JP2023049725A - catheter - Google Patents

Abstract

To provide a catheter capable of suppressing performance deterioration caused by plastic deformation more effectively, by using a member comprising a flat coil formed by molding spirally a spring steel having a flat cross section.SOLUTION: A catheter 100 has one or more lumens inside, and has, on a shaft part 30, a coil tube 35 formed by cold molding at least a flat spring steel into a coil shape compactly or with a gap of 0.1 mm or less, followed by heat treatment.SELECTED DRAWING: Figure 2

Description

The present invention relates to catheters.

In the case of a penetrating catheter for penetrating the embolus together with a guide wire, it is necessary to pierce the embolus with its tip to propel the embolus. However, if the shaft of the catheter has a tendency to bend, there is a problem that when the catheter is pushed in, the force escapes at the portion with the tendency to bend, and the force is not applied straight to the shaft.

This curving habit is mainly due to (1) the tendency of the catheter to become habituated when it is inserted into the body. For example, when a catheter is inserted into the body, it is inserted obliquely into the skin and then along the blood vessel. When pushing it in, there is a tendency to bend or the like that occurs when the hand side is gripped strongly.

In addition, (2) there are things that are addictive in packing and packaging. For example, catheters are often wrapped and packed in a hard resin tube. In such a case, there is a case where a curving habit is formed as a whole. This is likely to occur especially due to the application of heat during the sterilization process. In addition, when the catheter is taken out from this package during surgery, it may be bent at the extraction port.

As described above, when the catheter is bent, when it is pushed into the blood vessel, the force escapes at the portion of the bend and the catheter cannot be pushed in.

As a catheter preventing such a bending tendency, there is a medical catheter having one or more lumens inside and a metallic tubular member at least in part, wherein the metallic tubular member is A medical catheter characterized in that when the metal tubular member is bent to 90 degrees with a radius of curvature 50 times its outer diameter and released after being held for 1 minute, the bending angle generated in the metal tubular member is within 15 degrees. It has been proposed (Patent Document 1).

This invention controls the properties of the metal that is the material of the inner metal tube member by solution heat treatment, quenching, and tempering, and in particular, the strength, hardness, and creep characteristics are controlled by the conditions of solution heat treatment and tempering. is controlled to provide a metal tubular member having a specific property, thereby providing a medical catheter in which deterioration in performance due to plastic deformation is suppressed.

However, the medical catheter according to the above document must use a metal material that satisfies the conditions of solution heat treatment and tempering. was difficult. Furthermore, in the medical catheter according to the above document, suppression of deterioration in performance due to plastic deformation is still insufficient.

JP-A-2000-271208

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems. An object of the present invention is to provide a catheter in which deterioration in performance due to deformation is suppressed.

The present invention employs the following means to achieve the above objects.

The catheter according to the present invention is
A coil tube which has one or more lumens inside and which is cold-formed into a coil shape without gaps or with a gap of 0.1 mm or less and then heat-treated is used as the shaft part. It is characterized by having

In the catheter according to the present invention, a flat plate-shaped spring steel is inserted into the coil tube without any gaps or a coil tube formed in a coil shape with a gap of 0.1 mm or less, so that the coil does not shrink in the longitudinal direction. It is possible to provide a catheter having a shaft portion that is capable of improving push performance without flexing and has high straight-return performance that attempts to return to a straight shape when bent.

Furthermore, in the catheter according to the present invention,
In the coil tube, the ratio of the cross section of the flat coil is t:w = 1:6 to 1:15 when the thickness is t and the width is w, and the thickness t of the flat coil is the inner diameter of the coil tube. It may be 1/5 or less of _Φ1 , and the width w may be 1.5 times or less of the outer diameter _Φ2 of the coil tube.

By adopting such a configuration, a coil tube having high linear return performance can be obtained.

Furthermore, in the catheter according to the present invention,
When the shaft is opened after being bent to 90 degrees with a radius of curvature 17.9 times the outer diameter of the coil tube and held for 1 minute, the bending angle generated in the shaft is within 0 degrees. may be characterized by

ADVANTAGE OF THE INVENTION According to the catheter concerning this invention, the catheter which suppressed the performance deterioration by plastic deformation more effectively can be provided.

FIG. 1 is a side view of a catheter 100 according to an embodiment. FIG. 2 is an AA enlarged cross-sectional view of catheter 100 according to an embodiment. FIG. 3 is a perspective view showing the coil tube of the catheter 100 according to the embodiment. FIG. 4 is a schematic diagram showing a method for evaluating a catheter 100 according to the invention. FIG. 5 is a schematic diagram showing a method for evaluating a catheter 100 according to the invention. FIG. 6 is a table showing test results of an example and a comparative example of the catheter 100 according to the present invention.

