Six-minute walk distance predicts VO2 (max) in patients supported with continuous flow left ventricular assist devices

Abstract

Background: Six-minute walk distance (6MWD) and maximal oxygen uptake (VO2max) 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 VO2 max at normal, high or low speeds, generating twenty-four paired results. Results: The mean 6MWD was 438 (+/- 90 SD) m and the mean VO2 (max) was 14.12 (+/-1.87) ml/kg/ min. There was a modest correlation between VO2 (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 VO2 (max) in LVAD supported patients, with higher correlations in patients with better underlying cardiac function. © 2014 Wichtig Publishing.