Pediatric interventions using noninvasive vascular health indices.

H eart disease is currently the leading cause of death in the world. 1 It is estimated that greater than a third of the population in the United States has at least 1 type of cardiovascular disease. 2 Although its clinical manifestations typically emerge in middle age, the atherosclerotic process begins in childhood. 3 Proatherosclerotic fatty streaks and raised lesions, which are deposits of cholesterol/esters and fibrous plaques, respectively, are seen in children as young as 3 and increase in number and severity with age. 3 Children with cardiovascular risk factors will develop atherosclerosis in adulthood at an accelerated rate. 4 Therefore, interventions during childhood and adolescence could prevent the development of atherosclerosis in adulthood. Noninvasive modalities are ideal to assess these interventions in children because of their safety and feasibility. 5 Some of these techniques include carotid intima-media thickness (IMT) by ultrasound, endothelial function by reac-tive hyperemia, and arterial stiffness by tonometry, oscillom-etry, and ultrasound. 5–7 This article reviews studies of diet, exercise, and pharmacological interventions using noninvasive vascular health indices as outcomes in children and adolescents. An understanding of past investigations will guide future research in this field. One of the earliest detectable cardiovascular changes associated with disease is endothelial dysfunction. In normally functioning vasculature, the endothelium produces nitric oxide in response to shear stress caused by increased blood flow, 8 which results in compensatory vasodilatation. If an appropriate degree of dilation is not reached, this is classified as endo-thelial dysfunction. Endothelial dysfunction can be caused by the reduction of nitric oxide being released or the inactivation of nitric oxide by an excess of reactive oxidative particles. 9 Endothelial dysfunction is proinflammatory and prothrom-botic. 10 However, unlike atherosclerosis, endothelial dysfunc-tion is treatable and reversible. 11 Reactive hyperemia assessment is an established noninva-sive method to assess endothelial function when shear stress in the brachial artery is elicited after temporary occlusion of the vessel. Flow-mediated dilation (FMD), the measurement of the percent change of dimension in the brachial artery during reactive hyperemia using ultrasound, is an independent predictor of future cardiovascular events. 12 Pulse amplitude testing is an alternative method that uses fingertip probes to record arterial pulsatile volume changes. This method is less operator-dependent than FMD and provides a reactive hyper-emia index, a validated predictor for major adverse cardiovas-cular events in adults. Arterial stiffness results in increased central pulse pressure, left ventricular hypertrophy, and lowered perfusion pressure in coronary …