Comparison of functional capacity in patients with end-stage heart failure following implantation of a left ventricular assist device versus heart transplantation:: Results of the experience with left ventricular assist device with exercise trial

Background: Use of a permanent left ventricular assist device (LVAD) has been proposed as an alternate treatment of patients with end-stage heart failure. The purpose of this study was to compare the functional capacity of patients following implantation of a LVAD vs heart transplant (HTx). Methods: Eighteen patients from 6 centers who received an intracorporeal LVAD as a bridge to HTx underwent treadmill testing 1 to 3 months post-LVAD and again post-HTx. Baseline and peak measurements, including oxygen consumption, blood pressures, and respiratory rate were made during each treadmill test. Results: Peak oxygen consumption was 14.5 +/- 3.9 ml/kg/minute post-LVAD and 175 +/- 5.0 ml/kg/minute post-HTx (p < .005). The percentage of the predicted peak oxygen consumption based on gender, weight, and age was 39.5% +/- 5.5% post-LVAD and 47.7% +/- 10.9% post-HTx (p < .005). Exercise duration was lower post-LVAD than post-HTx (10.3 +/- 4.2 minute vs 12.5 +/- 5.4 minute, p < .05). After LVAD implantation, peak total oxygen consumption correlated with peak LVAD rate and output. Eight patients reached an LVAD rate of 120 beats per minute (bpm) before the conclusion of exercise, the maximum rate for the outpatient electric device. The peak respiratory exchange ratio post-LVAD was 1.15 +/- 0.22 and post-HTx was 1.15 +/- 0.18, consistent with a good effort in both groups. Conclusions: Patients demonstrated a lower functional capacity post-LVAD than post-HTx. For some patients functional capacity post-LVAD may be improved by a higher maximum LVAD rate and output.