Evaluation of the effect of nitric oxide inhalation in the patients with chronic thromboembolic pulmonary hypertension or pulmonary disease during balloon pulmonary angioplasty

Balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension (CTEPH) or pulmonary disease (CTEPD) is performed worldwide. High mean pulmonary arterial pressure (mPAP) during BPA is associated with aggravation of procedure‐related complications. Inhaled nitric oxide (NO) acts as a pulmonary vasodilator in CTEPH patients. The aim of this retrospective observational study was to evaluate the effects of inhaled NO in CTEPH/CTEPD patients during BPA. We assessed hemodynamic changes and the frequency of procedure‐related complications with or without NO inhalation. We performed 338 consecutive BPA in 72 CTEPH/CTEPD patients between April 2016 and November 2020. Since December 2019, all 16 patients (72‐BPA sessions) inhaled NO during the procedure as a routine. Inhaled NO significantly reduced mPAP from 31.3 ± 8.5 to 27.2 ± 6.8 mmHg (p < 0.001) without lowering systemic blood pressure (systolic: 139.9 ± 19.9 vs. 135.3 ± 21.8 mmHg; p = 0.247, diastolic: 82.8 ± 13.0 vs. 79.0 ± 9.3 mmHg; p = 0.085, before vs. after NO inhalation, respectively). Procedure‐related complications were observed in 46 sessions (13.6%). The incidence of hemoptysis was significantly higher in the NO group than in the non‐NO group (20.8% vs. 10.9%; p = 0.031). In contrast, all fatal complications (death and use of positive pressure ventilation) occurred in the non‐NO group, but the difference was not statistically significant (0 sessions [0.0%] vs. 7 sessions [2.6%], p = 0.353). Inhaled NO acts as a selective pulmonary vasodilator in CTEPH/CTEPD patients during the BPA procedure.