Angioplasty apparatus facilitating rapid exchanges

A catheter assembly for performing intraluminal ultrasound procedures within a patient's coronary artery, comprising:

• a) a guiding catheter having proximal and distal ends which is adapted to be disposed within a patient's cardiovascular system with the distal end seated within an ostium of the patient's coronary artery and the proximal end extending out of the patient;
• b) a guidewire with proximal and distal ends which is adapted to be disposed within the guiding catheter with the distal end of the guidewire extending out the distal end of the guiding catheter into the coronary artery of the patient and the proximal end of the guidewire extending out the proximal end of the guiding catheter which extends out of the patient;
• and
• c) an elongated ultrasound imaging catheter having an elongated catheter body with a proximal end adapted to extend out of the patient, a distal end, a first elongated inner lumen within the catheter body extending from the proximal end to the distal end, and a second much shorter inner lumen which is fixed with respect to said catheter body and which is defined at least in part by a tubular member extending substantially within the catheter body which is adapted to slideably receive the guidewire, the second inner lumen having a distal port located in the distal end of the catheter body and a proximal port extending through the catheter body, the proximal port of the imaging catheter being located at least 10 centimeters from the distal end of the catheter body.