COMMON CAROTID ARTERY ELASTICITY, INTIMA-DIAMETER RATIO, AND TENSILE STRESS IN PEDIATRIC PATIENTS WITH PRIMARY HYPERTENSION

Abstract

Objective: Elevated blood pressure (BP) lead to increased thickness of arterial wall and increased diameter of arteries, are risk factors of cardiovascular sequelae in adult populations. Intima-diameter ratio (IDR) and tensile stress (TS) may reflect arterial wall-remodeling to elevated BP. The aim was to evaluate common carotid artery elasticity, IDR, and TS in children with primary hypertension (PH). Design and method: 50 untreated patients with PH and we evaluated: common carotid artery(CCA) intima-media thickness (cIMT) and elasticity(E-tracking - ET), central BP and aortic elasticity (aPWV,AIx75HR), office BP and ABPM, and clinical, and biochemical data. IDR (cIMT/minimal diameter of CCA[D]) and TS (MAP∗D/cIMT) were calculated in all the subjects. Results: Patients with PH compared to CG were characterized by significantly higher peripheral, central office and ambulatory BP, BMI Z-score, uric acid, triglycerides, lower HDL-cholesterol and higher aPWV. PH patients had thicker cIMT and larger CCA D. The groups did not differ in parameters of CCA elasticity: beta stiffness index, CCA pulse wave velocity(PWVbeta) and pressure-strain elasticity modulus(Ep) and in IDR(0.08 ± 0.01vs.0.08 ± 0.02,p = 0.479) and TS(584.9 ± 135.5mmHg vs.529.7 ± 84.2,p = 0.095). We found correlations between cIMT(Z-score) and triglycerides, peripheral SBP Z-score, and ABPM MAP 24 h Z-score. CCA D correlated with BMI Z-score, uric acid and HDL-cholesterol, 24 h systolic blood pressure load(SBPL), Central systolic blood pressure(AoSBP) and peripheral diastolic BP Z-score. We found significant correlations between TS and uric acid, 24 h diastolic blood pressure load, and peripheral systolic and diastolic blood pressure Z-scores. There was no association between IDR and BP except for a weak correlation between IDR and SBPL. In PH patients, there was a strong correlation between cIMT and CCA D(r = 0.790,p < 0.001). Conclusions: In children with PH, structural changes and decreased elasticity primarily affect the aorta and to a lesser extent the muscular arteries. In children with PH, both CCA wall thickness and internal diameter are associated with BP, and are significantly higher in children with PH. The changes observed in the carotid artery are probably adaptive in nature, not associated with impaired arterial function, thus intima-diameter ratio or tensile stress measurement does not appear to contribute additional information in this group of patients.