as in the above-mentioned example is applied to this catheter body 1'and treated in the same manner as in the above-mentioned example to form a polyurethane porous layer 2, which is then impregnated with a PVA aqueous solution to form a hydrogel layer 3. Formed.

A cross-sectional view of the catheter obtained by the above processing is shown in FIG.

<< Effects of the Invention >> As described above, according to the present invention, it is possible to prepare an indwelling blood vessel catheter that hardly causes thrombus due to the excellent antithrombotic property of PVA hydrogel. Further, there is no change over time in the antithrombotic performance seen in the method of increasing the antithrombotic performance by immobilizing the anticoagulant or the fibrinolytic enzyme of the prior art, or by impregnating and slowly releasing it.
It is possible to develop stable antithrombotic performance for a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, and FIG. 2 is a sectional view showing the second embodiment. 1,1 ′ …… Catheter body 2 …… Porous polyurethane layer 3 …… Hydrogel layer 4 …… Reinforcement material

Claims (2)

[Claims] 1. A hollow tubular catheter body made of a flexible synthetic resin, a porous polyurethane layer surrounding and covering the outer periphery of the catheter body, and anchored to the pores of the porous polyurethane layer, An antithrombotic vascular indwelling catheter comprising a hydrogel-forming layer made of polyvinyl alcohol that surrounds and covers the outer periphery. 2. The antithrombotic vascular indwelling catheter according to claim 1, wherein a braid-like reinforcing material is embedded in the catheter body.