[Electromechanically controlled versus roengenologically guided percutaneous transluminal laser myocardial...

Transmyocardial laser revascularization is a modern therapeutic concept for patients with end-stage coronary artery disease not eligible for bypass surgery, percutaneous coronary interventions or heart transplantation. Although the principal idea of creating additional myocardial perfusion from the cavum of the left ventricle was derived from observations in reptile hearts, histological investigations suggest that channel patency is not the underlying mechanism for improved clinical symptoms. Sympathetic denervation and angioneogenesis may be additional explanations for improvement of angina and stress tolerance. The first experiences with transmyocardial laser revascularization were made using a surgical approach. Two randomized multicenter trials could show a significant improvement in angina and stress tolerance 12 months after creating channels using laser technique. While these results were obtained by performing thoracotomy, catheter-based systems have been designed for a less invasive approach of this technique. A further advantage of these new systems is that regions like the septum can be treated which are not eligible for a surgical approach. Using percutaneous transluminal catheter-based systems channels of up to 6 mm length can be created. Beside the fluoroscopic guided creation of myocardial channels a new mapping system has been applied using electromechanical features of viable myocardial tissue. This system is based on the observation that endocardial electrograms recorded from an infarcted area are characterized by very low amplitude and fractionated morphology. This system allows online mapping of viable myocardium and provides spatial, electrical, and mechanical information of the myocardium. This method of electromechanical mapping highly correlates with results obtained from myocardial perfusion scans. Recent preliminary clinical trials demonstrated that catheter-based creation of myocardial channels is a feasible and successful alternative to the surgical laser revascularization. Also with this approach a significant improvement in angina and stress tolerance can be achieved. The results of the PACIFIC study, the first randomized multicenter study using percutaneous transluminal laser revascularization, demonstrates that after 3 and 6 months more than half of the patients presented improved angina of at least 1 Canadian-Cardiovascular-Society class. Whether electromechanical guided myocardial laser revascularization is more efficient than fluoroscopic guided has not been proven yet. Further studies will have to evaluate this issue.