Percutaneous transmyocardial laser revascularization: overview of US clinical trials

Data from four surgical trials of laser transmyocardial revascularization (TMR) show pain reductions of at least two classes occurred among 25-76% of patients, significantly greater than with optimal medical therapy. The safety and feasibility of percutaneous TMR (PTMR) was proved in multiple uncontrolled registry studies. With PTMR in two randomized trials enrolling about 550 patients, improvements were found among 45% and 66% of patients as compared with 13% for best medical therapy. Other encouraging observations included significant improvements in exercise time (85 and 100 seconds) as compared with minimal or negative results for medical therapy, consistent overall exercise time improvements for PTMR, and overall patient perceptions of anginal stability and global health. Peri-procedural mortality is low and ranged from 0% to 0.6%. Some skepticism remains about the procedures, arising from failure in most cases to show improvements with SPECT imaging and lack of conclusive insights into the mechanism of action. A randomized 'blinded' study is underway to establish a definitive therapeutic value for catheter-based TMR. Nonetheless, preliminary clinical data seem promising for catheter-based TMR for obtaining symptomatic improvement in patients with chronic refractory ischemic coronary syndromes.