JPH0771579B2 - Medical balloon catheter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to medical use for dilation, patency of a narrowed part of a living body lumen such as an esophagus, a blood vessel, a bile duct and removal of a foreign substance such as a thrombus. It relates to a balloon catheter.

[Prior Art] Generally, when expanding a narrowed portion of a living body lumen, an elastic body such as rubber is used in order to prevent local pressure from being applied due to deformation of the balloon and to avoid expansion beyond a certain limit. Instead, it is useful because it uses a preformed balloon made of resin that does not expand or contract itself. However, these resin-made molded balloons usually serve as a purpose by inflating by injecting a liquid to maintain a constant shape, but when contracted, the balloon is attached around the catheter body in a bulky state. It is difficult to smoothly insert / remove the tube into / from the lumen, and in a thin blood vessel or the like, there is a possibility that the inner wall of the balloon may be damaged by a bulky balloon. As a method of manufacturing a molded balloon, there are generally many methods of molding and stretching in order to increase the strength, but when using a balloon with a larger diameter than the diameter of the catheter that is the basis for mounting, on the contrary, the wall thickness becomes too thin and the pressure resistance is increased. There is an unavoidable decrease in strength, and the balloon diameter is naturally limited due to the required pressure resistance. A method of inserting a reinforcing material to increase the strength of these molded balloons is also conceivable, but it is not inflatable / contractible and is bulky compared to the above resin-made molded balloons, and wrinkles occur when contracted. There is a problem that it is difficult to obtain a sufficient expansion diameter while remaining, it is easy to disturb insertion and removal. Further, what these balloons have in common is that since the balloon itself does not have a function of contracting, the fluid or the like injected to inflate normally is sucked and removed to contract the balloon, but the response is slow and There are drawbacks such as the force required to remove the fluid by suction.

On the other hand, there has been proposed a balloon in which an elastic material such as rubber is combined with a cloth or a braided material to increase the strength of the balloon and prevent the balloon from expanding beyond a certain limit.

For example, Japanese Patent Publication No. 57-23506 discloses a stenosis by a balloon catheter having a double rubber tube in the middle of which a cloth bag such as a spherical or square tube is interposed to form three layers, and a rubber band is adhered to the surface of the cloth bag. A dehiscence device is disclosed. This device has its own functions and features,
It is not always satisfactory in terms of difficulty and complexity in production such as overlapping of rubber tube and cloth bag, adhesion of rubber band, adjustment of the whole, or finish and bulkiness of the balloon portion. Furthermore, in order to manufacture such a balloon catheter with good reproducibility, skill is required, and since there is a limitation in controlling the inflation of the balloon, it is practically used except for the purpose of testing and research. It is hard to say that this is a technical method.

Further, in Japanese Patent Laid-Open No. 59-91970, a tube made of a braided material is used, an inelastic coating of a semi-hard material is applied to the outside of the portion that becomes the axis of the catheter, and the portion that becomes the axis is also made. A dilatation catheter is disclosed that has an elastic coating on the inside and on both the inside and outside of the portion that becomes the balloon. However, this catheter is reinforced with a braided material over almost its entire length, and the coating material is changed between the outside and the inside, or the shaft portion and the balloon portion, or the braided material is roughened only at the portion that becomes the balloon. However, there is a problem that the manufacturing process becomes extremely complicated.

[Object of the Invention]

In view of such problems of the conventional catheter for expanding and opening a narrowed portion in a living body lumen, the present invention does not expand beyond a certain limit during expansion and is excellent in shape retention and pressure resistance. It is a catheter with a high balloon that can be inflated and deflated, and it is easy to insert and withdraw, dilate the stenosis, and have patency, and does not damage the inner wall of the living body lumen. An object of the present invention is to provide a medical balloon catheter that can be manufactured and assembled in a simple manner.

