Pulmonary Vascular Thrombosis in COVID-19 Pneumonia

Abstract Objectives During SARS-CoV-2 infection, dramatic endothelial cell damage with pulmonary microvascular thrombosis has been hypothesized to occur. Our aim was to assess whether pulmonary vascular thrombosis is due to recurrent thromboembolism from peripheral deep vein thrombosis or rather to local inflammatory endothelial damage with a superimposed thrombotic late complication. Design Observational study Setting Medical and intensive care unit wards of a teaching hospital Participants We report a subset of patients included in a prospective institutional study (CovidBiob study) with clinical suspicion of pulmonary vascular thromboembolism. Interventions Computed Tomography Pulmonary Angiography and evaluation of laboratory markers and coagulation profile. Measurements and Main Results Twenty-eight out of 55 (50.9%) patients enrolled showed pulmonary vascular thrombosis, with a median time interval from symptoms onset of 17.5 days. Simultaneous multiple pulmonary vascular thromboses were identified in 22 cases, with bilateral involvement in 16, mostly affecting segmental/subsegmental pulmonary arteries branches (67.8% and 96.4%). Patients with pulmonary vascular thrombosis had significantly higher ground glass opacities areas (31.7% [22.9-41] vs. 17.8% [10.8-22.1] p Conclusions Our findings identify a specific radiological pattern of COVID-19 pneumonia with a unique spatial distribution of pulmonary vascular thrombosis overlapping areas of ground glass opacities. These findings support the hypothesis of a pathogenetic relationship between COVID-19 lung inflammation and pulmonary vascular thrombosis and challenge the previous definition of pulmonary embolism associated with COVID-19 pneumonia.