JP2891032B2 - Balloon catheter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balloon catheter and, more particularly, to a balloon catheter having no eccentricity when the balloon is inflated, protecting the catheter tip and electrodes attached to the tip, and loosening the balloon when the balloon is deflated. The present invention relates to a balloon catheter having no wrinkles.

[0002]

2. Description of the Related Art As a medical balloon-equipped catheter provided with a balloon in the vicinity of a catheter distal end (pointed end), for example, a catheter for indwelling in a blood vessel, a catheter for removing biliary calculi and renal ureteral calculi, etc. Various things are known. An example of a catheter for indwelling in a blood vessel is a pacing catheter with a balloon. When a disorder such as arrhythmia or heart failure occurs in the heart, a transvenous catheter electrode for extracorporeal pacemaking is inserted, and the activity of the heart is maintained by emergency pacing or temporary pacing. In this case, a pacing catheter with a balloon is usually used according to the catheter method, and pacing is performed by inserting the venous into the heart. That is, in the pacing catheter treatment method, a peripheral vein, such as a femoral vein or a subclavian vein, is usually punctured from an incision in the skin with a sheath introducer, and the pacing catheter is inserted into the body through the introducer. Then, when the balloon is inflated with carbon dioxide gas or air, the pacing catheter is placed on the blood flow in the blood vessel and the heart, and its distal end electrode is targeted via the vein, right atrium and tricuspid valve. It can be inserted up to the apical portion of the right ventricle and placed there. Since the distal end electrode of the pacing catheter is made of a hard metal such as stainless steel or platinum, it may damage the heart and blood vessels due to the distal end electrode at the time of insertion, or may cause perforation when attempting to insert it. To prevent danger, catheters are known which are covered by a balloon so that they do not protrude.

Another example of a catheter for indwelling in a blood vessel is a thermodilution catheter. The Fick method, which calculates oxygen consumption and the arterial blood oxygen difference, and the indicator, which measures how much the indicator injected in the peripheral vein diminishes in the central vein, can be used to measure the heart rate, which is an indicator of the function of the heart. There is a dilution method. In the thermodilution method (thermodilution method), how much the cold water as an indicator warms is measured. When inserting a thermodilution catheter, the catheter is inserted, for example, from the left elbow vein and advanced from the subclavian vein to the superior vena cava, where the balloon at the tip is inflated and slowly advanced to allow the balloon to enter the bloodstream. Ride easily into the right ventricle and pulmonary artery.
When the balloon is evacuated, the pressure of the pulmonary artery is increased, so the catheter is fixed at this site. The balloons provided on these catheters are made of a film (membrane) formed of an elastic material, and need not be loosened during contraction, have no eccentricity when inflated, and protect the catheter tip, It is desirable to have excellent mechanical properties and antithrombotic properties. As the material of the elastic material, for example, silicon rubber,
Examples include polyurethane and natural rubber. In order to manufacture a balloon using these elastic materials, a dipping method is generally adopted in which a polymer aqueous solution in an emulsion state is dipped and crosslinked, or a mold is immersed in an organic solvent solution of the elastic material to form a film. I have. In a conventional balloon catheter, as shown in a longitudinal sectional view at the time of deflation in FIG. 3, the balloon 2 is usually attached near a distal end 3 which is a point of the catheter 1. Depending on the application of the catheter, the distal end 3 is provided with a pointed hole, an electrode or a thermistor. When the balloon 2 is inflated in order to prevent the distal end from damaging a blood vessel wall or a built-in wall such as a heart, the balloon 2 covers the distal end 3 to prevent its protrusion.

