Cardiac Rehabilitation Increases the Reliability of the 6-Minute Walk Test in Patients After Coronary Artery Bypass Graft Surgery

Abstract

Background: Few data are available on the capacity for functional exercise after cardiac rehabilitation in patients who have undergone coronary artery bypass graft (CABG) surgery. The aim of this study was to determine the clinical and biochemical factors that affect the 6-minute walk test (6MWT) results in patients who have undergone CABG. Methods: Data were prospectively collected from 56 patients consecutively admitted at our hospital between January 2013 and May 2015 for a 3-month cardiac rehabilitation program. Data were analysed retrospectively up to 90 days after cardiac surgery. In addition to clinical and biochemical parameters, the functional capacity of patients was evaluated by an exercise 6-minute walking test and echocardiography. Functional capacity was evaluated at baseline and after three months of cardiac rehabilitation. Results: Before cardiac rehabilitation, the 6MWT values were negatively correlated with Body Mass Index (BMI) and abdominal and buttock diameters (r = -0.375, -0.386, and -0.370, respectively; P<.05), and were positively correlated with metabolic equivalent (MET) values (r = 0.493, P<.05). After cardiac rehabilitation, the 6MWT values were negatively correlated with body mass index (BMI) and abdominal and buttock diameters (r = -0.382, -0.274, and -0.405, respectively; P<.05) and were positively correlated with MET and VO2 max values (r = 0.456 and 0.573, respectively; P< 0.05). Before cardiac rehabilitation, VO2 max and FEV1/FEVC values were found as factors that significantly increased 6MWT values (P<.05). After cardiac rehabilitation, VO2 max values were found as factors that significantly increased 6MWT values (P<.05). Conclusion: Overall, in current clinical settings, cardiac rehabilitation increases the reliability of the 6MWT. Improvement in pulmonary function after cardiac rehabilitation reduces the impact of pulmonary function on 6MWT values. The functional capacity of patients may be more reliably determined by 6MWT after cardiac rehabilitation.