[Structure of Invention]

That is, according to the present invention, in a balloon catheter in which a narrowed portion in a living body lumen is expanded and opened by inflating the balloon, an elastic material is combined with and integrated with a stretchable knitted fabric that is a reinforcement material of the balloon. The knitted fabric is of a composite structure, and the knitted fabric is cylindrical by weft knitting and stretches mainly in the circumferential direction, and the outer diameter of the balloon when inflated is 1.5 to 10 times the outer diameter when it is deflated. It is a medical balloon catheter.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an overall schematic view showing the structure of a catheter which is an embodiment of the present invention. The catheter is basically composed of a main body tube (3), a central tube (4) provided in the inner center of the main body tube (3), and a balloon (1) fixed near the distal end portion (2) of the catheter. The terminal connector part (7)
And a branch connector (6) with a focusing part (9) is attached. The focusing portion (9) is used for injecting a fluid such as physiological saline into the balloon to inflate it, and from the cylinder fitted to the focusing portion (9), the main tube (3) and the central tube (4) are inserted. Fluid is injected into the balloon (1) through the space (5) formed in the catheter (5) and the opening (8) provided at the position of the body tube (3) inside the balloon (1), and the fluid is added. Pressure is transmitted. Further, the terminal connector (7) is fixed to the central tube (4), and a guide wire is passed through the lumen thereof,
Used to fit a syringe with a luer fitting to inject a contrast agent.

Structurally, the catheter does not have to have two concentric circular holes composed of two tubes as shown in FIG. Further, the balloon (1) is fixed around the body tube (3) as thinly as possible without being bulky. The tip portion (2) of the catheter has the same diameter as or slightly smaller than the diameter of the balloon (1) when it is deflated, and the joint with the balloon (1) has a smooth finish and tapers toward the tip direction. If it is thin, it is easy to insert and is preferable.

The structure of the balloon (1) portion of the tube body (3) does not pose any problem even if there is a discontinuous portion (10) where the tube body does not exist partially as shown in FIG. 2 (a). In this case, the central tube (4) is not fixed to the branch connector (6), has a structure that can slide while being sealed by a rubber seal (11), etc., and a terminal connector (12) that can be fitted with a lure at the terminal part. have. From this terminal connector (12), as shown in FIG. 2 (b), insert a needle (13) with a stopper (14) near the tip and push the tip (2) to the balloon (1). It is possible to make the outer peripheral portion of the balloon (1) thinner by stretching it so that it can be easily inserted into a blood vessel or the like, and a preferable result can be obtained depending on the application. Furthermore, when inserting into a blood vessel, if air leaks and mixes in the blood vessel, there is a risk of causing blockage. Therefore, replacement or discharge of air from the catheter inner space (5) used for inflation of the balloon (1) can be prevented. Therefore, a structure in which a vent tube is arranged may be adopted.

As the material of the tube body (3) and the central tube (4) of the catheter, soft vinyl chloride-based, polyethylene-based, polyurethane-based resin, etc. can be used, and the appropriate hardness and waist strength can be used according to the application. , You can choose a special product such as softness. In addition, the X-ray contrast line or the whole may contain a contrast agent, which is convenient for use under fluoroscopy.
If necessary, a spring of a stainless steel wire or a braided material may be arranged, or a structure reinforced by multilayer molding may be used.

By injecting a fluid or the like into the balloon (1) and applying an internal pressure, the base material having rubber elasticity of the balloon itself expands, and the stitches of the intervening knitting material (15) expand and form the knitting material. Since the thread itself also has some elasticity, it expands and the balloon (1) expands to the shape shown in FIG.

FIG. 4 is a schematic diagram showing the constitution of each material forming the balloon (1), which has a structure in which the knitted material (15) and an elastic body serving as a matrix phase are combined. As a method of forming a composite, a dipping method, a coating method, a laminating method,
An appropriate method suitable for the application such as overlapping may be used. Normally, in the dipping method and the coating method, FIG.
Elastic body (16) between the fibers of the knitting material (15) as shown in
Permeate to form a composite or integrated structure. In addition, in the laminating method and stacking, the knitted material (1
5) the outer elastic layer (17) and the inner elastic layer (1)
It has a structure that combines 8). The knitting material (1
5) and inner and outer elastic layers (17) and (18) are joined,
Although they are integrated, the layers are independent of each other in the case of superposition, and it is difficult to assemble the catheter (particularly, to fix the balloon (1) to the main body tube (3)). It is preferable that the parts are integrated by an adhesive agent or thermocompression bonding. The outer peripheral elastic layer (17) is indispensable, but the inner peripheral elastic layer is usually not particularly necessary and may be omitted.