An embodiment of the catheter 100 according to the present invention will now be described in detail with reference to the drawings. FIG. 1 is a side view of a catheter 100 according to an embodiment. FIG. 2 is an AA enlarged cross-sectional view of catheter 100 according to an embodiment. Note that cross-sectional lines are omitted for visibility. It should be noted that the embodiments and drawings described below illustrate a part of the embodiments of the present invention, and are not used for the purpose of limiting to these configurations, and do not depart from the gist of the present invention. It can be changed as appropriate within the range. For convenience of explanation, the terms "proximal side" and "distal side" in the claims and the specification refer to the proximal side (catheter hub portion side) shown in FIG. The proximal side is referred to as the "proximal side" and the distal side is referred to as the "distal side".

(First embodiment)
A catheter 100 according to the first embodiment mainly includes a distal end portion 10, a shaft portion 30, and a catheter hub portion 50, as shown in FIG.

As shown in FIG. 2, the tip portion 10 can be made of various materials and forms depending on the purpose of use. In the present embodiment, a tapered conical tip is used to penetrate the thrombus. Materials to be used are not particularly limited and may be metals, resins, or the like.

As shown in FIG. 2, the shaft portion 30 includes a resin tube 31, a braided body 33, a coil tube 35, and a resin coating 37 from the inner layer.

The resin tube 31 is a tube that forms an inner lumen through which medical devices such as guide wires and stents and balloon catheters are passed. It is arranged to prevent the guide wire and medical equipment from being caught, improve the slidability, prevent the braided body 33 from unraveling, and prevent the adhesion of thrombi. . Although the resin is not particularly limited, it is preferable to use polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), etc., which have high compatibility with the human body, excellent slidability and shape recovery performance. .

The braided body 33 is made by braiding metal wires or resin wires, and in addition to the coil tube 35 described later, contributes to improvement of kink performance and shaft pushing function. Furthermore, when the shaft portion 30 is bent, it also has the function of preventing the coil tube 35, which is helically wound in close contact, from being too far apart.

The coil tube 35 is made of a flat coil formed by spirally forming spring steel having a flat cross section. The spring steel used is not limited, but SUS301, SUS304, SUS316, etc. may be used. The cross-sectional ratio of the flat plate used for the flat plate coil is, as shown in FIG. ~1:12. Further, the thickness t is preferably ⅕ or less of the inner diameter Φ ₁ of the coil tube 35 . For example, if the inner diameter Φ ₁ =0.6 mm, it is preferable that t≦0.12 mm. Furthermore, the width w is preferably 1.5 times or less the outer diameter _Φ2 . For example, if the outer diameter Φ ₂ =0.72 mm, it is preferable that the width w≦1.08 mm. When it is formed into a spiral, it is formed such that adjacent spirals have no gap or a gap of 0.1 mm or less, like a so-called tight coil spring. In this way, by eliminating gaps or narrowing the gaps of the spiral by using the flat plate-shaped member, the rigidity of the shaft portion 30 is increased, and the performance of returning to a straight shape when bent can be improved. When forming into a spiral shape, first, it is formed into a spiral shape by cold forming. At this time, if it is directly wound around the resin tube 31, the resin tube 31 will be deformed by the tension of the spring steel at the time of winding, so the direct winding is impossible. Therefore, the flat coil alone is formed in advance into a coil tube shape. After molding, heat treatment such as quenching and tempering or low temperature annealing is performed to remove residual stress. As the wire diameter increases with respect to the outer diameter of the product, the elastic force increases, but stress is likely to be applied to the repeated resilience (settling), so the settling becomes easier. Since the coil tube 35 according to the present invention is made of a flat coil, the wire diameter is formed thicker than the outer diameter. , the stress is so strong that it does not return to its original shape, and it bends easily. Therefore, heat treatment is performed to remove the stress.

The resin coating 37 is the outermost layer of the shaft portion 30 and prevents the coil tube 35 from coming into direct contact with the body such as a blood vessel, and when the shaft portion 30 is bent, the coil is positioned at a predetermined position. It has the function of holding

The catheter hub part 50 is not particularly limited, and a known catheter hub can be used as appropriate.

