A perfusion balloon catheter (10), as for angioplasty by dilatation, has the balloon (30) formed so that, when inflated within a vas or coronary artery, one or more channels (40) are provided for the flow of bodily fluids or blood past the inflated balloon. In one embodiment, the balloon has a toroidal...http://www.google.co.uk/patents/US5470314?utm_source=gb-gplus-sharePatent US5470314 - Perfusion balloon catheter with differential compliance
