PRIORITY CLAIM

This application claims priority under 35 U.S.C. § 119 and all applicable statutes and treaties from prior European Application EP 18179524.6, filed Jun. 25, 2018.

FIELD OF THE INVENTION

The present invention relates to a balloon catheter, and to a method for producing a balloon catheter. One application of the invention is to percutaneous transluminal coronary angioplasty (PCTA) catheters. Another application of the invention is to balloon catheters used to unfold stents or heart valve prostheses.

BACKGROUND

A balloon catheter is a tubular structure, which for example can be introduced for therapeutic purposes into a body lumen, in particular a vessel, of a patient. A specific field of application is percutaneous transluminal coronary angioplasty (PCTA) catheters, which are used to widen or reopen a constricted or closed coronary vessel. The catheter has a balloon that can be inflated by a fluid (in particular compressed air) and expands in the vascular constriction. A catheter of this kind can be guided or pushed to the location of the vascular constriction with the aid of a guide wire.

Typical conventional balloon catheters have a two-membered shaft construction. A proximal shaft segment is provided, which is usually formed by a metallic tubular element (for example a hypotube) and is equipped at a joint with a coaxial portion. The proximal shaft segment is connected via the joint to a distal shaft segment, which in turn connected to the balloon. A guide wire exit point or opening is typically provided at the joint.

Three-membered shaft designs are also known. In such designs, the proximal shaft segment (for example hypotube) firstly transitions into a support tube and then transitions via a connection point, at which the guide wire exit point or the sideport is provided, into a distal and coaxial shaft segment.

For example, Jowett & Kelly document EP1084728A1, entitled A Balloon Catheter describes a catheter in which a relatively rigid and chamfered hypotube is connected via a transition region to a relatively soft distal module.

Furthermore, Garakani document US2010/0168669A1, entitled Balloon Catheter describes a catheter in which a relatively rigid proximal shaft portion and a distal shaft portion are connected to one another via a flexible transition element, wherein the distal shaft portion has a guide wire lumen.

SUMMARY OF THE INVENTION

A preferred balloon catheter has an outer shaft which surrounds a shaft lumen. The outer shaft has a proximal outer shaft portion connected to a distal outer shaft portion. An inner shaft is in a distal portion of the shaft lumen. A guide wire lumen is in the inner shaft. An opening at a proximal end portion of the inner shaft permits the guide wire to be guided out from the outer shaft. A metallic tube is in the shaft lumen. The proximal end portion of the inner shaft is engaged with the metallic tube. A separate, elongate and metallic stiffening element is in the shaft lumen, and is connected to the metallic tube and protrudes from the metallic tube into the distal portion of the shaft lumen and into the proximal portion of the shaft lumen to stiffen portions of the outer shaft.

