Benefits of Percutaneous Coronary Revascuiarization in Patients with Adequately Collateralized Chronic Total Occlusions

摘要

The terms "hibernating" or "stunned" myocardium refer to the continued viability of individual cardiomyocytes, despite a chronic, angiographically totally occluded coronary artery supplying that distribution. Although the subtended myocardial segment appears akinetic or noncontractile, function may return upon restoration of blood supply by mechanical revascuiarization. The phenomenon is believed to occur due to collateral circulation, or tiny vascular channels, which reroute flow from another vessel. At times, the collateral flow can originate from the same artery just proximal to the occlusion (known as "bridge" collaterals). In these situations, I often tell my patient that the heart has, in effect, grown its own bypass.While collateral circulation is typically associated with chronic total occlusions (CTOs), the vascular channels can form during the acute setting. The presence of these vessels, however, is of less clear significance in an acute myocardial infarction (AMI). Analysis of the EMERALD (Enhanced Myocardial Efficacy and Recovery by Aspiration of Liberalized Debris) trial data demonstrated no clear benefit conferred by collaterals during an AMI. In contrast, Perez-Castellano et al reported improved in-hospital survival and lower incidence of cardiogenic shock associated with collateral vessels in patients with anterior AMIs. It should be noted, however, that EMERALD excluded shock patients.