JPH0323072B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a balloon catheter for indwelling in a blood vessel, which has a freely inflatable balloon attached to its tip.

(Prior art) This type of balloon catheter for intravascular indwelling involves introducing the tip of the catheter into the blood vessel using an insertion device such as an introducer, and then indwelling it at a predetermined site for measurement, treatment, etc. is common.

However, with conventional balloon catheters, the outer diameter of the attached balloon (before expansion) is larger than the outer diameter of the catheter, and it protrudes outside, so when inserting it into a blood vessel, the insertion device There were problems such as the balloon getting stuck on the inner wall of attached check valves and other equipment, causing damage.

Therefore, it has been proposed to make the tip of the catheter smaller in diameter than the catheter size and attach a balloon thereon to make the diameter the same as the catheter size. However, in this case, the catheter can be inserted into the blood vessel using a sheath with the same diameter as the catheter size, reducing the burden on the blood vessel, but the balloon is larger than the outer diameter of the catheter tip at the upper end of the balloon. Since there is a step between the catheter tip and the catheter tip, there remains a risk that the balloon will come into direct contact with a check valve installed at the insertion port of the blood vessel insertion device and be damaged. As another method, a method has been proposed in which the boundary between the upper end of the attached balloon and the catheter tip is potted with adhesive or the like to smoothly connect the catheter tip and the balloon attachment surface.

However, in this case, although the problem of balloon damage mentioned above has been resolved, since the outer diameter of the device balloon is larger than the outer diameter of the catheter tip, it is necessary to use a sheath that matches the balloon diameter that is larger than the catheter size diameter. First, this increases the burden on the blood vessels, and since the potting part is not integrally molded from the same material, there remains the problem of peeling of the adhesive part, so the risk of placing the catheter in the blood vessel is completely eliminated. It is not possible.

Furthermore, since this type of intravascular balloon catheter has an extremely small diameter, it has been extremely difficult to mass-produce the balloon in a structure that does not protrude from the outer diameter of the adjacent catheter.

(Problems to be Solved by the Invention) 1 This invention eliminates the risk of the attached balloon being damaged due to it hitting the check valve or other inner wall member of the blood vessel insertion device, and also eliminates the risk of damage due to the balloon being attached to the blood vessel insertion device, and the sheath is larger than the diameter of the catheter during insertion. The purpose of the present invention is to provide a method for manufacturing a balloon catheter having a structure that places less burden on blood vessels since it is not necessary to use a balloon catheter.

2 Furthermore, the present invention aims to provide a method for manufacturing a balloon catheter, which allows the balloon to be expanded symmetrically without causing damage to the blood vessel wall.

(Means for Solving the Problems) As a means for solving the first problem, the present invention provides a catheter body for a balloon catheter made of a thermoplastic material and having a predetermined internal passage formed therein. without disappearing,
A step of reducing the diameter of the distal end portion and forming a portion to which a balloon is to be attached and a portion to be processed for the tip of the catheter distal end thereof, and an outer portion of the thinned portion to which a balloon is to be attached is formed. A step of inserting and protecting a tubular heat-resistant member having an inner diameter that is approximately the same as the diameter of the tubular heat-resistant member; a step of molding the portion to be processed, which is reduced in diameter and protruding from the tubular heat-resistant member, into a desired catheter tip shape; The present invention provides a method for manufacturing a balloon catheter, which comprises the steps of: removing the balloon, and then attaching an inflatable balloon to the portion where the balloon is to be attached.

Furthermore, as a means for solving the second problem, the present invention molds the catheter tip, removes the tubular heat-resistant member, and then R-processes the edge portion of the catheter tip in contact with the balloon adhesive part. According to the requirements, a method was adopted in which the surface was formed into a curved surface by surface treatment with a solvent.

In the above manufacturing method, in the step of reducing the diameter of the catheter tip, a heat-resistant rod-like body such as a metal rod is inserted in advance into the internal passageway to be left, and in that state, heat molding, ultrasonic processing, or high-frequency processing is performed. It is preferable to do this.

Further, the step of forming the tip of the catheter is preferably carried out using an appropriate mold so that the tip has a relatively flat convex shape.

It is desirable that the tubular heat-resistant member fitted into the diameter-reduced portion be configured to be separable along the longitudinal direction.

In the balloon attachment step, it is preferable to attach the balloon so that the outer diameter of the attached balloon is the same as or smaller than the outer diameter of the catheter tip.

