Clinical and experimental parallels in the assessment of microcirculatory dysfunctions of the lungs in thoracic radiology

Introduction . Chronic obstructive disease (COPD) and thromboembolism of the branches of the pulmonary artery or pulmonary embolism (PE) remain the most common and socially significant lung diseases. Circulatory disorders in these pathologies play a critical role in the development of the disease. Radiation techniques, such as computed tomography/angiography and single-photon emission computed tomography (SPECT), are the leading ones in recognizing changes in the lung parenchyma and vessels. Many questions can be successfully solved experimentally. The main radiation techniques used to study the vascular bed when modeling lung diseases in experimental animals are microangiography and perfusion scintigraphy. Purpose. To show the capabilities of radiation diagnostic methods for identifying vascular disorders in COPD and PE in experiments and clinical manifestations. Material and methods . A clinical and experimental comparison of pulmonary circulation changes during COPD and PE was carried out based on the results of perfusion scintigraphy/SPECT in 55 rats with simulated COPD- like condition and 622 patients with COPD of varying severity, as well as 58 rats with simulated PE and 180 patients with PE . Results . When modelling lung diseases (PE and COPD), the results similar to blood circulation and structural changes in the lung parenchyma in patients with these nosologies were obtained. In COPD, changes in the lung parenchyma correlated with disturbances in functional indicators (microcirculation, PaO2, PaCO2, DSLzd, DLco/VA, SDPA) and increased levels of endothelin-1 (r=0.72) and endothelial growth factor (VEGF-A) (r=0.79). Analysis of experimental and clinical data on PE showed the importance of identifying minor forms of thromboembolism. Conclusion . 1. Persistent microcirculatory dysfunctions in the pulmonary circulation play an important role in the pathogenesis of chronic broncho-obstructive pathology. After just 7 days, initial signs of emphysema can be detected in the ischemic area of the lung tissue, and by the 60th day typical bullous cavities can be detected. 2. In the chronic course of minor forms of thromboembolism of small branches of the pulmonary artery, local emphysema is formed. 3. At the early stages of COPD formation, regional zones of emphysematous restructuring of the lung tissue with a predominance of ventilation dysfunctions and zones of «compressive ischemia» with prevailing vascular disorders are formed. As the pathological process progresses, the ischemia factor acquires independent significance in the pathogenesis of the disease.