788-1 The 6-Minute Walk Test Predicts Maximal Oxygen Consumption and Survival in Advanced Heart Failure

Abstract

Although maximal oxygen consumption (MVO 2 ) is useful in predicting prognosis and need for cardiac transplantation (TX) in patients with advanced heart failure (HF), its determination requires sophisticated equipment. The six-minute walk test (6-MW) is a simple indirect measure of functional capacity, and predicts survival in moderate HF To assess the predictive value of the 6-MW, MVO 2 , and percent predicted age-sex adjusted MVO 2 (%MVO 2 ) in advanced HF, 45 pts (age 49 ± 8 yrs mean ± SD, LVEF 0.20 ± 0.06, RVEF 0.31 ± 0.11) underwent cardiopulmonary exercise testing (cycle ergometry) and the 6-MW during TX evaluation. Mean 6-MW distance ambulated was 310 ± 100 meters, MV02 12.2 ± 4.5 ml/kg/min, and %MVO 2 38 ± 11%. Multivariate analysis of patient characteristics, resting hemodynamics and 6-MW (age, sex, weight, peak HR and BP during the 6-MW, right and left ventricular ejection fraction, right atrial pressure, mean pulmonary artery pressure, and cardiac index) identified distance ambulated during the 6-MW as the strongest predictor of MVO 2 (p < 0.000) and %MVO 2 (p < 0.000). In univariate survival analysis, 6-MW > 300 meters predicted survival to the combined end-point death or hospital admission for inotropic/mechanical support (IN) as a bridge to TX (p < 0.05). but not overall survival (p = 0.075). In multivariate proportional hazards survival analysis designed to compare %MVO 2 , MVO 2 , and 6-MW, MVO 2 was selected as the best predictor of overall survival, and %MVO 2 as the best predictor of IN-free survival. 6-MW was not selected in any multivariate analysis. In pts with advanced HF evaluated for TX, distance ambulated during the 6-MW predicts 1) MVO 2 and %MVO 2 and 2) IN-free survival but not overall survival. MVO 2 and %MVO 2 may be superior to the 6-MW as predictors of survival in these pts: however, further studies to es1ablish the prognostic utility of the 6-MW in pts with advanced HF are warranted.