Current assessment of treatment adequacy in congestive heart failure (CHF) relies on subjective reporting of symptoms, physical findings, and New York Heart Association Functional Class (NYHA-FC). Newer measures include B-Type Natriuretic Peptide (BNP) and the Kansas City Cardiomyopathy Questionnaire (KCCQ), a disease-specific quality of life (QoL) measure. The six-minute walk test (6MWT) is a simple measure that is reproducible and correlates with prognosis. This study was designed to describe the relationships of the 6MWT to other measures.
55 outpatients with CHF (left ventricular ejection fraction (LVEF) ≤40% and recent hospitalization) were enrolled over six months. A standard 6MWT was performed and baseline BNP was measured. LVEF was obtained from echocardiogram or ventriculogram (radionuclide or angiographic). NYHA-FC was assigned by the treating physician. Patients completed the KCCQ, providing a global estimate of QoL, ranging from 0 to 100. Correlation coefficients were obtained and linear regression analyses were performed.
There was an inverse correlation between six-minute walk distance (6MWT) and Functional class(NYHA-FC) (r=0.14, p=0.008) and a positive correlation with the KCCQ-QoL score (r=0.11, p=0.019). There was no significant correlation between walk distance and BNP or LVEF.CONCLUSIONS: The 6MWT correlates well with NYHA-FC, and KCCQ-QoL - both well-validated methods of assessing patients with CHF. Objective measures such as 6MWT, BNP, QoL and LVEF provide additional information in assessing status of CHF. The simple, reproducible, and inexpensive 6MWT correlates well with NYHA functional classification and KCCQ scores.
The 6MWT provides similar prognostic information as similar information toother measures of CHF at a fraction of the cost in dollars, time, and potential risk. This test is commonly used as a research tool, but remains underutilized in practice. The results of this study suggest that the 6MWT may have a place in assessing the continuing care of CHF.
D.M. Safley, None.