Differential exercise performance on ventricular assist device support

Background: Ventricular assist devices (VADs) are approved for destination therapy because they improve survival in end-stage heart failure (HF). VADs are powered pneumatically or electrically. Pneumatic and electric left ventricular assist devices (LVADs) and biventricular assist devices (BiVADs) provide excellent hemodynamic support at rest, but differences in their effects on exercise tolerance are unclear. We sought to evaluate the effect of devices with varying operating parameters on exercise capacity. Methods: Exercise physiology data obtained during maximal exercise with on-line gas-exchange analysis were collected for 38 consecutive VAD-implanted HF patients referred for exercise testing. Results: Electric LVADs were implanted in 18 patients, and pneumatic LVADs in 10 patients. Percent of predicted peak exercise oxygen consumption (Vo₂%) was significantly greater in pneumatic LVAD patients (52.1 ± 11.1% vs 38.2 ± 11.3%, p < 0.05). The 10 patients implanted with a pneumatically powered LVAD were compared to 10 patients implanted with a pneumatically powered BiVAD. LVAD-supported patients had a higher Vo ₂% (52.1 ± 11.1% vs 36.5 ± 17.7%, p < 0.05). Conclusions: HF patients supported with a pneumatic LVAD appear to have better exercise tolerance than those receiving an electric LVAD. Patients on LVAD support have better exercise tolerance than BiVAD-supported patients. This highlights the importance of right ventricular function to exercise tolerance in HF patients, and may have implications for future VAD design.