Rapidly exchangeable coronary catheter

Claim 1

A balloon dilatation catheter for percutaneous transluminal coronary angioplasty, the catheter having proximal, intermediate and distal segments (28,30,32) the intermediate segments (30) being plastic and elongate and attached to the distal end of the proximal segment (28) and having two lumens formed therethrough including an inflation lumen (40) terminating in an outlet port (42) and a guidewire lumen (44) extending parallel to the first lumen and being adapted to receive a guidewire, the guidewire lumen (44) having a proximal opening (46) in the region of the juncture of the intermediate and proximal segments (28,30); the distal segment (32) being attached to the distal end of the intermediate segment (30) and defining an elongate lumen (48) in communication with and a continuation of the distal end of the guidewire lumen (44) of the intermediate segment, and terminating, at its distal tip, in a distal outlet (33); a dilatation balloon (34) having proximal and distal ends, the distal end of the balloon being mounted on the distal segment and the proximal end of the balloon being mounted on the intermediate segment, the interior of the balloon being in communication with the outlet port of the inflation lumen, the proximal segment (28) being elongate and substantially stiffer than the intermediate segment (30); characterised in that the proximal segment (28) has a single inflation lumen (36) extending therethrough and is substantially smaller in diameter than the intermediate segment, the proximal segment (28) having sufficient column strength to resist buckling when advanced through a patient's arteries whereby when a guidewire is received in the guidewire lumen (44) the catheter will have continuous column support fully along its length from the proximal end of the tubular shaft to the distal outlet of the distal segment.