Executive function and cerebrovascular reactivity in pediatric hypertension.

Primary hypertension is associated with decreased performance on neurocognitive testing and a blunted cerebrovascular reactivity to hypercapnia. Parents of 14 children with hypertension and prehypertension completed the Behavior Rating Inventory of Executive Functions. Children underwent 24-hour ambulatory blood pressure monitoring and transcranial Doppler with reactivity measurement using time-averaged maximum mean velocity and end-tidal carbon dioxide during hypercapnia-rebreathing test. Comparing the reactivity slope for the patients to historical controls showed a statistically significant difference (t = -5.19, df = 13, P < .001), with lower slopes. Pearson correlations of the Behavior Rating Inventory of Executive Functions scores with the reactivity slopes showed a statistically significant inverse relationship with Behavioral Regulation Index (r = -.60, P = .02), Metacognition Index (r = -.40, P = .05), and the Global Executive Component (r = -.53, P = .05). Children with hypertension have decreased executive function, and this correlates to low transcranial Doppler-reactivity slopes, suggesting that the brain is a target organ in hypertensive children.

Hypertension impairs vascular reactivity in the pediatric brain.

BACKGROUND AND PURPOSE: Chronic hypertension impairs cerebrovascular regulation in adults, but its effects on the pediatric population are unknown. The objective of this study was to investigate cerebrovascular abnormalities in hypertensive children and adolescents. METHODS: Sixty-four children and adolescents aged 7 to 20 years underwent transcranial Doppler examinations of the middle cerebral artery at the time of rebreathing CO2. Time-averaged maximum mean cerebral blood flow velocity and end-tidal CO2 were used to quantify cerebrovascular reactivity during hypercapnia. Patients were clinically categorized as hypertensive, prehypertensive, or white coat hypertensive based on 24-hour ambulatory blood pressure measurements. Their reactivities were compared with 9 normotensive control subjects and evaluated against baseline mean blood pressure z-scores and loads. RESULTS: Untreated hypertensive children had significantly lower hypercapnic reactivity than normotensive children (2.556 +/- 1.832 cm/s x mm Hg versus 4.256 +/- 1.334 cm/s x mm Hg, P < 0.05). Baseline mean diastolic blood pressure z-scores (r = -0.331, P = 0.037) and diastolic blood pressure loads (r = -0.351, P = 0.026) were inversely related to reactivity. CONCLUSIONS: Untreated hypertensive children and adolescents have blunted reactivity to hypercapnia, indicating deranged vasodilatory reactivity. The inverse relationship between diastolic blood pressure indices and reactivity suggests that diastolic blood pressure may be a better predictor of cerebral end organ damage than systolic blood pressure.

The effects of hypertension on the paediatric brain: a justifiable concern.

The prevalence of hypertension in children is increasing but its neurological effects are under-recognised. Here, we describe acute and chronic effects of childhood hypertension on the nervous system. Acute neurological involvement ranges from posterior reversible encephalopathy syndrome to, possibly, infarction and haemorrhage. Children with chronic hypertension are likely to have learning disabilities and deficiencies in executive function, which are potentially reversible with antihypertensive treatment. These cognitive defects may be secondary to abnormal regulation of cerebral blood flow. Raised blood pressure in childhood could also contribute to the early development of atherosclerosis, which can have both short-term and long-term adverse effects on vasculature. Clinical studies are needed to better define the full clinical range of paediatric hypertension on a child's nervous system. Furthermore, accurate biomarkers to define cognitive abnormalities and cerebral involvement need to be identified.

Improvement of left ventricular mass with antihypertensive therapy in children with hypertension.

There is paucity of data on the regression of left ventricular hypertrophy (LVH) in hypertensive children. This study assessed the effects of antihypertensive therapy on left ventricular mass in children with and without LVH. Medical records of hypertensive patients who had a baseline and follow-up echocardiogram (echo 1, echo 2) were reviewed. Fifteen of 22 treated patients had LVH at echo 1. Enalapril alone or combined was used in 21/22 cases. Echo 2 was performed at a mean interval of 15 +/- 7 months. The LVH group showed significant decrease in systolic blood pressure z-score (SBPZ) (2.89 +/-1.61 to 1.40 +/- 1.19; p=0.01), diastolic blood pressure z-score (DBPZ) (1.44 +/- 0.90 to 0.26 +/- 0.82; p<0.001), and LV mass index (LVMI) (56.2 +/- 12.50 to 43.7 +/- 8.30; p=0.001), but no significant change in body mass index z-score (BMIZ) (1.79 +/- 0.75 to 1.69 +/- 0.69; p=0.74). In the no-LVH group, SBPZ (3.03 +/- 1.68 to 2.27 +/- 1.81; p=0.356), DBPZ (1.00 +/- 0.87 to 0.63 +/- 0.68; p=0.409), BMIZ (1.08 +/- 0.98 to 1.27 +/- 0.89; p=0.672), and LVMI (29.47 +/- 5.51 to 33.89 +/ -3.06;p=0.374) did not change significantly. Simple linear regression demonstrated that the change in LVMI in the combined group had a significant correlation (r=0.477; p=0.025) with the percentage change in SBPZ. This study demonstrates that LVH in hypertensive children improves with effective blood pressure control.