Determinants for residual symptoms in chronic thromboembolic pulmonary hypertension patients with mean pulmonary arterial pressure <25 mmHg after balloon pulmonary angioplasty

Abstract

Abstract Background Balloon pulmonary angioplasty (BPA) improves hemodynamics and exercise capacity in inoperable patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, some symptoms, such as dyspnea on exertion, had remained in more than half of the patients even after BPA could decrease mean pulmonary artery pressure (PAP) <25 mmHg in a Japanese multicenter registry. In addition, previous report indicated that impaired exercise capacity was observed in about half of the patients with CTEPH who achieved mean PAP <25 mmHg at rest after BPA. Lowering mean PAP alone would not be sufficient as a treatment goal of BPA to eliminate residual symptoms in the patients. Purpose The purpose of this study was to elucidate the determinants of residual symptom in patients who had achieved mean PAP <25 mmHg after BPA. Methods Among 310 CTEPH patients who received BPA in our center, 217 patients (70.0%) could achieve mean PAP <25mmHg at six months after the final BPA were enrolled in this study. The patients were divided into two groups based on the necessity of additional BPA due to residual symptoms; additional BPA group and non-additional BPA group. Clinical parameters including resting hemodynamics at 6 months follow up were retrospectively investigated between the two groups. Results Additional BPA had been underwent in 67 patients (30.9%). No significant differences in mean PAP were identified between the additional and non-additional BPA groups (20.4±2.5 mmHg vs. 19.7±2.7 mmHg, p=0.106). In additional BPA group, cardiac index (CI), heart rate (HR) and percutaneous oxygen saturation (SpO2) was lower than non-additional BPA group, and pulmonary vascular resistance (PVR) was higher than non-additional BPA group (CI, 2.51±0.41 L/min/m2 vs. 2.72±0.56 L/min/m2, p=0.016, HR, 62.9±9.7 bpm vs. 67.8±10.8 bpm, p=0.003, SpO2, 94.3±3.7% vs. 95.9±3.5%, p<0.001, PVR, 3.67±1.18 W.U. vs. 3.11±1.09 W.U. p=0.001). In a multivariate analysis, CI, SpO2 and PVR were associated with residual symptoms requiring additional treatment in patients with mean PAP <25mmHg after BPA (95% confidence interval: CI; 0.221–0.900, SpO2; 0.825–0.976, PVR; 1.000–1.785). Conclusion Low CI and SpO2 and High PVR were determinants for residual symptoms in CTEPH patients who could achieve mean PAP <25 mmHg after BPA. To eliminate the residual symptoms, treatment goals of BPA in inoperable CTEPH patients should be increasing CI and SpO2 and lowering PVR in addition to normalizing mean PAP. Funding Acknowledgement Type of funding sources: None.