The impact of protocol-based high-intensity pharmacological thromboprophylaxis on thrombotic events in critically ill COVID-19 patients.
The reported incidence rate of venous and arterial thrombotic events in critically ill patients with COVID-19 infections is high, ranging from 20-60%. We adopted a patient-tailored thromboprophylaxis protocol based on clinical and laboratory presentations for these patients in our institution. We hypothesised that patients who received high-intensity thromboprophylaxis treatment would experience fewer thrombotic events. The aims of our study were to explore the incidence of thrombotic events in this population; to assess independent factors associated with thrombotic events and to evaluate the incidence of haemorrhagic events. A retrospective chart review of all adult patients with confirmed SARS-CoV-2 infection admitted to the intensive care unit between 1 March and 29 May 2020 was performed. The primary outcome was a composite of venous and arterial thrombotic events diagnosed during the intensive care unit stay. Multivariable logistic regression was used to identify the independent factors associated with thrombotic events. A total of 188 patients met the inclusion criteria. All received some type of thromboprophylaxis treatment except for 6 patients who did not receive any prophylaxis. Of the 182 patients who received thromboprophylaxis, 75 (40%) received high-intensity thromboprophylaxis and 24 (12.8%) were treated with therapeutic anticoagulation. Twenty-one patients (11.2%) experienced 23 thrombotic events (incidence rate of 12.2% (95%CI 7.9-17.8)), including 12 deep venous thromboses, 9 pulmonary emboli and 2 peripheral arterial thromboses. The multivariable logistic regression analysis showed that only D-dimer (OR 2.80, p=0.002) and high-intensity thromboprophylaxis regimen (OR 0.20, p=0.01) were independently associated with thrombotic events. Thirty-one patients (16.5%) experienced haemorrhagic events; among them, 13 were classified as major bleeding according to the International Society on Thrombosis and Haemostasis criteria. Therapeutic anticoagulation, but not the high-intensity thromboprophylaxis regimen, was associated with major bleeding. A proactive approach to the management of thromboembolism in critically ill COVID-19 patients utilising a high-intensity thromboprophylaxis regimen in appropriately selected patients may result in lower thrombotic events without increasing the risk of bleeding.