The knitting material (15) used in the present invention is a cylindrical knitted material and is not particularly limited in terms of material, but is preferably a fiber having a certain elastic force from the viewpoint of function,
Spandex (polyurethane fiber), wooly nylon, etc. are suitable, but polyester fibers, polyamide fibers, etc. can also be used for applications that do not require large elongation. Further, for the purpose of balancing the required strength and degree of extension, it is preferable to use a yarn in which fibers of other materials are combined, because the strength and elongation can be easily adjusted. As a method of knitting a knitting material, one having a large degree of expansion and contraction of the stitches is preferable, and a weft knitting knitting which mainly expands and contracts in the circumferential direction is suitable, and among them, a flat knitting (commonly known as a tenjiku knitting, It is preferable to use knitting) and rubber knitting.

As the material of the elastic bodies (15), (17) and (18), a rubber material such as latex rubber, silicone rubber or thermoplastic elastomer suitable for expansion and contraction may be used. Used as a composite.

The outer diameter of the balloon (1), which is a part of the balloon catheter of the present invention when expanded, is 1.5 to 10 times, preferably 5 to 8 times the outer diameter when contracted.
Adjust to double. If the expansion ratio of the balloon is less than 1.5 times, the effect of expanding the stenosis is small and it is not practical, and if it is more than 10 times, the stitch is too wide to reinforce although it depends on the stitch structure of the knitting material. Further, the effect of shape retention is reduced, and there is no danger of the balloon itself bursting, but since the elastic layer expands greatly, fine defects such as pinholes are likely to occur.

As a method for adjusting the expansion ratio, strength, and easiness of expansion of the balloon, it is possible to appropriately select and combine the type of yarn, knitting method, stitch density, type of elastic material, etc. constituting the knitting material. , Specifically, change the type of thread. For example, for balloons that require large strength with a small diameter, use polyester fibers or polyamide fibers with a small elongation of the thread itself, and for balloons that require a large expansion ratio with a large diameter, 100-800% Spandex fibers with elongation are suitable. Woolly nylon having an elongation of 20 to 50% is used for an intermediate purpose, but different kinds of yarns may be used in combination.

Change the thread thickness. Usually, a yarn of 50 to 200 denier is used, but by using a thicker yarn up to about 300 denier, the knit material can be made difficult to stretch.

Change the knitting method. Of the weft knitting, knitting or rubber knitting is usually used, but when it is difficult to stretch, tuck knitting, floating knitting or the like, which is difficult to stretch, is used.

Change the stitch density. Normally, the number of wales (the number of stitches per 1 inch in the vertical row) is 40 to 65, and the number of courses (the number of stitches per 1 inch in the horizontal row) is 50 to 75, but the number of wales and the number of courses are 20 respectively. It can be made difficult to grow by increasing it by ~ 30, and can be increased by decreasing it. Usually, one yarn is used for knitting, but a method of adding another yarn having the same thickness or a different thickness to form two yarns is also effective.

Change the type of elastic material. A rubber material such as latex rubber or silicone rubber is preferably used for a balloon having a large expansion ratio, and a thermoplastic elastomer is preferably used to make it relatively difficult to stretch.

In the catheter of the present invention, it is desirable that the outer diameter of the balloon (1) when it is deflated is made thin so as to be the same as the outer diameter of the main body tube (3). For that purpose, the wall thickness of the balloon (1) should be made as thin as possible, depending on the material and application of the elastic material used, but considering the pressure resistance when inflated, it will be around 0.2 to 1 m / m. Is appropriate. The pressure resistance varies depending on the use, but it is preferably ² to 8 kg / cm ² or more.

