Several studies have demonstrated endothelial dysfunction in patients with essential hypertension. However, the presence of endothelial dysfunction in children with white-coat hypertension has not been studied. We evaluated the endothelial function in children with white-coat hypertension and essential hypertension using a novel method based on the assessment of flow-mediated dilation (FMD). Study involved 106 children: 30 white-coat hypertensives (age 16.3 ± 1.3 years, mean ± SD), 30 essential hypertensives (age 16.4 ± 1.3 years), and 46 healthy controls (age 16.2 ± 1.4 years). Ultrasound scans of the right brachial artery were performed using Prosound F75 Aloka system during protocol: baseline (1 min), forearm ischemia (5 min), and post-occlusion phase (3 min). FMD (%) was expressed as a change of the arterial diameter from baseline to maximum post-occlusion value and the values < 5% were considered as deficient FMD. We found significantly lower FMD in both essential and white-coat hypertension compared to control group (p < 0.05 for both) with no significant difference between the hypertensive groups. Deficient FMD was found in both hypertensive groups, but not in the control group. The occurence of deficient FMD was significantly higher in both essential and white-coat hypertensives compared to controls (p < 0.01 for both) with no significant difference between the hypertensive groups. Our findings of endothelial dysfunction indicated by impaired FMD in pediatric patients with white-coat hypertension could help to elucidate the mechanisms of the increased cardiovascular risk that could be similar as found in essential hypertension; therefore, white-coat hypertension should not be considered a benign phenomenon.
Keywords: Children; Endothelial function; Essential hypertension; Flow-mediated dilation; White-coat hypertension.