[Myocardial laser revascularization in therapy-refractory angina pectoris].

In patients with coronary artery disease and intractable angina, who are not candidates for either coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA), transmyocardial laser revascularization (TMR) has been developed as a new treatment. Several recently published, randomized trials have consistently shown improvement of clinical symptoms and increased exercise capacity after TMR compared to medical therapy. However, surgical thoracotomy is required for TMR with considerable morbidity and mortality. Therefore, catheter-based systems have been developed, which allow creation of laser channels in the myocardium from within the left ventricular cavity. These systems for "percutaneous myocardial revascularization" (PMR) use laser energy generated by Holmium: YAG lasers, which can be transmitted to the myocardium via flexible optical fibers. PMR leads to significant improvement of clinical symptoms and increased exercise capacity similar to TMR. The CCS classification is improved about 1.5 classes, independent of the PMR system used. However, evidence of improved perfusion after PMR is still lacking. The pathophysiologic mechanisms of myocardial laser revascularization are still poorly understood. Experimental studies indicate myocardial neoangiogenesis and myocardial denervation after TMR; however, clinical studies have not yet found evidence of improved myocardial perfusion after myocardial laser revascularization.