Effect of Telmisartan on Forearm Postischemic Hyperemia and Serum Asymmetric Dimethylarginine Levels

BACKGROUND: Although telmisartan may be more beneficial for glucose metabolism than other angiotensin II receptor blockers (ARBs), it has not been determined whether telmisartan exerts more favorable effects on biological and functional parameters related to endothelial function than other ARBs. METHODS: A study with a crossover design was conducted in 40 hypertensive patients (61 +/- 10 years old, mean +/- SD) who had previously been treated with ARBs other than telmisartan or valsartan (ie, ARBs were switched to either telmisartan 40 mg/day or valsartan 80 mg/day, administered alternately for 12 weeks each). Blood examinations were conducted, and the mean reactive hyperemia ratio (mRHR) was measured by plethysmography for each treatment regimen. RESULTS: There were no significant differences in either blood pressure or plasma levels of monocyte chemoattractant protein-1, C-reactive protein, 3-nitrotyrosine, or vascular cell adhesion molecule-1 between the two treatment regimens. The mRHR (2.7 +/- 1.0 v 2.4 +/- 1.0, mean +/- SD) was larger (P < .05), and the plasma levels of asymmetric dimethylarginine (ADMA) (0.45 +/- 0.08 v 0.50 +/- 0.17 micromol/L, mean +/- SD) and the homeostasis model assessment index of insulin resistance (HOMA-IR) (2.3 +/- 1.6 v 2.8 +/- 2.1, mean +/- SD) were lower (P < .05) in telmisartan-treated patients than in valsartan treated patients. The percent change in ADMA, but not in HOMA-IR, correlated significantly with that in the mRHR (beta = -0.33, t value = -2.00, P = .04). CONCLUSIONS: At doses producing equivalent hypotensive effects, telmisartan apparently had a more favorable effect on functional parameters related to endothelial function than did valsartan. The reduction in plasma ADMA levels may contribute to this more favorable effect of telmisartan.