Magnitude and time course of changes induced by continuous-flow left ventricular assist device unloading in chronic heart failure: insights into cardiac recovery

Abstract

Objectives: This study sought to prospectively investigate the longitudinal effects of continuous-flow left ventricular assist device (LVAD) unloading on myocardial structure and systolic and diastolic function.

Background: The magnitude, timeline, and sustainability of changes induced by continuous-flow LVAD on the structure and function of the failing human heart are unknown.

Methods: Eighty consecutive patients with clinical characteristics consistent with chronic heart failure requiring implantation of a continuous-flow LVAD were prospectively enrolled. Serial echocardiograms (at 1, 2, 3, 4, 6, 9, and 12 months) and right heart catheterizations were performed after LVAD implant. Cardiac recovery was assessed on the basis of improvement in systolic and diastolic function indices on echocardiography that were sustained during LVAD turn-down studies.

Results: After 6 months of LVAD unloading, 34% of patients had a relative LV ejection fraction increase above 50% and 19% of patients, both ischemic and nonischemic, achieved an LV ejection fraction ≥ 40%. LV systolic function improved as early as 30 days, the greatest degree of improvement was achieved by 6 months of mechanical unloading and persisted over the 1-year follow up. LV diastolic function parameters also improved as early as 30 days after LVAD unloading, and this improvement persisted over time. LV end-diastolic and end-systolic volumes decreased as early as 30 days after LVAD unloading (113 vs. 77 ml/m(2), p < 0.01, and 92 vs. 60 ml/m(2), p < 0.01, respectively). LV mass decreased as early as 30 days after LVAD unloading (114 vs. 95 g/m(2), p < 0.05) and continued to do so over the 1-year follow-up but did not reach values below the normal reference range, suggesting no atrophic remodeling after prolonged LVAD unloading.

Conclusions: Continuous-flow LVAD unloading induced in a subset of patients, both ischemic and nonischemic, early improvement in myocardial structure and systolic and diastolic function that was largely completed within 6 months, with no evidence of subsequent regression.

Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. Serial echocardiographic changes

LVEDVI (left ventricular end diastolic volume index), LVEF (left ventricular ejection fraction), LVESVI (left ventricular end systolic volume index). Data is presented as means and confidence intervals, *p

Figure 2. Relative increase in left ventricular ejection fraction (LVEF) defined as ‘pre-LVAD to highest LVEF post-LVAD’

Data is presented as percentages, means and confidence intervals, *p

Figure 3. Highest left ventricular ejection fraction (LVEF) achieved after LVAD unloading

Data is presented as percentages, means and confidence intervals, *p

Figure 4. Serial changes on diastolic function echocardiographic parameters

E=mitral valve inflow early velocity, E′= early diastolic motion of the mitral annulus. Data is presented as means and confidence intervals, *pvs. Pre LVAD.