Clinical Experience of HeartMate II to HeartWare Left Ventricular Assist Device Exchange: A Multicenter Experience

Background: Despite improvements in pump design and durability, left ventricular assist device patients still suffer from life-threatening complications such as pump thrombosis (PT) and infection, often necessitating device exchange. Surgical exchange from HeartMate II (HM2; Abbott, Pleasanton, CA) to another HM2 is safe and associated with low mortality, but recurrent device thrombosis rates are high. Switching from axial-flow to centrifugal-flow pump, such as the HeartWare ventricular assist device (HVAD; Medtronic, Framingham, MA) may offer certain advantages due to it being a smaller, newer generation device, although there are limited data to support this strategy. Herein, we aimed to assess the surgical approach and feasibility, safety, and outcomes of surgical exchange from HM2 to HVAD.

Methods: We evaluated HM2 patients who underwent device exchange to HVAD due to PT or infection at 4 large-volume left ventricular assist device implant centers.

Results: Twenty-four patients underwent HM2 to HVAD exchange due to PT (92%) and refractory infection (8%). Patients were male (75%), white (88%), with ischemic cardiomyopathy (54%), Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) scale level 1-3 (90%), and destination therapy (62%). The majority underwent redo-sternotomy (79%) and the remainder underwent minimally invasive thoracotomy with subcostal approach. The existing HM2 outflow graft was maintained in 79% of cases. Recurrent PT was noted in 9% of patients. Mortality was 8% at 30 days and 33% at 1 year.

Conclusions: The surgical exchange from a HM2 to HVAD is safe and feasible, despite the differences in device specifications and surgical adaptation required. Newer-generation pumps are increasingly considered for exchange in the setting of HM2 device complication, and increasing experience with modified surgical approaches may be valuable in the current era.