P4675The utility of additional balloon pulmonary angioplasty for residual hypoxemia in normohemodynamic chronic thromboembolic pulmonary hypertension patients after invasive treatments

Abstract Background Balloon pulmonary angioplasty (BPA) improves hemodynamics, symptoms and exercise capacity in patients with chronic thromboembolic pulmonary hypertension (CTEPH) who are ineligible for pulmonary endarterectomy (PEA). However, certain patients still have hypoxemia after BPA or PEA despite normalization of hemodynamics. In CTEPH, hypoxemia is related increased dead space ventilation caused by vascular obstruction. Purpose This study was aimed to clarify whether additional BPA can improve hypoxemia of CTEPH patients after normalization of hemodynamics. Methods A total of 335 patients who underwent initial series of BPA in our institute were followed up. Sixty-four patients with mean pulmonary artery pressure (mPAP) <30mmHg and percutaneous oxygen saturation (SpO2) <95% without oxygen inhalation at more than 6 months after the initial series of BPA and of patients who could reevaluate hemodynamics and oxygenation after additional BPA were enrolled. These patients were divided into two groups with or without additional BPA procedures. Change of hemodynamics and SpO2 were retrospectively investigated. Results Thirty-three of 64 patients underwent additional BPA procedures. Patients' age was older in BPA group than those in non-BPA group (71.3±10.4 vs. 66.5±9.4 years old, p=0.02). mPAP and pulmonary vascular resistance (PVR) was significantly higher in BPA group (mPAP: 23.9±3.2 vs. 20.7±3.8 mmHg, p=0.001, PVR: 4.2±1.2 vs. 3.5±1.4 wood unit, p=0.03, respectively). Among the 1.8±1.4 BPA procedures per person, total 6.6±3.8 segmental pulmonary arteries per person were treated. While no obvious improvements were observed in non-BPA group, PVR and SpO2 in BPA group were significantly improved (4.2±1.2 to 3.7±1.3 wood unit, p=0.002, 90.7±3.1% to 94.1±3.6%, p<0.001, respectively). In the multivariate logistic regression analysis, additional BPA procedures were associated with further improvement of SpO2 (hazard ratio, 3.7; 95% confidence interval, 1.2–11.5; P=0.02). Conclusions Additional BPA procedure was associated with improvement of hypoxemia in CTEPH patients after normalization of hemodynamics. Treating as many lesions as possible in BPA might relieve the patients' residual dyspnea.