Metabolic equivalent of exercise stress test explained by six-minute walk test in post coronary artery bypass graft and post percutaneous coronary intervention patients

Abstract

© 2014, Medical Association of Thailand. All rights reserved. Objective: To investigate the relationship among metabolic equivalents of an exercise stress test (METs of EST), demographic parameters (age, body weight, height, BMI), peak oxygen consumption (VO<inf>2</inf> peak), and six-minute walk distances (6MWD) determined from a six-minute walk test (6MWT). Material and Method: Exercise capacity was estimated by a 6MWT and EST at the sixth week post operation in post coronary artery bypass graft (post CABG, n = 17) and post percutaneous coronary intervention (post PCI, n = 13) patients. Results: METs of EST showed: high correlation (p<0.01) with VO<inf>2</inf> peak of 6MWT (r = 0.94), 6MWD (r = 0.92); muscle strength (r = 0.78), moderate correlation (p<0.01) with height (r = 0.53); negative correlation with age (r = -0.50). Low correlation was found (p<0.05) with step length (r = 0.43), and weight (r = 0.38). No correlation was found among METs of EST and rating perceived exertion (RPE) of EST and 6MWT. The multiple linear regression equation for explaining METs of EST is as follows: METs of EST = -2.94+0.02 (6MWD), (r = 0.923, R² = 0.85, p<0.001). Conclusion: The 6MWT may possibly be used as an alternative choice for estimating energy expenditure to design exercise programs for these post operation groups.