COVID-19 PULMONARY PATHOLOGY: A MULTI-INSTITUTIONAL AUTOPSY COHORT FROM LVIV AND LVIV REGION

Abstract

Introduction. Worldwide, more than 182 million cases of COVID-19 and more than 3.9 million deaths have been confirmed since the virus was first identified. Advanced age and some comorbid conditions, such as diabetes and cardiovascular diseases, are considered risk factors for the adverse course of the discussed pathology. In recent years, several reports have been published about the results of the pathological examination of patients with COVID-19. Most often, in fatal cases, diffuse alveolar damage is described, which is characterized by intraalveolar edema, the appearance of "hyaline” membranes and the proliferation of pneumocytes and fibroblasts. However, the nature of the damage caused by SARS-CoV-2 remains unclear. The study of pathomorphological changes in severe fatal cases of COVID-19 is important for a better understanding of pathogenetic mechanisms of the development of pulmonary complications and the development of new effective methods of antiviral treatment. The aim of the current study is to evaluate the gross and microscopic findings in COVID-19 patients' autopsy to investigate the clinicopathologic basis for adverse outcomes with a fatal course of the disease. Methods. A retrospective analysis of 1036 consecutive autopsies associated with COVID-19 in 2020 was conducted based on Lviv Regional Office for Autopsy and Lviv Railway Clinical Hospital. The diagnosis of COVID-19 was confirmed by clinical signs of viral pneumonia, nasopharyngeal smear analysis, and radiological changes. A statistical study was performed with IBM SPSS Statistics 24.0. Results. The majority (72.4%) were elderly (60+) males (54.1±1.5%) and females (45.9±1.5%), with an age range from 19 to 93 years (mean age 66.9 ± 0.4 years). All examined patients had pneumonia, which was detected during a clinical examination with CT diagnosis and confirmed at autopsy. The acute exudative phase of pneumonia was diagnosed in 18.5±1.2% of cases, proliferative phase - in 18.5±1.2%, and fibrotic phase - in 5.9±0.7%. And in 53.5±1.5% of cases, signs of progressive fibrosis associated with exudative lesions prevailed. COVID-19 was the single original cause of death in 88.7±1.0% of cases. The following were identified in the lungs: typical virus-induced changes in epithelial cells of the trachea, bronchi, bronchioles and alveoli (100%, n=1036);different phases of diffuse alveolar damage in the majority of cases (96.5±0.6%);manifestations of innate immunity were described;pathological changes in the microvasculature (large vessel thrombi were detected in 37.9±1.5%). Conclusion. Our study results prove the importance of pathological examination of tissues during autopsies to determine the pathophysiological mechanisms and underlying causes of death of patients with COVID-19. © Yuliia Kuzyk, Olena Gavrilyuk, Marta Semko, Borys Ribun, Anna Arefyeva, 2022.