Lung diffusion capacity and efficiency of pulmonary gas exchange in chronic thromboembolic pulmonary hypertension

Aim: to study lung diffusion capacity and efficiency of pulmonary ventilation in patients with chronic thromboembolic pulmonary hypertension (CTEPH) depending on the severity of pulmonary hypertension. Materials and Methods. The study included 139 patients with CTEPH. The parameters of body plethysmography, lung diffusion capacity, efficiency of pulmonary ventilation and their interrelation with results of angiopulmonography were assessed. Results. Patients were divided according to systolic pulmonary artery pressure (SPAP): group 1-< 50, group 2-50-80, group 3-> 80 mm Hg. The lung diffusion capacity and the efficiency of pulmonary ventilation in patients with CTEPH were reduced against the background of normal spirometric parameters, most pronouncedly in group 3. Regression analysis revealed an inverse relationship between severity of pulmonary hypertension and lung diffusion capacity (regression coefficient-13.7 [-19.1;-8.3], p<0.001), pulmonary ventilation efficiency (regression coefficient-1.4 [-3.5;-0.1], p=0.046), and arterial oxygenation (regression coefficient-1.3 [-2.0;-0.7], p=0.001). Conclusion. In patients with CTEPH against a background of normal basic spirometric parameters, the lung diffusion capacity and efficiency of pulmonary ventilation were significantly decreased, most pronouncedly at SPAP > 80 mm Hg. The results of the study demonstrate the close relationship between pulmonary hypertension and respiratory ventilation-diffusion disorders in patients with CTEPH.