Bypass Without the Surgeon: The Coronary Veins as Arterial Conduits.

More than a century ago, Pratt demonstrated that perfusion of arterial blood through the coronary veins could sustain myocardial viability during acute ischemia. Recognition that atherosclerosis spared the coronary veins and that these vessels frequently followed a parallel course to the corresponding artery provided the necessary stimulus for the development and evaluation of several methods of venous retroperfusion. Although most of these procedures have now been superseded, the coronary veins remain a tempting therapeutic target when direct arterial revascularization is not feasible. Novel percutaneous strategies using these vessels to provide definitive myocardial revascularization have been proposed and extensively tested in animals.