Abstract 18774: Increased Central Artery Pulse Pressure and Stiffness in Overweight/Obese African-American Adolescents
Background: Obesity is an independent predictor of blood pressure (BP) elevation in African American (AA) adolescents. However, whether overweight/obese AA adolescents demonstrate greater changes in central compared with peripheral artery pulsatile BP components and stiffness is largely unknown.
Methods: Peripheral (brachial) and central (aorta) artery BP, augmentation index adjusted to heart rate of 75 bpm (AI%HR75, generalized transfer function, Sphygmocor), carotid-femoral (CF) and carotid-radial (CR) artery pulse wave velocity (PWV), and body composition (dual energy x-ray absorptiometry) were determined in 59 overweight/obese (BMI percentile,% ≥85; age 17.0 ± 0.2 yrs; 28M/31F; BMI%= 93 ± 1) and 103 normal-weight (BMI% <85; age 16.8 ± 0.1 yrs; 61M/42F; BMI%= 53 ± 1) AA adolescents (age range 15-19 yrs).
Results: Overweight/obese subjects demonstrated higher central pulse pressure (PP, 43 ± 1 vs. 38 ± 1 mmHg, P=0.03) and CF-PWV (5.8 ± 0.1 vs. 5.4 ± 0.8 m/sec, P<0.01) compared with normal-weight. In contrast, mean BP and other central and peripheral BP components, CR-PWV and AI%HR75 did not differ between groups (all P>0.05). In the pooled cohort, CF-PWV, but not CR-PWV, was associated with BMI% (r=0.24, P<0.01), weight (r=0.27, P<0.01), body fat% (r=0.18, P=0.02), waist (r=0.23, P<0.01) and hip girth (r=0.23, P<0.01), after adjusting for age, gender, height, heart rate and mean BP. After the same adjustments, central systolic BP and PP were associated with BMI%, body fat%, weight, waist and hip girth (range r=0.18 to r=0.24, all P<0.05); whereas peripheral PP was related only to BMI% and weight (r=0.17 and 0.22, P<0.05). Central and peripheral diastolic BPs were inversely related to BMI%, body fat%, weight, and waist (r=-0.17 to -0.27, all P<0.05).
Conclusions: Overweight/obese AA adolescents demonstrate higher central artery PP and stiffness, but not peripheral PP, stiffness or augmentation index, compared with their normal-weight peers. These data suggest an augmented forward central, rather than reflected, pressure wave may contribute to the higher central artery PP in this group. Whether these altered central pulsatile hemodynamics are clinical predictors of target organ damage in overweight/obese AA adolescents remains to be investigated.
- © 2010 by American Heart Association, Inc.