Endothelial dysfunction as assessed by flow-mediated dilation in patients with cardiac syndrome X: role of...

Endothelial dysfunction, reduced coronary flow reserve and increased markers of inflammation are detectable in cardiac syndrome X (CSX). In this study we investigated the relation between inflammation and systemic endothelial function in CSX patients.

We studied 42 CSX patients (55 +/- 6 years, 14 men) and 20 healthy subjects (52 +/- 7 years, 9 men). Systemic endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery after 5-minute of forearm cuff inflation. Serum C-reactive protein (CRP) was measured by a high-sensitivity method.

FMD was significantly lower in CSX patients compared to controls (4.8 +/- 4.4 vs. 13.7 +/- 4%, p < 0.001), whereas CRP levels were higher in CSX patients than in controls (2.7 +/- 2.4 vs. 0.7 +/- 0.4 mg/L, p = 0.001). In CSX patients FMD showed a significant inverse correlation with CRP levels, even after adjustment for potentially confounding variables (r = -0.34, p = 0.006).

An impaired FMD is detectable in CSX patients, suggesting a generalized abnormality in vascular function. Subclinical inflammation se is to play a significant role in the impairment of endothelium-dependent vasodilator function of these patients.