ABSTRACT
There are an increased number of patients with advanced coronary artery disease (CAD) who are not amenable to conventional catheter-based or surgical revascularization strategies. This emerging cohort of refractory or ‘no option’ patients has stimulated an increased investigational effort for alternative myocardial revascularization modalities. Over the last decade various mechanical devices and energy sources designed to enhance myocardial tissue perfusion have been explored.1-4 The vast majority of experimental and clinical experiences are derived from studies utilizing lasers as the energy source. It has been suggested that the likely mechanism of direct myocardial revascularization (DMR) using laser energy is the induction of transient localized inflammatory processes, which stimulate and amplify endogenous expression of a variety of angiogenic cytokines acting in concert and in a time-dependent manner to initiate and maintain microvessel formation (i.e. angiogenesis).5,6 The generic term DMR is meant to apply to all technologies attempting to ‘directly’ (not via the epicardial coronaries) improve myocardial perfusion, either surgical or catheter-based, using lasers or other energy sources. Clinical experience with surgical ‘transmyocardial’ laser revascularization (TMR) has grown, with several thousands of patients having been treated with different laser systems. Most of these studies suggest that TMR used as sole therapy may result in the significant, long-term reduction of symptoms despite absence of clear evidence of improvement in tissue perfusion.
