The association of elevated white blood cell count and C-reactive protein with endothelial dysfunction in cardiac syndrome X.

Background: The aim of the study is to evaluate the association of inflammatory markers with endothelial function in syndrome X.

Methods: The study population consisted of 59 prospectively enrolled patients (28 women and 31 men; mean age, 50.29 +/- 6.48 years) and 51 healty control subjects (18 women and 33 men; mean age, 51.04 +/- 7.25 years). High-sensitive CRP (hs-CRP), white blood cell (WBC) count and its subtypes [neutrophil (N), lymphocyte (L) and monocyte (M)] were measured in each subject. Endothelial function was assessed with the brachial artery flow-mediated dilatation (FMD) technique.

Results: WBC counts and hs-CRP levels were significantly higher in patients who had syndrome X than in control subjects (7.53 +/- 1.52 x 10(9) cells/L versus 6.21 +/- 1.17 x 10(9) cells/L, P = 0.0001, and 3.11 +/- 0.63 mg/L versus 2.68 +/- 0.76 mg/L, P = 0.002, respectively). Neutrophil count and N/L ratio was significantly increased in syndrome X when compared with the control subjects (5.14 +/- 1.10 x 10(9) cells/L versus 4.11 +/- 0.76 x 10(9) cells/L, P = 0.0001 and 2.75 +/- 1.06 versus 2.37 +/- 0.65, P = 0.02, repectively). Other subtype counts were similar between the groups. FMD was impaired significantly in patients who had syndrome X in comparison with the control subjects (5.71 +/- 4.08% versus 16.02 +/- 4.13%, P = 0.0001). There was a significant correlation between hs-CRP levels and FMD measurements (r = -0.44; P = 0.0001). Furthermore, the correlation between WBC count and FMD measurements were also significant (r = -0.48; P = 0.0001).

Conclusions: The present study showed that hs-CRP and WBC count were higher in patients with syndrome X than in control subjects. Furthermore, endothelial function was impaired significantly in patients with syndrome X.The increased levels of hs-CRP and WBC count may suggest that these markers may be used in clinical practice for the assessment of the inflammatory status of the endothelium in syndrome X.