Impact of aortic valve closure on adverse events and outcomes with the HeartWare ventricular assist device.

BACKGROUND

This study examined whether aortic valve opening (AVO) and other echocardiographic parameters influence outcomes in patients on left ventricular (LV) assist device (LVAD) support. Pump thrombosis (PT) and ischemic stroke (IS) are known complications of LVAD, but mechanisms that could influence them are not completely understood.

METHODS

This was a retrospective analysis of 147 patients who received a HeartWare Ventricular Assist Device ( HeartWare International) as a bridge to transplant or to candidacy between July 2009 and August 2015, of whom 126 had at least 30 days of follow-up before the first event (30-days-out cohort). Outcomes included survival, PT, IS, and PT+IS (combined thrombotic event; CTE).

RESULTS

Median time on support was 518 days. Of the 30-days-out cohort, 29% had a first PT and 19% a first IS. AVO was associated with longer survival on device (1,081 vs 723 days; p = 0.01) in the entire cohort. In the 30-days-out cohort, the aortic valve was more frequently closed in patients with lower ejection fractions on support (14% ± 6% vs 18% ± 9%; p = 0.009), more dilated pre-event echocardiogram (LV end-diastolic diameter, 66 ± 12 mm vs 62 ± 10 mm; p = 0.04), and pre-implant LV end-diastolic diameter (70 ± 10 mm vs 66 ± 9 mm; p = 0.06). CTE-free survival on the device was lower with a closed aortic valve (897 vs 1,314 days; p = 0.003) as was PT-free survival on the device (1,070 vs 1,457 days; p = 0.02). Cox regression analysis showed that AVO was an independent predictor of CTE (p = 0.03) CONCLUSIONS: Thrombotic events are relatively frequent in patients on long-term LVAD support. A closed aortic valve was associated with decreased overall survival, thrombosis-free survival, and poorer LV function on support. These are high-risk patients, so whether they require more intense anti-coagulation or prioritizing for transplantation requires further research.