CATHETER HAVING IMPROVED SHAPE RETENTION

摘要

A catheter for use in a body vessel includes a relatively stiff proximal shaft that is shaped as a tube formed with a lumen and having a proximal end and a distal end. Further, the catheter includes a relatively flexible dista l tube formed with a lumen and having a proximal end and a distal end. An inflatable balloon may be attached to the outer wall of the distal tube near the distal end. The proximal end of the distal tube is attached to the distal en d of the proximal shaft at a transitional joint. The transitional joint provides a gradual transition in flexibility over the length of the joint between the stiff proximal shaft and the flexible distal tube. Importantly, the transitional joint includes an extension made of a material having superelastic properties when positioned inside the body vessel. One end of the extension is attached to t he distal end of the proximal shaft. The other end of the extension projects in to the lumen of the distal tube. The extension may be formed as a ribbon, core wire or may constitute a tapered section of the proximal shaft.