Balloon catheter with distal guide wire lumen

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BACKGROUND OF THE INVENTION

The present invention relates to the field of angioplasty. In particular, the present invention relates to a dilatation balloon catheter of the "over-the-wire" type having a relatively short distal guide wire lumen extending through the balloon of the catheter.

Angioplasty procedures have gained wide acceptance in recent years as efficient and effective methods for treating types of vascular disease. In particular, angioplasty is widely used for opening stenoses in the coronary arteries, although it is also used for the treatment of stenoses and other parts of the vascular system.

The most widely used form of angioplasty makes use of a dilatation catheter which has an inflatable balloon at its distal end. Typically, a hollow guide catheter is used in guiding the dilatation catheter through the vascular system to a position near the stenoses (e.g., to the coronary artery ostia). Using fluoroscopy, the physician guides the dilatation catheter the remaining distance through the vascular system until a balloon is positioned to cross the stenoses. The balloon is then inflated by supplying fluid under pressure through an inflation lumen in the catheter to the balloon. The inflation of the balloon causes stretching of the artery and pressing of the lesion into the artery wall, to reestablish acceptable blood flow through the artery.

There has been a continuing effort to reduce the profile and shaft size of the dilatation catheter so that the catheter not only can reach but also can cross a very tight stenosis. A successful dilatation catheter must also be sufficiently flexible to pass through tight curvatures, especially in the coronary arteries. A further requirement of a successful dilatation catheter is its "pushability". This involves the transmission of longitudinal forces along the catheter from its proximal end to its distal end so that a physician can push the catheter through the vascular system and the stenoses.

Two commonly used types of dilatation catheters are referred to as "over-the-wire" catheters and "non-over-the-wire" catheters. An over-the-wire catheter is one in which a separate guide wire lumen is provided in the catheter so that a guide wire can be used to establish the path through the stenoses. The dilatation catheter can then be advanced over the guide wire until the balloon on the catheter is positioned within the stenoses. One problem with the over-the-wire catheter is the requirement of a larger profile and a generally larger outer diameter along the entire length of the catheter in order to allow for a separate guide wire lumen therethrough.

A non-over-wire catheter acts as its own guide wire,