Pulmonary post-mortem findings in a large series of COVID-19 cases from Northern Italy

Luca Carsana; Aurelio Sonzogni; Ahmed Nasr; Roberta Rossi; Alessandro Pellegrinelli; Pietro Zerbi; Roberto Rech; Riccardo Colombo; Spinello Antinori; Mario Corbellino; Massimo Galli; Emanuele Catena; Antonella Tosoni; Andrea Gianatti; Manuela Nebuloni

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.19.20054262 doi: medRxiv preprint 5 proliferative phases of DAD were found, while the fibrotic phase was rare. The peculiar histopathological findings were atypical pneumocytes (reactive atypia) and diffuse thrombosis of the peripheral small vessels. In our study, fibrin thrombi of small arterial vessels (diameter < 1mm) were observed in 33 /38 patients, half of them with >25% of tissue involvement and associated with high levels of D-dimer in blood. These findings might explain the severe hypoxemia which characterizes the clinical feature of ARDS in SARS-CoV-2 patients. Our data strongly support the hypothesis proposed by recent clinical studies, that COVID-19 is complicated or anyway strictly related to coagulopathy and thrombosis; moreover detection of D-dimer values >1 μg/ml have been associated with fatal outcome of COVID-19. For these reasons, the use of anticoagulants has been recently suggested as potentially beneficial in patients with severe COVID-19, albeit its efficacy and safety have not been demonstrated 9 .