TEMPORAL EVOLUTION OF THE HUMAN CORONARY COLLATERAL CIRCULATION AFTER MYOCARDIAL-INFARCTION

An analysis of the coronary collateral circulation in a consecutive series of 116 postinfarction angiograms from patients with persistent 100% occlusion of their infarct artery is reported. Patients were classified into 4 groups according to the interval between acute infarction and angiography. Of 42 patients studied within 6 h of infarction (Group I), 52% had no evidence of any coronary collateral development as compared with only 8% (1 of 16 patients) studied 1 day to 2 wk after infarction (Group II). Virtually all patients studied beyond 2 wk after myocardial infarction (14 to 45 days, Group III) and later than 45 days (Group IV) had visible collateral flow. Angiographically well developed collateral channels were seen in only 16% of Group I patients compared with 62, 75 and 84% of patients in Groups II to IV, respectively. Of 6 patients studied twice, on the day of the infarction and 2 wk later, only 1 patient had collateral vessels on the day of infarction, whereas all 6 patients did at follow-up study. Group I patients were studied as part of a randomized acute myocardial infarction reperfusion trial, whereas the other patients were referred for angiography primarily because of postinfarction ischemia. Within the limitations imposed by the patient selection process, well developed coronary collateral vessels are rarely present at the time of infarction. After infarction, they develop rapidly and are generally demonstrable within 2 wk. The preservation of ischemic myocardium by well developed coronary collateral vessels at the time of myocardial infarction may be an uncommon occurrence.