JPS6338469A - Medical balloon catheter - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a medical device used for dilating and opening constricted portions of biological lumens such as the esophagus, blood vessels, and bile ducts, and for removing foreign bodies such as blood clots. This invention relates to a balloon catheter.

[Prior art]

Generally, when dilating a narrowed part of a biological lumen, the balloon itself is used instead of using an elastic material such as rubber to prevent localized pressure from being applied due to deformation of the balloon and to prevent it from expanding beyond a certain limit. It uses a pre-molded balloon made of resin that does not inflate or deflate, and is very useful. However, these molded resin balloons usually achieve their purpose by inflating with liquid and maintaining a certain shape, but when deflated, the balloon is attached in a bulky state around the catheter body, so it may cause damage to the body. It is difficult to smoothly insert and remove the balloon into the lumen, and there is also a risk that the bulky balloon portion may damage the inner wall of a small blood vessel. Generally speaking, molded balloon fissures are often formed and stretched to increase strength, but when using a balloon with a large diameter compared to the diameter of the catheter that will be the attachment base, the wall thickness may become too thin. A decrease in pressure resistance is unavoidable, and there is a natural restriction on the balloon diameter due to the required pressure resistance. It is possible to add reinforcing material to increase the strength of these molded balloons, but they are not able to expand and deflate freely, are bulkier than the resin molded balloons mentioned above, and tend to wrinkle when deflated. There is a problem that the remaining part tends to get in the way of insertion, removal, etc., and it is difficult to obtain a sufficient expansion diameter. Furthermore, what these balloons have in common is that the balloon itself does not have the function of deflating, so normally the fluid injected for inflation is removed by suction to deflate the balloon, but the response is slow and There are drawbacks such as the need for force to suction and remove fluids, etc.

On the other hand, a balloon has been proposed in which the strength of the balloon is increased by combining an elastic material such as rubber with cloth or a braided material, and the balloon is prevented from expanding beyond a certain limit.

For example, in Japanese Patent Publication No. 57-23506, stenosis is achieved using a balloon catheter in which a three-layer cloth bag is interposed between a double rubber tube and a spherical or square tube, and a rubber band is adhered to the surface of the cloth bag. A cleaving device is disclosed. Although this device has certain functions and features, it is difficult and complicated to manufacture, such as overlapping the rubber tube and cloth bag, attaching the rubber band, and overall adjustment, or the finishing of the balloon part. It is not necessarily satisfactory in terms of weight and bulk. Furthermore, manufacturing such a balloon catheter with good reproducibility requires skill and
It is difficult to say that this is a practical method except for purposes such as testing, research, etc., which have limitations in controlling the way the balloon is inflated.

In addition, Japanese Patent Application Laid-open No. 59-91970 discloses that a tube made of a braided material is used, and the outside of the portion that will become the shaft of the catheter is coated with an inelastic coating of semi-hard material. 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 along its entire length, and the coating material is different on the outside and inside, or between the shaft and the balloon part), or the braided material is used only in the part that will become the balloon. If methods such as roughening are used, the manufacturing process becomes extremely complicated.

[Purpose of the invention]

In view of the problems of conventional catheters that are used to dilate and open constricted areas in biological lumens, the present invention has been developed to overcome the problems of conventional catheters that do not expand beyond a certain limit when inflated, has excellent shape retention, and has high pressure resistance. It is a catheter with a balloon that can be inflated and deflated, and is easy to insert and remove, dilate a stenotic area, and open a stenotic area. The object of the present invention is to provide a medical balloon catheter whose manufacturing and assembly processes can be simplified.

