Serum uric acid and slow coronary flow in cardiac syndrome X

It has been recently shown that cardiac syndrome X (CSX) patients with slow coronary flow (SCF) have a worse long-term prognosis than those with normal coronary flow. Increased uric acid levels were shown to be associated with atherosclerosis, oxidative stress, and endothelial dysfunction. The purpose of the study was to investigate the relationship between coronary flow assessed with TIMI frame count (TFC) and serum uric acid (SUA) levels in patients with CSX.

The study population consisted of 113 consecutive patients with typical cardiac CSX and 41 controls without cardiac CSX. Frequencies of risk factors as well as biochemical and hematological data were recorded for all participants. Coronary blood flow was evaluated by TFC. All patients with a TFC greater than two standard deviations from the published normal range for any one of the three vessels were accepted as having slow coronary flow (SCF group), while those whose TFC values fell within the standard deviation of the published normal range for all of the three vessels were considered to have normal coronary flow.

Of the 113 CSX patients enrolled, 40 (35.4%) had SCF. The mean TFC value was strongly positively correlated with SUA level, but weakly correlated with male sex, hypertension, diabetes, smoking, serum creatinine level, and hemoglobin. Multivariate regression analysis showed that only the SUA level was independently associated with SCF. The cut-off value for uric acid obtained by the ROC curve analysis was 4.55 mg/dl for the prediction of SCF (sensitivity, 77.5%; specificity, 73.6%).

The SUA level is independently associated with SCF in patients with CSX.