Abstract 9203: Relationships Among Left Ventricular Geometry, Arterial-Ventricular Stiffening and Insulin Resistance in Childhood Obesity

Abstract

Background: Insulin resistance has been implicated in the mechanism of cardiovascular dysfunction in adulthood obesity. However, few studies have examined insulin resistance and cardiovascular function in overweight/obese children. The purpose of this study is to assess the relationship between arterial-ventricular stiffness and cardiovascular risk factors in children. Methods: Echocardiography was performed in 146 children aged 7 to 15 years (BMI 18 to 34 kg/m2). Left ventricular (LV) end-diastolic volume, LV mass, transmitral peak flow velocity (E), and mitral annular myocardial velocity (Em) were measured. LV mass/volume ratio was calculated. Stroke volume (SV) was measured using aortic diameter and pulsed Doppler velocity profile. SV was indexed for body surface area (SVI). Effective arterial elastance (Ea) was estimated by end-systolic pressure/SVI. End-systolic elastance (Ees) was calculated by a modified single-beat method. End-diastolic elastance (Ed) was calculated from Doppler indices reflective of atrial pressures (E/Em) and the diastolic filling volume (SV). High sensitive C-reactive protein (hs-CRP), fasting glucose, insulin, and homeostasis model assessment for insulin resistance (HOMA-IR) were also assessed. Results: Ea, Ees, and Ed all increased significantly with BMI(r = 0.33, 0.26, and 0.34, p < 0.01, respectively). LV mass/volume ratio was positively associated with increased BMI (r = 0.48, p < 0.01). There were significant relationships between BMI and fasting glucose (r = 0.20, p < 0.05), insulin (r = 0.61, p < 0.01), HOMA-IR (r = 0.64, p < 0.01), and hs-CRP (r = 0.41, p < 0.01). Ea, Ees, Ed, and LV mass/volume ratio correlated significantly with insulin(r = 0.34, 0.28, 0.27, and 0.36, p < 0.01, respectively) and HOMA-IR (r = 0.31, 0.24, 0.23, and 0.35, p < 0.01, respectively). No significant relationships were observed between LV mass/volume ratio and arterial-ventricular stiffness and hs-CRP. Conclusions: Insulin resistance, concentric LV hypertrophy, and combined arterial-ventricular stiffening may contribute to the increased prevalence of later cardiovascular diseases.