Methodological Issues of Assessment of Six-minute Walk Test in Patients with Coronary Artery Disease

Abstract

The six-minute walk test (6MWT) is an easily performed and well-studied method for assessing exercise tolerance. Despite its availability, there are no standardized approaches to the evaluation of test results in patients with coronary artery disease (CAD). The current review summarizes the evidence and the practical issues of the 6MWT data interpretation in CAD patients. It is recommended by researches to follow current recommendations and protocols of 6MWT in order to achieve high accuracy and reproducibility of the test. The value of the 6MWT distance depends on gender, age, anthropometric and echocardiography parameters. Multiple tests on the same patient cannot be recommended due to the possible development of the “learning effect”. The prognostic value of the 6MWT results was recently established in patients with various diseases. The value of the 6MWT distance ≤ 300 meters in patients with heart failure with a reduced ejection fraction was associated with a significant increase in the risk of death and cardiovascular events; stable results of the 6MWT within one year were associated with a higher survival rate of patients. The concept of the minimally clinically significant difference (MCSD) in the distance of the 6MWT during cardiac rehabilitation of patients was presented. According to the recent data, the MCSD of the 6MWT distance in patients after acute coronary syndrome was 25 meters. The data of our research, the main methods and examples of calculating changes in the 6MWT distance are presented in the article. The results obtained indicate that a comprehensive analysis and simultaneous use of several methods of the 6MWT distance assessment improve the accuracy of rehabilitation results evaluation. Thus, the 6MWT is an affordable way to assess exercise tolerance. It may provide reliable information about changes in the functional capacity of CAD patients in everyday clinical practice.