Method of manufacturing a differentially heat treated catheter guide wire

Abstract

A catheter guide wire is provided for guiding a catheter into a body cavity such as a blood vessel. The base material constituting the wire is made of an elastic alloy wire and subjected to a heat treatment such that its flexibility is sequentially increased from its proximal to distal end portions. A thermoplastic resin or / and a coil spring can be applied to at least the distal end portion of the wire base material. A method of manufacturing the catheter guide wire is also provided. The method is characterized in that the leading end side of the base material is divided into a plurality of areas and subjected to a heat treatment by changing the heat treatment temperature and the time conditions in units of the areas so that the flexibility of the base material is sequentially increased from the proximal to distal end portions of the leading end side.

Description

TECHNICAL FIELDThe present invention relates to a catheter guide wire for guiding a clinical or testing catheter to a predetermined portion of a body cavity such as a blood vessel, a digestive tract, and a windpipe and holding it therein, and a method of manufacturing the same.PRIOR ARTWhen a catheter is to be guided to a branching peripheral portion of a blood vessel or the like, first, a guide wire must be guided to a target portion. In this case, since a target portion is generally thin and thus tends to be easily damaged, the distal end portion of the guide wire must be flexible so that it will not damage a blood vessel wall, will follow the shape of the blood vessel well even if the blood vessel is curved, and can be inserted in a complex branching blood vessel. Meanwhile, the proximal end portion of the guide wire must have torque transmitting performance so that a manual operation performed at the proximal end portion is transmitted to the distal end portion. Thus, the proxim...

AI Technical Summary

Benefits of technology

The present invention has been made in view of the above situation and has as its object to provide a catheter guide wire wherein its distal end portion is very flexible, buckling deformation is difficult to occur, and its proximal end portion is very rigid, thus having a good torque transmitting performance to the distal end portion, and a method of manufacturing the same.

In order to solve the above problems, according to the present invention, a wire member made of an elastic alloy, and preferably a very elastic alloy, is used as a core member of a catheter guide wire and subjected to a heat treatment by changing the treatment conditions along its longitudinal direction, so that the rigidity at its proximal end portion becomes comparatively high, the flexibility at its distal end portion is increased, and kinking deformation will not easily occur in its distal end portion.

More specifically, according to the present invention, there is provided a catheter guide wire having leading and trailing end sides, characterized in that the guide wire comprises a wire member made of an elastic alloy member, at least the leading end side thereof has an outer diameter equal to or smaller than a minimum inner diameter of a catheter, and the wire member is subjected to a heat treatment so that its flexibility is sequentially increased from a proximal to distal end portion of the leading end side thereof.

In this case, the coil spring is preferably made of a material having a high X-ray impermeability in order to allow an X-ray photographing to be easily confirmed. Therefore, the presence of the coil spring is advantageous in giving a sufficient thickness in an X-ray image without badly affecting the flexibility of the guide wire.

Furthermore, according to the present invention, there is provided a method of manufacturing a catheter guide wire fabricated by using an elastic alloy wire as a base material, characterized in that a leading end side of the base material is divided into a plurality of areas, and a heat treatment is performed by changing the temperatures and time in units of the areas so that the flexibility of the base material is sequentially increased from the proximal to distal end portion of the leading end side.

In a conventional catheter guide wire, a diameter at a proximal end portion of a wire member made of an elastic alloy or a very elastic alloy is merely increased, and a diameter at its distal end portion is relatively decreased, thereby making the proximal end portion rigid and the distal end portion flexible. Unlike such a conventional catheter guide wire, according to the present invention, a wire member is subjected to a heat treatment by sequentially changing the confunction along its longitudinal direction. As a result, the physical characteristics of the wire member can be set in an ideal state as a catheter guide wire.

Problems solved by technology

However, plastic deformation can easily occur in these conventional guide wires, and some manual operation can kink the guide wires.

A kinked portion becomes an obstacle during introduction of a catheter, thus rendering smooth introduction operation of a catheter impossible as well as greatly degrading its torque transmitting performance.

Therefore, such a guide wire cannot be easily broken during operation and will not easily attain a bending tendency.

However, such guide wire has a high elasticity at its distal end portion and is thus infavorable in terms of flexibility.

Then the diameter of its proximal end portion is 0.5 mm or less, the rigidity is insufficient and the torque transmitting performance is poor.

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