Objective: We set out to analyze the incidence and predictive factors of pulmonary embolism (PE) in hospitalized patients with Covid-19. Methods: We prospectively collected data from all consecutive patients with laboratory-confirmed Covid-19 admitted to the Hospital de la Santa Creu i Sant Pau, a university hospital in Barcelona, between March 9 and April 15, 2020. Patients with suspected PE, according to standardized guidelines, underwent CT pulmonary angiography (CTPA). Results: A total of 1,275 patients with Covid-19 were admitted to hospital. CTPA was performed on 76 inpatients, and a diagnosis of PE was made in 32 (2.6% [95%CI 1.7-3.5%]). Patients with PE were older, and they exhibited lower PaO 2 :FiO 2 ratios and higher levels of D-dimer and C-reactive protein (CRP). They more often required admission to ICU and mechanical ventilation, and they often had longer hospital stays, although in-hospital mortality was no greater than in patients without PE. High CRP and D-dimer levels at admission (≥150 mg/L and ≥1,000 ng/ml, respectively) and a peak D-dimer ≥6,000 ng/ml during hospital stay were independent factors associated with PE. Prophylactic low molecular weight heparin did not appear to prevent PE. Increased CRP levels correlated with increased D-dimer levels and both correlated with a lower PaO 2 :FiO 2. Conclusions: The 2.6% incidence of PE in Covid-19 hospitalized patients is clearly high. Higher doses of thromboprophylaxis may be required to prevent PE, particularly in patients at increased risk, such as those with high levels of CRP and D-dimer at admission. These findings should be validated in future studies.

Thrombophylaxis with low molecular weight heparin (LMWH) in hospitalized patients with COVID-19 is mandatory, unless contraindicated. Given the links between inflammation and thrombosis, the use of higher doses of anticoagulants could improve outcomes. We conducted an open-label, multicenter, randomized, controlled trial in adult patients hospitalized with non-severe COVID-19 pneumonia and elevated D-dimer. Patients were randomized to therapeutic-dose bemiparin (115 IU/Kg daily) vs. standard prophylaxis (bemiparin 3,500 IU daily), for 10 days. The primary efficacy outcome was a composite of death, intensive care unit admission, need of mechanical ventilation support, development of moderate/severe acute respiratory distress and venous or arterial thrombosis within 10 days of enrollment. The primary safety outcome was major bleeding (ISTH criteria). A prespecified interim analysis was performed when 40% of the planned study population was reached. From October 2020 to May 2021, 70 patients were randomized at 5 sites and 65 were included in the primary analysis; 32 patients allocated to therapeutic-dose and 33 to standard prophylactic-dose. The primary efficacy outcome occurred in 7 patients (21.9%) in the therapeutic-dose group and 6 patients (18.2%) in the prophylactic-dose (absolute risk difference 3.6% [95% CI, -16%- 24%]; odds ratio 1.26 [95% CI, 0.37-4.26]; p=0.95). Discharge in the first 10 days was possible in 66% and 79% of patients, respectively. No major bleeding event was registered. Therefore, in patients with COVID-19 hospitalized with non-severe pneumonia but elevated D-dimer, the use of a short course of therapeutic-dose bemiparin did not improve clinical outcomes compared to standard prophylactic doses.

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