Impact of Aortic Valve Closure on Adverse Events and Outcomes with the HeartWare HVAD

It is not known whether aortic valve opening (AVO) is beneficial or detrimental in patients with continuous flow ventricular assist devices (VAD). Retrospective analysis of 147 patients that received a HeartWare HVAD® as bridge to transplant or bridge to candidacy between July 2009 and August 2015, of whom 126 had at least 30 days follow-up before first event. Aortic valve opening (AVO) included complete opening, partial in every cardiac cycle, or in only a proportion of cycles but on a regular basis. The aortic valve was considered closed when it was completely closed, when opening was very occasional and not regular, or the leaflets moved slightly without demonstrable flow through the valve. Outcomes included survival, pump thrombosis (PT), and ischemic stroke (IS), or combined thrombotic event (PT + IS = CTE). Median time on HVAD support was 495 days (IQR 228-1045). Mean device speed was 2584±185 rpm. Of the 126 patients with at least 30 days of follow-up until first event, 29% had an episode of first PT, and 19% IS. Aortic valve did not open in 37% of patients. AVO was associated with better survival on device (1180 vs 617 days; p=0.01) in the whole cohort of 147 patients. In the 126 patients with at least 30 days of follow-up before events, AV was more frequently closed in patients with worse ejection fraction on support (14±6% vs 18±9%; p=0.009), more dilated pre-adverse event echocardiogram (LV end-diastolic diameter (LVEDD): 66±12 mm vs 62±10 mm; p=0.04) and pre-implant LVEDD (70±10 mm vs 66±9 mm; p=0.06). CTE-free survival on the device was significantly lower in patients with a closed aortic valve (median 791 vs 1426 days; p=0.008) as well as PT-free survival on the device (median 1063 vs 1689 days; p=0.05). Aortic valve closure was associated with worse post-implant LV function, greater LV dilatation, and increased likelihood of serious thrombotic adverse events. This reflects the higher risk profile of those subjects with very poor post-operative LV function and dilated ventricles. Prospective studies are required to determine whether ensuring aortic valve opening reduces thrombotic risk and overall survival.