[Structure of the invention]

That is, the present invention provides a balloon catheter that dilates and opens a constricted part in a biological lumen by inflating a balloon, in which the balloon is a reinforcing material that combines and integrates a stretchable knitted knitted fabric and an elastic material. The knitted fabric has a cylindrical shape made of weft knitted fabric, expands and contracts mainly in the circumferential direction, and the outer diameter when the balloon is inflated is 1.5 to 10 times the outer diameter when it is deflated. This is a medical balloon catheter characterized by the following.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Figure 8g1 is an overall schematic diagram showing the structure of a catheter that is an embodiment of the present invention. The catheter includes a main body tube (3), a central tube (4) provided at the inner center of the main body tube (3), and a distal end portion (
2) It basically consists of a balloon (1) fixed in the vicinity, and a branch connector (6) having a terminal connector part (7) and a focus part (9) is attached to the terminal part. There is. The focusing part (9) is used to inflate the balloon by injecting fluid such as physiological saline into the balloon, and the main body tube (
3) and the central tube (4), and the balloon (5) of the main tube (3).
Fluid is injected into the balloon (1) through an opening (8) provided in the vertical direction of the balloon (1), and pressurizing force is transmitted. Further, the terminal connector (7) is fixed to the central tube (4) 9 and is used to pass a guide wire through its lumen or to inject a contrast medium by fitting a syringe with Luer.

Structurally, the catheter does not have to have two concentric holes made up of two tubes as shown in FIG. 1; it may have two parallel holes. Further, the balloon (1) is fixed around the main body tube (3) as thinly and without bulk as possible. The distal end (2) of the catheter has a balloon (
The diameter is the same or slightly smaller than the deflated diameter of (1), and the joint with balloon (1) has a smooth finish.
It is preferable that the tube be tapered in a Z-shape toward the distal end, since this facilitates insertion.

There is no problem in the structure of the balloon (1) portion of the tube body (3) even if there is a partially interrupted portion (10) where the tube body does not exist, as shown in FIG. 2(a). In this case, the center tube (4) is not fixed to the branch connector (6), but has a structure in which it can slide while being sealed with a rubber seal (11), etc., and the terminal part has a terminal connector ( 12). From this terminal connector (12), insert a needle (13) with a truss (14) near the tip as shown in Fig. 2(b), push the tip (2), and press the balloon (1).
) By stretching the balloon (1), the outer circumference of the balloon (1) can be made narrower so that it can be easily inserted into a blood vessel, etc., which may give preferable results depending on the application. Furthermore,
When inserting the balloon into a blood vessel, there is a risk of causing an embolus if air leaks into the blood vessel.
A vent tube may be provided to displace and discharge air from the catheter interior space (5) used for inflation.

In addition, the tube body (3) of the catheter and the central tube (
As the material for 4), resins such as soft vinyl chloride, HIJ ethylene, and urethane can be used, and if you choose one with appropriate hardness, stiffness, and softness depending on the application. good. In addition, a contrast agent may be contained in the X-ray contrast line or the entire area, which is convenient for use under fluoroscopy69, and further,
If necessary, a stainless steel wire spring or braided material may be arranged, or the structure may be reinforced by multi-5 layer molding.

By injecting a fluid or the like into the balloon (1) and applying internal pressure, the rubber elastic base material of the balloon itself expands, and the intervening knitted material (15) expands.
Moreover, since the yarn itself constituting the knitted fabric material has an elasticity of f-3 degrees, it stretches and the balloon (1) is inflated into the shape shown in FIG.

FIG. 4 is a schematic diagram showing the composition of each material forming the balloon (1), which has a composite structure of a knitted fabric material (15) and an elastic body serving as a matrix phase.

As a method for compositing, an appropriate method suitable for the purpose may be used, such as a dipping method, a coating method, an f1 layer method, and a superposition method. In the dipping method or the coating method, the elastic body (16) infiltrates between the fibers of the knitted fabric material (15) as shown in FIG. or superposition, Fig. 4 tb)
Knitted fabric material (15) K outer peripheral elastic layer (In
, b, and an inner peripheral elastic layer (18). In the lamination method, the knitted fabric material (15) and the inner and outer elastic layers (17) and (18) are combined and integrated, but in the case of lamination, each layer is independent from each other, Since assembling the catheter (particularly fixing the balloon (1) to the main body tube (3)) is difficult, it is preferable to integrate both ends of the balloon with adhesive or heat-pressing. Note that although the outer peripheral elastic layer (17) is essential, the inner peripheral elastic layer is usually not particularly necessary, and there is no harm in omitting it.

