Cardiovascular events are frequently seen in association with coronavirus disease-2019 (COVID-19), particularly thromboembolisms. Researchers from Brigham and Women’s Hospital in Massachusetts just published results from their multicentre, observational cohort study investigating thromboembolism in patients with COVID-19 (COVID-19 Registry to Assess Frequency, Risk Factors, Management, and Outcomes of Arterial and Venous Thromboembolic Complications [CORONA-VTE NET], ClinicalTrials.gov identifier NCT04535128). The team analyzed a retrospective cohort of 1,114 patients with COVID-19, with a primary outcome of arterial or venous thromboembolism over 30 days.
Researchers first analyzed all 1,114 patients as a total cohort and then subdivided it into three smaller cohorts by site of care. These mutually exclusive cohorts consisted of patients who were admitted to the intensive care unit (ICU), patients who were admitted to hospital but not the ICU, and patients who were not hospitalized (outpatients).
Adverse outcomes more likely in ICU patients, despite receiving thromboprophylaxis
In the cohort of hospitalized patients who were admitted to ICU (n=170), 152 (89.4%) received prophylactic anticoagulants. ICU patients were more likely to experience major arterial or venous thromboembolism events (15.9% vs. 0.7%), major adverse cardiovascular events (20.2% vs. 1.1%), and symptomatic venous thromboembolism (VTE) (11.5% vs. 0.1%) than the 18 who were not receiving thromboprophylaxis.
At 30 days from diagnosis, major arterial or venous thromboembolic events, major adverse cardiovascular events, and symptomatic VTE occurred in 35.3%, 45.9%, and 27.0% of patients in this cohort, respectively.

In the cohort of hospitalized patients who were not admitted to the ICU (n=229), 194 (84.7%) received prophylactic anticoagulants. These patients were more likely to experience major arterial or VTE events (1.4% vs. 0.1%), major adverse cardiovascular events (3.8% vs. 0.1%), and symptomatic VTE (1.4% vs. 0.0%) than the 35 who were not receiving thromboprophylaxis.
At 30 days from COVID-19 diagnosis, major arterial or VTE events, major adverse cardiovascular events, and symptomatic VTE occurred in 2.6%, 6.1%, and 2.2% of patients in this cohort, respectively. The outpatient cohort (n=715) rarely used thromboprophylaxis. This cohort had a low risk of major arterial or VTE events, major adverse cardiovascular events, and symptomatic VTE.
Better strategies needed to identify risk in COVID19 patients
The high rate of major arterial or venous thromboembolism, major adverse cardiovascular events, and symptomatic VTE despite thromboprophylaxis in patients with COVID-19 necessitates the creation of better strategies for risk identification and mitigation.
This study lacked a control group of patients who had similar illnesses and risk factors but not COVID-19. Therefore, the extent to which COVID-19 itself increases the risk of thromboembolic events is unknown.
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Author: Kelly Schoonderwoerd
References
Original Article: Piazza G, et. al. JACC 2020 Nov 3; 76(18): 2060-72.