Abstract 10045: Higher Renal Vascular Resistance is Associated With Greater Body Mass Index in Children

Abstract

Background: Obesity is associated with increased risk for cardiovascular and renal diseases, however, there has been little focus on renal vascular function. The purpose of this study is to assess renal vascular flow regulation and investigate their relation to cardiovascular risk factors in obese children. Methods: Noninvasive ultrasonographic measurements were made in 108 overweight/obese children aged 7 to 13 years (body mass index 18 to 33kg/m 2 ). Using color Doppler sonography, peak systolic (PSV), end-diastolic (EDV), and average peak flow (APV) velocities of renal artery were measured. Pulsatility index as a parameter of vascular resistance was calculated. Pulsatility index was defined as (PSV-EDV)/APV. Quantitative B-mode ultrasound scans were used to measure intima-media thickness and diameters of the common carotid artery. Plasma lipid concentrations, uric acid, homeostasis model assessment of insulin resistance, and high sensitivity C-reactive protein were assessed in the obese children. Results: Compared with overweight children with body mass index <25 kg/m 2 , pulsatility index in obese children with body mass index≥25 kg/m 2 was significantly higher (1.24 ±0.13 vs. 1.13 ±0.14 cm/sec, p < 0.01), because APV and EDV were significantly lower (35 ±3 vs. 38 ±7 cm/sec and 21± 3 vs. 25 ±5 cm/sec, p <0.05, respectively), although PSV was not significantly different. Pulsatility index correlated significantly with body mass index (r =0.58, p < 0.01), insulin (r = 0.24, p < 0.05), homeostasis model assessment of insulin resistance (r =0.25, p < 0.01), triglycerides (r = 0.26, p < 0.01), uric acid (r = 0.22, p < 0.05), systolic blood pressure (r = 0.31, p < 0.01), and carotid intima-media thickness (r = 0.36, p<0.01). Renal blood flow velocities did not correlate with high sensitivity C-reactive protein. Conclusions: The present study indicates that obesity can adversely affect renal vascular flow and resistance in children. Obesity-related insulin resistance may be a main risk factor for renal vascular flow changes. Obesity not only is a risk factor for later cardiovascular disease, but also is associated with significant impairment of renal arterial flow dynamics.