Effects of Pulsatile- and Continuous-flow Left Ventricular Assist Devices on Left Ventricular Unloading

Background: In patients with end-stage heart failure, the use of left ventricular assist devices (LVADs) has improved clinical outcomes. Although newer continuous-flow devices have significant advantages, the effect of continuous flow on left ventricular unloading and hemodynamics is less well established. The aim of this investigation was to compare the effects of pulsatile- vs continuous-flow LVADs on left ventricular reverse remodeling and hemodynamic indices. Methods: Thirty-five patients undergoing implantation with a pulsatile volume displacement pump operating at fixed speed (n = 15; HeartMate XVE; Thoratec Corp., Pleasanton, CA) or a continuous-flow rotary pump with an axial design operating at a fixed rotor speed (n = 20; HeartMate II; Thoratec) were evaluated. Right heart catheterization and echocardiography were performed pre-operatively, and at 1- and 6-month follow-up intervals. Results: Thirty-five of 40 eligible patients with end-stage heart failure were included in this study. When used at fixed speed, use of both devices led to a substantial reduction in left ventricular volumes and dimensions at 1 month (p < 0.01). A marked and sustained reduction in filling pressures was also noted with both devices at 1 and 6 months (p < 0.01). The volume and pressure unloading effects of the HeartMate XVE were not superior to those with the HeartMate II (all p-values not statistically significant). Conclusions: Substantial left ventricular unloading and hemodynamic improvement is achieved with the HeartMate XVE and the HeartMate II. We conclude that continuous-flow LVADs are as effective as pulsatile-flow LVADs with regard to degree of left ventricular unloading and cardiac hemodynamics.