The knitted fabric material (15) used in the present invention is a cylindrical knitted fabric and is not particularly limited in terms of material, but it is preferably a fiber having a certain degree of elasticity from a functional standpoint. rRMI), woolly nylon, etc. are suitable, but for applications that do not require large elongation, dIJ ester fibers, boriad fibers, etc. can also be used.

Further, for the purpose of achieving a balance between the required strength and the degree of elongation, it is preferable to use a yarn that is a composite of fibers of other materials, since the strength and elongation can be easily adjusted.

How to knit knitting materials? Thick stitches with a high degree of stretch and retraction are best, and weft stockinette knitting, which stretches and contracts mainly in the circumferential direction, is suitable, and among these, flat knitting (commonly known as stockinette knitting and stockinette knitting) is suitable. , rubber knitting, etc. are preferably used.

The elastic bodies (15), (17), and (18) may be made of rubber materials suitable for expansion and contraction, such as latex rubber, silicone rubber, or thermoplastic elastomer. Use in combination.

Balloon (1) that forms part of the balloon catheter of the present invention
), the outer diameter when expanded is 1.5 to 10 times the outer diameter when deflated, preferably 5 to 8 times, depending on the purpose of use.
Adjust to double. Balloon inflation magnification is 1.5
If the size is larger than 10 times, the stitches will become too wide and will be reinforced. In addition, the shape-retaining effect is reduced, and although there is no danger that the balloon itself will burst, the elastic layer is stretched significantly, making it more likely that minute defects such as pinholes will occur.

The expansion ratio, strength, and ease of stretching of the balloon can be adjusted by appropriately selecting and combining the type of yarn, knitting method, stitch density, type of elastic material, etc. that make up the knitting material. ,Specifically, ■Change the type of thread. For example, for small-diameter balloons that require great strength, polyester fibers with low elongation are used! +) For balloons that use amide fibers, etc. and require a large diameter and a large expansion ratio,
Snow index fibers with an elongation of 0% are suitable. Woolly nylon with an elongation of 20 to 50 is used for intermediate purposes, but a combination of different types of yarn may be used.

■Change the thickness of the thread. Usually, threads of 50 to 200 denier are used, but by using thicker threads of up to about 300 denier, the knitted material can be made difficult to stretch.

■Change the way you knit. Of the weft stockinette knits, stockinette knits or rubber knits are usually used, but if you want it to be difficult to stretch, tuck knits, floating knits, etc., which are difficult to stretch, are used.

■Change stitch density. Normally, the number of wales (the number of stitches per inch in the vertical row) is in the range of 40 to 65, and the number of courses (the number of stitches per inch in the horizontal row) is in the range of 50 to 75, but the number of wales and the number of courses are 20 to 20 each. By increasing it by ~30, it becomes difficult to elongate, and by decreasing it, it becomes possible to increase elongation. Furthermore, although knitting is usually done with one thread, it is also effective to add one more thread of the same thickness or a different thickness to create two-strand knitting.

■Change the type of elastic material. It is preferable to use a rubber material such as a balloon outer diameter having a large expansion ratio, latex rubber, or silicone rubber, and to make it relatively difficult to stretch, it is preferable to use a thermoplastic elastomer.

In the catheter of the present invention, it is desirable that the outer diameter of the balloon (1) when deflated be made smaller and equal to the outer diameter of the main body tube (3). To this end, the wall thickness of the balloon (1) should be as thin as possible, depending on the material and purpose of the elastic material used, but considering the pressure resistance during inflation, etc., it is 0.2 to 1%. The range of positions is appropriate. Although the compressive strength varies depending on the application, it is preferably 2 to 84/cλ or more.