(Function) In the method for manufacturing a balloon catheter of the present invention, the diameter of the tip portion of the catheter body including the portion to which the balloon is to be attached is sufficiently reduced in diameter, and then a heat-resistant tube such as a metal tube is inserted into the portion to which the balloon is to be attached. Since the distal end of the catheter is molded into a desired shape while that portion is protected, it can be easily processed so that the outer diameter of the distal end is the same as or larger than the outer diameter of the balloon when it is attached.

(Example) Next, a preferred example of a balloon catheter manufactured by the method of the present invention will be described with reference to the drawings.

FIG. 2 shows a catheter main body 1 made of a flexible tube body with a distal end 1a having a substantially convex shape and an annular groove 1b formed along the circumferential direction adjacent to the distal end 1a. . Inside the catheter body 1, as shown in FIG. 1, there are a first internal passage 1c opening at the convex surface of the distal end 1a, and a second internal passage 1d opening at the bottom of the annular groove 1. It is formed along the longitudinal direction.

A cylindrical balloon 2 is attached to the annular groove 1b portion of the catheter body 1 so as to cover the groove bottom. The balloon 2 is fixed using the attachment thread 3 so that its outer diameter is equal to or smaller than the maximum outer diameter l of the distal end portion 1a of the catheter body 1 when the balloon 2 is not expanded. Therefore, the groove 1b is formed sufficiently deep considering the mounting thickness of the balloon 2.

Further, the upper edge 1e of the wall surface of the annular groove 1b on the side in contact with the distal end portion 1a of the catheter body 1 is formed to form a smooth curved surface.

As the material for the catheter body 1, thermoplastic resins such as polyolefin, ethylene-vinyl acetate copolymer, polyester, polyvinyl chloride, polyurethane, fluorine resin, and nylon are generally used.

The material of the balloon 2 can be appropriately selected from elastic materials such as silicone rubber and polyurethane latex.

To explain how to use this balloon catheter, as shown in FIG. 4 and gradually introduced into the blood vessel 5.

In this operation, since the outer diameter of the balloon 2 is equal to or smaller than the outer diameter of the distal end 1a of the catheter body 1, a check valve (not shown) disposed at the insertion port 4a of the blood vessel insertion device 4, etc. There is no risk of getting hit. Further, since the inner diameter of the blood vessel insertion device 4 does not need to be larger than the diameter of the catheter, the burden on the blood vessel is also reduced. Furthermore, since the distal end portion 1a of the catheter main body 1 that has reached the blood vessel has a substantially flat convex shape (or disk shape), it can be introduced to a predetermined position within the blood vessel 5 without stimulating the blood vessel wall.

Next, carbon dioxide gas is passed through the second internal passage 1d.
By introducing another fluid into the balloon 2, the balloon 2 can be expanded to a predetermined size as shown in FIG. 3, and the catheter can be introduced to a predetermined position. In this case, since the edge portion 1e of the catheter body 1 has a smooth curved surface, the expansion of the balloon 2 is performed smoothly without being hindered by this portion, and a bulge having a well-symmetrical shape is obtained. When you want to deflate balloon 2 again, use the second
The fluid inside the balloon 2 may be discharged through the internal passage 1d.

Next, an example of manufacturing this balloon catheter will be described.

(Manufacturing example) A polyvinyl chloride catheter body 1 consisting of four or five lumens of French size 4Fr to 8Fr is prepared, and a pressure measurement cavity 7 and a pressure measurement cavity 7 are prepared as shown in FIG. Metal rods 9 and 10 were inserted into the balloon expansion cavity 8, respectively, in order to leave them as internal passages. In order to prevent distortion during processing, rods 11 and 12 made of polyvinyl chloride, which are the same as those of the catheter body 1, were inserted into the lumen. In this state, the tip part of the catheter body 1 is heated and formed using a glass mold or a metal mold to a predetermined length (i.e., a length that includes the part where the balloon is to be attached and the part where the tip is to be processed) with a thin diameter. (See Figure 6). This processing can be similarly performed by ultrasonic processing or high frequency processing using a metal mold.

Next, as shown in FIG. 7, a stainless steel tubular body 13, which can be divided into two in the longitudinal direction, was inserted into the reduced diameter portion 14 so as to cover the portion where the balloon was to be attached. Next, the distal end portion 15 exposed from the upper end of the tubular body 13 is subjected to heat molding, ultrasonic processing, or high frequency processing using a glass mold or metal mold having a shape corresponding to the catheter distal end portion 1a shown in FIG. After processing, a product with a shape almost corresponding to that shown in Fig. 2 was obtained. Next, after dividing and removing the tubular body 13, the metal rods 9 and 10 are taken out from the tip of the catheter body, and the pressure measurement cavity (first
(corresponds to the first internal passage 1c shown in the figure) and the balloon expansion cavity (corresponds to the second internal passage 1d shown in Fig. 1).
(equivalent to ) was penetrated.

