Abstract 18354: Chronic Pressure-Dependent Cardiac Unloading With a Novel Intra-Atrial Shunt (V-Wave Device) in an Ovine Model of Ischemic Heart Failure: Evidence for Shunt-mediated Improvements in Function and Survivability

Abstract

Introduction: Progressive elevations in left-ventricular (LV) filling pressures, as occurring during heart failure (HF), increase myocardial energy demand and facilitate maladaptive remodeling. We hypothesized that chronic selective left-atrial unloading can mitigate LV remodeling and functional deterioration in HF. Hence, we studied a novel intra-atrial device designed to act as a selective/pressure-dependent one-way (left-to-right) shunt, implanted in sheep with chronic ischemic HF. Methods: Sheep (45 ± 2 Kg) underwent serial/selective coronary embolizations resulting in chronic left HF (EF: 65±1 to 36±1%, LVIDd: 3.5±0.1 to 4.9±0.1 cm; P<0.05). Subsequently, sheep were instrumented via a thoracotomy with indwelling catheters into the pulmonary artery, the left atrium, and the right atrium/superior vena cava in order to monitor pressures and oxygen saturations. The animals were assigned either to serve as controls (CTRL, n = 7) or had the V-Wave device (n = 14) deployed into the fossa ovalis. After recovery, valved-shunt patency (via Fick’s method), mean atrial/pulmonary pressures, and LV function (echocardiography) were evaluated weekly for up to 12 weeks. Results: The deployed shunts acutely lowered left-atrial pressures (LAP, 17±1 to 14±1 mmHg, P<0.05) without increasing right-atrial/pulmonary-artery pressures. Implanted shunts were patent for the duration of the study (mean Qp/Qs: 1.17±0.03 vs 0.76±0.03 in CTRL, P<0.05). Chronically, shunt-treated sheep had improved LV loading/function when compared to controls, which progressively deteriorated; over the 12-week study, treated sheep had lower filling pressures (LAP: 14±1 vs. 22±2 mmHg in CTRL, P<0.05) and preserved LV function (EF: 42±3 vs. 25±2% in CTRL, P<0.05) . Notably, the 12-week survival in treated animals was 93%, while only 57% of the untreated controls survived the monitoring period. Conclusion: The V-Wave device, a novel intra-atrial shunt designed to selectively unload the left-heart in a pressure-dependent manner, lead to chronically reduced filling pressures, preserved right-sided pressures, and improved LV function in a clinically-relevant chronic model of ischemic heart failure.