MICROVASCULAR CHANGES IN COVID-ASSOCIATED PNEUMONIA

COVID-associated pneumonia is characterized by pronounced microvascular disturbances that determine the severity of hypoxemia, the development of respiratory failure, and systemic complications. Morphological studies demonstrate significant endothelial damage manifested by endothelial swelling, vacuolization, areas of desquamation, and impairment of the vascular barrier function. These changes are accompanied by interstitial edema and impaired perfusion. A key morphological feature is diffuse capillary microangiopathy with erythrocyte stasis, capillary dilation, and perivascular lympho-macrophage infiltration. In contrast to other viral pneumonias, COVID-19 is characterized by marked microthrombosis in capillaries, arterioles, and venules, forming a pattern of thrombotic vasculopathy. A unique feature is intussusceptive angiogenesis, reflecting a compensatory remodeling of the vascular bed in response to hypoxia and vascular injury. Taken together, these changes allow COVID-associated pneumonia to be regarded as a specific form of virus-induced microvascular vasculopathy. Understanding microvascular disturbances is of great importance for clarifying the pathogenesis of the disease and for the development of targeted therapeutic strategies.