Abstract 16348: Does the 6 Minute Walk Test Provide Useful Prognostic Information in Systolic Heart Failure Patients?
Introduction: The Six Minute Walk (6MW) test is a convenient and inexpensive test of physical function, but concerns remain regarding reliability of the information it provides for systolic heart failure (SHF) patients. Peak oxygen consumption (VO2) and minute ventilation-carbon dioxide production (VE/VCO2) slope obtained from cardiopulmonary exercise (CPX) testing are often regarded as better prognosticators than 6MW distance (D).
Methods: We compared 6MWD and CPX results collected at baseline in HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise TraiNing) patients with stable SHF (LVEF≤35%) to assess their relationship with all-cause death/hospitalization and all-cause death (based on C-indices) over the 4-year trial. The degree of association between 6MW and CPX parameters was examined with unadjusted correlations and partial correlation coefficients from covariate-adjusted models. Covariates were identified using multivariable proportional hazard models with backward elimination methods. Prognostic power of 6MWD and CPX parameters was compared in separate multivariable proportional hazard models.
Results: 2054 of the 2331 HF-ACTION patients had both 6MW and treadmill-based CPX data (1317 NYHA class II; 737 NYHA class III); median age was 59 years, 29% were women. 6MW distance (median; interquartile range) was 372 (300, 434) meters. Peak VO2 was 14.6 (11.7, 17.7) ml/kg/min and VE/VCO2 slope was 32.4 (28.1, 38.3). 6MWD correlated significantly with peak VO2 and VE/VCO2 slope, respectively: unadjusted r = 0.537 and -0.259 and adjusted r = 0.333 and -0.176 (p<.0001 in all). C-indices for 6MWD to predict hospitalization/death and death (unadjusted and adjusted) were similar to those for peak VO2 and VE/VCO2 slope (Table).
Conclusion: In stable NYHA Class II-III SHF outpatients, 6MWD, even when adjusted for key covariates, provides valuable prognostic information comparable to that provided by peak VO2 and VE/VCO2 slope.
- © 2011 by American Heart Association, Inc.