TRANSMYOCARDIAL LASER REVASCULARIZATION I N END-STAGE CAD WITH UNSTABLE AND STABLE PATIENTS

Endstage coronary artery disease still remains a therapeutic challenge . An increasing number of patients is no longer amenable for direct re vascularization by PTCA or coronary bypass surgery and does also no lo nger respond to maximum medical therapy. This fact has directed the in terest again towards surgical techniques of indirect revascularization , had been introduced by Beck and other surgeons more than 60 years ag o. Among these attempts we can also find transmyocardial needle punctu res, firstly performed by Sen in Bombay. In the early eighties it was Mirhoseini, who used a laser for creating these transmural channels, p rimarily in combination with coronary bypass surgery at the arrested h eart and later on together with Crew as a sole therapy at the beating heart. The idea behind this transmyocardial laser revascularization (T MLR) was a ''reptilization'' of the human heart, which meant a direct blood supply from the ventricle into the ischemic myocardium. Whereas this theory has not proven to be true, as the surface area of these ch annels is not sufficient for the nutrition of the surrounding myocardi al tissue by diffusion or convection, different models have been devel oped by anatomical, experimental and clinical studies, such as the con nection between the laser channels and intramyocardial vessels or capi llaries, analogous to ventriculo-coronary connections in human anatomy or pathology as for example those connections described in children w ith pulmonary atresia and intact ventricular septum or the Thebesian v eins. Moreover the laser trauma may also simply contribute to the indu ction of neoangiogenesis.While the function of TMLR is still not clear ly defined, clinical studies in the United States and also in other co untries have proven the clinical efficacy in a cohort of severely dise ased patients undergoing this procedure. Accordingly more than 2/3 of all patients after TMLR showed a significant improvement of more than 2 angina classes (CCS) as well as a decrease in medication and hospita lization. Moreover there was also a reduction of ischemic areas demons trated by szintigraphy and, in one study from Houston, also by positro n emission tomography. While the overall mortality in all those studie s is still considerably high, a reduction could be achieved by a stric ter selection of patients excluding especially those with a severely i mpaired left ventricular function. As demonstrated by preliminary data from the last phase III FDA-study, TMLR may even reduce long-term mor tality compared to maximum medical therapy in a randomized group of pa tients. Our own experiences in 134 patients also confirmed a significa nt reduction of angina after TMLR alone (n = 67) or in combination wit h bypass surgery (n = 67) with the majority of patients being in angin a class 1 and 2 (CCS) 6 months after surgery. All of these patients we re in angina class 3 and 4 before surgery. Nuclear scans could demonst rate an improved perfusion in more than 40%. Further studies as well a s other clinical and also experimental investigations have still to be awaited, before the definitive role of TMLR within the armamentarium against coronary artery disease can be determined. However, it is alre ady a therapeutic option for those highly symptomatic patients, who ca nnot be offered a different treatment modality.