TRANSMYOCARDIAL LASER REVASCULARIZATION - ANATOMIC EVIDENCE OF LONG-TERM CHANNEL PATENCY

Transmyocardial laser revascularization, a new surgical technique, is being tested in patients with chronic obstructive coronary artery dise ase that is refractory to conventional revascularization techniques an d to maximal medical therapy. During the operation, which is performed on the beating heart through a left thoracotomy, a high-energy CO2 la ser is used to bore transmural channels (1 mm in diameter) into the le ft ventricle. Each high-energy laser pulse is delivered during end dia stole and transects the heart within 10 to 60 msec. The operation is b ased on the theory that blood will flow directly from the left ventric le into the channels and then into the myocardial vascular plexus. Res toring perfusion should alleviate ischemia in potentially viable myoca rdium and improve ventricular function. Recently, one of our patients died 3 months after transmyocardial laser revascularization of causes unrelated to the operation. Histologic analysis enabled us to obtain, for the lst time, anatomic evidence of patent laser channels. Routine staining of cardiac tissue with hematoxylin and eosin revealed multipl e patent channels, running perpendicular to and interconnecting with t he native vasculature. Although reactive fibrous scar tissue had cause d narrowing of the original laser tract, the channels had endotheliali zed and they contained red blood cells. These findings suggest that th e laser channels were functional. We report this interesting case and briefly discuss the anatomic and physiologic phenomena involved in est ablishing camerosinusoidal blood flow by use of transmyocardial laser revascularization.