Randy J. Kesten

Percutaneous method of laser transmyocardial revascularization

Laser transmyocardial revascularization (TMR) creates conduits from the left ventricular cavity into the myocardium and has been forwarded as a potential method of perfusing ischemic myocardium. The procedure typically employs a CO2 laser to produce transmyocardial channels from the epicardial to the endocardial surface via an open thoracotomy. Preliminary studies in animals and human subjects have yielded promising results, and clinical trials evaluating the long-term efficacy of the procedure are in progress. We now report the use of a percutaneous method of TMR using a laser delivered through a novel catheter system. To assess the feasibility of performing percutaneous TMR, studies were performed on 15 adult canine subjects utilizing a holmium:YAG laser. Via a femoral artery approach, novel laser catheters were introduced into the left ventricular cavity under fluoroscopic guidance. Biplane coronary angiography, ventriculography, and transesophageal echocardiography were employed to direct catheters to specific regions and assess the efficacy of creating transmyocardial channels. Multiple channels could be created in the anterior, lateral, inferoposterior, and septal regions as demonstrated by contrast ventriculography with confirmation by subsequent gross and histologic examination. The procedure was tolerated well without any ventricular dysfunction or sustained ventricular arrhythmias. We have demonstrated that laser transmyocardial revascularization via a percutaneous approach is feasible with creation of channels from the endocardial surface of the left ventricle into the myocardium. On gross and histological examination, these channels are similar in appearance to those created by the currently employed open chest, epicardial method of TMR.