JPH08289934A - Medical balloon dilatation catheter - Google Patents

Abstract

PURPOSE: To pass an expansion catheter even through a harshly strictured morbid part in the catheter provided on the outer peripheral surface of an inner pipe in an expansion balloon with a marker unpermeable to X-rays by making the outer diameter of an inner pipe in a position occupied at least by the marker smaller than the outer diameter of the inner pipe in the other positions. CONSTITUTION: This expansion catheter is provided with a recessed groove in a position to which a marker unpermeable to X-rays is mounted on the outer peripheral surface of an inner pipe 2 in a balloon 1. The marker unpermeable to X-rays is fitted in this recessed groove 6 to be covered with a heat contracted tube 4. The depth of the recessed groove 6 is equivalent to or more than the total thickness of the marker unpermeable to X-rays 3 and tube 4 and generally about 10-150μm. The recessed groove 6 is provided over at least 180 deg. on the outer peripheral surface of the inner pipe 2. A substance unpermeable to X-rays is vaporized or spattered to make a film of the marker unpermeable to X-rays and gold, platinum, irridium or alloy of these is preferably used for the substance unpermeable to X-rays.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical balloon dilatation catheter for expanding a stenosis generated in a blood vessel to increase the blood flow rate on the peripheral side of the stenosis. More specifically, it relates to an improvement of a medical balloon dilatation catheter having a radiopaque marker on the outer peripheral surface of the inner tube inside the dilatation balloon.

[0002]

2. Description of the Related Art Angioplasty, which has been conventionally used as an operation for narrowed arteries such as coronary arteries, uses a dilatation catheter having a balloon at the distal end of a hollow shaft. In these balloon dilatation catheters, a radiopaque marker ring is fitted on the outer peripheral surface of the inner tube having a constant outer diameter inside the balloon, and a heat shrinkable tube is attached so as to cover the marker ring for fixing. ing. Another purpose of depositing the heat-shrinkable tube is to prevent damage to the balloon due to contact between the metal radiopaque marker and the balloon. A conventional balloon dilatation catheter has a dilatation balloon 1 as shown in FIG.
The X-ray opaque marker ring 3 is fitted on the outer peripheral surface of the inner tube 2 having a constant outer diameter inside the tube, and in order to fix the X-ray opaque marker ring 3 and prevent the balloon from being damaged, a heat-shrinkable tube is provided so as to cover the marker ring 3. Since 4 is attached, the outer diameter of that portion is larger than the outer diameter of the inner pipe.

[0003]

However, when the balloon dilatation catheter is clinically used, the outer diameter when the balloon is deflated is reduced because it passes through a narrowed portion such as a narrowed blood vessel. Is very important.
The maximum outer diameter (crossing profile) P of the balloon portion when the balloon is deflated is determined by the following equation. P = Id + 2C + 2Tm + 2Tc + 2Tb Id: Inner tube outer diameter C: Clearance between X-ray opaque marker inner diameter and inner tube outer diameter Tm: X-ray opaque marker thickness Tc: Heat shrink tube thickness Tb: Balloon The total thickness of the balloon layer when the balloon is deflated and folded In the conventional balloon dilatation catheter, as is clear from FIG. There is a problem in that the dilatation catheter cannot be passed through the lesion where the lesion becomes severely stenotic.

[0004]

In order to solve the above problems, the inventors of the present invention have conducted diligent research, and as a result, determined that the outer diameter of the inner tube at the site where the radiopaque marker is located is different from that of the inner tube at another site. It has been found that the above problem can be solved by making the diameter smaller than the outer diameter, and further, by providing an X-ray opaque substance such as gold or platinum or an alloy thereof with iridium by vapor deposition, sputtering, etc., the inner diameter of the X-ray opaque marker can be reduced. It was found that the clearance (C) between the inner diameter and the outer diameter of the inner tube can be eliminated, and the maximum outer diameter of the balloon portion when the balloon is deflated can be more effectively reduced, and the present invention has been completed.

To achieve the above object, the medical balloon dilatation catheter of the present invention is a balloon dilatation catheter having an X-ray opaque marker on the outer peripheral surface of the inner tube inside the dilatation balloon, and at least X-ray impermeable. The outer diameter of the inner tube at the site where the transmission marker is located is smaller than the outer diameters of other sites. In order to achieve the above object, the medical balloon dilatation catheter of the present invention is made of X, such as gold, platinum, iridium or alloys thereof.
It is formed by coating a line opaque material by vapor deposition or sputtering.

