JPS61193670A - Catheter - 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 [Field of Industrial Application] The present invention relates to the structure of a catheter used for contrast agent injection and the like.

[Conventional technology]

Generally, catheters used for contrast agent injection are made of polyethylene tubes woven with stainless steel wire.

By the way, the characteristics required of a catheter include: (1) Twisting from the distal end is easily transmitted to the distal end. ■
It must be flexible because it is guided to the target area through blood vessels.

■The introduction tip must be more flexible than other parts to avoid damaging blood vessels.

is required.

[Problem that the invention seeks to solve]

However, since conventional catheters use polyethylene tubes woven with stainless steel wire as mentioned above, they do not have the above-mentioned characteristics. It was complemented by a wire. As described above, conventional catheters do not have the above-mentioned characteristics (1) to (3), and therefore have the problem that the structure of the guide wire is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a catheter in which the catheter itself has flexibility and pliability, and the structure of a guide wire used together with the catheter can be simplified.

[Means for solving problems]

Alternatively, a catheter characterized in that it is constructed by coating a thermoplastic resin on a tubular member formed in a coil shape can be obtained.

〔Example〕

The present invention will be described below based on examples, but before that, a general outline of shape memory alloys will be given.

Titanium nickel alloy (hereinafter referred to as TiNi alloy).

) is a remarkable shape memory effect (hereinafter abbreviated as SME) accompanying the reverse transformation of thermoelastic martensitic transformation and this S
It is known that a pseudoelastic effect (hereinafter abbreviated as PE) is exhibited in association with ME.

SME refers to the property that when a T1Ni alloy undergoes apparent plastic deformation, it returns to its initial shape when this alloy is heated to a so-called reverse transformation temperature (hereinafter abbreviated as Af point). In addition, PE is T1 at a temperature of A4 point or higher.
This refers to the property that when stress is applied to a Ni alloy to cause apparent plastic deformation, the shape of the alloy is completely restored as soon as the stress is removed.

So-called shape memory alloys such as SME and PE, including this T1Ni alloy, are expected to be applied as temperature sensors, actuator heaters, and energy storage materials.

Next, an example of the present invention will be described.
It is called 1 at% Ni alloy. ) is subjected to normal cold working, and then the alloy wire is used to knit a tubular member into a net shape (hereinafter simply referred to as a net member) and a tubular member formed into a helical coil shape (hereinafter simply referred to as a helical coil). ) was produced. Next, these tube members were heated for 10 minutes at a temperature of 400°C.
Heat treatment was performed for ~30 minutes. In addition, Ti-5 after heat treatment
The wire diameter of the 1 at% Ni alloy wire is 0.3 mm, and the tube diameter is still 6 mm.

The net member subjected to the above heat treatment is heated to a temperature (T) of 0 to 40.
A stress-strain curve calculated based on the results of a tensile test at a temperature range of .degree. C. is shown in FIG. In general, the elastic limit of stainless steel wire is about 7.0.2% in elongation, but as shown in Figure 2, Ti-51at%Ni alloy wire can be completely restored even if stretched to about 5%. I understand. This means that the above Ti
This means that the -51 at% Ni alloy wire is far superior in flexibility to the stainless steel wire. Note that the above-mentioned characteristics are also the same for helical coils.

Next, referring to FIGS. 1(,) and (b), the above net member 1 and helical coil 2 are respectively immersed in a polyethylene melt bath and subjected to a thin coating treatment. A catheter 4 was manufactured by applying a polyethylene coating 3 to the helical coil 2. Still for comparison, T
A stainless steel net member and helical coil having the same shape as the i-51 at% Ni net member and helical coil were manufactured.

This stainless wire net member and helical coil were each immersed in a polyethylene melt tank.

A thin coating is applied to the catheter (not shown).
was produced.

A 180 degree bending test was conducted on the Ti-51 at% Ni catheter 4 and the stainless steel catheter described above.

As a result, in the case of the Ti-51at%Ni catheter, it spontaneously almost completely recovered, but in the case of the stainless steel catheter, some strain remained.

It never returned to its original shape.

Furthermore, when the Ti-51at%Ni catheter was repeatedly bent 180 degrees (100 times), there was no deformation at all, whereas the stainless steel catheter broke when it was repeatedly bent 30 times.

In this way, in the case of Ti-51atq6N+ catheter.

The catheter itself is more flexible than a stainless steel catheter, so the guidewire only needs to be flexible at its tip, making the structure of the guidewire simpler than in the past.

Furthermore, since the Ti-51at%Ni catheter has extremely good flexibility, it can be easily deformed and restored along the blood vessel into which it is inserted, so that it is less likely to damage the blood vessel. Furthermore, *'rl-51at%Ni catheter is resistant to repeated bending.

Compared to stainless steel catheters, it can be used repeatedly and costs are reduced.

Hiko, when considering the use in the human body, the Ti-Ni alloy wire mentioned above has a Ni > 50.3 at% and a cold working rate (9
) to 50%, and the heat treatment conditions are preferably 350 to 400°C. Further, the relationship between the wire diameter of the Ti--Ni alloy wire, the diameter of the mesh member or warto-helical coil, and the thickness of the polyethylene coating film is adjusted so as not to impair the flexibility of the catheter.

Margins below [Effects of the Invention] As explained above, according to the present invention, the catheter itself has flexibility and pliability, so the structure of the guide wire used together with the catheter can be simplified.

[Brief explanation of drawings]

FIG. 1(,) is a sectional view showing one embodiment of the catheter according to the present invention, FIG. 1(b) is a sectional view showing another embodiment of the catheter according to the present invention, and FIG. 2 is a sectional view showing another embodiment of the catheter according to the present invention. T
It is a figure showing the stress-strain curve of the tube member which knitted i-51at%Ni alloy wire in the shape of a net. 1... Net member, 2... Helical coil. 3... Polyethylene coating membrane, 4... Tube.

Claims (1)

[Claims] 1. A tubular member knitted or coiled with shape memory alloy wire exhibiting thermoelastic martensitic transformation is coated with a thermoplastic resin. catheter. 2. In the statement of claim 1, the shape memory alloy is a titanium-nickel alloy, the atomic concentration of nickel is 50.3% or more, and the titanium-nickel alloy is cold worked. rate 50-50% and heat treatment conditions 3
A catheter characterized in that it is processed at a temperature of 50 to 400°C. 3. In the description of claims 1 and 2,
A catheter characterized in that the thermoplastic resin is polyethylene.