Abstract
Elevated brachial blood pressure (BP) in childhood tracks into adulthood. Central BP and measures of arterial stiffness, such as aortic augmentation index (AIx) and pulse wave velocity (PWV), have been associated with future cardiovascular disease. This pilot study assessed the feasibility of noninvasively measuring these parameters in preschool children and explored factors that may be associated with elevated BP in this age group. Brachial BP was measured using an electronic oscillometric unit (Dinamap PRO 100) and defined as elevated when systolic BP (SBP) and/or diastolic BP (DBP) was ≥ the 90th percentile for age, gender, and height. Central BP, AIx, and PWV were measured using applanation tonometry (SphygmoCor). C-reactive protein (CRP) was measured in serum samples. Sixteen African-American preschool children were recruited (4.4 ± 0.8 years, 69% males), 6 (38%) of whom had an elevated brachial BP (110 ± 10/69 ± 4 vs. 96 ± 8/55 ± 6 mm Hg, Cohen's d = 2.2). Children with elevated brachial BP had higher central SBP (d = 1.6) and DBP (d = 1.96) (97 ± 6/68 ± 4 vs. 85 ± 8/57 ± 6 mm Hg), AIx (d = 0.88) (31 ± 8 vs. 18 ± 16%, standardized to heart rate), and CRP (3.1 [2.3-6.3] vs. 0.1 [0.1-0.3] mg/dL, d = 2). There was no significant difference in PWV between groups (d = 0.26). CRP and SBP (Spearman r = 0.70), DBP (r = 0.68), central SBP (r = 0.58), and central DBP (r = 0.71) were positively correlated. Wide confidence intervals for the estimated effect sizes indicated a large degree of uncertainty about all estimates due to the small sample size. Noninvasive assessment of central BP and arterial stiffness is feasible in preschool children. Vascular inflammation may be an important factor that influences BP at an early age. Further studies in preschool children are needed to elucidate mechanisms of early onset hypertension.