[0004] If the inflated balloon shape is biased,
For example, in the case of an intravascular indwelling catheter, it is difficult for the balloon to cover the distal end portion, and the heart and the inner wall of the blood vessel may be damaged by the hard metal distal end electrode. In addition, there is a risk that arrhythmia may occur due to stimulation of the inner wall of the heart by the distal end. In the case of a thermodilution balloon catheter, accurate measurement becomes impossible if the tip is too eccentric and too close to the inner wall. However, conventional balloons often do not inflate uniformly and tend to be uneven in shape. As schematically shown in the inflated state in FIG. 3, in (A) using a short tube having a large elongation rate, the tube is protected by covering up to the distal end of the balloon. On the other hand, in the case of a long tube made of latex having a low elongation rate (B), since the distal end of the catheter is not protected, the distal end of the catheter may damage living tissue. Therefore, it is often desirable to make a balloon with a short tube having a large elongation rate, but in this case, since the tube is elongated at a large elongation rate, even a slight adhesion unevenness tends to cause eccentricity,
There is a problem that loosening easily occurs even during contraction.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a balloon in which the shape of the balloon during expansion is extremely small and the tip of the catheter is covered with the balloon and hardly sags during deflation. It is in. The present inventor has conducted research on the cause of the occurrence of bias in the balloon shape of the catheter, and when the conventional balloon was inflated until the distal end was hidden, the expansion rate was large, so there was a small gap in the bonding portion with the catheter. Also found that eccentricity occurred. The inventor of the present invention is able to eliminate the influence of uneven adhesion by providing a balloon with a ring-shaped non-extendable portion covering the distal end of the catheter and forming the non-extendable portion to be folded back. Conceived that it was possible to hide and protect the distal end of the catheter, and repeated tests to complete the present invention.

[0006]

Thus, according to the present invention, in a balloon catheter having a balloon attached to the distal end, one edge is adhered to the outer periphery of the catheter at a position distal to the balloon vent of the catheter, The balloon-forming elastic tube that covers the catheter distal end and has an annular non-extendable portion provided at an intermediate predetermined position is turned around at the end of the non-extendable portion, and the folded tube includes the non-extendable portion. A balloon catheter is provided in which the elastic tube and the subsequent catheter tip are covered and another edge is adhered to the outer periphery of the catheter at a position proximal to the balloon vent. The present invention will be described based on an example of a catheter provided with an electrode at the tip. FIG. 1A shows
It is a longitudinal cross-sectional view of the balloon catheter tip part along the central axis of the catheter before inflation. An end of a tube 5 made of an elastic material is adhered to the periphery of the catheter 1 at a position distal to the ventilation hole 4 for the balloon, and covers the catheter 1 up to the vicinity of the electrode 6 at the tip of the catheter. Form a non-extended portion 7 which is annular and hard. The tube portion ahead of the non-extended portion is turned over at the tip portion of the non-extended portion with the outer peripheral surface inverted, and the turned upside-down tube 8 covers the annular non-extended portion 7, the tube 5, and the vent hole portion for the balloon. The edge is adhered to the outer periphery of the catheter at a position closer to the balloon ventilation hole 4. Next, a state when the balloon catheter is inflated is shown in FIG. At the same time as the inversion tube 8 is inflated to form a balloon by being pressurized with gas, the tube 5 extends distally along the outer periphery of the catheter tube, and the rigid non-extended portion 7 reaches a position beyond the distal electrode 6. The inverting tube 8 expands in a spheroidal or spherical shape between the catheter bonding portion and the non-extended portion, and its distal end protrudes from the distal end of the catheter, and covers the distal electrode 6 inside. When the gas in the balloon is released, the balloon returns to a contracted state due to elasticity.

The catheter of the present invention usually has an outer diameter of 5 to 15F.
At about r, the tube itself may be multi-lumen, and is used as a passage for an electrode cord, a hole for injecting a drug solution, and a gas flow hole for a balloon. The distal end of the catheter may be of a non-profile type in order to facilitate insertion into the body or to place the balloon in a blood vessel, in which case a step may be provided at the distal end of the catheter tube. The material of the catheter tube is preferably formed from polyurethane, silicone, polyvinyl chloride, or the like. Balloon tube length is 1-3c
m, outer diameter 5Fr-15Fr, thickness 100-300μm
Is common. The material is made of natural rubber latex, polyurethane, silicone rubber, polyethylene or the like. The non-stretchable portion of the tube may be made of a small band made of rubber or plastic, or a substantial portion thereof may be coated with a curable polymer such as an epoxy-based or acrylic-based polymer to impart non-stretchability.

[0008]

In the balloon catheter of the present invention, by providing a rigid annular non-extending portion at the distal end of the balloon tube, the annular non-extending portion moves forward along the catheter tube wall when the balloon is inflated, and this movement causes the tube to move forward. Is absorbed, so that a spheroidal or spherical balloon without eccentricity is formed. When the balloon is inflated, the distal end of the non-extended portion protrudes slightly beyond the catheter tip electrode and the like, and a balloon is formed between the protruding end and the adhesive portion at the back of the balloon (hand side). It is protected by the tip expansion. In addition, even when deflated by deflation, the non-extended portion is pulled back along the catheter tube, and the balloon tube does not loosen or wrinkle.

