Pulmonary Embolism and COVID-19, an Unexpected Association: Experience from Two Centers in the Core of the Infection Italian Peak

Background: Pulmonary embolism (PE) in COVID-19 patients can play a key role in precipitating clinical conditions. We aimed to evaluate PE distribution on CTA images and to investigate any possible association between PE and D-dimer, pulmonary stage of disease and short-term prognosis. Methods: COVID-19 patients of two affiliated Hospitals, undergone a CTA examination for PE clinical suspicion, were retrospectively enrolled.  Comorbidities, laboratory tests and clinical outcomes (hospitalization, discharge, death) were assessed. The assigned parenchymal stages (early, progressive, peak, absorption) described lung involvement as showed on CT images. Findings: A cohort of 114 patients (mean age 61 years; 26·3% females) with COVID-19 pneumonia were evaluated. At follow-up 77 patients (67·5%) were hospitalized, 25 (22%) have been discharged and 12 (10.5%) were dead. Eighty-eight patients (77·2%) had at least one comorbidity, being cardiovascular ones the most frequent (44·7%). CTA revealed PE in 65 patients (57%), with concomitant pulmonary trunk and/or main arteries involvement in 16·9% cases. PE defects were ubiquitous in 18·5% of cases. The predominant parenchymal stages were the progressive (24·6%) and peak (67·7%) ones. D-dimer levels showed a significant correlation with PE occurrence and extent in pulmonary branches, despite anticoagulant therapies; trend of correlation with pulmonary stage was also noted.  Interpretation: PE is a frequent complication in COVID-19 patients, particularly during central parenchymal stages and despite ongoing anticoagulant therapy. CTA and D-dimer levels play a crucial role in the assessment of suspected PE, despite anticoagulant therapies, along with proper information about lung involvement extent. Funding Statement: None. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The ethical approval for this retrospective study was obtained from the local ethics committee of Papa Giovanni XXIII Hospital, Bergamo.