Aim. To evaluate the effect of non-invasive ventilation (NIV) in CPAP (continuous positive airway pressure) mode on the development of reperfusion pulmonary edema after percutaneous balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH).Materials and methods. The study included 70 patients with CTEPH who underwent the first stage of BPA. Prevention of reperfusion edema was carried out using NIV in the CPAP mode starting from the early postoperative period in combination with oxygen and diuretic therapy (as nedeed). The presence and severity of pulmonary edema was assessed based on clinical signs and data from computed tomography or chest radiography.Results. Patients after BPA were on CPAP therapy: average pressure: 10.0±0,7 hPa. During 1st day, the average time of use was: 990±417 minutes. Prolongation of CPAP therapy >1 day occurred in 26 (37%) patients. Depending on the severity of reperfusion edema to the lungs, patients were divided into 2 groups: group 1 (grade 1, n=42) and group 2 (grade 3-4, n=12). During the observation period, there were no cases of severe reperfusion edema (grade 5), and no cases required the use of invasive ventilation or extracorporeal membrane oxygenation. No complications of CPAP therapy were recorded. The number of PA segments and ΔPFG did not differ, but the PEPSI index was higher in group 2: 41,9 [16,0; 57,9] vs 80.5 [52,5; 111,25], p=0,0146. The number of days before discharge after BPA in patients of group 2 was higher: 4.0 [3,9; 5,5] vs 7,0 [4,6; 10,0] days, p=0,013. Despite the development of reperfusion edema, before discharge the SpO2 values in group 2 were comparable to the baseline: 93,0 [89,9; 94,2] vs 93,0 [89,7; 94,4]Conclusion. Preventive use of NIV in the CPAP mode, starting from the early postoperative period, is safe and makes it possible to achieve optimal clinical results in patients even with moderate and severe lung reperfusion edema after large volumes of surgical intervention.