The catheter 100 configured as described above is manufactured as follows. First, as described above, a flat coil is formed into a coil tube shape, and heat treatment such as quenching and tempering or low temperature annealing is performed to remove residual stress, to obtain the coil tube 35. The coil tube that has completed the heat treatment. A resin tube 31 wound with a braided body 33 is inserted from the end into the interior of 35 and covered with resin. Then, the tip is joined to the tip. As shown in FIG. 2, a radiopaque marker 60 or the like may optionally be attached when joining the distal ends. On the other hand, a catheter hub portion 50 is attached to the proximal end to complete the catheter.

The shaft portion of the catheter manufactured in this manner was bent to 90 degrees with a curvature radius 20 times the outer diameter of the coil tube 35, held for 1 minute, and then released. It is possible to obtain a catheter that does not have a tendency to bend and has a high straightness return performance.

(Example)
A flat coil having a thickness t of 0.09 mm and a width w of 1.0 mm was used as the coil tube of the shaft portion 30, and a coil tube having a coil outer diameter of 0.84 mm was prepared. The braided body 33 is wound inside the coil tube 35 using the coil tube, the coil tube annealed at 380 ° C. for 20 minutes as Example 2, and the coil tube of Example 2 as Example 3. A resin tube 31 was inserted from the end to prepare a resin-coated catheter. As a comparative example, a catheter incorporating a coil made of a round wire of 0.03Φ without annealing (Comparative Example 1) and a stainless steel tube (SUS304) without annealing were laser cut to obtain a thickness t of 0.06 mm and a width of A catheter (Comparative Example 2) incorporating a flat plate coil with w=5.0 mm, a pitch of about 5 mm, and a coil gap of 0.03 mm was prepared.

These were 11.9 times (radius 5 mm), 17.9 times (radius 7.5 mm), 23.8 times (radius 10 mm), 29.8 times (radius 12.5 mm), 35 times the outer diameter of the coil tube. 7 times (radius 15 mm), 41.7 times (radius 17.5 mm), 47.6 times (radius 20 mm), 59.5 times (radius 25 mm) bent to 90 degrees and kept for 1 minute After that, when the shaft was opened, the bending angle generated in the shaft portion was measured. It should be noted that bending the metal tubular member to 90 degrees with a radius of curvature that is 50 times (50A) the outer diameter (A) of the tubular member indicates a method as shown in FIG. That is, the coil tube 35 with one end fixed is bent along the circumferential direction of a cylinder having a radius 50 times larger than the coil tube 35 so that the extension line angle of the unbent portions at both ends of the cylinder is 90 degrees. be. The bend angle is the angle α of the intersection of the extensions of the straight portions of the bent member as shown in FIG. The measurement results are shown in FIG.

According to FIG. 6 showing the measurement results, in the case of the unannealed coil tube (Example 1), the coil tube 35 has no tendency to bend at 23.8 times or more the diameter (outer diameter) of the coil tube 35, and the linear return property is good. It could be a taller catheter. In the annealed coil tube (Example 2) and the catheter using this coil tube (Example 3), the diameter (outer diameter) of the coil tube 35 was 17.9 times or more, and there was no tendency to bend and the catheter was straight. A catheter with high reversibility could be obtained. On the other hand, in Comparative Example 1, the curl remains at all diameter magnifications, and in Comparative Example 2, kink (bending) occurs at diameter magnifications of 11.9 times to 35.7 times, making measurement impossible. became. From this, it can be seen that if the width (w) is too wide with respect to the diameter, kinking will occur in the case of a sharp curvature, rather than a flat coil.

As shown in the above-described embodiments, it can be used as an aid in surgery using guide wires and catheters.

DESCRIPTION OF SYMBOLS 10... Tip part 30... Shaft part 31... Resin tube 33... Braided body 35... Coil tube 37... Resin covering body 50... Catheter hub part 60... X-ray opaque marker 100... Catheter

Claims (3)

A coil tube which has one or more lumens inside and which is cold-formed into a coil shape without gaps or with a gap of 0.1 mm or less and then heat-treated is used as the shaft part. A catheter comprising: In the coil tube, the ratio of the cross section of the flat coil is t:w = 1:6 to 1:15 when the thickness is t and the width is w, and the thickness t of the flat coil is the inner diameter of the coil tube. 2. The catheter according to claim ₁ , wherein the width w is 1/5 or less with respect to Φ1, and the width w is 1.5 times or less with respect to the outer diameter _Φ2 of the coil tube. The shaft portion is bent to 90 degrees with a radius of curvature 17.9 times the outer diameter of the coil tube, held for 1 minute, and then opened. 3. The catheter of claim 1 or 2, wherein a.

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