Abstract 048: Systolic and Diastolic Ambulatory Blood Pressure Affect Target Organ Damage Differently in Adolescents: The SHIP AHOY Study

Abstract

Hypertensive target organ damage (TOD) is associated with increased risk for CV events. Ambulatory BP (ABP) measures are more strongly related to TOD than casual BP in adults but data in youth are lacking. Our objective was to determine which ABP parameters associated with TOD in adolescents. We evaluated casual BP (mean of 6 measures by auscultation), ABP (Spacelabs OnTrak), anthropometrics, labs, LVM, pulse wave velocity (PWV), diastolic function (E/E’ ratio), and systolic function (global longitudinal strain, GLS) in 132 adolescents (mean 15.8 + 1.4 yrs, 66% white, 57% male). Day, night and 24H SBP and DBP index (mean/95 th %ile for sex and height) and loads (%readings above the 95 th %ile) were defined according to sex and height-specific pediatric cut-points. General linear models were used to determine independent associations between ABP and TOD. Only systolic ABP means and loads were associated with LVMI and diastolic function, while both systolic and diastolic ABP means and loads were associated with PWV. There was a weak association between systolic and diastolic loads and GLS. In multiple regression analysis (full model: demographics, age, BMI, HR, ABP, metabolic profile, CRP) day SBP index was the strongest predictor of LVMI (β=15.2, R 2 0.4, p=0.006) and E/E’ (β=5.2, R 2 0.23, all p=0.007), while day DBP index was the strongest predictor of PWV (β=3.0, R 2 0.37, p<0.0001). Day DBP load was the sole independent ABP predictor of GLS (β=0.05, R 2 0.25, p=0.02). We conclude that during adolescence, systolic and diastolic ABP parameters are differentially associated with TOD: SBP predicted LVMI, while DBP predicted PWV. ABP parameters may be used to evaluate risk for BP-related TOD.