Proof of Concept. Hemodynamic Response to Long-Term Partial Ventricular Support With the Synergy Pocket Micro-Pump

Objectives: The purpose of this study was to test the hemodynamic effects of partial ventricular support in patients with advanced heart failure. Background: The use of current left ventricular assist devices (VADs) that provide full circulatory support is restricted to critically ill patients because of associated risks. Smaller, less-invasive devices could expand VAD use to a larger pool of less-sick patients but would pump less blood, providing only partial support. Methods: The Synergy Pocket Micro-pump device (CircuLite, Inc., Saddle Brook, New Jersey) pumps ∼3.0 l/min, is implanted (off pump) via a mini-thoracotomy, and is positioned in a right subclavicular subcutaneous pocket (like a pacemaker). The inflow cannula inserts into the left atrium; the outflow graft connects to the right subclavian artery. Results: A total of 17 patients (14 men), age 53 ± 9 years with ejection fraction 21 ± 6%, mean arterial pressure 73 ± 7 mm Hg, pulmonary capillary wedge pressure 29 ± 6 mm Hg, and cardiac index 1.9 ± 0.4 l/min/m² received an implant. Duration of support ranged from 6 to 213 (median 81) days. In addition to demonstration of significant acute hemodynamic improvements in the first day of support, 9 patients underwent follow-up right heart catheterization at 10.6 ± 6 weeks. These patients showed significant increases in arterial pressure (67 ± 8 mm Hg vs. 80 ± 9 mm Hg, p = 0.01) and cardiac index (2.0 ± 0.4 l/min/m² vs. 2.8 ± 0.6 l/min/m², p = 0.01) with large reductions in pulmonary capillary wedge pressure (30 ± 5 mm Hg vs. 18 ± 5 mm Hg, p = 0.001). Conclusions: Partial support appears to interrupt the progressive hemodynamic deterioration typical of late-stage heart failure. If proven safe and durable, this device could be used in a relatively large population of patients with severe heart failure who are not sick enough to justify use of currently available full support VADs. (Safety and Performance Evaluation of CircuLite Synergy; NCT00878527).