Intracardiac Thrombus in COVID-19 Inpatients: A Nationwide Study of Incidence, Predictors and Outcomes

Background: COronaVIrus Disease 2019 (COVID-19) has been observed to be associated with a hypercoagulable state. Intracardiac thrombosis is a serious complication but has seldom been evaluated in COVID-19 patients. We assessed the incidence, associated factors, and outcomes of COVID-19 patients with intracardiac thrombosis. Methods: COVID-19 inpatients during 2020 were retrospectively identified from the national inpatient sample (NIS) database, and data retrieved regarding clinical characteristics, intracardiac thrombosis, and adverse outcomes. Multivariable logistic regression was performed to identify the clinical factors associated with intracardiac thrombosis and in-hospital mortality and morbidities. Results: A total of 1,683,785 COVID-19 inpatients were identified in 2020 from NIS, with a mean age of 63.8 {+/-} 1.6 years, and 32.2% females. Intracardiac thrombosis was present in 0.001% (1,830) patients. Overall, in-hospital outcomes include all-cause mortality 13.2% (222,695/1,683,785), cardiovascular mortality 3.5%, cardiac arrest 2.6%, acute coronary syndrome (ACS) 4.4%, heart failure 16.1%, stroke 1.3% and acute kidney injury (AKI) 28.3%. The main factors associated with intracardiac thrombosis were a history of congestive heart failure and coagulopathy. Intracardiac thrombosis was independently associated with a higher risk of in-hospital all-cause mortality (OR: 3.32, 95% CI: 2.42-4.54, p<0.001), cardiovascular mortality (OR: 2.95, 95% CI: 1.96-4.44, p<0.001), cardiac arrest (OR: 2.04, 95% CI: 1.22-3.43, p=0.006), ACS (OR: 1.62, 95% CI: 1.17-2.22, p=0.003), stroke (OR: 3.10, 95% CI: 2.11-4.56, p<0.001), and AKI (OR: 2.13 95% CI: 1.68-2.69, p<0.001), but not incident heart failure (p=0.27). Conclusion: Although intracardiac thrombosis is rare in COVID-19 inpatients, its presence was independently associated with higher risks of in-hospital mortality and most morbidities. Prompt investigations and treatments for intracardiac thrombosis are warranted when there is a high index of suspicion and a confirmed diagnosis respectively.