JP3163445B2 - catheter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a catheter used for injection of a contrast medium or the like.

[0002]

2. Description of the Related Art Generally, a catheter used for injection of a contrast medium or the like uses a polyethylene tube in which a stainless wire is woven. By the way, the characteristics required for catheters include that the torsion from the distal end is easily transmitted to the distal end, and that the catheter has flexibility because it is guided to the target site through the blood vessel. .

[0003]

However, since the conventional catheter is made of polyethylene woven with a stainless steel wire as described above, it does not have the above-mentioned characteristics. It was complemented by a guidewire used with the catheter. Therefore, there is a disadvantage that the structure of the guide wire is complicated.

Accordingly, it is an object of the present invention to provide a catheter which has flexibility and flexibility in the catheter itself and can simplify the structure of a guide wire used together with the catheter.

[0005]

According to the present invention SUMMARY OF], a warp comprising a plurality of shape memory alloy wire arranged alongside one another in one direction, and a circular plurality of weft consisting of textiles excluding metal fiber A catheter is obtained in which the weft is knitted in a tube shape so as to be spaced from each other in the direction intersecting the warp yarn and in the one direction, and the tube is coated with a resin. According to the present invention, a catheter characterized in that the shape memory alloy wire is a titanium-nickel alloy wire showing superelasticity at least at body temperature (37 ° C.).

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments, but before that, an outline of a shape memory alloy will be given.

The titanium-nickel alloy (hereinafter referred to as TiNi alloy) has a remarkable shape memory effect (hereinafter abbreviated as SME) accompanying the reverse transformation of the thermoelastic martensitic transformation and a superelastic effect accompanying this SME. (Hereinafter abbreviated as PE).

[0008] The SME is a property in which when a TiNi alloy is subjected to apparent plastic deformation, the alloy is heated to a so-called reverse transformation temperature (hereinafter abbreviated as Af point) and returns to an initial shape. PE refers to the property of completely restoring the shape of an alloy when a stress is applied to the TiNi alloy to cause apparent plastic deformation at a temperature equal to or higher than the Af point. So-called shape memory alloys such as TiNi alloys and SMEs and PEs are expected to have stress as temperature-sensitive sensors, actuators, and energy storage materials.

Next, a catheter according to an embodiment of the present invention will be described with reference to FIGS. 1 (a), 1 (b) and 1 (c). The TiNi alloy wire and warp, the weft with a polyurethane, the warp 1 and weft yarns 2 is formed a mesh member 10 which intersect in as in FIG. 1 (c). The net member 10 will be coated with the inner tube 3 and the net member 1 by resin coating in the future.
It is knitted sufficiently loosely so that 0 is tightly joined.
Further, it is desirable that the warp yarns 1 are arranged so that the yarns do not come into contact with each other so that the movement as the elastic body is not damaged. As an example, a polyethylene tube is arranged as the inner tube 3 as the inner tube, and the net member 10 is incorporated on the outside thereof, coated with polyethylene,
The coating film 4 was formed on the outside of the mesh member 10 to produce a catheter. Further, for comparison, a mesh using the alloy wire for both the helical, coil, vertical and horizontal sides of the alloy wire and a mesh using a stainless steel wire for the warp were manufactured, and a catheter similar to the above was manufactured. As this net member, a Ti-Ni alloy wire containing 51 atomic concentration of Ni (hereinafter, atomic concentration is abbreviated as at%) is generally used for a Ti-Ni alloy wire (hereinafter, this Ti-Ni alloy is referred to as Ti-51at% Ni alloy). After cold working, a tubular member (hereinafter simply referred to as a mesh member) knitted in a mesh shape using the alloy wire was manufactured. Next, these net members were heat-treated at a temperature of 400 ° C. for 10 to 30 minutes. The wire diameter of the heat-treated Ti-51at% Ni alloy wire is 0.3 mm, and the tube diameter is 3 mm.

[0010] The mesh member subjected to the heat treatment was subjected to a tensile test at a temperature (T) of 0 to 40 ° C. FIG. 2 shows a stress-strain curve calculated based on this result.
In general, the elastic limit of the stainless wire is about 0.2%, as shown in FIG.
It can be seen that the i-alloy wire is completely restored even when it is extended to about 5%. This means that the above-mentioned Ti-51at% Ni alloy wire is slightly superior in suppleness to stainless steel wire.

Next, regarding the manufactured catheters according to the example and the comparative example of the present invention, torque transmission by 360-degree rotation, flexibility by ring-shaped winding, and
A test was conducted based on the deformation restoration property by bending at an angle of 80 degrees. The results are shown in Table 1, and in each case, the catheter according to the example of the present invention was most excellent. T of Comparative Example
The catheter using the iNi wire was excellent in flexibility and restorability, but lacked torque transmission as compared with the catheter according to the embodiment of the present invention. This is because the catheter according to the embodiment of the present invention arranges linear TiNi alloy wires in the longitudinal direction of the catheter at equal intervals in a circular shape, and each one is independent without being entangled. In the comparative example, the wire is crossed or helical, so the absorption of torque at the entangled portion and the length of helical transmission are effective. Seems to be. Further, the TiNi alloy wire according to the embodiment of the present invention is preferably Ni > 50.3 at%, cold working 30 to 50%, and heat treatment condition at 350 to 400 ° C. Any fiber is acceptable.

[0012]

[Table 1]

[0013]

As described above, according to the present invention,
It is possible to provide a simple catheter having a structure having extremely high torque transmission, flexibility and flexibility.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a catheter of the present invention. (A) and (b) are cross-sectional views, and (c) shows the mesh members before catheter processing in (a) and (b), respectively.

FIG. 2 is a stress-strain diagram of a Ti-51at% Ni alloy wire used for a catheter according to an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shape memory alloy wire 2 Resin fiber 3 Inner tube 4 Coating film 10 Net member

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A61M 25/00

Claims (2)

(57) [Claims] And warp consisting of a plurality of shape memory alloy wire according to claim 1 were arranged parallel to each other in one direction, in the direction of the circular plurality of weft consisting of textiles excluding metal fiber wherein the weft intersecting the warp The catheter is knitted in a tube shape so as to be spaced apart from each other in the one direction, and the tube is coated with a resin. 2. The catheter according to claim 1, wherein the shape memory alloy wire is a titanium-nickel alloy wire showing superelasticity at least at body temperature (37 ° C.).