Clinical Research
Heart Failure
Short-Term Change in Distance Walked in 6 Min Is an Indicator of Outcome in Patients With Chronic Heart Failure in Clinical Practice

https://doi.org/10.1016/j.jacc.2006.02.061Get rights and content
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Objectives

The purpose of this study was to investigate the prognostic value of change in distance walked in 6 min in chronic heart failure (CHF).

Background

The strongest indication for the 6-min walking test (6MWT) is for measuring the response to therapeutic interventions in patients with CHF. Whether the increase in distance walked after a therapeutic intervention translates into improved clinical outcome is largely unknwon.

Methods

We studied 476 CHF patients with left ventricular systolic dysfunction who were referred to our institution for adjustment of heart failure therapy because of persisting or worsening symptoms. Adjustment of therapy involved four classes of drugs: angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, beta-blockers, loop diuretics, and aldosterone antagonists. A standardized 6MWT was performed at baseline and at discharge.

Results

After 15.2 ± 8 days, the distance walked increased from 326 ± 107 m to 408 ± 109 m (+25%; p = 0.001). During a mean follow-up of 23.9 months, 94 patients died and 12 patients underwent cardiac transplantation. Among a set of variables, New York Heart Association functional class (p = 0.02), serum creatinine concentration (p = 0.01), left ventricular ejection fraction (p = 0.002), distance walked at baseline (p = 0.0002), and change in distance walked (p = 0.002) were significant independent predictors of survival. When the patients were divided into two subgroups according to the median value of the distance walked at baseline, the increase in walking distance was significantly associated with survival only in the subgroup of patients who walked <340 m at baseline.

Conclusions

Our data indicate that repeating a 6MWT after drug intervention provides independent prognostic information in CHF patients with more compromised exercise capacity.

Abbreviations and Acronyms

6MWT
6-min walking test
ACEI
angiotensin-converting enzyme inhibitor
ARB
angiotensin II receptor blockers
CHF
chronic heart failure
LVEF
left ventricular ejection fraction
Vco2
exercise carbon dioxide output
Vo2
exercise oxygen consumption

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