Thromboembolic complications during and after hospitalization for COVID-19: Incidence, risk factors and thromboprophylaxis.

Introduction: The incidence of thromboembolism during COVID-19 and the use of thromboprophylaxis vary greatly between studies. Only a few studies have investigated the rate of thromboembolism post-discharge. This study determined the 90-day incidence of venous and arterial thromboembolic complications, risk factors for venous thromboembolic events and characterized the use of thromboprophylaxis during and after hospitalization. Materials and methods: We retrospectively reviewed medical records for adult patients hospitalized for >24 h for COVID-19 before May 15, 2020, in ten Norwegian hospitals. We extracted data on demographics, thromboembolic complications, thromboembolic risk factors, and the use of thromboprophylaxis. Cox proportional hazards regression was used to determine risk factors for VTE. Results: 550 patients were included. The 90-day incidence of arterial and venous thromboembolism in hospitalized patients was 6.9% (95% CI: 5.1-9.3) overall and 13.8% in the ICU. Male sex (hazard ratio (HR) 7.44, 95% CI 1.73-32.02, p = 0.007) and previous VTE (HR 6.11, 95% CI: 1.74-21.39, p = 0.005) were associated with risk of VTE in multivariable analysis. Thromboprophylaxis was started in 334 patients (61%) with a median duration of 7 days (25th-75th percentile 3-13); in the VTE population 10/23 (43%) started thromboprophylaxis prior to diagnosis. After discharge 20/223 patients received extended thromboprophylaxis and 2/223 (0.7%, 95% CI: 0.3-1.9) had a thromboembolism. Conclusions: The 90-day incidence of thromboembolism in COVID-19 patients was 7%, but <1% after discharge. Risk factors were male sex and previous VTE. Most patients received thromboprophylaxis during hospitalization, but only <10% after discharge.

Treatment of Homozygous Type II Antithrombin Heparin-Binding Site Deficiency in Pregnancy.

Pregnancy is associated with an increased risk of venous thromboembolism (VTE). Previous VTE and severe thrombophilia are important risk factors. Our case was a 36-year-old woman, gravida 6, para 0, with antithrombin (AT) deficiency caused by a homozygous mutation in the heparin-binding site (HBS). Her history included seven prior VTEs, three early and two late pregnancy losses. She was prophylactically treated with both human plasma-derived AT concentrate (hpATC) and low molecular weight heparin (LMWH), resulting in a successful 6th pregnancy and a healthy live born baby. There is limited evidence and guidance on the management of AT deficiency in pregnancy. Dosing and monitoring of anticoagulants, alone or together with hpATC, must be based on individual risk assessment. The severity of clinical manifestations varies with the type of AT deficiency. Characterization of the AT mutation may aid in the decision-making process and optimize pregnancy outcomes.