[Mechanism of acute coronary syndrome studied with coronary arteriograms].

Numbers of studies using the coronary arteriograms (CAG) have been reported on the mechanism of the acute coronary syndrome (ACS) since 1980. DeWood et al. have shown that the rate of total occlusion in the culprit lesions gradually decreases as the interval from attack to CAG increases, suggesting that the occlusion is total or subtotal at the onset of acute myocardial infarction (AMI). Additionally, the stenosis is significantly mild in unstable angina compared with non-Q AMI. Ambrose et al. classified the morphology of the culprit lesions on CAG and revealed that their type II eccentric lesion or multiple irregularities, which are considered to be related to plaque rupture with or without thrombus, are more common in ACS than the other morphologies. The concept of ACS by Fuster et al. is substantially based on these angiographical findings. Little et al. reported that the pre-existing stenosis 1-2 years before the onset of AMI is mostly mild to moderate, indicating that the prediction of future AMI by CAG findings is of difficulty. Our study suggested the stenosis deteriorates abruptly and reached severe level in some cases just before the attack of ACS. Therefore, the continuous effort is needed to clarify the mechanism of the progression of coronary lesions which result in ACS.