Balloon catheter

The invention relates to a balloon catheter and particularly to a PTCA catheter for dilatation of stenoses in the vascular system.

For the treatment of blood vessels of the vascular system are PTCA catheter used (Percutaneous Transluminal Coronary Angioplasty). This is by balloon catheter over a guide wire through the bends of Vascular Systems are pushed to the destination.

The distal tip of a PTCA balloon catheter has a high have compression stability, so that they can narrow stenoses happen. Despite the Compression stability must be flexible catheter tip, so that the can bring entire catheter into the tortuous vasculature. at conventional PTCA catheters, the distal (patient side) Hose section, ie the section of tubing beyond the balloon, from Sections of different materials with different mechanical Properties manufactured. Individual pieces of tubing are successively set and joined by welding. This is a high production cost and connected correspondingly high costs.

A balloon catheter, from which the preamble of claim 1 is described in US 6,165,152 A. In this balloon catheter inner tube provided in a distal tube portion with recesses, whereby the Flexibility this tube portion is increased. The recesses extend only partially through the tube wall, ie they are not continuous. The with a laser beam generated recesses may consist of a helical line or discrete blind holes exist. They cause a Structuring or roughening of the outer surface of the distal tube portion.

The present invention has for its object, a balloon catheter to create, the distal tube section to achieve a desired Flexibility is indeed worked, but not that the smoothness of the surface would adversely changed.

The balloon catheter according to the invention comprises the features of claim 1 on. These require that the skin of the balloon distal collar forms, which for achieving a smoothed outer surface, the entire with the Recesses provided length of the inner tube closely surrounds. The Balloon skin thus extends over the entire by subsequent Editing structured surface region of the inner tube to the immediate vicinity of the catheter tip.

While in U.S. Patent 6,165,152, the structured region by the distal collar of the balloon passes and thereby necessarily on a Part of its length is covered with no particular intention, according to the invention is the Balloon skin to used previously to cover patterned surface and the caused by the removal of material change in structure of the healing surface. Thus, the risk of injury or of peeling is of vascular deposits due to the recesses and bending of the distal Tube portion decreases. The invention is based on the idea that the skin of the balloon has a small thickness and therefore an ideal envelope for smoothing narrow range over the distal tubular portion of the Inner tube forms.

According to a preferred embodiment of the invention, the distal cuff welded to the recesses provided with the length. When welding the distal cuff on the weakened by the recesses distal Hose section results in a smooth outer surface, which is advantageous in Penetrating a stenosis. By welded enveloping Balloon layer the flexibility of the tubular section is also uniform. If the recesses consist of discrete holes, causing the welded Cuff better load distribution, whereby local Voltage peaks can be prevented. In addition, the risk of buckling is reduced.

The distal sleeve can consist of a shrink tube. On Shrinkable tubing takes by heating back to its original shape. in the the present case, it shrinks on to the outer surface of the inner tube, wherein In addition, a weld joint can be performed.

The preparation of the recesses is preferably carried out with a UV laser or Excimer laser or by mechanical means. With laser machining can also a tapered catheter tip are formed. Preferably this is a CO₂-Laser. Here, the tube material is not broken down, but fused and moved.

In the following, with reference to the drawings, embodiments the invention described in greater detail.

Show it:<dl tsize="6"><dt>Fig. 1</dt><dd>is a partial view of the balloon catheter, partially in longitudinal section,</dd><dt>FIG. 2</dt><dd>a side view of the distal tubular portion of the Inner tube, and</dd><dt>Fig. 3</dt><dd>A second embodiment of a balloon catheter according to the Invention.</dd></dl>

The balloon catheter includes an elongated outer tube 10 and a in the outer tube extending to inner tube 11th At the distal end of the The outer tube 10, a balloon 12 is attached, in the lumen 13 of the Outer tube opens. By injecting a pressurized fluid into the lumen 13, the balloon 12 is expanded to perform a dilation of a stenosis. The hoses are made of polyamide or appropriate Material mixtures.

The inner tube 11 extends through the balloon 12 passes. The distal Tube portion 14 terminates in a tapered catheter tip 15. By the lumen 16 of the inner tube 11, a (not shown) be advanced guidewire from the catheter distal tip 15 protrudes out.

The balloon 12 is connected to a proximal sleeve 17 to the outer tube 10 welded. At the distal end of the balloon 12 having a distal cuff 18 which is welded to the inner tube 11th The cuffs are preferably an integral part of the balloon. Alternatively, you can be welded or consist of several parts.

The distal tube portion 14 of the inner tube 11 is provided with recesses 20 provided to increase the flexibility of the hose portion. Of the Tube section 14 is an integral component of the inner tube 11. The Recesses 20 are in the present embodiment, holes with a laser beam are baked and penetrate the catheter wall. Alternatively, there is the possibility of the recesses as non-continuous form weakened areas. is the preferred form of the recesses around. However, the recesses may have any shape, for example, Elliptical shape with running in the tube longitudinal major axis, or Rectangular shape. The preparation of through recesses in the form of Holes is simpler and does not lead to unintended leaks, because the entire area of ​​the recesses with the skin 21 of balloon 12 closely enveloped fitting. This means that the cuff 18 over the covers entire length of the recess portion and all recesses covered. Thereby, the outer surface of the distal tube section 14 smoothed.

Figure 2 shows a side view of the provided with the recesses 20 distal tube portion 14 of the inner tube 11, wherein the balloon skin 21, covering the recesses, shown in phantom. The balloon skin is 21 fully laminated to the hose section 14, in particular by Weld. It therefore causes a voltage compensation and Bridging the recesses 20th

Figure 3 shows a modified embodiment of the tip portion of the Balloon catheter. The area of ​​the inner tube 11, to which the recesses 20 are provided, is also covered with the collar 18 of the balloon 12th On the sleeve 18 a shrink tube sitting 22 which is distal to the End of the inner tube extending and possibly protrudes above. If the Shrink tubing 22 is heated, for example, by laser irradiation, so reduces its diameter. Due to the pressure which the heat-shrinkable tube 22 and exerts by the heat of laser irradiation is applied to the cuff 18 the inner tube 11 is welded and molded simultaneously. In molding the catheter tip is carried out a control of the laser process. Of the Shrink tube 22 remains in this embodiment, after the Shrinking process to the catheter.

In a further embodiment not shown, of the tip portion of the Balloon catheter is the shrink tube after already described Shrinking process from the catheter. The area of ​​the inner tube, at the recesses are provided which, in this embodiment, completely covered by the sleeve of the balloon.