In vivo demonstration of microvascular thrombosis in severe Covid-19

Abstract

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.

Low ADAMTS13 Activity Correlates with Increased Mortality in COVID-19 Patients

“…Also, the correlation of high D-dimer and FM levels with LDH and the occasional finding of fibrin strands in peripheral blood smears suggests that high D-dimer levels may be a direct product of small vessel thrombosis (arterial and venous), which have been documented in COVID-19 autopsies. [34][35][36][37][38][39] Microvascular thrombosis leads to ischemic end-organ damage, most commonly affecting kidneys, but other organs can also be affected. COVID-19 primarily manifests as respiratory failure, however, renal and cardiovascular complications are common in COVID-19.…”

Evidence for secondary thrombotic microangiopathy in COVID-19

“…Also, the correlation of high D-Dimer and FM with LDH and the occasional finding of fibrin strands in peripheral blood smears suggests that high D-Dimer levels may be a direct product of small vessel thrombosis (arterial and venous), which have been documented in COVID-19 autopsies. [27][28][29][30][31][32] Microvascular thrombosis leads to ischemic end-organ damage, most commonly affecting kidneys, but other organs can be affected in TMA. COVID-19 primarily manifests as respiratory failure, however, renal and cardiovascular complications are common in COVID-19.…”

High levels of plasminogen activator inhibitor-1, tissue plasminogen activator and fibrinogen in patients with severe COVID-19

“…Increased thrombosis and thrombotic complications have been widely associated with COVID-19 (Bikdeli et al, 2020;Magro et al, 2020;Giannis et al, 2020;Klok et al, 2020;do Espírito Santo et al, 2020), and abnormal coagulation is correlated with COVID-19 severity (Tang et al, 2020b). Changes in conventional parameters such as international normalized ratio (INR), fibrinogen level and platelet counts may be useful for the rapid detection of hypocoagulation in COVID-19 patients (Tang et al, 2020a;Xiong et al, 2020), but do not fully explain the pathophysiology of hypercoagulability seen in some of these patients.…”