Relation between renal function within the normal range and central and peripheral arterial stiffness in hypertension

Chronic kidney disease is accompanied by increased large-artery stiffness, but the relation between glomerular filtration rate within the reference range and central or peripheral arterial stiffness has been understudied. The link between renal function and arterial stiffness was assessed in 305 patients with never-treated essential hypertension (men: 58%; age: 48 +/- 11 years, blood pressure: 151/95 +/- 20/11 mm Hg), free from overt cardiovascular disease and with serum creatinine values < 1.4 mg/dL (men) and < 1.2 mg/dL (women), who underwent noninvasive aortic and upper-limb pulse wave velocity (PWV) determination. Aortic PWV was strongly related to age (r=0.55; P < 0.001), whereas upper-limb PWV had a weaker nonlinear relation with age (ss=1.392; P < 0.001 for age; ss=-1.312; P < 0.001 for age squared) and a weak relation with aortic PWV (r=0.22; P < 0.001). Glomerular filtration rate (GFR), estimated according to the Mayo clinic equation for healthy subjects, was inversely correlated with large-artery stiffness, as assessed by aortic PWV (r= -0.34; P < 0.001), and with peripheral artery stiffness, as assessed by upper-limb PWV (r=-0.25; P < 0.001). In a multivariate linear regression, aortic PWV was independently predicted by age (ss=0.48; P < 0.001), mean arterial pressure (ss=0.14; P = 0.013), and GFR (ss=-0.13, P = 0.029). Upper-limb PWV was predicted by GFR (ss=-0.24; P < 0.001) and mean arterial pressure (ss=0.20; P < 0.001). We conclude that, in hypertensive patients with normal renal function, an inverse relationship exists between GFR and stiffness of both central elastic and peripheral muscular arteries. These relations are in part independent from the effect of several confounders, including age, sex, and blood pressure values.