Effects of Xanthine Oxidase Inhibition With Allopurinol on Endothelial Function and Peripheral Blood Flow in Hyperuricemic Patients With Chronic Heart Failure

Abstract
Background— In patients with chronic heart failure (CHF), hyperuricemia is a common finding and is associated with reduced vasodilator capacity and impaired peripheral blood flow. It has been suggested that the causal link of this association is increased xanthine oxidase (XO)–derived oxygen free radical production and endothelial dysfunction. We therefore studied the effects of XO inhibition with allopurinol on endothelial function and peripheral blood flow in CHF patients after intra-arterial infusion and after oral administration in 2 independent placebo-controlled studies. Methods and Results— In 10 CHF patients with normal serum uric acid (UA) levels (315±42 μmol/L) and 9 patients with elevated UA (535±54 μmol/L), endothelium-dependent (acetylcholine infusion) and endothelium-independent (nitroglycerin infusion) vasodilation of the radial artery was determined. Coinfusion of allopurinol (600 μg/min) improved endothelium-dependent but not endothelium-independent vasodilation in hyperuricemic patients ...