SECONDARY PULMONARY HYPERTENSION: SOME ASPECTS OF PATHOGENESIS

Aim. To study morphofunctional condition of pulmonary vessels in chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), to specify the role of endothelial dysfunction in pathogenesis of secondary pulmonary hypertension (SPH). Material and methods. Functional examination of cardiovascular and respiratory systems, measurement of systolic pressure (SP) in the pulmonary artery were made in 178 patients: 99 with COPD (8 females and 91 males, mean age 57.2 ± 9.8 years), 79 with IPF (58 females and 21 males, mean age 54.1 ± 12.7 years). The examination has detected echocardiographic signs of pulmonary hypertension (PH). Then 45 PH patients (22 with COPD and 23 with IPF) were tested for vasoreactivity in response to inhalation of O 2, NO in combination with O 2 and iloprost (prostacycline i 2) with О 2. Next stage of the study was morphometric and immunohistochemical examinations of small branches of the pulmonary artery (PA). Results. PA SP in COPD patients was 42.8 ± 11.1 mmHg, in IPF patients — 41.8 ± 12.6 mmHg. Elevation of PA SP above 35 mmHg was registered in 48.5% patients with COPD and in 43.0% with IPF. Patients of both groups responded to a vasodilating impact of inhalatory NO and iloprost while reaction to O 2 inhalation was absent. Morphological study of PA small branches revealed marked changes in the structure of vascular wall which were most manifest in the intima. Conclusion. The findings evidence for an essential role of endothelial dysfunction in formation and progression of PH in pulmonary pathology.