Transmyocardial laser revascularization: Experimental studies in healthy porcine myocardium

Background. Clinical studies have demonstrated a significant reduction of c ardiac index shortly after transmyocardial laser revascularization in patie nts with low ejection fraction. We analyzed the influence of transmyocardia l laser revascularization on healthy myocardium in pigs. Methods. Carbon dioxide channels were created in 20 pigs which were observe d for 6 hours. Ten pigs received one laser channel and ten pigs two laser c hannels per cm(2) in the left anterior descending artery region. Seven pigs served as controls. Perfusion (microspheres), function, histochemical, and histologic assessments were subsequently performed. Results. A significant deterioration of left ventricular stroke work index was observed shortly after transmyocardial laser revascularization in both laser groups (p < 0.05). After 6 hours the left ventricular stroke work ind ex did not increase and showed significantly reduced values at rest (p < 0. 05) and during stress in the laser groups (p < 0.01). Normal regional perfu sion, small ischemic and necrotic areas, open laser channels in the left an terior descending artery region and significantly increased myocardial wate r content were observed in the laser groups (p < 0.01). Conclusions. Carbon dioxide laser channels significantly decrease global he art function shortly after transmyocardial laser revascularization in healt hy porcine myocardium. This myocardial tissue showed no recovery 6 hours po stoperatively. (C) 1999 by The Society of Thoracic Surgeons.