Transient appearance of collaterals during vasospastic occlusion in patients without obstructive coronary atherosclerosis.

Coronary angiography of both right and left coronary arteries, using the Sones technique, was performed during the attack of total spastic obstruction in 11 patients with clinically documented history of variant angina. None of the patients had more than 70% stenosis of organic atherosclerosis in any coronary artery and none had a history of myocardial infarction. Total spastic obstruction occurred spontaneously in 3 of 11 patients, and was provoked by ergonovine maleate in eight patients. Six patients had total spastic obstruction in the left anterior descending coronary artery, four patients had total obstruction in the right coronary artery, and one patient had total obstruction in the left anterior descending and right coronary arteries. In 7 of 11 patients, the coronary artery distal to the total spastic obstruction received collaterals from the nonspastic artery. The collaterals disappeared promptly when the spastic coronary artery was patent. These patients had ST segment elevation in the ECG during the attacks. In the remaining four patients, the spastic artery did not receive any collaterals from the nonspastic artery, associated with ST segment elevation during the attacks. These findings suggest that the brief, repetitive total occlusion of the coronary artery may stimulate the enlargement of collaterals. These collaterals may not always function to prevent the ischemia of the myocardium on the ECG.