We sought to evaluate the efficacy and safety of refined balloon pulmonary angioplasty (BPA) in the treatment of patients with chronic thromboembolic pulmonary hypertension (CTEPH). BPA is rapidly evolving therapeutic option for patients with nonsurgical CTEPH. There are few US studies that have reported on the outcomes of this novel therapeutic option. This is a retrospective study of CTEPH patients that underwent BPA at Temple University Hospital. The primary efficacy endpoint was the change in pulmonary vascular resistance (PVR) after BPA as compared to baseline and the primary safety endpoint was the rate of hemoptysis within 24 hours. Secondary endpoints included death, WHO functional class, and 6-minute walk distance (6MWD). We used logistic regression to evaluate factors associated with a hemodynamic and functional response. A total of 211 BPA sessions were performed on 77 patients (average 2.7 ± 1.7 sessions/patient). After BPA the mean PVR improved by 26% (P<0.001) while the mean 6MWD improved by 71.7 meters (P <0.001) and WHO functional class improved by one functional class (P 3 BPA sessions per patient. This single center study from the US showed that BPA with refined techniques in patients with CTEPH was safe and was associated with significant improvements in pulmonary hemodynamics and functional capacity.