LAUSR

Introduction: Left Ventricular Assist Devices (LVAD) decrease cardiac mechanical work and metabolic demand and may decrease cardiomyocyte oxidative stress, followed by cell cycle re-entry and cell regeneration. We tested whether LVAD long-term support is associated with myocardial regeneration. Methods: Viability fluorodeoxyglucose (18FDG) - positron-emission tomography scans were performed >3 months after LVAD implantation and every 6 months thereafter. 4 patients aged 18-70 with end-stage non-ischemic (NICM, n=3) or ischemic cardiomyopathy (ICM, n=1) were included. Low metabolic activity myocardial regions of interest (ROI) at <15th percentile of relative 18FDG signal intensity were identified on the baseline scan. Global signal and co-registered low-intensity ROIs were analyzed on subsequent scans vs. baseline. Results: LV ejection fraction ranged 0-35% at baseline. Two patients (LVAD speed 2660 rotations per minute - RPM, output 3.4-4.1 and 5.6-5.9 liters per minute (LPM), respectively) underwent 2 scans before cardiac transplantation, exhibiting borderline increased global signal (1-4%) and significantly increased 18FDG signal in the baseline low-intensity ROI on the follow-up scan (67.7, 75.7%). The other 2 patients (LVAD parameters: 5600 RPM/ 4.6-5.8 LPM; 9200 RPM/ 4.3-4.8 LPM) exhibited decreased global 18FDG signal (10-16%) and increased signal in the co-registered baseline low-intensity ROIs (1.7-21.5%) (Figure). Conclusions: LVAD long-term support is associated with a global decrease in myocardial 18FDG uptake signal over time, and with increased viability signal in baseline low-intensity ROIs, suggestive of myocardial regeneration in metabolically inactive regions. Future research is required to identify patient subgroups that are most likely to exhibit high regeneration potential upon long-term LVAD support.