Catheter having improved flexibility control

Abstract

Catheters having improved flexibility control, which can be provided by a slidable core wire disposed within the catheter and by shafts formed from segmented spine wires disposed within polymeric tubes. One catheter is an angioplasty catheter including an axially slidable core wire disposed within an inflation lumen, and having a pressure seal disposed about the core wire extending proximally from the catheter proximal end. The slidable core wire can provide a varying degree of stiffness to the catheter. The catheter can have greater stiffness when the core wire is axially distally extended and less stiffness when the core wire is retracted. One catheter has a shaft including a spine wire or stiffening element within an outer polymeric tube. The spine wire can include multiple segments having alternating wide and narrow segments, with the wide segments contacting the outer tube and contributing stiffness to the shaft and with the narrow segments contributing flexibility to the shaft. In one catheter, the wide segments have apertures therethrough allowing fluid flow through the polymeric tube. In one catheter, the wide segments have distally increasing inter-segment distance, providing distally increasing flexibility.