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
Andrea Passantino, MD*,
Rocco Lagioia, MD,
Filippo Mastropasqua, MD and
Domenico Scrutinio, MD
Division of Cardiology and Cardiac Rehabilitation, IRCCS Fondazione Salvatore Maugeri, Institute of Cassano Murge, Bari, Italy.
Manuscript received November 29, 2005;
revised manuscript received January 18, 2006,
accepted February 17, 2006.
* Reprint requests and correspondence: Dr. Andrea Passantino, Fondazione "S. Maugeri" IRCCS, Istituto di Cassano Murge, 70020 Cassano Murge (Bari), Italy. (Email: apassantino{at}fsm.it).
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.
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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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