O1012: Reference Values for Blood Pressure Response During Peak Exercise in Pediatric Patients with Structurally Normal Hearts

Background: A hypertensive blood pressure (BP) response to exercise is a risk factor for the development of hypertension and cardiovascular disease in both pediatric and adult populations. Normative treadmill-based cardiopulmonary exercise testing (CPET) BPs are not well established for the pediatric population. Many labs use a systolic BP (SBP) value of 220 mmHg as the hypertension threshold for all pediatric CPETs. The aim of this study was to establish reference standards for CPET-derived BP response in children and adolescents with structurally normal hearts. Additionally, we sought to determine if there were differences in patient characteristics among those with a normal, elevated, or hypertensive BP response.

Methods: We performed a retrospective analysis of 1,610 CPETs from patients aged 6-18 years without heart disease. Patients included in the study completed the Bruce protocol and achieved a maximal effort CPET (respiratory exchange ratio ≥ 1.10). For analysis, patients were subdivided into the following age groups: 6-9, 10-12, 13-15, and 16-18 years. Age- and sex-specific statistical analyses were performed to determine BP percentiles (%ile) at peak exercise. A normal SBP response to exercise was defined as < 90th %ile, an elevated SBP response was 90th to < 95th %ile, and a hypertensive SBP response was ≥ 95th %ile for age- and sex-specific groups. ANOVA was performed to determine factors associated with abnormal BP response for patients aged 13-18 years. This age group was chosen due to a small number of patients in younger age groups and to align with published adolescent BP guidelines.

Results: The maximal exercise SBP %ile data are presented in Table 1. While peak exercise SBP is similar for males and females during childhood, by adolescence, males have a higher peak SBP than females. A comparison of the normal, elevated, and hypertensive response groups for CPET is presented in Table 2. In both males and females, patients with elevated and hypertensive responses to exercise had higher BMI and higher resting SBP. There were no significant differences in maximal heart rate or peak aerobic capacity based on the peak SBP response to exercise.

Conclusion: Our study provides reference standards for SBP response to peak exercise in pediatric and adolescent patients with structurally normal hearts using the Bruce protocol. We show that a hypertensive BP response to exercise is lower than the commonly used threshold of 220 mmHg across both sexes and all ages. Our data help define pediatric and adolescent BP responses to peak exercise and lay the groundwork for future studies on the prognostic significance of a hypertensive response to exercise.