Comment on six-minute walk test as an outcome measure for the assessment of treatment in intervention trials of chronic heart failure
Alfred Hager
Department of Pediatric Cardiology and
Congenital Heart Disease
Deutsches Herzzentrum München
Klinik an der Technischen
Universität München
Lazarettstr. 36
D-80636 München
Germany
Tel: +49 89 1218 1650
Fax: +49 89 1218 3013
E-mail address: a-hager{at}web.de
Olsson et al.1 outlined in their article that the 6-minute walk test (6MWT) has not yet been proven to be a robust test for identification of the effectiveness of pharmacological treatment because of many even subtle factors influencing the results. They also found that in many studies the exact protocols of the 6MWT were not reported. Especially, practice runs prior to baseline measurements and standardization of patient motivation are urgently needed. In an editorial to that article, Refsgaard2 even suggested that no encouragement at all should be given to the patients during the test. However, as mentioned in the conclusions, the test may be of greater value with more advanced heart failure, where it may function as [a maximal exercise test]. This can hardly be obtained without encouragement. The American Thoracic Society published guidelines3 on the 6MWT, where many details such as the length of the corridor, or even the exact wording of the encouragement and its timing were fixed. If all centers abide by those guidelines, or at least report where they did not, results will be much more comparable.
The golden standard of heart failure assessment (at least for survival4,5 and indication for transplatation)6 remains the maximal cardiopulmonary exercise test (CPET) with measurement of peak
O2, even though it does not reflect daily activity. Also there is a lack of data on patients being treated with ß-blocking agents and/or ICD's, that have proven to prolong survival but do not increase or even decrease
O2max, and a CPET is not as easily performed as a 6MWT.
References
- Olsson LG, Swedberg K, Clark AL, Witte KK, Cleland JG. Six minute corridor walk test as an outcome measure for the assessment of treatment in randomized, blinded intervention trials of chronic heart failure: a systematic review. Eur Heart J 2005;26:778793.[Abstract/Free Full Text]
- Refsgaard J. This is a walking test, not a talking test: the six minute walking test in congestive heart failure. Eur Heart J 2005;26:749750.[Free Full Text]
- ATS. ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002;166:111117.[Free Full Text]
- Myers J, Gullestad L, Vagelos R, Do D, Bellin D, Ross H, Fowler MB. Clinical, hemodynamic, and cardiopulmonary exercise test determinants of survival in patients referred for evaluation of heart failure. Ann Intern Med 1998;129:286293.[Abstract/Free Full Text]
- Cahalin LP, Mathier MA, Semigran MJ, Dec GW, DiSalvo TG. The six-minute walk test predicts peak oxygen uptake and survival in patients with advanced heart failure. Chest 1996;110:325332.[Abstract/Free Full Text]
- Hunt SA, Baker DW, Chin MH, Cinquegrani MP, Feldman AM, Francis GS, Ganiats TG, Goldstein S, Gregoratos G, Jessup ML, Noble RJ, Packer M, Silver MA, Stevenson LW, Gibbons RJ, Antman EM, Alport JS, Faxon DP, Fuster V, Jacobs AK, Hiratzka LF, Russell RO, Smith SC Jr. ACC/AHA guidelines for the evaluation and management of chronic heart failure in the adult: Executive Summary Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1995 Guidelines for the Evaluation and Management of Heart Failure) developed in Collaboration with the International Society for Heart and Lung Transplantation and endorsed by the Heart Failure Society of America. Circulation 2001;104:29963007.[Free Full Text]