Plaque erosion is a major substrate for coronary thrombosis in acute myocardial infarction

OBJECTIVE To evaluate the prevalence of plaque erosion as a substrate for coronary thrombosis. DESIGN Pathological study in patients with acute myocardial infarction not treated with thrombolysis or coronary interventional procedures. PATIENTS 298 consecutive patients (189 men, mean (SD) age 66 (11) years; 109 women, 74 (8) years) dying in hospital between 1984 and 1996 from acute myocardial infarction, diagnosed by ECG changes and rise in cardiac enzymes. MAIN OUTCOME MEASURES Histopathological determination of plaque erosion as substrate for acute thrombosis; location and histological type of coronary thrombosis; acute and healed myocardial infarcts; ventricular rupture. RESULTS Acute coronary thrombi were found in 291 hearts (98%); in 74 cases (25%; 40/107 women (37.4%) and 34/184 men (18.5%); p = 0.0004), the plaque substrate for thrombosis was erosion. Healed infarcts were found in 37.5% of men v 22% of women (p = 0.01). Heart rupture was more common in women than in men (22%v 10.5%, p = 0.01). The distribution of infarcts, thrombus location, heart rupture, and healed infarcts was similar in cases of plaque rupture and plaque erosion. CONCLUSIONS Plaque erosion is an important substrate for coronary thrombosis in patients dying of acute myocardial infarction. Its prevalence is significantly higher in women than in men.