Abstract: A method of making a dilatation balloon with a high percentage of the maximum tensile strength of the balloon material from a thin wall parison of a biaxially orientable polymer, such as polyethylene terephthalate (PET). A reverse temperature gradient (decreasing going from the inner to outer diameters) is applied across the sidewall of the parison by flowing a heated fluid through the parison and then sealing one end of the parison and expanding with a heated expansion fluid. Decreases in wall thickness and/or increases in burst strength across the wall can be achieved.

Abstract: A low profile, steerable balloon dilatation catheter for dilating obstructions in blood vessels is provided which also enables catheter exchanges to be performed without losing guidewire position. The system includes a guidewire and catheter that can be locked together to be operated in a manner as that of an integral wire catheter, or alternatively, they can be unlocked to allow the guidewire to be operated independently in a manner similar to that of an over-the wire catheter system. In the latter mode of operation, the length of the guidewire, at its proximal end, can be extended and the catheter can be withdrawn from the patient without causing a loss of guidewire position. With the guidewire position so maintained, a succeeding catheter can be advanced over the guidewire to the vascular location being treated.