[Examples 1 to 2] Using 100 denier woolly nylon yarn, two types of cylindrical knitted knitted fabrics were obtained using knitted l14 yarn, each having an outer diameter (when contracted) of about 5 different numbers of wales and different numbers of courses. This was placed over a core bar, dipped 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. Further, the mixture was heated and vulcanized at 80° C. for 30 minutes to obtain a balloon tube for a balloon catheter, which was a composite of knitted knitted fabric and rubber.

The number of wales, number of courses, and outer diameter of the balloon at maximum inflation of the stockinette knitted fabric were as shown in the Kx table.

Table 1 [Examples 3 to 5] Three types of cylindrical knitted fabrics were obtained in the same manner as in Examples 1 to 2. The core was immersed in a silicone rubber solution and dried to form a film with a thickness of 0.3 m on the surface, which was then coated with the above-mentioned stockinette fabric, and then with a separately prepared layer of thickness Q, 3 we.
An, a silicone rubber tube with an inner diameter of 5 tubes was covered and overlapped. Both ends of the tube were heated and pressurized to bond and integrate the silicone rubber and the stockinette knitted fabric, and then the core was removed to obtain a balloon tube for a Siballoon catheter.

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

Table 2 [Examples 6 to 10] Using 60 denier woolly nylon yarn, five types of cylindrical stockinette knitted fabrics having an outer diameter of approximately 2 feet and having different numbers of wales and courses were obtained using rubber bias.

Using the same procedure as in Examples 3 to 5, the thickness of the silicone rubber was 0.
．． A balloon tube of 2 m and an outer diameter of 2.2+III when deflated was obtained.

The number of wales, the number of courses, and the outer diameter of the balloon at the time of large expansion of the knitted fabric were as shown in Table 3.

Table 3 [Examples 11 to 13] Cylindrical stockinette knitted fabrics using 120 denier Snokundenox fibers with an elongation of 520% and having an outer diameter (when contracted) of approximately 8rrunO with different numbers of wales and courses. I got 3 types. This was placed over the core metal, dipped in a silicone rubber solution, air-dried for 30 minutes at room temperature, and then
After drying at 110°C for 6 minutes, the mixture was heated and vulcanized at 200°C for 60 minutes to obtain a balloon tube for a balloon catheter.

The number of wales, number of courses, and outer diameter of the balloon at maximum inflation are as shown in Table 4, which is 7t.

Table 4 [Effects of the Invention] As explained above, the medical balloon catheter according to the present invention can be inserted into living body lumens such as the esophagus, blood vessels, bile ducts, etc.
The balloon can be easily and safely removed, the esophageal stenosis can be dilated and the vascular stenosis can be opened reliably and effectively, and the balloon can be inflated beyond a certain limit (inflating the biological tube). It is an object of the present invention to provide a medically extremely useful tool that allows therapeutic treatment to be performed effectively and safely without causing injury to the cavity, is easy to manufacture and assemble, and is extremely useful medically.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the structure of a balloon catheter according to an embodiment of the present invention, Fig. 2 is a schematic diagram showing the structure of another embodiment of the balloon catheter, and Fig. 3 shows the balloon in an inflated state. It is a diagram. Moreover, FIG. 4 is a schematic diagram showing the structure of the material forming the balloon.

Claims (1)

[Claims] (1) A balloon catheter that dilates and opens a constricted area in a biological lumen by inflating a balloon, which has a composite structure in which a stretchable stockinette fabric and an elastic material are combined and integrated, with the balloon serving as a reinforcing material. The knitted fabric has a cylindrical shape made of weft knitted fabric, expands and contracts mainly in the circumferential direction, and the outer diameter when the balloon is inflated is 1.5 to 10 times the outer diameter when it is deflated. medical balloon catheter.