Revascularization of the heart through the coronary veins

Fifty-six dogs were used in a study to evaluate perfusion of the left anterior descending vein by the internal mammary artery in hearts with normal coronary arteries and those with ligated desending coronary arteries. Perfusion of the myocardium with arterial blood through the cardiac veins offers minimal immediate protection from infarction, as evidenced by light and electron microscopy studies. This protection is of short duration due to intimal fibrosis and luminal stenosis or obstruction of the perfused veins. Nineteen animals in which the coronary vein was perfused and the corresponding coronary artery was not ligated died within sixty hours from the time of operation. Pathological examination revealed patent grafts in all the animals. There was marked congestion of the myocardium with petechial hemorrhages over the surface of the heart. No evidence of myocardial infarction was found.