Abstract 16805: Early Short-Term Unloading with Left Ventricular Assist Device Prevents Remodeling, Reduces Regional Hypertrophy After Myocardial Infarction via Multiple Pathways
Introduction Left ventricular assist device (LVAD) has garnered great interest recently for its remodeling reversal of end-stage heart failure (HF). However, recovery sufficient to permit device removal is low, with relatively high incidence of early HF recurrence. In the present study, we utilized early intervention and placement of a minimally-invasive axial LVAD post-MI to prevent cardiac remodeling after MI.
Methods Eighteen sheep were used in the study. Six sheep underwent an apical MI and were unloaded with an axial LVAD in first 2 weeks and terminated at 12 weeks. Eight sheep with MI and Four sham sheep were used as control. Sixteen sonomicrometry transducers were implanted to record the deformation of the end-diastolic LV geometry (diastolic strain). Global hypertrophy was evaluated by mass index. Regional hypertrophy in non-ischemic adjacent zone (AZ) and remote zone (RZ) of MI were evaluated by thickness of free wall of the LV and cardiomyocyte size. Three pro-hypertrophic pathways, PI3K/Akt/GSK-3β, Calcineurin/NFAT, Raf/MEK/ERK1/2 pathway were investigated regionally.
Results LV dilation and dysfunction post MI were mitigated in the MI+LVAD group (LVEDV: 85.9±7.3 ml vs 106.1±14.3 ml; EF: 44.9±1.7% vs 39.4±2.4%, P<0.05). Adjacent zone strain was exacerbated in the MI group, whereas MI+LVAD group strain was ameliorated in comparison. Regional hypertrophy was evident in adjacent zone compared with in remote zone in the MI group (thickness of the wall: 0.96±0.13cm vs 0.71±0.22cm; the increase of cardiomyocyte size: 76.2±6.1% vs 14.5±3.5%, P<0.05). There was no significant regional hypertrophy in the MI+LVAD group. All the three mechanical stress related hypertrophic pathways were activated in the adjacent zone in MI group but not in MI+LVAD group as shown in table 1.
Conclusions Early short-term LVAD unloading could prevent cardiac remodeling; reduce regional hypertrophy after MI through inhibiting the activation of multiple hypertrophic pathways.
- © 2011 by American Heart Association, Inc.