Transmyocardial laser revascularization: historical background and future directions.

Transmyocardial laser revascularization (TMLR) was investigated as a possible treatment alternative for patients with refractory coronary artery disease. This paper is a summary of nearly four decades of research by the authors. Beginning in 1969 experimental studies were conducted on the beating heart. A prototype 450 W carbon dioxide laser was used to create channels in the ischemic myocardium. Initial clinical studies began in 1984. A protocol was developed for TMLR as an adjunct to CABG in those patient who had at least one vessel which could be bypassed and areas of ischemia which were not amenable to bypass. In the early 1990's the development of a 850 W CO2 laser for clinical use allowed us to begin investigation of TMLR on the beating heart. Patients with end stage coronary artery disease who were not candidates for other forms of treatment were selected. The early results are encouraging with patient followup of from 3 months to 5 years. There are numerous controversies regarding the effects of TMLR on myocardial function and perfusion. To quantify these effects the authors have performed acute and chronic studies on swine using sophisticated techniques with 3D cine magnetic resonance imaging. We concluded TMLR improved left ventricular function and perfusion in acute and chronic ischemia.