Point of View Recent Insights Into Coronary Collateral Circulation

T he coronary collateral circulation is an alterna-tive source of blood supply to the myocardium jeopardized by failure of the original vessel to provide adequate flow to the major epicardial branches of the coronary artery. There has been considerable debate, however, concerning the functional role of collaterals in humans.1-9 Extensive studies carried out in the past several years in experimental animals, in au-topsy materials, or in intact human hearts have con-firmed the substantial potential of collaterals in limiting the extent of myocardial ischemia, preventing cell death, and altering the clinical outcome of ischemic heart disease, although these effects depend largely on the rate at which the collateral circulation develops and the magnitude of flow permitted by the newly recruite