Christine Kehrer

Angiotensin Receptor Blockade Improves Vascular Compliance in Healthy Normotensive Elderly Individuals: Results From a Randomized Double-Blind Placebo-Controlled Trial

The renin‐angiotensin system (RAS) may play a role in vascular aging. The authors hypothesized that blockade of the angiotensin II type 1 receptor with an angiotensin receptor blocker in healthy elderly subjects improves vascular compliance and endothelial function. Thirty‐five healthy elderly subjects were randomized to valsartan or placebo in a double‐blind crossover study after baseline testing for pulse wave velocity, aortic augmentation index, and brachial artery flow‐mediated dilation. Angiotensin II type 1 receptor blockade with valsartan improved vascular compliance but not flowmediated dilation. Changes in pulse wave velocity with valsartan were correlated with change in central systolic blood pressure and pulse pressure and remained associated on multivariate analysis. Change in pulse wave velocity after adjusting for degree of blood pressure change, age, and sex remained correlated with assignment to the angiotensin receptor blocker but not placebo. These data suggest that angiotensin II type 1 receptor blockade improves aging‐related vascular compliance without alterations in flow‐mediated dilation. Mechanisms regulating compliance and endothelial function are complex and may not necessarily converge in aging.

Valsartan improves insulin sensitivity without altering vascular function in healthy overweight adults without the metabolic syndrome

Background. We investigated hyperactivity of the renin-angiotensin system (RAS) as a cause of endothelial dysfunction in obese humans. Methods. Thirty five healthy overweight (BMI = 33.6 +/- 6.6 kg m (2)) adults (33 +/- 10 years old) without cardiovascular risk factors received valsartan (160 mg) orally daily or a matching placebo for 6 weeks each. Results. Baseline flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD) were not altered by placebo or valsartan. However, fasting plasma insulin was significantly decreased by valsartan compared to placebo (-4.6 +/- 16.0 muUmL(1) versus -0.4 +/- 11.6 muUmL(1), P = 0.032) with no changes in glucose. A secondary analysis in patients with elevated waist to hip ratios (ÿ0.85, n = 18) showed an increase in FMD with valsartan. Conclusions. Our findings suggest that angiotensin 2 receptor blockade may aid in the prevention of diabetes even at the earliest stages of risk due solely to uncomplicated obesity. The lack of an improvement in FMD does not support a central role of RAS-hyperactivity in the etiology of the vascular dysfunction due solely to obesity. However, it is possible that obese patients with central adiposity may improve FMD with RAS blockade, and future investigation is warranted in this subgroup.