Percutaneous myocardial laser revascularization (PMR)

In patients with severe angina pectoris due to coronary artery disease, who are not candidates for either percutaneous coronary angioplasty or coronar y artery bypass surgery, transmyocardial laser revascularization (TMR) ofte n leads to improvement of clinical symptoms and increased exercise capacity . One drawback of TMR is the need for surgical thoracotomy in order to gain access to the epicardial surface of the heart. Therefore, a catheter-based system has been developed, which allows creation of laser channels into th e myocardium from the left ventricular cavity. Between January 1997 and November 1999, this "percutaneous myocardial laser revascularization" (PMR) has been performed in 101 patients at the Herzzen trum Leipzig. In 63 patients, only 1 region of the heart (anterior, lateral , inferior or septal) was treated with PMR, in 38 patients 2 or 3 regions w ere treated in 1 session. There were 12.3 +/- 4,5 (range 4 to 22) channels/ region created into the myocardium. After 3 months, the majority of patients reported significant improvement o f clinical symptoms (CCS class at baseline: 3.3 +/- 0.4, after 6 months: 1. 6 +/- 0.8) (p < 0.001) and an increased exercise capacity (baseline: 397 +/ - 125 s, after 6 months: 540 +/- 190 s) (p < 0.05). After 2 years, the majo rity of patients had experienced sustained clinical benefit after PMR, the CCS class after 2 years was 1,3 +/- 0,7, exercise capacity was 500 +/- 193 s. However, thallium scintigraphy failed to show increased per fusion in th e PMR treated regions. The pathophysiologic mechanisms of myocardial laser revascularization is no t yet understood. Most of the laser channels are found occluded after vario us time intervals after intervention. Other possible mechanisms include myo cardial denervation or angioneogenesis after laser revascularization, howev er, unequivocal evidence for these theories is not yet available. In conclusion, PMR seems to be a safe and feasible new therapeutic option f or patients with refractory angina pectoris due to end-stage coronary arter y disease. The first results indicate improvement of clinical symptoms and increased exercise capacity, whereas evidence of increased perfusion after laser revascularization in the laser-treated regions is still lacking.