Effect of Angiotensin AT1-Receptor Blockade with Candesartan Cilexetil on Impaired Nitric Oxide Bioavailability in the Retinal Vasculature of Hypertensive Patients
Michelson G.1, Harazny J.1, Delles C.2; Oehmer S.2; Hilgers K.2, Schmieder R.2
1Departments of Ophthalmology and 2Nephrology , University of Erlangen-Nuremberg, Erlangen
Purpose: Arterial hypertension constitutes a central factor in the pathogenesis of stroke. In patients at early stages of essential hypertension we examined endothelium-dependent vasodilation of the retinal vasculature as a model of the cerebral vasculature
Method: We conducted a randomized, double-blind, placebo-controlled, cross-over study in 19 young patients with mild-to-moderate essential hypertension and 19 normotensive control subjects. All participants were treated with the angiotensin AT1-receptor blocker candesartan cilexetil (16 mg o.d.) and placebo each over 7 days. Perfusion of the central retinal artery was assessed after each treatment phase with pulsed Doppler ultrasound at rest and during flicker light stimulation which is known to stimulate nitric oxide availability. Retinal capillary flow was assessed with scanning laser Doppler flowmetry at rest and following infusion of NG-monomethyl-L-arginine, an inhibitor of endothelial NO synthase.
Results: At base-line, perfusion of the central retinal artery and retinal capillary flow were similar between normotensive and hypertensive subjects. In normotensive subjects, mean blood fl
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