Does the 6-minute walk test predict the prognosis in patients with NYHA class II or III chronic heart failure?, ,

Background We prospectively evaluated the potential of the 6-minute walk test compared with Peak V̇ o2 in predicting outcome of patients with New York Heart Association (NYHA) class II or III heart failure. Methods and Results Patients with a history of heart failure caused by systolic dysfunction were included. The combined final outcome (death or hospitalization for heart failure) was used as the judgment criterion. One hundred twenty-one patients (age 59 ± 11 years; left ventricular ejection fraction 29.6% ± 13%) were included and followed for 1.53 ± 0.98 years. Patients were separated into two groups according to outcome: group 1 (G1, 74 patients), without events, and group 2 (G2, 47 patients), who reached the combined end point. Peak V̇ o2 was clearly different between G1 and G2 (18.5 ± 4 vs. 13.9 ± 4 ml/kg/min, p = 0.0001) but not the distance walked (448 ± 92 vs 410 ± 126 m; p = 0.084, not significant). Survival analysis showed that unlike Peak V̇ o2, the distance covered was barely distinguishable between the groups (p < 0.08). However, receiver operating characteristic curves revealed that the best performances for the 6-minute walk test were obtained for subjects walking ≤300 m. These patients had a worse prognosis than those walking farther (p = 0.013). In this subset of patients, there was a significant correlation between distance covered and Peak V̇ o2 (r = 0.65, p = 0.011). Thus it appears that the more severely affected patients have a daily activity level relatively close to their maximal exercise capacity. Nevertheless, the 300 m threshold suggested by this study needs to be validated in an independent population. Conclusions A distance walked in 6 minutes ≤300 m can predict outcome. Moreover, in these cases there is a significant correlation between the 6-minute walk test and Peak V̇ o2 demonstrating the potential of this simple procedure as a first-line screening test for this subset of patients. (Am Heart J 1998;136:449-57.)