Thromboprophylaxis in hospitalized COVID-19 patients: the efficacy and safety of the approved hospital protocol.

Introduction: Prothrombotic coagulopathy in COVID-19 has led to a strong recommendation for thromboprophylaxis in all hospitalized patients, although there are large differences in the dosage regimens among hospitals and their outcomes remain uncertain. Objectives: We aimed to determine the incidence of thrombotic events and bleeding in patients with COVID-19 using the approved local thromboprophylaxis protocol. Patients and methods: We adapted a self-developed pharmacological thromboprophylaxis protocol based on clinical and laboratory risk assessment of thrombosis in 350 consecutive patients (median age, 67 years) with confirmed COVID-19, treated in designated wards at a single center in Kraków, Poland from October 10, 2020, to April 30, 2021. We recorded in-hospital venous and arterial thromboembolic events, major or clinically relevant bleeding, and deaths along with other complications related to heparin administration. Results: Thromboprophylaxis with low-molecular-weight heparin was administered in 99.7% of patients, 57 (16%) were treated in the intensive care unit. As many as 92% of patients followed the protocol for more than 85% of hospitalization time. Thromboembolic events occurred in 16 patients (4.4%): venous thromboembolism (n = 4; 1.1%), ischemic stroke (n = 4; 1.1%), and myocardial infarction (n = 8; 2.2%). Hemorrhagic complications were observed in 31 patients (9%), including fatal bleeds (n = 3; 0.9%). The overall mortality was 13.4%. The prophylactic, intermediate, and therapeutic anticoagulation preventive strategies with heparin were not related to any of the outcomes. Conclusions: The thromboprophylaxis protocol approved in our institution was associated with a relatively low risk of thromboembolism and bleeding, which provides additional evidence supporting the adoption of institutional strategies to improve outcomes in hospitalized patients with COVID-19.