Effects of Allopurinol on Coronary Microvascular and Left Ventricular Function in Patients With Idiopathic Dilated Cardiomyopathy

Background: Uric acid (UA) is an independent marker of mortality and associated with increased oxidative stress in patients with congestive heart failure (CHF). The present study aimed to investigate the effect of allopurinol on left ventricular (LV) function and coronary microvascular integrity in patients with idiopathic dilated cardiomyopathy (IDC). Methods: Thirty-nine consecutive IDC patients were divided into 2 groups: elevated (>7 mg/dL for men and >6.5 mg/dL for women; n = 24) and normal (n = 15) UA. Allopurinol 300 mg per day was given to the elevated UA group. Patients with elevated UA were assessed after a 3-month treatment period. Echocardiography assessing coronary flow reserve (CFR) and systolic and diastolic LV functions were studied. Results: LV ejection fraction was significantly lower in elevated UA group: mean (interquartile range), 32.3% (26.0-36.5%) vs 37.3% (35.5-39.1%) (P < 0.01). Also, CFR and LV diastolic and combined function parameters were more prominently impaired in the elevated UA group. After allopurinol treatment, UA was significantly decreased (7.2 mg/dL [6.8-7.8] to 4.4 mg/dL [3.9-5.8]; P < 0.001) and CFR was markedly improved (1.87 [1.63-2.00] to 2.20 [1.87-2.49]; P < 0.001). The therapeutic effect of allopurinol on the reduction of UA from baseline was directly related to the improvement of CFR (r = 0.49; P = 0.01). Mitral A and E/E' were reduced, while S', E', E/A, and E'/A' were increased significantly. Conclusions: The present study showed that 3-month treatment with allopurinol was significantly associated with reduced UA levels, and improvement of CFR and LV functions in patients with IDC and hyperuricemia.