Capacidade funcional e nível de atividade física emCoronariopatas: estudo de validade do incremental shuttlewalk test

Abstract

Coronary artery disease (CAD) is among the leading burdens of disease worldwide.In Brazil, CAD has high rates of hospitalizations, and high costs for the Unified healthsystem. In medium and low incomes countries, there is a scarce implementation ofsecondary prevention strategies, such as Cardiac Rehabilitation (CR). Although CRis a multi-component program, physical exercise is considered the main. Recentguidelines on CR delivery in underdeveloped countries emphasize the need ofidentify and use of more accessible and low-cost approaches. Therefore, theidentification of simpler and more effective tests to evaluate functional capacity isindicated as a way to classify patients who have lower risk of participate in physicalexercise programs without performing tests considered gold standard, as well as tomonitor the progression of functional capacity throughout the training. In this way, theobjectives of this study were (1) to evaluate the validity of a walking test, known asIncremental Shuttle Walk Test (ISWT) and (2) to test it as a risk stratification tool inRC, also analyzing its relationship with other assessment instruments physicalactivity. This is an exploratory cross-sectional study carried out at the CardiacRehabilitation Section of the Hospital das Clinicas of Belo Horizonte / MG, rightlyapproved by the Research Ethics Committee. To attend the objective, patients withCAD, adults and clinically stable patients referred to the CR Service were submittedto the ISWT, after performing the maximum stress test (ST). In addition, wore apedometer for 7 days and completed the Godin-Shepherd Leisure-Time physicalactivity questionnaire to identify the level of physical activity. Furthermore, thedistance walked in the ISWT, the metabolic equivalents of the task (MET) achieved inthe ISWT were calculated from formulas available in the literature for walking tests.Through the receiver operating characteristic curve (roc curve), the best distance andMET obtained by the ISWT were identified that showed better sensitivity andspecificity to identify the 7 MET cutoff point in the exercise test (considered as one ofthe parameters for low risk of moderate intensity exercise). Correlation analyzes bythe Spearman method were made among the variables obtained by the variousinstruments to assess functional capacity and level of physical activity. Data areexpressed as mean ± standard deviation. One hundred and fifteen patients (82 men),aged 59 ± 9.44 presented 7.57 ± 2.51 MET in the ST; walked 370,27 ± 120,85meters of distance, equivalent to 4,38 ± 0,90 MET in the ISWT; mean of steps perday of 4,556.71 ± 3,280.88 and 13.08 ± 15.19 points in the physical activityquestionnaire. The correlation both ISWT distance and MET with the MET of the STwas moderate (0,58 and 0.61 respectively) and significant (p = 0.001), but weak andsignificant with the mean steps per day and the questionnaire score. MET in theISWT and the walking distance accurately predicted the MET of the ST (area underthe ROC curve = 0.79). The ability to walk more than 410 meters in the ISWTpredicted a specificity of 81.5% and a sensitivity of 65.6%, functional capacity above7 MET in the ST. In conclusion, ISWT is an alternative way to evaluate functionalcapacity and can contribute to the process of identifying low-risk patients for acardiac event during exercise at moderate-intensity.