Next, the peripheral edge of the catheter tip 1a in contact with the balloon attachment part (corresponding to the annular groove 16 in FIG. 1) is heat-formed, R-processed using high frequency or ultrasonic waves, and surface treated with tetrahydrofuran solution to create a smooth curved surface. Finished in a shape. Next, one end of the balloon made of a silicone rubber tube and latex rubber was fixed to the distal end of the balloon attachment part with an attachment thread as shown in Figure 3, and the other end was fixed to the proximal end of the balloon attachment part with the same attachment thread. did.

As a result, the outer diameter of the attached balloon 2 could be made equal to or smaller than the maximum outer diameter of the catheter tip. Furthermore, when the balloon was expanded through the balloon expansion cavity, the expanded shape had good symmetry.

(Effects of the Invention) As detailed above, according to the manufacturing method of the present invention, the tip of the catheter is processed and the balloon attachment portion is processed so that the outer diameter of the attached balloon is the same as or smaller than the outer diameter of the catheter tip. It becomes possible to reduce the diameter with good mass production, avoid the problem of balloon breakage during catheter operation, and manufacture a balloon catheter that can obtain a balloon expanded shape with good symmetry.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the distal end portion of a balloon catheter according to an embodiment of the present invention, and FIG.
3 is a side view showing the catheter main body portion of the balloon catheter shown in FIG. 3; FIG. 3 is a cross-sectional view showing the balloon catheter shown in FIG.
FIG. 4 is a schematic diagram showing a state in which the balloon catheter is inserted into a blood vessel, and FIGS. 5 to 7 are perspective views illustrating the manufacturing process of the balloon catheter of the present invention in order of process. In the figure, 1... Catheter body, 1a... Tip part, 1b... Annular groove, 1c... First internal passage,
1d...Second internal passage, 1e...Edge, 2...
...Balloon, 3... Attachment thread, 4... Blood vessel insertion device, 5... Blood vessel, 6... Balloon catheter, 7
... Pressure measurement cavity, 8... Balloon expansion cavity,
9, 10... Metal rod, 11, 12... Polyvinyl chloride rod, 13... Stainless steel tubular body, 14...
Thinning portion, 15... portion scheduled for tip processing.

Claims (1)

[Claims] 1. A catheter body for a balloon catheter made of a thermoplastic material and having a predetermined internal passage formed therein;
A step of reducing the diameter of the distal end portion without eliminating the internal passage to form a portion to be attached with a balloon and a portion to be processed for the catheter tip distal end thereof, and a step of attaching the balloon to the thinned portion. a step of inserting and protecting a tubular heat-resistant member having an inner diameter approximately the same as the outer diameter of the reduced diameter portion into the planned portion;
A step of molding the thinned-diameter portion to be processed that protrudes from the tubular heat-resistant member into a desired catheter tip shape, and after removing the tubular heat-resistant member,
A method for manufacturing a balloon catheter, comprising the step of attaching an inflatable balloon to the portion where the balloon is to be attached. 2. The method for manufacturing a balloon catheter according to claim 1, wherein a heat-resistant rod-shaped body is inserted in advance into the internal passageway in which the tip portion is to be left in the diameter-reducing step, and thermal processing is carried out in that state. 3. The method of manufacturing a balloon catheter according to claim 1, wherein the catheter tip forming step is to form the tip into a relatively flat convex tip shape. 4. The method of manufacturing a balloon catheter according to claim 1, wherein the balloon mounting step is a step of mounting the balloon so that the outer diameter of the balloon is the same as or smaller than the outer diameter of the tip of the catheter. 5. The method of manufacturing a balloon catheter according to claim 1, wherein the tubular heat-resistant member is configured to be separable along the longitudinal direction. 4. The method for manufacturing a balloon catheter according to claim 1, wherein the catheter tip forming step is performed under heat forming. 7. The method for manufacturing a balloon catheter according to claim 1, wherein the catheter tip forming step is performed by ultrasonic processing. 8. The method of manufacturing a balloon catheter according to claim 1, wherein the catheter tip forming step includes a step of forming an edge portion of the catheter tip in contact with the balloon mounting portion into a smooth curved surface.