The Six-Minute Walk Test Predicts Peak Oxygen Uptake and Survival in Patients With Advanced Heart Failure

Abstract

The 6-min walk test (6'WT) is a simple measure of functional capacity and predicts survival in patients with moderate heart failure (HF). 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. Mean 6'WT distance ambulated was 310 +/- 100 m and peak oxygen uptake (peak Vo2) was 12.2 +/- 4.5 mL/kg/min. There was a significant correlation between 6'WT distance ambulated and peak Vo2 (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 Vo2 (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 Vo2 was the best predictor of long-term overall and event-free survival. In patients with advanced HF evaluated for cardiac transplantation, distance ambulated during the 6'WT predicts (1) peak Vo2 and (2) short-term event-free survival.