Survival with total occlusion of the left main coronary artery. Significance of the collateral circulation.

Four patients with total occlusion of the left main coronary artery are described. Angina pectoris was severe (NYHA class 3--4) and had lasted 20 months to seven years. Three patients had experienced a myocardial infarction. All displayed large collaterals arising from a nearly normal right coronary artery and feeding both the left anterior descending and the left circumflex arteries. The left ventricular ejection fractions ranged from 20% to 65%, and all patients had varying degrees of left ventricular asynergy. Coronary artery bypass surgery resulted in a marked improvement in three patients; one patient who underwent an aneurysmectomy died two months after the operation. The data show that total occlusion of the left main coronary artery is compatible with survival if adequate collateral supply develops from the right coronary artery. In this rare angiographic subset collateral circulation is clearly functionally significant.