Clinical characteristics of acute lower extremity deep venous thrombosis diagnosed by duplex in patients hospitalized for coronavirus disease 2019

OBJECTIVE: Little is known about coronavirus disease 2019 (COVID-19)-associated hypercoagulability. We sought to characterize patients with deep venous thrombosis (DVT) identified after admission for COVID-19. METHODS: All adult patients admitted to Montefiore Medical Center from March 1, 2020, to April 10, 2020, and undergoing lower extremity venous duplex for DVT evaluation were included. Patients admitted with suspicion of COVID-19 were divided into severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive and SARS-CoV-2 negative groups based on in-hospital test results. Patients without clinical suspicion for COVID-19 were not tested. A retrospective case-control study design was used to identify potential risk factors for DVT in patients with COVID-19. Demographic, radiographic, and laboratory values were abstracted and analyzed. RESULTS: During the study period, 3404 patients with confirmed COVID-19 were admitted to the hospital. Of the 135 SARS-CoV-2 patients who underwent duplex scanning, there were 18 (13.3%) noted to have DVT compared with 72 of the 711 patients (10.1%) who were either SARS-CoV-2 negative or untested. The odds ratio for DVT in COVID-19 was 1.35 (95% confidence interval, 0.78-2.34; P = .289). Baseline characteristics for COVID-19 patients with and without DVT were overall similar. COVID-19 patients with DVT had an elevated median first d-dimer (18.88 μg/mL [interquartile range (IQR), 7.79-20.00] vs 2.55 μg/mL [IQR, 1.45-6.28]; P = .002; reference value, <0.5 μg/mL), average in-hospital d-dimer (median, 11.93 μg/mL [IQR, 8.25-16.97] vs 3.54 μg/mL [IQR, 2.05-8.53]; P < .001) and median fibrinogen level (501.0 [IQR, 440.0-629.0] vs 654.5 [IQR, 535.8-780.0]; P = .002; reference range, 187-502 mg/dL). There was a trend to significance for COVID-19 patients with DVT compared with without DVT in median d-dimer levels at the time of the duplex (13.61 μg/mL [IQR, 4.04-19.97] vs 3.58 μg/mL [IQR, 2.51-9.62]; P = .055) and median ferritin levels (1679.0 ng/mL [IQR, 1168.0-2577.0] vs 1103.0 ng/mL [IQR, 703.5-2076.5]; P = .055; reference range, 25-270 ng/mL). Twelve of the 18 patients with COVID who developed DVT did so despite chemical thromboprophylaxis, and 2 developed DVT despite therapeutic anticoagulation CONCLUSIONS: We found only a modestly increased risk of DVT in patients with COVID-19, likely underestimated owing to limitations in duplex testing early in the epidemic. Elevated d-dimer and a less elevated fibrinogen are associated with DVT in patients with COVID-19 who seem to form thrombus despite conventional chemical thromboprophylaxis. Additionally, an increasing d-dimer over time may be a reflection of the development of DVT in patients with COVID-19.