Six-Minute Walk Distance Predicts VO 2 (max) in Patients Supported with Continuous Flow Left Ventricular Assist Devices

Abstract

Background

Six-minute walk distance (6MWD) and maximal oxygen uptake (VO_{2 max}) 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 VO₂ 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.