Transmyocardial laser revascularization. Anatomic evidence of long-term channel patency

Abstract

Transmyocardial laser revascularization, a new surgical technique, is being tested in patients with chronic obstructive coronary artery disease that is refractory to conventional revascularization techniques and to maximal medical therapy. During the operation, which is performed on the beating heart through a left thoracotomy, a high-energy CO2 laser is used to bore transmural channels (1 mm in diameter) into the left ventricle. Each high-energy laser pulse is delivered during end diastole and transects the heart within 10 to 60 msec. The operation is based on the theory that blood will flow directly from the left ventricle into the channels and then into the myocardial vascular plexus. Restoring perfusion should alleviate ischemia in potentially viable myocardium 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 1st time, anatomic evidence of patent laser channels. Routine staining of cardiac tissue with hematoxylin and eosin revealed multiple patent channels, running perpendicular to and interconnecting with the native vasculature. Although reactive fibrous scar tissue had caused narrowing of the original laser tract, the channels had endothelialized and they contained red blood cells. These findings suggest that the laser channels were functional. We report this interesting case and briefly discuss the anatomic and physiologic phenomena involved in establishing camerosinusoidal blood flow by use of transmyocardial laser revascularization.