Pulmonary embolism in patients with severe COVID-19 treated with intermediate- to full-dose enoxaparin

Background: Coronavirus disease 2019 (COVID-19) may predispose patients to venous thromboembolism (VTE) due to inflammation, hypoxia, immobilization, and diffuse intravascular coagulation, despite standard thrombopropylaxis. Our retrospective study reports the incidence of pulmonary embolism (PE) in patients with COVID-19 and severe respiratory failure(SRF) treated with intermediate to full-dose enoxaparin. .Methods: This retrospective case series analysed data from patients with COVID-19 pneumonia and severe respiratory failure (SRF) admitted to our Respiratory Intensive Care Unit (RICU) between February 27 and April 20, 2020 for non-invasive positive-pressure ventilation. All patients received at least intermediate-dose enoxaparin (40 mg twice daily). If PE was suspected or diagnosed, patients were treated with full-dose enoxaparin (1 mg/kg twice daily). Computed tomography pulmonary angiography (CTPA) was used to detect PE in patients with elevated D-dimer levels (> 3000 ng/mL) and/or other clinical indicators, including sudden worsening of cardiopulmonary status.Results: Ninety-two patients (71 males, 21 females; mean age 58 ± 11 years) with COVID-19 pneumonia and SRF (mean arterial oxygen partial pressure/fractional inspired oxygen [PaO2/FiO2] of 143 ± 45 mm Hg) were admitted to our RICU. Twenty-two patients underwent CTPA (24%), with PEs detected in 11 (12%). Mean PaO2/FiO2 and mean D-dimer levels did not significantly differ between patients with or without PE. Eleven patients (12%) died in the hospital, with a mean age of 70 ± 11 years for deceased patients and 56 ± 11 years for surviving patients (p < 0.0001).Conclusions: PE was diagnosed in 12% of patients despite intermediate to full-dose enoxaparin treatment. However the incidence of PE in our patients was lower than that previously reported. We hypothesize that this reduced PE incidence may have been secondary to the higher than prophylactic enoxaparin dose that was used.