A balloon dilatation catheter construction having an elongated shaft with a guide wire lumen and an inflation lumen therethrough, and a balloon member mounted on its distal end in combination with the inflation lumen where unwanted gases are vented from the balloon interior by first directing the gases...http://www.google.ca/patents/US5176698?utm_source=gb-gplus-sharePatent US5176698 - Vented dilatation cathether and method for venting
