Abstract: AIM: To study the plaque morphological characteristics of acute myocardial infarction by intravascular ultrasound(IVUS), comparing plaque morphology in acute myocardial infarction and stable angina pectoris. METHODS: 59 patients with acute myocardial infarction (male 43, mean age 60 ±9 years) and 50 patients with stable angina pectoris (male 38, mean age 62 ±10 years) underwent coronary artery angiography (CAG) and IVUS examinations.The plaque morphology, including incidence of eccentric plaque, subtle dissections, low echoic thrombus, calcification, echolucent areas, and bright speckled echo material, were assessed by IVUS. RESULTS: There were no significant differences in plaque eccentricity or plaque calcification between the two groups, except low echoic thrombus(acute myocardial infarction 15 % vs stable angina pectoris 0 %), subtle dissection (37 % vs 4 %), echolucent areas (31 % vs 0 %), and bright speckled echo material (90 % vs 0 %) (P < 0.001 for all). CONCLUSION: Low echoic thrombus, subtle dissection, echolucent areas, and bright speckled echo material are morphological characteristics associated with plaque at the time of acute myocardial infarction.It is confirmed that the rupture of plaque is related to the occurrence of acute myocardial infarction.

Key words: acute myocardial infarction, intravascular ultrasound, plaque morphology, plaque rupture