In vivodemonstration of microvascular thrombosis in severe Covid-19

Several autopsies studies showed the presence of microthrombi in the pulmonary circulation of the severe COVID-19. The major limitation of these investigations is that the autopsy provided static information. Some of these alterations could be secondary to the disseminated intravascular coagulation (DIC) observed as the final common pathway of the multisystem organ failure exhibited in the critical patient. We report the preliminary results of an in vivo evaluation of the sublingual microcirculation in thirteen patients with severe COVID-19 requiring mechanical ventilation at the beginning of the hospitalization. They did not have any laboratorial DIC evidence. We observed multiple filling defects moving within the sublingual microvessels indicative of microthrombi in 11 (85%) patients. This is the first imaging documentation of microvascular thrombosis in living patients with severe COVID-19. The clinical relevance of microvascular thrombosis in this disease requires further research. Highlights The presence of microthrombi in the pulmonary circulation is a common finding in autopsies of severe COVID-19. In vivo evaluation of the sublingual microcirculation of severe COVID-19 showed multiple filling defects moving within the microvessels indicative of thrombi in most of these patients. This is the first imaging documentation of microvascular thrombosis in living patients with severe COVID-19. The clinical relevance of microvascular thrombosis in COVID-19 requires further research.