Reference values for blood pressure response to cycle ergometry in the first two decades of life : comparison with patients with a repaired coarctation of the aorta

BACKGROUND: It is now common practice to use hemodynamic responses to exercise as markers of diagnosis for cardiac diseases in children, systolic blood pressure especially. However, the reference values for SBP in children at peak exertion level are outdated, and, without a current definition of normal, clinicians cannot determine the physiologically impaired. OBJECTIVE: This study aimed to establish current reference values for peak systolic blood pressure (SBP), rate pressure product (RPP), and circulatory power (CircP). A secondary aim was to compare the values to pediatric patients after correction of coarctation of aorta (CoA). METHODS: Medical records were used from past children who underwent cycle testing at Wilhelmina Children's Hospital. These records were categorized as healthy (N=184), and CoA patients (N=25). Mean age of the healthy was 12.6±2.9 years (range: 6.2 -18.6 years), mean age of the CoA patients was 13.0±3.2 years (range: 6.1- 18.7 years). With the Lambda-Mu-Sigma (LMS) method, smooth percentile curves were made to show normal distributions of SBP, CircP, and RPP in function of Wpeak. The LMS method normalizes data through a power transformation that stretches and shrinks the tails of the distribution to remove skewness. Reference data were compared to that of the CoA patients to validate the reference values. RESULTS: Regression analysis showed that peak work rate was the best predictor of peak blood pressure during exercise. SBP could be described the best by the equation: (0.2853 x Wpeak) + 111.46; CircP by: (10.56 x Wpeak) + 2550.2. and RPP by: (61.879 x Wpeak) + 19887. Compared with the reference values, the CoA patients showed significantly increased values for SBP at peak exercise (Z-score 1.063 ± 1.347). CONCLUSION: This study provides reference values for SBP, RPP, and CircP at peak exercise. These values can be used for objective evaluation of participants 6-18 years of age in a Dutch population