An improved technique for positioning a balloon dilatation catheter. When the balloon catheter approaches an obstruction that is difficult to enter, a drive catheter having a rotatable head is inserted into a central passageway in the catheter. The drive catheter bores through the obstruction allowing...http://www.google.co.uk/patents/US4798586?utm_source=gb-gplus-sharePatent US4798586 - Method and apparatus for aiding dilatation catheterization
