Coronary flow reserve and coronary microvascular functions are strongly related to serum uric acid concentrations in healthy adults

Background Uric acid is a well known antioxidant; however, the relationship between serum uric acid levels and oxidative stress-caused disorders including cardiovascular diseases is not clear yet. Transthoracic Doppler echocardiographic measurement of coronary flow reserve is a useful too[ to investigate coronary flow reserve and coronary microvascular functions. In this study, we investigated the possible association between serum uric acid concentrations and coronary flow reserve in healthy adults. Methods One hundred healthy volunteers with normal uric acid levels, between 18 and 55 years of age, were included in this study. The study group was divided into two with regard to the serum uric acid levels. Coronary diastolic peak flow velocities were measured at baseline and after dipyridamole infusion (0.56 mg/kg over 4 min) using echocardiography. Results Coronary flow reserve and hyperemic mean peak flow velocity were significantly greater in participants with lower serum uric acid concentrations (<= 234 mu mol/l for women, <= 302 mu mol/l for men) than in those with higher serum uric acid concentrations (> 234 mu mol/l for women, > 302 mu mol/l for men) (2.91 +/- 0.5 vs. 2.47 +/- 0.5, P < 0.001; 66.8 +/- 11.4 vs. 61.1 +/- 16.5, P=0.04). The baseline mean peak flow velocity was significantly greater in participants with higher serum uric acid concentrations than in those with lower serum uric acid concentrations (24.7 +/- 4.1 vs. 23.1 +/- 2.4, P=0.02). Conclusion Lower serum uric acid concentrations might be regarded as indicative of coronary microvascular and conductance vessel functionality.