Frequency and Healing of Nonculprit Coronary Artery Plaque Disruptions in Patients With Acute Myocardial Infarction

The pathophysiology of plaque disruption and healing in nonculprit segments has not been clarified. Therefore, we investigated the frequency of plaque disruptions in nonculprit segments and whether those plaques are stabilized during follow-ups in patients with acute myocardial infarction (AMI) by serial angioscopic observations. Analyzed were 13 consecutive patients with AMI in whom infarct-related arteries were serially observed by angioscopy immediately after reperfusion and at 1- and 6-month follow-ups. Color of plaques was graded as 0 (white), 1 (slight yellow), 2 (yellow), or 3 (intensive yellow). Plaques with thrombus were defined as disrupted. Although number of nonculprit yellow plaques did not change from immediately after reperfusion to 6 months, the maximum color grade of those plaques and incidence of disrupted plaques in nonculprit segments (immediate vs 1 month vs 6 months 31% vs 8% vs 0%) decreased significantly by 6 months. Plaque stabilization as shown by disappearance of thrombus was significantly associated with plaque regression as shown by a decrease of maximum yellow color grade in nonculprit segments. In conclusion, patients with AMI frequently had disrupted and actively thrombogenic yellow plaques in nonculprit segments of the culprit vessel, and those plaques healed with decreases of yellow color grade and thrombogenicity during 6-months follow-up. Plaque disruption and healing occur not only at the culprit lesion but may be a pan-coronary process in patients with AMI.