Reperfusion in acute ischemic myocardium by transmyocardial revascularization using CO2 laser

Transmyocardial laser revascularization (TMLR) is currently applied to provide clinical benefits in the patients with end-stage coronary artery disease. However, this method is so far indicated only for chronic status of ischemic heart disease. In this study, we have investigated in the canine model whether acute ischemic myocardium could be reperfused by TMLR using CO2 laser. A CO2 laser was used to create transmural myocardial channels. The ischemic areas of 3 cm in diameter were created on the left ventricle with multiple coronary ligations. Laser procedure was carried out 30 minutes after coronary ligation in TMLR group (n = 6), while laser treatment was not performed after coronary ligation in acute myocardial infarction (AMI) group (n = 6). The level of MB isozyme of creatinine kinase (CK-MB) derived from coronary sinus was measured at 0, 3, 6, 12, 18, 24, and 48 hours after coronary ligations, and the pattern of serial CK-MB changing was analyzed. Animals were sacrificed 48 hours after treatment and histologically investigated. The time to peak level of CK-MB in TMLR group appeared significantly earlier (13.0 +/- 2.4 hours) than that in AMI group (22.0 +/- 3.1 hours). The value of CK-MB of 24 hours after ligation in TMLR group (1985 +/- 805 IU/L) was significantly lower than that in AMI group (4759 +/- 778 IU/L). The channels on the gross section after 48 hours of TMLR were patent with some of fibrin network. Red blood cells were scattered in the lumens. It was suggested that acute ischemic myocardium was directly reperfused through the open laser channels from the left ventricular chamber in the canine model.