Abstract

Transmyocardial laser revascularization is a new technique for treating patients with angina pectoris where standard methods such as PTCP or CABG are contraindicated. Although clinical reports are promising the mechanism of action of this laser procedure is largely undefined and controversially discussed. The present study was conducted to comprehensively evaluate and compare the short and long-term tissue effects and the basic interaction mechanisms of CO₂, Ho:YAG and Er:YAG laser radiation with myocardium. Minimal acute thermal damage by Er:YAG laser resulted in small scars without neovascularization. Initial tissue tearing caused by pulsed Ho:YAG irradiation is stronger than after continuous wave CO₂ irradiation. It leads to scars extending along separated fiber planes. After 6 weeks the scar is, however, indistinguishable from CO₂ laser. Both are characterized by newly formed vessels and a large number of capillaries in the scar region. No patent channels were found.

© 1998 Optical Society of America