[Examples 1 and 2] Using 100 denier wooly nylon yarn, two types of cylindrical knitted knits having different wales having an outer diameter (when contracted) of about 5 mm by knitting and a different number of courses were obtained. This was covered with a core metal, immersed in natural rubber latex for about 10 seconds to impregnate the latex, and then air-dried at room temperature until the surface became non-sticky. Furthermore, it was heated at 80 ° C. for 30 minutes and vulcanized to obtain a balloon tube for a balloon catheter in which the knitted knitted fabric and rubber were combined and integrated.

The number of wales, the number of courses, and the outer diameter of the balloon when the knitted knitted fabric was inflated at maximum were as shown in Table 1.

[Examples 3 to 5] Three types of cylindrical knitted fabrics obtained in the same manner as in Examples 1 and 2 were obtained. The cored bar is dipped in a silicone rubber solution and dried to form a 0.3 mm thick coating on the surface, which is then covered with the above knitted fabric and then a separately prepared 0.3 mm thick, 5 mm inner diameter silicone rubber tube. I put them together. Both ends of the tube were heated and pressed to bond and integrate the silicone rubber and the knitted knitted fabric, and then the core metal was removed to obtain a balloon tube for a balloon catheter.

The number of wales, the number of courses, and the outer diameter of the balloon at the time of maximum inflation of the knitted fabric were as shown in Table 2.

[Examples 6 to 10] Using 60 denier wooly nylon yarn, five kinds of cylindrical knitted knitted fabrics having an outer diameter of about 2 mm and different numbers of courses by rubber knitting were obtained. In the same procedure as in Examples 3 to 5, the thickness of the silicone rubber was 0.2 mm and the outer diameter when contracted was 2.2.
A mm balloon tube was obtained.

The number of wales, the number of courses, and the outer diameter of the balloon at the maximum inflation of the knitted knit fabric were as shown in Table 3.

[Examples 11 to 13] Using 120 denier spandex fibers having an elongation of 520%, three types of cylindrical knitted knits having different wales and outer diameters (when contracting) of about 8 mm by knitting and different courses are prepared. Obtained. This is covered with a cored bar, immersed in a silicone rubber solution, air dried at room temperature for 30 minutes, further dried at 110 ° C for 6 minutes, then heated at 200 ° C for 60 minutes and vulcanized to obtain a balloon tube for a balloon catheter. It was

The number of wales, the number of courses, and the outer diameter of the balloon at the time of maximum inflation of the knitted fabric were as shown in Table 4.

[Effects of the Invention] As described above, the medical balloon catheter according to the present invention has an esophagus, a defect, insertion into a living body lumen such as a bile duct,
Removal can be performed easily and safely, expansion of the esophageal stenosis and patency of the defect stenosis can be performed reliably and effectively, and the balloon is inflated beyond a certain limit to the living body lumen. (EN) Provided is a device which can be effectively and safely treated without causing obstacles, is easy to manufacture and assemble, and is extremely useful medically.

[Brief description of drawings]

FIG. 1 is a schematic view showing the structure of a balloon catheter according to an embodiment of the present invention, FIG. 2 is a schematic view showing the structure of another embodiment of the balloon catheter, and FIG. 3 is a state in which the balloon is inflated. It is a figure. Further, FIG. 4 is a schematic view showing the constitution of the material forming the balloon.

Claims (1)

[Claims] 1. A balloon catheter in which a narrowed portion in a living body lumen is expanded and opened by inflating the balloon, wherein an elastic material is combined with an elastic knitted fabric which is a reinforcing material of the balloon and is integrated. The knitted fabric is of a composite structure, and the knitted fabric is cylindrical by weft knitting and stretches mainly in the circumferential direction, and the outer diameter of the balloon when inflated is 1.5 to 10 times the outer diameter when it is deflated. Medical balloon catheter.