Background: The pathophysiological mechanism in cardiac syndrome X has been suggested as impairment in normal endothelial function of the coronary microvasculature, resulting in inadequate flow reserve. However, despite the extensive studies, the precise mechanisms in cardiac syndrome X remain unclear.
Purpose: The present study was, therefore, to investigate whether inflammatory cells and markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) might be involved in the pathogenesis of cardiac syndrome X.
Methods: Thirty-six female patients with cardiac syndrome X and 30 sex-matched normal controls were prospectively enrolled in this study. Blood samples were drawn for measuring white blood and monocyte cells, inflammatory markers such as CRP and IL-6, and data were compared between patients with cardiac syndrome X and normal controls.
Results: The data showed that increased numbers of white blood and monocyte cells were found in patients with cardiac syndrome X compared with normal controls (white blood cells: 7072+/-1146/mm(3) vs. 6138+/-1079/mm(3); monocyte cells: 612+/-186/mm(3) vs. 539+/-190/mm(3)p<0.05, respectively). Moreover, patients with cardiac syndrome X were detected to have significantly higher plasma CRP and IL-6 levels in comparison with patients with normal controls (CRP: 0.48+/-0.26 mg/L vs. 0.22+/-0.15 mg/L; IL-6: 13.4+/-1.2 pg/dl vs. 6.2+/-0.6 pg/dl, p<0.01, respectively). The multivariate analysis showed that CRP was the independent variable most strongly associated with cardiac syndrome X.
Conclusions: Our data suggested that low-grade, chronic inflammation might contribute to the development of cardiac syndrome X manifested by increased plasma levels of inflammatory cells and inflammatory markers.