JPH08112351A - Balloon catheter - Google Patents

Abstract

PURPOSE: To provide a balloon catheter which is capable of expanding the constricted part of a blood vessel or enables dosing of medicines or the expanding and moving of a stent without stopping blood flow by providing the sectional shape of a direction perpendicular to the catheter axis of a balloon formed at the front end with plural radial projecting parts. CONSTITUTION: This balloon catheter is composed of a catheter tube consisting of an inside tube 2 and an outside tube 3 and the balloon 4. The inside tube 2 has a lumen 5 opened at the front end for insertion of a guide wire therein. The outside tube 3 is inserted with the inside tube 2 therein and is provided with the front end in a position slightly retreating from the front end of the inside tube 2. The inside surface of the outside tube 3 and the outside surface of the inside tube 2 form the lumen 7 of which the front end communicates with the rear end in the balloon 4. The balloon 4 is foldable and attains the state folded on the outer periphery of the inside tube 2 in the non-expanding state. The sectional shape of the balloon 4 along a line A-A is a shape having plural projecting parts 13, for example, a stellar shape. The blood flows in the projecting parts 14 of the balloon 4 and the blood vessel is expanded by recessed parts 13.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to balloon catheters. More specifically, the present invention relates to a balloon catheter capable of expanding a vascular stenosis, or administering a drug or expanding or moving a stent without stopping blood flow.

[0002]

2. Description of the Related Art In recent years, a dilatation catheter having a balloon at its tip is frequently used to dilate a stenosis formed in a blood vessel, a bronchus, a bile duct, or the like. In a normal balloon, when the balloon is inflated to expand the narrowed portion of the blood vessel, the blood flow is stopped by the balloon.

In order to sufficiently dilate the blood vessel, it is necessary to dilate the stenosis with a balloon for a certain period of time, but for that reason, it is often dangerous to stop the blood flow for a long time.

In recent years, attempts to administer an antisense gene for preventing intimal wall thickness in a blood vessel by using a gel-coated balloon have been increasing. It has been pointed out that it is affected by the contact time and contact pressure between the gel and cells.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a balloon catheter capable of expanding a vascular stenosis, administering a drug or expanding or moving a stent without stopping blood flow.

[0006]

The above problems can be solved by the present invention described below.

(1) A balloon catheter characterized in that a balloon is provided at the distal end of the catheter, and a cross-sectional shape of the balloon in a direction perpendicular to the catheter axis has a plurality of radial projections.

The present invention will be described by taking the vascular stenosis of coronary arteries, which is seen in ischemic heart disease such as myocardial infarction, as an example. However, in the present invention, "lesion of blood vessel or living tissue" or "catheter system" “Type” and the like are not limited to the following examples.

For prevention and treatment of vascular stenosis, antithrombotic therapy (thrombolytic therapy, anticoagulant therapy, antiplatelet therapy) and a method of expanding the stenosis with a balloon attached to the catheter tip [percutaneous coronary angioplasty] (PTCA)] is performed. The balloon catheter of the present invention has a cross-sectional shape in a direction perpendicular to the catheter axis of the balloon that is radially formed to have a plurality of convex portions, thereby expanding the vascular stenosis portion for a long time without stopping blood flow, Expansion and movement,
It can be effectively used for prevention and treatment of restenosis caused by drug administration.

That is, as shown in FIG. 1, the balloon catheter 1 comprises a catheter tube consisting of an inner tube 2 and an outer tube 3 and a balloon 4. The inner tube 2 has a first lumen 5 having an open tip. The first lumen 5 is a lumen for inserting a guide wire (not shown). The outer tube 3 is provided at a position where the inner tube 2 is inserted into the outer tube 3 and the tip is slightly retracted from the tip of the inner tube 2. The inner surface of the outer tube 3 and the outer surface of the inner tube 2 are
The lumen 7 is formed. The second lumen 7 is
The tip of the balloon communicates with the rear end of the balloon 4 described later, and a liquid (for example, containing a blood vessel contrast agent) for inflating the balloon 4 is flowed into the balloon 4. The tip of the outer tube 3 is fixed to the inner tube 2 without closing the second lumen 7. Specifically, as shown in FIG. 5, it is fixed by a filling member 6 provided between the inner pipe 2 and the outer pipe 3,
The filling member 6 has a partially defective portion 6a, and the defective portion 6a allows the second lumen 7 and the inside of the balloon 4 to communicate with each other. And the balloon 4 has a rear end 9
Is liquid-tightly fixed to the tip of the outer tube 3, and the tip 8 is the inner tube 2
Liquid-tightly fixed to the tip of the expansion space 10 between the inner surface of the balloon and the outer surface of the inner tube 2, and at the rear end of the expansion space 10 through the defective portion 6a of the filling member 6 It communicates with lumen 7.

Further, a reinforcing member 11 is provided on the outer surface of the inner tube 2, and the reinforcing member 11 is composed of a coil spring, and in order to easily confirm the position of the balloon 4 under fluoroscopy, the balloon 4 is The outer surface of the inner tube 2 near the center of
It is located on the outer surface of the inner tube 2 near the tapered portion of the balloon 4 (near the tip of the outer tube 3). Instead of the coil spring, a radiopaque platinum marker or the like is also used.

