To test the potential clinical use of a heated laser angioplasty catheter, we performed percutaneous laser angioplasties in a large animal model of human atherosclerosis developed in our laboratory. In this model an atherosclerotic human coronary artery (CA)segment is inserted via plastic connectors in the mid-portion of a bypass graft created between the aorta and distal LAD of large adult pigs. The bypass graft was cannulated with a standard angiographic catheter and the laser catheter was passed via a guidewire into the human increments via a metal-tipped 300µ silica optical fiber (Trimedyne-Laser Probe) heated by 9 watts of laser power. Ten laser angioplasties were performed in six separate pigs. The atherosclerotic CAs were 3-5 cm in length. Two Cas were totally occluded and one CA had a severe subtotal occlusion. The other Cas had varying degrees of significant atherosclerosis. The heated-tip laser catheter was successful in reestablishing luminal blood flow in the total and subtotal occluded Cas as well as improving luminal diameters in the other seven Cas. Only one perforation was observed related to a technical problem with the model. No electrocardiographic or hemodynamic changes occurred after lasing suggesting the lack of toxic effect son the myocardium from laser by-products. Thus, preliminary experience with the heated-tip laser catheter suggests that it has potential for treating CA stenoses without untoward effects. In relatively straight Cas, perforation does no appear to be a major problem. Further study is underway to determine its utility in tortuous and bifurcating coronary arteries.
Johnston, WD, Gregory KW, Nahais R, Sato D. Berkley R, Mallory J, Henry WL: Percutaneous coronary laser angioplasty in a large animal model of human coronary atherosclerosis. JACC, (Suppl A) 9:104A, 1987.