Balloon catheter devoid of guidewire or guidewire lumen and having a proximal shaft with only a single continuous lumen. A coil assembly is mounted at its proximal end to the distal end of the proximal shaft defining an interface therebetween. Disposed about a distal section of the proximal shaft and a proximal section of the coil assembly is a sleeve. A balloon, having a vent hole, forms a proximal leg seal about an outer surface of a distal end of the sleeve and an opposite distal leg seal. The sleeve covers the interface and extends axially in a distal direction terminating underneath the proximal leg seal of the balloon. A distal section of the coil assembly at least partially coincides with the distal leg seal of the balloon. A wire member secured at a plurality of connection points along the coil assembly extends axially within the balloon.
