The six-minute walk test predicts peak oxygen uptake and survival in patients with advanced heart failure

Background: The 6-min walk test (6'WT) is a simple measure of functional capacity and predicts survival in patients with moderate heart failure (HF). Methods: To assess the role of the 6'WT in the evaluation of patients with advanced HF, 45 patients (age 49±8 years, mean±SD; New York Heart Association class 3.3±0.6; left ventricular ejection fraction 0.20±0.06; right ventricular ejection fraction 0.31±0.11) underwent symptom-limited cardiopulmonary exercise testing and the 6'WT during cardiac transplant evaluation. Results: Mean 6'WT distance ambulated was 310±100 m and peak oxygen uptake (peak V̇O₂) was 12.2±4.5 mL/kg/min. There was a significant correlation between 6'WT distance ambulated and peak V̇O₂ (r=0.64, p<0.001). Multivariate analysis of patient characteristics, resting hemodynamics, and 6'WT results identified the distance ambulated during the 6'WT as the strongest predictor of peak V̇O₂ (p<0.001). 6'WT distance ambulated less than 300 m predicted an increased likelihood of death or pretransplant hospital admission for continuous inotropic or mechanical support within 6 months (p=0.04), but did not predict long-term overall or event-free survival with a mean follow-up of 62 weeks. Peak V̇O₂ was the best predictor of long-term overall and event-free survival. Conclusions: In patients with advanced HF evaluated for cardiac transplantation, distance ambulated during the 6'WT predicts (1) peak V̇O₂ and (2) short-term event- free survival.