Six-minute walk distance predicts VO_{2 (max)} in patients supported with continuous flow left ventricular assist devices

Background: Six-minute walk distance (6MWD) and maximal oxygen uptake (VO_2max) are used as prognostic tools in patients with heart failure (HF). Whether these tests provide similar information in the LVAD population is not known. Methods: Eight patients supported with VentrAssist rotary blood pump LVADs, underwent three days of testing that included 6MWD and VO_{2 max} at normal, high or low speeds, generating twenty-four paired results. Results: The mean 6MWD was 438 (+/- 90 SD) m and the mean VO_{2 (max)} was 14.12 (+/-1.87) ml/kg/ min. There was a modest correlation between VO_{2 (max)} and 6MWD (r = 0.56 p = 0.004), which improved (r = 0.72 p = 0.002) when patients with higher resting Pro BNP levels and larger left ventricular end diastolic diameters (LVEDD) were excluded. Conclusions: 6MWD is correlated with VO_{2 (max)} in LVAD supported patients, with higher correlations in patients with better underlying cardiac function.