We initially developed laser microsurgical techniques centered on ophthalmological applications (pulsed carbon dioxide lasers and pulsed ND:YAG slit lamp-based laser systems). Our primary focus for the last seven years, however, has been in cardiological applications--in particular, laser angioplasty and the development of pulsed, solid-state infrared lasers for microsurgery. We demonstrated the feasibility of transmission through flexible fiber optics of pulsed IR, visible and UV lasers, and tissue responses to these lasers. Specifically, we measured the dependence of acoustic transients and ablation efficiency on increasing pulse fluence with catheter systems used clinically. We concluded that acoustic transients play a dominant role in the clinical results of pulsed laser angioplasty. We developed new IR laser sources in conjunction with the Naval Research Lab and Quantronix Corporation that utilize strong water absorption and can be transmitted through low-loss, cladded optical fibers. Clinical trials of peripheral and coronary laser angioplasty were completed, using either pulsed-dye or pulsed infrared lasers with computer-controlled fluorescence guidance. Recent work has involved identification of the tissue and biological effects of pulsed lasers--in particular, the large role that acoustic transients and transient, moderate (~60~C) thermal elevations play in acute and chronic clinical responses. Since pulsed laser angioplasty primarily disrupts the atheroma at stenoses mechanically rather than ablating or removing it, we must balance optimization of clinical results against increased rates of dissection.
