LAUSR

Background: Coronavirus disease 2019 (COVID-19) is associated with elevated rates of major and fatal thrombotic events, postulated to be the result of a hypercoagulable state mediated through inflammatory and immunomodulatory mechanisms. Early observational studies showed that disease severity and elevated serum D-dimer levels can predict thrombotic risk in patients hospitalized with COVID-19 and reported an alarming phenomenon of breakthrough thrombosis despite standard-of-care prophylaxis, suggesting the need for enhanced thromboprophylactic strategies. Areas of Uncertainty: Data on anticoagulant agent selection, dosing, and duration for COVID-19 inpatients are now poised to inform updated professional society guidance. However, there remains limited high-quality data regarding postdischarge and especially ambulatory patients with COVID-19. Data Sources: This review includes published, peer-reviewed, observational, and randomized controlled trial data and major professional society guidance informing thrombosis prevention and treatment in patients with COVID-19. Therapeutic Advances: There remains great variability in the approach to anticoagulation in COVID-19. This article will review pathogenesis of COVID-related thrombosis and the evidence guiding thromboprophylaxis particularly in inpatients, with attention to the INSPIRATION, ACTION, RAPID, HEP-COVID, and multiplatform trials. Emerging thromboprophylaxis data from the postdischarge setting (particularly the recently published MICHELLE trial), and the outpatient setting, will be examined. Finally, thrombosis treatment considerations will briefly be reviewed. Conclusions: Substantial high-quality data support practice changes to COVID-19 thromboprophylaxis. Risk stratification by setting, disease severity, and biomarkers such as D-dimer is critical in considering choice, dose, and duration of anticoagulants.