Hypertension Impairs Vascular Reactivity in the Pediatric Brain

• Published in: Stroke (1970) Vol. 42; no. 7; pp. 1834 - 1838
• Main Authors: WONG, Linda J, KUPFERMAN, Juan C, PROHOVNIK, Isak, KIRKHAM, Fenella J, GOODMAN, Sharon, PATERNO, Kara, SHARMA, Madhu, BROSGOL, Yuri, PAVLAKIS, Steven G
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.07.2011
• Subjects: Adolescent; Adult; Biological and medical sciences; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Brain - physiopathology; Carbon Dioxide - metabolism; Cerebrovascular Circulation - physiology; Child; Female; Humans; Hypercapnia - complications; Hypertension - complications; Hypertension - physiopathology; Injuries of the nervous system and the skull. Diseases due to physical agents; Male; Medical sciences; Neurology; Pediatrics; Traumas. Diseases due to physical agents; Ultrasonography, Doppler - methods; Vascular diseases and vascular malformations of the nervous system; Human; Doppler ultrasound study; Hypertension; Stroke; Nervous system diseases; Respiratory disease; Carbon dioxide; Cardiovascular disease; Cerebral disorder; Blood flow; Encephalon; pediatric; Vascular disease; Hypercapnia; transcranial Doppler; Central nervous system disease; cerebral blood flow; cerebrovascular reactivity; Child; Cerebrovascular disease
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/STROKEAHA.110.607606

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. 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. 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. 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.