Clinical benefits of partial circulatory support in New York Heart Association Class IIIB and Early Class IV patients

Abstract

Full mechanical support with a left-ventricular assist device (LVAD) is generally limited to end-stage heart-failure patients. We have been studying the safety and efficacy of the partial support Synergy® Pocket Micro-pump as bridge-to-transplant in a less-sick group of patients as a prelude to a study of its use for destination therapy. The CircuLite® Synergy device is implanted via a small right-sided thoracotomy with an inflow cannula in the left atrium and an outflow graft connected to the right subclavian artery without the use of extracorporeal circulation. The micro-pump is the size of an AA battery, sits in the 'pacemaker' pocket subcutaneously in the right clavicular groove and pumps up to 3.0 l min⁻¹ from the left atrium to the right subclavian artery. The device has been implanted in 27 patients awaiting cardiac transplant (22 males), age 54.8 ± 10.0 years with ejection fraction (EF) 21 ± 6%, mean arterial pressure 73.5 ± 8.8 mm Hg, pulmonary capillary wedge pressure (PCWP) 27.5 ± 7.8 mm Hg and cardiac index (CI) 2.0 ± 0.4 l min⁻¹ m⁻². Duration of support has ranged from 6 to 281 days. Right-heart catheterization showed significant hemodynamic improvement in the short- and intermediate term after implant, with increases in CI from 2.0 ± 0.4 to 2.8 ± 0.6 l min⁻¹ m⁻² (p < 0.001) and reductions in PCWP from 28 ± 6 to 18 ± 7 mm Hg (p = 0.002) at an average of 9.5 ± 5.5 weeks. The Synergy device provides partial hemodynamic support and its use is associated with significantly improved hemodynamics, thus appearing to interrupt and partially reverse the progressive hemodynamic deterioration typical of end-stage heart failure. Ongoing efforts are aimed at demonstrating additional clinical benefits and continuing to further improve the risk/benefit ratio.