[0006]

With the balloon dilatation catheter having the above structure, the maximum outer diameter when the balloon is deflated can be made smaller than that of the conventional dilatation catheter by the reduced outer diameter.
Even a lesion with severe stenosis can be passed through the dilatation catheter. Further, by coating the X-ray opaque substance by vapor deposition or sputtering, at least the clearance (C) between the inner diameter of the X-ray opaque marker and the outer diameter of the inner tube can be eliminated. It is possible to effectively reduce the maximum outer diameter.

[0007]

The present invention will be described in detail with reference to the accompanying drawings showing examples, but the present invention is not limited to these.

As shown in FIG. 1, the dilatation catheter of the present invention is provided with a concave groove 6 at a position on the outer peripheral surface of the inner tube 2 inside the balloon 1 to which the radiopaque marker 3 is attached. An X-ray opaque marker 3 is fitted into the inside of the 6, and a heat-shrinkable tube 4 is covered thereon. The depth of the concave groove 6 is equal to or more than the total thickness of the thickness of the radiopaque marker 3 and the thickness of the heat shrinkable tube 4, and is appropriately determined depending on the thickness of both, but is generally about 10 to 150 μm. Is the depth of. The groove 6 is at least 180 ° on the outer peripheral surface of the inner pipe.
It is provided over. As a method of providing the concave groove 6,
Polishing and wet or dry etching methods can be used. In the case of etching, it is usual that a mask is required for the non-etched portion.

FIG. 2 shows another embodiment of the present invention, which comprises a structure in which the outer diameter of the entire distal portion of the inner tube 2 is smaller than that of the radiopaque marker 3 (the portion 7 having the smaller outer diameter). . The corners of the heat-shrinkable tube 4 are rounded and chamfered so that the balloon 1 is not damaged even if the balloon 1 comes into contact with the tube 4 when the balloon is deflated.

In the present invention, a conventional marker ring can be used as the X-ray opaque marker 3,
By forming a film of an X-ray opaque substance by vapor deposition or sputtering, the inner diameter of the X-ray opaque marker 3 and the inner tube 2
The clearance with the outer diameter of the balloon can be made zero, and the maximum outer diameter when the balloon is deflated can be reduced more effectively. The film thickness of the X-ray opaque substance is 20 to 100 μm.
The range of about m is preferable, and if it is less than 20 μm, the effect as an X-ray opaque marker is insufficient.
Even if it exceeds m, no further effect can be obtained, which is rather uneconomical. As the X-ray opaque substance, substances having an atomic number of about 50 or more, for example, lead, barium, iodine, tungsten, gold, platinum, iridium and the like can be used, but it is considered to be used in vivo. And barium,
Iodine, tungsten, gold, platinum, iridium, etc. are excellent in safety, workability, and cost. Further, as the vapor deposition or sputtering substance, gold, platinum, iridium, or alloys thereof are preferable. Of these, platinum is more advantageous in consideration of reducing the film thickness.
An image of sufficient density can be formed on an X-ray fluoroscopic image with a size of about μm. Further, by forming a film of an X-ray opaque substance with a sputtering device, a vapor deposition device, or the like, it is possible to obtain good adhesion, and it is possible to make the edge portion smooth, that is, chamfered. In this case, there is an advantage that the heat-shrinkable tube for fixed protection can be eliminated and the process can be simplified.

[0011]

Industrial Applicability The medical balloon dilatation catheter of the present invention has a maximum outer diameter (crossing profile) of the balloon portion when the balloon is deflated, which is at least the outer diameter of the inner tube smaller than that of the conventional product (the concave groove is formed). When provided, the depth can be reduced by twice the depth of the groove, and even a lesion with severe stenosis can be passed without damaging the lesion.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an essential part showing an embodiment of a balloon dilatation catheter of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part showing another embodiment of the balloon dilatation catheter of the present invention.

FIG. 3 is a schematic sectional view of a main part of a conventional balloon dilatation catheter.

[Explanation of symbols]

 1 Balloon 2 Inner Tube 3 Radiopaque Marker 4 Heat Shrink Tube 5 Outer Tube 6 Recessed Groove 7 Part with Reduced Outer Diameter

Claims (4)

[Claims] 1. A balloon dilatation catheter having a radiopaque marker on the outer peripheral surface of an inner tube inside a dilatation balloon, wherein the outer diameter of the inner tube is at least at the site where the radiopaque marker is located. A medical balloon dilatation catheter characterized by being made smaller than the outer diameter of the inner tube. 2. The medical balloon dilatation catheter according to claim 1, wherein a radiopaque substance is coated as a radiopaque marker over at least 180 ° on the outer peripheral surface of the inner tube. 3. The medical balloon dilatation catheter according to claim 2, wherein the radiopaque substance is coated by vapor deposition or sputtering. 4. The medical balloon dilatation catheter according to claim 2, wherein the radiopaque substance is gold, platinum, iridium or an alloy thereof.