Objectives: We aimed to compare the effects of the angiotensin II receptor blocker (ARB) olmesartan versus the calcium channel blocker (CCB) amlodipine on coronary endothelial dysfunction in patients with hypertension. Background: Angiotensin II receptor blockers are thought to have greater beneficial effects than CCBs on coronary vasomotion by directly blocking action of angiotensin II. Methods: Twenty-six patients with untreated essential hypertension were prospectively assigned to treatment with either olmesartan (27.7 ± 12.4 mg/day, n = 13) or amlodipine (5.6 ± 1.5 mg/day, n = 13) for 12 weeks. Changes of corrected myocardial blood flow (ΔMBF) and coronary vascular resistance (ΔCVR) from rest to cold pressor were measured by using 15O-water and positron emission tomography before and after treatment. Blood biomarkers including lipids, glucose, insulin, high-sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-alpha, and superoxide dismutase (SOD) were also measured. Results: Olmesartan and amlodipine reduced blood pressure (BP) to the same extent (-28.7 ± 16.2 mm Hg vs. -26.7 ± 10.8 mm Hg). In the olmesartan group, ΔMBF tended to be greater (-0.15 ± 0.19 ml/g/min vs. 0.03 ± 0.17 ml/g/min, p = 0.09 by 2-way analysis of variance), and ΔCVR was significantly decreased (7.9 ± 23.5 mm Hg/[ml/g/min] vs. -16.6 ± 18.0 mm Hg/[ml/g/min], p < 0.05) after treatment, whereas these parameters did not change in the amlodipine group (ΔMBF: -0.15 ± 0.12 ml/g/min vs. -0.12 ± 0.20 ml/g/min; ΔCVR: 6.5 ± 18.2 mm Hg/[ml/g/min] vs. 4.8 ± 23.4 mm Hg/[ml/g/min]). Serum SOD activity tended to increase (4.74 ± 4.77 U/ml vs. 5.57 ± 4.74 U/ml, p = 0.07 by 2-way analysis of variance) only in the olmesartan group. Conclusions: Olmesartan, but not amlodipine, improved endothelium-dependent coronary dilation in hypertensive patients independent of BP reduction. These beneficial effects on coronary vasomotion might be via an antioxidant property of ARBs.
All Science Journal Classification (ASJC) codes
- Cardiology and Cardiovascular Medicine