STRETCH Study: Effect of Distensibility on Endothelial-Dependent Vasoreactivity in Patients With ISH

* Explore several independent variables as potential independent predictors of vascular stiffness and endothelial function. These parameters include patient age, body mass index, gender, renal disease, history of cardiovascular disease, serum cholesterol, and antihypertensive medication use. * Provide insight into nitric oxide-dependent endothelial function in the setting of increased arterial stiffness by determination of substances in the nitric oxide signaling pathway (specifically, levels of serum cGMP; serum nitrate and nitrite; and serum asymmetric dimethylarginine \[ADMA\], an endogenous inhibitor of nitric oxide synthase). * Provide insight into changes in AGE levels and collagen metabolism in response to alagebrium therapy \[specifically, AGEs: pentosidine, carboxymethyllysine, carboxyethyllysine, furosine; Collagen markers: procollagen I carboxyterminal propeptide (PICP), procollagen type I N terminal propeptide (PINP), cross-linked carboxyterminal telopeptide of Type I collagen (ICTP), n-terminal propeptide of type III procollagen (PIIINP)\]. * Provide insight into changes in markers of inflammation in response to alagebrium therapy \[specifically, free and total serum matrix metalloproteinase-1(MMP-1), free tissue inhibitor of metalloproteinase 1 (TIMP1), intercellular adhesion molecule-1 (ICAM), P-selectin, von Willebrand factor (vWf), interleukin-6 (IL-6), and high-sensitivity C reactive protein (hs CRP)\].