Clinical and morphological characteristics of air leak and hemorrhagic complications in patients with COVID-19

To date, COVID-19 remains a challenge for modern medicine. The prognosis of the disease is often associated with the development of complications caused by SARS-CoV-2 virus. Hemorrhagic complications of COVID-19 account for the highest incidence, ranging from 3.0% to 31.1%. Air leak syndrome has been observed from the respiratory system side. Surgical complications in COVID-19 constitute from 1% to 2.4%, with mortality rates varying from 7.9% to 78.5%. The aim of the study was to determine the optimal approaches to the diagnosis and treatment of patients with air leak and hemorrhagic complications of COVID-19, taking into account the data of clinical laboratory, instrumental, pathomorphological and immunohistochemical studies. clinical-laboratory, instrumental, pathomorphological, and immunohistochemical data. Materials and methods: The study included 213 patients who developed air leak syndrome, 332 patients with gastrointestinal bleeding, and 39 patients with spontaneous soft tissue hematomas. Results: It was established that surgical complications most frequently occurred in patients with a burdened premorbid background during the late stages of COVID-19 progression. Based on correlation analysis of clinical-laboratory and instrumental indicators, predictors for the development of air leak syndrome and gastrointestinal bleeding were identified with a significance level p<0.05. A prognostic model was constructed using logistic regression with Wald’s criterion calculation. The model’s quality was assessed using ROC curves: for air leak syndrome (AUC=0.97) and for gastrointestinal bleeding (AUC=0.78). Immunohistochemical studies using monoclonal antibodies against the SARS-CoV-2 spike S-protein (COVID-19 spike antibody) revealed SARS-CoV-2 viral particles in endothelial cells. Expression of CD31, CD34, CD68, and vWF receptors reflected SARS-CoV-2-associated systemic endothelial changes considering coagulopathy factors and proinflammatory responses. In cases of air leak syndrome, one key factor was the formation of endothelial microthrombi; in hemorrhagic events, degenerative changes in the endothelium were prominent. Conclusion: The cytopathic effect of SARS-CoV-2 led to degradation of the endothelial monolayer, contributing to vascular wall destruction and the development of clinically significant hemorrhagic events. Implementing predictive methods for assessing the risk of air leak syndrome and bleeding in COVID-19 patients in clinical practice allowed some patients to be prophylactically protected against complications. The preferred treatment algorithm for spontaneous soft tissue hematomas in COVID-19 patients involves a sequential transition from non-invasive to minimally invasive methods for hemostasis.