Endothelial dysfunction represents one of the key pathomechanisms in many diseases, including hypertension. Peripheral arterial tonometry (PAT) evaluates the functional status of microvascular endothelium and offers a biomarker of early, potentially reversible, vascular damage. This study aimed to assess endothelial function using conventional and novel indices of PAT in pediatric hypertensives. As such, 100 adolescents with normal blood pressure, and essential and white-coat hypertension were examined using EndoPAT 2000. Conventional reactive hyperemia index (RHI) and novel indices of hyperemic response, including the area under the curve of hyperemic response (AUC), were evaluated. AUC was the only parameter sensitive to the effect of hypertension, with significantly lower values in essential hypertensives compared to normotensives and white-coat hypertensives (p = 0.024, p = 0.032, respectively). AUC was the only parameter significantly correlating with mean ambulatory monitored blood pressure (r = -0.231, p = 0.021). AUC showed a significant negative association with age (p = 0.039), but a significant positive association with pubertal status indexed by plasma levels of dehydroepiandrosterone (p = 0.027). This is the first study reporting early signs of microvascular endothelial dysfunction evaluated using PAT in adolescents with newly diagnosed essential hypertension. Detailed analysis of hyperemic response using overall magnitude indexed by AUC provided a more robust method compared to the conventional evaluation of RHI.
Keywords: adolescence; blood pressure; endothelial function; essential hypertension; peripheral arterial tonometry; white-coat hypertension.