Abstract P033: Higher Ambulatory Sbp Is Associated With Increasing Number Of Target Organ Abnormalities In Youth: The Ship Ahoy Study

Abstract

Hypertension is associated with elevated left ventricular mass index (LVMI), cardiac dysfunction and increased arterial stiffness in adults which predict cardiovascular (CV) events. The extent to which elevated BP in youth is associated with subclinical CV target organ damage (TOD) is not known. We explored the relation between BP level and number of TOD abnormalities (nTOD). We measured clinic and ambulatory BP (ABP), anthropometrics, and nTOD in 244 adolescents (mean 15.5 + 1.8 years, 67% white, 60% male). Subjects were recruited as low-risk (L=98, SBP%<80 th %), mid-risk (Mid=60, SBP% 80-<90 th %); and high-risk (H=86, SBP% >=90 th %) based on mean of 6 aneroid clinic BPs by age-, sex- and height-specific cut-points. 24-hour ABP was measured with an oscillometric device per pediatric guidelines. Four measures of TOD were: LVMI > 38.6 g/m 2.7 ; LV systolic strain (Strain %) > -18; LV diastolic function (E/e’) > 8; pulse wave velocity (PWV) > 5.8 m/sec. ANOVA was used to evaluate differences in CV risk factors and chi square for differences in nTOD across groups. Logistic regression models were used to determine if clinic and/or ABP was an independent predictor of nTOD after adjustment for age, sex, race, and BMI z-score. BP groups did not differ in BMI z-score. Clinic and ABP systolic and diastolic BP increased across BP groups. The distribution of nTOD was shifted towards higher BP group with most nTOD= 0 (47%) in the L and all (100%) nTOD = 4 in the H group (X 2 = 0.08) and became significant when L (clinic SBP<75 th %) was compared to M+H (clinic SBP > 80 th %; X 2 =0.04). Daytime ABP index (subject daytime systolic ABP/95 th % for daytime systolic ABP) and BMI z-score (both p < 0.003) were significantly associated with nTOD in a model containing clinic SBP, age, sex and race (other covariates NS; full model p < 0.0001, R 2 =0.22). We conclude that higher ABP is associated with a greater number of cardiac and vascular abnormalities in youth. ABP should be applied in youth with elevated BP to evaluate need for intensification of therapy to prevent CV TOD.