Evaluation of red blood cell distribution width in patients with cardiac syndrome X.

BACKGROUND

Cardiac syndrome X (CSX) is a condition characterized by chest pain with normal coronary arteries. However, its pathogenesis has not fully been understood yet. Red blood cell distribution width (RDW) has recently been suggested as a marker of acute and chronic cardiovascular diseases, while no data is available in patients with CSX.

METHODS

One hundred and twenty consecutive patients with CSX and 102 normal controls were prospectively enrolled in this study. Blood samples were drawn from all individuals for measuring RDW and high-sensitivity C-reactive protein (CRP). The baseline data were compared between patients with CSX and normal controls.

RESULTS

The RDW levels were significantly higher in patients with CSX than that in those with normal controls (13.1 ± 2.1 versus 12.3 ± 1.8, p=0.011). Moreover, the data showed that the levels of plasma CRP were marked higher in patients with CSX than those that were observed in normal controls (CRP: 2.8 ± 2.2 mg/L versus 2.0 ± 1.7 mg/dl, p=0.014). In addition, the multivariate analysis indicated that peripheral monocyte cell, CRP and RDW were the independent variables most strongly associated with CSX. In a receiver operating characteristic (ROC) curve analysis, we found that an RDW value of 12.8% was used as an effective cut-point in the segregation of the presence or absence of cardiac syndrome X, a sensitivity of 52.0% and a specificity of 65.4% were obtained. Finally, correlation analysis suggested that there was positive correlation between plasma levels of CRP and RDW levels (n=120, γ =0.381, P=0.013).

CONCLUSIONS

The present study, for the first time, demonstrated that elevated RDW and CRP levels were independently associated with the presence of CSX.