Transmyocardial laser revascularization with the Holmium : YAG laser does not improve myocardial perfusion in the acutely ischemic heart: an experimental study measuring myocardial perfusion by a thermal imaging camera

Background: Transmyocardial laser revascularization (TMLR) is a new surgica l therapy for patients with end-stage coronary artery disease refractory to conventional therapy. TMLR should act by improvement of perfusion of the l asered myocardium. Blood should be delivered from the cavity of the heart t o the surface of the myocardium. The aim of this study was to measure perfu sion of normal, ischemic, and ischemic myocardium after TMLR. Method: We us ed a new method of perfusion measurement by an infrared thermal imaging sys tem in an open-chested adult sheep model with temporary and permanent occlu sion of the dominant diagonal branch. Results: A significant fall from norm al perfusion of the myocardium to reduced after inducing ischemia (p<0.01) and a significant rise again after reperfusion (p<0.001) could be shown. Pe rfusion measurements after TMLR did not significantly differ from perfusion measurements after inducing ischemia (p=0.2). Conclusion: In the presented sheep model, laser revascularization could not improve myocardial perfusio n after acute ischemia as seen by the infrared thermal imaging system.