Association between coronary occlusions and myocardial infarcts

The number of angiographically documented coronary occlusions and the incidence of Q-wave myocardial infarcts were retrospectively compared in 348 patients with moderate coronary artery disease from the INTACT study (International Nifedipine Trial on Antiatherosclerotic Therapy). In only 68 out of 118 infarcts (58%) an occlusion of the respective coronary artery was found, suggesting a spontaneous recanalization rate of 42%. On the other hand, only 68 out of 150 coronary occlusions (45%) had resulted in a Q-wave infarct. Considering the high spontaneous recanalization rate of the occlusions, it seemed possible that roughly only every fourth coronary occlusion might result in a myocardial infarct. This hypothesis was confirmed in the prospective 3 years follow-up of the identical patients during which 41 new occlusions developed causing only 10 myocardial infarcts (24%). These findings might contribute to explain the relatively low incidence of clinically apparent coronary heart disease in the general population despite a high prevalence of coronary artery disease.