Low total antioxidative capacity levels are associated with augmentation index but not pulse-wave velocity

It is well known the relationship between oxidative stress and vascular function. However, association between total antioxidative capacity and arterial stiffness was not studied in patients with hypertension (HT). This study investigated whether total antioxidative capacity is associated with arterial stiffness and wave reflections. We studied 46 (age 48.5 +/- 10.6 years) never treated patients with HT and age-matched control group of 40 (age 47 +/- 8.6 years) normotensive individuals. Total antioxidative capacity level was determined in all subjects. We evaluated arterial stiffness and wave reflections of the study population, using applanation tonometry (SphygmoCor). Carotid-femoral pulse-wave velocity (PWV) was measured as index of aortic stiffness. The heart rate-corrected augmentation index (AIx@75) was estimated as a composite marker of wave reflections and arterial stiffness. Carotid-femoral PWV (10.5 +/- 2.2 vs 8.7 +/- 1.6, m/s, P = 0.0001) and AIx@75 (22.7 +/- 9.5 vs 15 +/- 11, %, P = 0.001) were significantly higher in patients with HT compared with age-matched control subjects. Total antioxidative capacity level (274 +/- 70 vs 321 +/- 56 micromol/l, P = 0.001) was significantly lower in hypertensive patients than controls. In the whole population, total antioxidative capacity level negatively correlated with AIx@75 (r = -0.24, P = 0.02) in univariable analysis, but not with carotid-femoral PWV (r = -0.08, P = 0.43). Also, we found that total antioxidative capacity level (beta = -0.21, P = 0.03) was an independent determinant of AIx@75 in multivariable analysis. Our results suggest that the decrease in the ability of antioxidant defenses contributes significantly to increased wave reflections.