Microthrombi as a Major Cause of Cardiac Injury in COVID-19

Background: Cardiac injury is common in patients who are hospitalized with coronavirus disease 2019 (COVID-19) and portends poorer prognosis. However, the mechanism type of myocardial damage associated severe acute respiratory syndrome 2 (SARS-CoV-2) remain uncertain. Methods: We conducted a systematic pathological analysis 40 hearts from dying COVID-19 Bergamo, Italy, to determine mechanisms cardiac injury. divided according presence or absence myocyte necrosis then determined underlying Results: Of examined, 14 (35%) had evidence necrosis, predominantly left ventricle. Compared subjects without tended be female, have chronic kidney disease, shorter symptom onset admission. The incidence coronary artery (ie, >75% cross-sectional narrowing) was not significantly different between those necrosis. Three (21.4%) showed infarction, defined as ≥1 cm area whereas 11 (78.6%) focal (>20 necrotic myocytes an ≥0.05 mm but <1 ) thrombi were present cases (14.2%) having epicardial thrombi, 9 (64.3%) microthrombi capillaries, arterioles, small muscular arteries. compared COVID-19–positive autopsy intramyocardial thromboemboli well aspirated obtained during primary percutaneous intervention uninfected COVID-19–infected presenting ST-segment–elevation infarction. Microthrombi greater fibrin terminal complement C5b-9 immunostaining COVID-19–negative thrombi. There no significant differences constituents –negative Conclusions: most cause microthrombi. composition retrieved Tailored antithrombotic strategies may useful counteract effects infection.