The features of thrombogenesis in COVID-19-associated pneumonia compared to bacterial pneumonia: the key role of fibrinolysis

ABSTRACT

The aim was to estimate the autopsy features of COVID-19 comparing with bacterial pneumonia. Material(s) and Method(s) 15 patients died from COVID-19 pneumonia and 13 patients with CABP. On autopsy of COVID-19 patients macroscopically - enlarged, plethoric lungs, exudate with hemorrhagic components, areas of thrombosis, developing fibrosis (Figure 1A). Figure 1B - microscopical changes in COVID-19 artery of medium caliber, branching of the pulmonary artery, vascular endothelial integrity violation, the arrow indicates a pale pink non-nuclear mass in the form of threads - fibrin clot. On autopsy of CABP patients macroscopically - compressed, dense, infiltrated lungs, filled with purulent exudate (Figure 1C). Figure 1D demonstrates an example of microscopical changes in CABP mixed thrombi in the lumen of the arteries, more often in average caliber were found. This thrombus had a head (the structure of a white thrombus), a body (actually a mixed thrombus) and a tail (the structure of a red thrombus). The head was attached to the endothelial lining of the vessel, which distinguishes a thrombus from a posthumous blood clot or from an embolus. Conclusion(s) 1) problems in fibrinolysis system, which is the main difference between CABP;in died patients with COVID-19 pneumonia the level of PAI-1 is associated with the disease severity and could be the crucial marker for patients' distribution. (Figure Presented).