Serum levels of C-reactive protein and uric acid in patients with cardiac syndrome X

Objectives - Angina-like chest pain, a positive result from a stress test, and normal coronary arteries are characteristics of patients with cardiac syndrome X (CSX). Serum levels of C-reactive protein (CRP), which is a marker of a systemic inflammatory state, are associated with coronary atherosclerosis and endothelial dysfunction. Serum uric acid (UA) levels have also been implicated in the development of atherosclerotic cardiovascular disease. However, little is known about the association of serum UA and CRIP levels with CSX. Methods - In all, 250 subjects (100 patients with CSX, 100 with coronary artery disease (CAD), and 50 control subjects) were enrolled in the study. Coronary arteries were evaluated by conventional coronary angiography in the CSX and CAD groups. All patients underwent a noninvasive stress test. To determine whether they are potential risk factors for CSX, serum CRP and UA levels were compared among the 3 groups. Results - Serum levels of CRP were higher in patients with CSX or CAD than in the control subjects (4.4 +/- 3.1 and 4.5 +/- 2.9 mg/L, respectively, vs. 1.9 +/- 1.6 mg/L; P < 0.001), but those levels were similar in patients with CSX or CAD. Uric acid levels were higher in patients with CSX or CAD than in the control subjects (5.5 +/- 1.1 mg/dl and 5.9 +/- 1.4 mg/dl, respectively, vs. 4.4 +/- 1.2 mg/dl; P < 0.001), but those levels were also similar in patients with CSX or CAD. Conclusions - In patients with CSX, serum CRIP and UA levels were as high as those in patients with CAD. Elevated serum CRP and UA levels may contribute to the development of CSX.