Higher anticoagulation targets and risk of thrombotic events in severe COVID-19 patients: bi-center cohort study

BACKGROUND: Thromboprophylaxis of COVID-19 patients is a highly debated issue. We aimed to compare the occurrence of thrombotic/ischemic events in COVID-19 patients with acute respiratory distress syndrome (ARDS) treated with either prophylactic or therapeutic dosage of heparin. All patients referred for COVID-19 ARDS in two intensive care units (ICUs) from two centers of a French tertiary hospital were included in our cohort study. Patients were compared according to their anticoagulant treatment to evaluate the risk/benefit of prophylactic anticoagulation versus therapeutic anticoagulation. Medical history, symptoms, biological data and imaging were prospectively collected. RESULTS: One hundred and seventy-nine patients (73% men) were analyzed: 108 in prophylactic group and 71 in therapeutic group. Median age and SAPS II were 62 [IQR 51; 70] years and 47 [IQR 37; 63] points. ICU mortality rate was 17.3%. Fifty-seven patients developed clinically relevant thrombotic complications during their ICU stay, less frequently in therapeutic group (adjusted OR 0.38 [0.14–0.94], p = 0.04). The occurrences of pulmonary embolism (PE), deep vein thrombosis (DVT) and ischemic stroke were significantly lower in the therapeutic group (respective adjusted OR for PE: 0.19 [0.03–0.81]; DVT: 0.13 [0.01–0.89], stroke: 0.06 [0–0.68], all p < 0.05). The occurrence of bleeding complications was not significantly different between groups, neither were ICU length of stay or mortality rate. D-dimer levels were significantly lower during ICU stay, and aPTT ratio was more prolonged in the therapeutic group (p < 0.05). CONCLUSION: Increasing the anticoagulation of severe COVID-19 patients to a therapeutic level might decrease thrombotic complications without increasing their bleeding risk.