Thromboprophylaxis in COVID-19: Weight and severity adjusted intensified dosing

Abstract

Background: Venous thromboembolism (VTE) frequently occurs in hospitalized patients with coronavirus disease 2019 (COVID-19). The optimal dose of anticoagulation for thromboprophylaxis in COVID-19 is unknown.

Aims: To report VTE incidence and bleeding before and after implementing a hospital-wide intensified thromboprophylactic protocol in patients with COVID-19.

Methods: On March 31, 2020, we implemented an intensified thromboprophylactic protocol consisting of 50 IU anti-Xa low molecular weight heparin (LMWH)/kg once daily at the ward, twice daily at the intensive care unit (ICU). We included all patients hospitalized in a tertiary care hospital with symptomatic COVID-19 between March 7 and July 1, 2020. The primary outcome was the incidence of symptomatic or subclinical VTE and major bleeding during admission. Routine ultrasound screening for VTE was performed whenever logistically possible.

Results: We included 412 patients, of which 116 were admitted to the ICU. Of 219 patients with standard a prophylactic dose of LMWH, 16 (7.3%) had VTE, 10 of which were symptomatic (4.6%). Of 193 patients with intensified thromboprophylaxis, there were no symptomatic VTE cases, three incidental deep venous thrombosis cases (1.6%), and one incidental pulmonary embolism (0.5%). The major bleeding rate was 1.2% in patients with intensified thromboprophylaxis and 7.7% when therapeutic anticoagulation was needed.

Conclusion: In hospitalized patients with COVID-19, there were no additional symptomatic VTEs and a reduction in incidental deep vein thrombosis after implementing systematic thromboprophylaxis with weight-adjusted prophylactic (ward) to intermediate (ICU), but not therapeutic dosed anticoagulation. This intensified thromboprophylaxis was associated with a lower risk of major bleeding compared with therapeutic dosed anticoagulation.

Keywords: COVID‐19; anticoagulants; hemorrhage; heparin; low‐molecular‐weight; thrombosis.

FIGURE 1

Patient selection. Abbreviations: DVT, deep vein thrombosis; ICU, intensive care unit

FIGURE 2

Incidence of venous thromboembolism. (a) Incidence of symptomatic venous thromboembolism (VTE) with the standard and the intensified protocol. (b) Incidence of incidental deep vein thrombosis (DVT) in patients screened with venous ultrasound (VUS). Abbreviations: ICU, intensive care unit; PE, pulmonary embolism

FIGURE 3

Incidence of major bleeding. The incidence of major bleeding was significantly higher in patients in need for therapeutic doses of anticoagulation compared with patients treated with nontherapeutic thromboprophylaxis. Abbreviations: BID, twice daily; LMWH, low molecular weight heparin; ns, not significant; OAC (vitamin K antagonists and direct oral anticoagulation), oral anticoagulation; OD, once daily; tLMWH, therapeutic dose of LMWH; tUFH, therapeutic dose of unfractionated heparin; **, p = 0.003