The balloon 4 is foldable and can be folded around the outer circumference of the inner tube 2 when not expanded. The balloon 4 has a shape in which the cross-sectional shape of the balloon 4 along the line AA of FIG. 1 has a plurality of convex portions 13 such as a star shape so as not to stop the blood flow when expanded as shown in FIG. The blood flow flows through the concave portion 14 of the balloon 4 and the convex portion 13 expands the blood vessel.

The balloon can be manufactured by using a star-shaped mold with a polyethylene original tube as a base material. It should be noted that the tip of the convex portion 13 may be provided with a pore or a gel layer for drug administration.

The material of the catheter or balloon is not particularly limited. For example, olefin polymers include polyethylene, polypropylene, polybutene, polybutadiene and copolymers thereof, halides and ionomers, and condensation polymers include copolymers of various polyesters, polyamides and polyethers thereof. , Polyurethane, etc. can be exemplified. The catheter or balloon may have a composite structure including a coil of a superelastic alloy pipe or metal.

The inner tube 2 constituting the catheter has an outer diameter of 0.30 to 2.50 mm, preferably 0.40.
2.40 mm with an inner diameter of 0.20 to 2.35 mm,
It is preferably 0.25 to 1.80 mm. The outer tube 3 is
Outer diameter is 0.50 to 4.30 mm, preferably 0.60
4.00 mm with an inner diameter of 0.40 to 3.80 mm,
It is preferably 0.50 to 3.00 mm. Balloon 4
Is preferably the outer diameter of the convex portion 13 when it is expanded is 1.5
mm to 20.0 mm, and the outer diameter of the recess 14 is preferably 0.6 mm to 19.0 mm.

Further, as the filler 6 for the catheter, a material having adhesiveness to the inner tube 2 and the outer tube 3 is preferably used. For example, when the inner tube 2 and the outer tube 3 are made of a polyolefin material, PE is used. (Polyethylene), EVA (ethylene vinyl acetate), etc. are preferably used as the filler 6
The length is 1 to 10 mm, preferably 2 to 8 mm, and as shown in FIG. 3, it is preferable to have a thick portion of 1/3 or more, preferably 1/2 or more of the entire circumference. Alternatively, they may be bonded by heat fusion without using a filler.

The outer surface of the balloon catheter of the present invention may have pores for drug administration. in this case,
The size of the pores is preferably 0.1 μm to 1000 μm,
It is made by excimer laser processing. Further, it may have a gel in the pores. In this case, the gel is, for example,
N, N-dimethylacrylamide, N-isopropylacrylamide, N, N-diethylacrylamide, N,
Examples thereof include homopolymers or copolymers of alkylacrylamides such as N-dimethylaminopropylacrylamide and acryloylmorpholine.

The drug used in the present invention is not particularly limited as long as it can be used for treating or preventing a lesion.
For example, in the aforementioned vascular stenosis, thrombolytic agents such as urokinase, pro-urokinase, streptokinase, plasminogen activator, heparin, warfarin, aspirin, synthetic antithrombin drugs, smooth muscle cell proliferation, etc. A suppressor, a gene therapy vector, a drug that controls NOS synthesis production, antisense DNA, and the like can also be administered.

Further, the P of the balloon catheter of the present invention is
In order to insert into the blood vessel or improve slidability in the blood vessel when using TCA, for example, dimethylacrylamide-glycidyl methacrylate (molar ratio 6: 1) is provided on the outer surface of the balloon.
You may coat with a block copolymer etc.

[0020]

【Example】

(Example 1) Modified polyethylene (SF230, manufactured by Mitsubishi Petrochemical / Mitsubishi Kasei Co., Ltd.) having an outer diameter of 1.1 mm and an inner diameter of 0.7 mm
After being molded into a tube of No. 2, the balloon was biaxially stretched and oriented to prepare a balloon as shown in FIG. That is, after pulling and stretching the tube in the tube axial direction, by using a mold (not shown) having an uneven portion in the shape of the expanded state of the balloon, the inside of the tube is pressurized and expanded in the tube radial direction, It was molded into a balloon shape (outer diameter of convex portion 3.0 mm, outer diameter of concave portion 1.2 mm).

[0021]

The balloon catheter of the present invention has a balloon at the distal end of the catheter, and the cross-sectional shape of the balloon in the direction perpendicular to the catheter axis has a plurality of radial projections. Since the blood flow is not stopped, the stenosis site can be expanded for a relatively long time, and drug administration and expansion or movement of the stent can be continued.

[Brief description of drawings]

FIG. 1 is a sectional view of a distal end portion of a balloon catheter according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

[Explanation of symbols]

 1 Catheter 2 Inner Tube of Catheter Tube 3 Outer Tube of Catheter Tube 4 Balloon 5 First Lumen 6 Filler 6a Filler Defect 7 Second Lumen 8 Tip of Balloon 9 Balloon Rear End 10 Balloon Expansion Space 11 Coil Spring 12 Pore 13 Balloon convex 14 Balloon concave

Claims (1)

[Claims] 1. A balloon is provided at the tip of a catheter,
A balloon catheter characterized in that a cross-sectional shape of the balloon in a direction perpendicular to the catheter axis has a plurality of radial projections.