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Improved Renal Denervation Mitigated Hypertension Induced by Angiotensin II Infusion

Improved Renal Denervation Mitigated Hypertension Induced by Angiotensin II Infusion

Published on: May 26, 2022

Olmesartan, but not amlodipine, improves endothelium-dependent coronary dilation in hypertensive patients

Masanao Naya¹, Takahiro Tsukamoto, Koichi Morita

¹Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.

Journal of the American College of Cardiology

|September 18, 2007

Insights

Olmesartan, an angiotensin II receptor blocker (ARB), improved coronary endothelial function in hypertensive patients more than amlodipine, a calcium channel blocker (CCB). This suggests ARBs may offer superior cardiovascular benefits through antioxidant properties.

Area of Science:

Cardiology
Pharmacology
Hypertension Research

Background:

Angiotensin II receptor blockers (ARBs) are hypothesized to improve coronary vasomotion more than calcium channel blockers (CCBs) due to direct angiotensin II blockade.
Coronary endothelial dysfunction is a key factor in hypertension-related cardiovascular complications.

Purpose of the Study:

To compare the efficacy of olmesartan (ARB) versus amlodipine (CCB) in improving coronary endothelial function in patients with essential hypertension.
To investigate the impact of these antihypertensive agents on coronary blood flow and vascular resistance.

Main Methods:

A prospective study involving 26 untreated hypertensive patients randomized to 12 weeks of olmesartan or amlodipine.
Coronary endothelial function assessed by measuring changes in myocardial blood flow (MBF) and coronary vascular resistance (CVR) using positron emission tomography (PET) with 15O-water.
Analysis of various blood biomarkers, including lipids, glucose, and inflammatory markers, alongside superoxide dismutase (SOD) activity.

Main Results:

Both olmesartan and amlodipine effectively reduced blood pressure to a similar extent.
Olmesartan treatment showed a trend towards increased myocardial blood flow (DeltaMBF) and significantly decreased coronary vascular resistance (DeltaCVR), indicating improved vasodilation.
Amlodipine did not significantly alter DeltaMBF or DeltaCVR, and serum SOD activity showed a trend to increase only in the olmesartan group.

Conclusions:

Olmesartan demonstrated a significant improvement in endothelium-dependent coronary vasodilation in hypertensive patients, independent of blood pressure reduction.
These beneficial effects suggest that ARBs, potentially through antioxidant mechanisms like increased SOD activity, may offer superior cardiovascular protection compared to CCBs.
The findings highlight the potential of ARBs in managing endothelial dysfunction in hypertension.

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Abstract

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 (DeltaMBF) and coronary vascular resistance (DeltaCVR) 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, DeltaMBF 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 DeltaCVR 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 (DeltaMBF: -0.15 +/- 0.12 ml/g/min vs. -0.12 +/- 0.20 ml/g/min; DeltaCVR: 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.

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