Extensive Thrombosis in a Severe COVID-19 Patient Despite Prophylactic Low Molecular Weight Heparin

D-dimer >1 mcg/L has been shown to be an independent predictor of mortality, and experts from China have recommended starting prophylactic doses of anticoagulation in severe coronavirus disease 2019 (COVID-19) unless contraindicated. We present a case of extensive intravascular thrombosis in an otherwise healthy patient with severe COVID-19 disease despite prophylactic anticoagulation.