Abstract 19303: Balloon Pulmonary Angioplasty Improves Right Ventricular Energetic Efficiency via the Improvement of Right Ventricular-Pulmonary Artery Coupling in Patients With Chronic Thromboembolic Pulmonary Hypertension
Introduction: Balloon pulmonary angioplasty (BPA) improves hemodynamics and functional capacity in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). However the impact of BPA on right ventricular (RV) function and energetic efficiency remains unknown. Although the pressure-volume relationship has been originally established in the left ventricle to evaluate load independent index of contractility and energetics, it is applicable to the right ventricle.
Hypothesis: BPA for CTEPH improves the RV energetic efficiency.
Methods: In 15 consecutive patients with CTEPH (62±10 yo, 2 male), we measured RV volumes (RVEDV and RVESV) and stroke volume (SV) by MRI. We measured RV pressure, pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure and cardiac output by right heart catheterization. We derived the RV pressure-volume relationship by merging the result of MRI and catheterization before and after BPA (duration: 73±36 days). We estimated RV contractility, Ees, as the ratio of RV ESP to RVESV and RV afterload, Ea, as the ratio of mean PAP to SV. We estimated the pressure-volume area (PVA) and ventricular-arterial coupling by Ea/Ees as an index of RV energetic efficiency.
Results: BPA significantly improved 6-minute walking distance (403±94 vs. 452±88 m, p<0.01), mean PAP (42±11 vs. 33±8 mmHg, p<0.0001), pulmonary vascular resistance (6.5±2.1 vs. 5.1±2.1 wood units, p<0.0001), RVEDV index (113±42 vs. 102±43 ml/m2, p<0.05), RVESV index (69±45 vs. 61±42 ml/m2, p<0.05) without changing cardiac index (3.5±0.9 vs. 3.4±0.9 L/min/m2, p=0.21). BPA significantly decreased Ea (0.90±0.30 vs. 0.62±0.22 mmHg/ml·m2, p<0.0005) and PVA (3150±1119 vs 2406±997 mmHg·ml/m2, p<0.0005), while did not change Ees (0.65±0.37 vs. 0.63±0.33 mmHg/ml·m2, p=0.32). Therefore, BPA decreased oxygen consumption and lowered Ea/Ees (1.9±1.3 vs 1.4±1.1, p<0.0005), thereby improved energetic efficiency of RV contraction.
Conclusions: BPA markedly improved functional capacity, hemodynamics and energetic efficiency without changing RV contractility. The fact that BPA lessens RV oxygen consumption and improved metabolic efficiency may impact on the hard endpoints in the long term.
Author Disclosures: T. Sakamoto: None. K. Abe: None. K. Horimoto: None. K. Hosokawa: None. K. Oi: None. Y. Mukai: None. Y. Yamasaki: None. M. Nagao: None. K. Sunagawa: None. H. Tsutsui: None.
- © 2016 by American Heart Association, Inc.