Importance

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Abstract

This invention provides a cylindrical plastic catheter of the type having a distal end portion movable over a guide wire to a treatment site such as a stenosis in the cardiovascular system, wherein the catheter shape gradually changes from a tubular configuration with a cylindrical skin defining an interior inflating lumen. The skin configuration and internal lumen changes shape gradually along the catheter length for insertion of the wire into a resident guide lumen resident only in the distal end portion without bends or kinks in the wire and retaining a generally parallel disposition to the catheter axis from which it departs to penetrate the catheter. Thus a guiding groove in the skin gradually transforms into a crescent partly surrounding the guide wire before changing into a toroidal body defining a guide wire lumen. The diameter of the catheter is thus kept constant and small with consistent axial stiffness throughout its length for supporting withdrawal and intrusion from external axial forces. The balloon mounts on the catheter body cylinder for a better, more secure seal and the axial forces along the catheter are balanced about the axis so that there is no tendency to buckle or veer with entry or withdrawal forces. By supplying a groove along the length of the catheter body to receive nested therein a parallel guide wire, the outer circumferencial dimension of the combination guide wire-catheter body may be reduced for entry into vessels of restricted size.

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First Claim