[0009]

EXAMPLE A balloon catheter of the present invention was produced by the method shown in the following explanatory drawing. That is, in FIG. 2A, for example, an elastic tube having an outer diameter of 7 Fr and a thickness of 0.2 mm is bonded to the distal end side of the ventilation hole with a width of about 1 mm. It is 10 from this adhesion part
An annular non-extendable portion is provided at a width of 2 mm apart from the center. This non-extended portion was obtained by applying a cyanoacrylate-based curing agent to a width of 2 mm. At this time, the end of the non-extended portion is prevented from protruding from the electrode tip. Next, as shown in FIG. 2 (B), the tube is turned upside down using a sheath dilator so that the inner surface of the tube becomes the surface, and the end of the inverted tube is adhered at a predetermined position behind the catheter vent. Formed. When about 1 ml of air was injected into the balloon catheter with a syringe, the balloon catheter was inflated to form a spherical balloon having a diameter of about 1 cm without eccentricity.

Next, the performance of the balloon catheter of the present invention shown in FIG. 1 and the conventional balloon catheter shown in FIG. 3 produced by the above method was evaluated for the following items. 1. Measurement of Balloon Shape Outer Diameter A predetermined amount of air (0.8 cc) was injected into a balloon attached to a catheter tube, and the balloon shape was measured with a laser outer diameter measuring device (LS-3100, manufactured by Keyence Corporation). The maximum value of the measured balloon outer diameter was defined as the balloon outer diameter. 2. Balloon shape deviation degree, deviation occurrence rate Balloon outer diameter is divided into upper and lower lengths a and b from the horizontal center plane of the catheter distal end, and the ratio of a / b (or b / a) is defined as the deviation degree, and measured for each sample. The average of the numbers given is shown.
When the degree of bias was 1.2 or more, the rate of occurrence of bias was defined as the rate of occurrence of bias in each sample. 100 total samples
It was made into pieces. 3. Degree of catheter distal end exposure In the case of an indwelling intravascular catheter, if the distal end is exposed when the balloon is inflated, it may damage the heart and the inner wall of the blood vessel, and the distal end may stimulate the inner wall of the heart. It is necessary to have no exposure of the distal end because of the risk of arrhythmias. Therefore, those in which the distal end of the catheter was exposed from the expanded balloon,
Those that were not performed were marked with ○. 4. Rate of occurrence of loosening The balloon was inflated and then deflated, and the shape at that time was visually determined, and a case where loosening was clearly observed was evaluated as "looseness". The results are shown in Table 1 below. The tube length of the example in the table indicates the length between the back end (hand side) of the balloon and the folded end of the non-extended portion, and the tube length of the comparative example is the length between the front and rear bonded portions of the tube. , Material NR means natural rubber, and PU means polyurethane.

[0011]

[Table 1]

As can be seen from the results in Table 1, the balloon catheter of the present invention is excellent in terms of the occurrence of slack, the occurrence of deviation, and the protection of the distal end, but in Comparative Example 1, deviation occurs.
No protection is provided at the tip, and in Comparative Example 2, both the slack occurrence rate and the bias occurrence rate are poor.

[0013]

According to the balloon catheter of the present invention, there is no deviation when the balloon is inflated, the catheter distal end is securely covered, and no slack occurs when the balloon is deflated. It is very useful as a balloon catheter for a dilution method.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view of a balloon catheter according to the present invention when the balloon is deflated and when inflated.

FIG. 2 is an explanatory view showing a method for producing a balloon catheter according to the present invention.

FIG. 3 is an enlarged vertical sectional view of a conventional balloon catheter at the time of contraction and inflation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Catheter 2 Balloon 3 Distal end 4 Vent hole 5 Tube 6 Tip electrode 7 Non-extended part 8 Inversion tube

Claims (1)

(57) [Claims] In a balloon catheter having a balloon attached to a distal end thereof, one edge is adhered to the outer periphery of the catheter at a position distal to a balloon ventilation hole of the catheter to cover the distal end of the catheter and to be positioned at an intermediate predetermined position. A balloon-forming elastic tube provided with an annular non-extending portion is turned around at the tip of the non-extending portion while being turned around, and the folded tube covers the elastic tube including the non-extending portion and a subsequent catheter tip portion. A balloon catheter having another edge bonded to the outer periphery of the catheter at a position proximal to the balloon vent.