Incidence of asymptomatic coronary thrombosis and plaque disruption: comparison of non-cardiac and cardiac deaths among autopsy cases

Abstract

Background: Autopsy studies have revealed a high incidence of thrombus formation in patients who died of acute myocardial infarction (AMI) or sudden coronary death. However, the incidence of thrombus formation and plaque disruption in patients with non-cardiac death (NCD) remains unclear.

Methods: To evaluate the incidence and morphological characteristics of thrombi and plaque disruption in patients with NCD, we examined 102 hearts from NCD autopsy cases and 19 from those who had died of AMI.

Results: We found fresh coronary thrombi in 10 cases with NCD and in 14 with AMI (10% vs. 75%, p < 0.001). Seven and three thrombi were associated with plaque erosion and rupture, respectively among the NCD cases. The incidence of plaque rupture was significantly higher in AMI than in NCD (54% vs. 3%, p < 0.001). The size of coronary thrombi in NCD cases was small and the luminal areas were not significantly affected. Plaques beneath thrombi in NCD had a smaller lipid core and a thicker fibrous cap than those in AMI. Among risk factors for cardiovascular events, hypertension and diabetes mellitus were significantly associated with the incidence of thrombosis in patients with NCD.

Conclusion: Coronary thrombosis is a frequent complication in patients with NCD. These small thrombi might not be associated with the onset of clinical events, but with plaque progression in atherosclerosis.