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

Abstract

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.

Ventricular Flow Field Visualization During Mechanical Circulatory Support in the Assisted Isolated Beating Heart

“…Clinically, it is known that this area is prone to thrombus formation. The apparent low velocities further substantiate the connection between no aortic valve opening and prevalence of thromboembolic events, 8,13,36,37,46 which was also demonstrated in other experimental and simulation studies. 33,43,45,52 To prevent thrombus formation in these regions, LVAD research has focused on periodic or synchronous pump speed changes 21,29,32,52,55 to promote aortic valve opening and minimize potential stagnation areas within the ventricle and the pump.…”

Comparative analysis of cardiac mechano-energetics in isolated hearts supported by pulsatile or rotary blood pumps

“…While it is possible to fully assist the failing left ventricle with an RBP by delivering the entire cardiac output through the pump, it is clinically recognized that at least intermittent aortic valve opening is preferable for various reasons (i.e. thrombus formation, aortic valve function) 26 . Fully assisting the ventricle may also detrimentally affect myocardial reverse remodeling and recovery: A pump in full support unloads the heart but at the potential consequence of leading to atrophy of the myocardium due to excessive reduction in wall stresses.…”

Beat‐to‐beat detection of aortic valve opening in HeartWare left ventricular assist device patients

“…AV opening is increasingly considered a key index of patient‐pump interaction for cf‐LVAD patients, and numerous studies have recognized the importance of AV opening in its associations with multiple cf‐LVAD complications including AV fusion aortic incompetence and thrombosis . Despite this, the assessment of AV opening in cf‐LVAD patients remains problematic, not least because the current standard, intermittent supine resting echocardiography, only provides a brief and non‐dynamic evaluation of AV function.…”

“…Continuous flow LVADs (cf‐LVADs) dramatically alter aortic valve (AV) biomechanics, with preferential ejection of blood through the pump often resulting in reduced or absent AV opening. This results in increased AV leaflet strain and has been linked to increased risk of AV commissural fusion , de novo aortic incompetence and thrombotic events . Numerous studies have also described increased gastrointestinal bleeding risk in patients with a closed AV .…”