Serum ADMA concentration – an independent factor determining FMD impairment in cardiac syndrome X

Mechanisms of decreased endogenous vascular reactivity in individuals with cardiac syndrome X (CSX) are not fully understood. AIM: To evaluate the following serum markers: total nitric oxide (NO), asymmetric dimethylarginine (ADMA), platelet-derived growth factor (PDGF), and to establish their relation to ultrasound indexes of endothelial function and structural remodeling in CSX patients. METHOD: The study group consisted of 43 CSX patients (mean age: 56.3 ± 9 years), while the control group included 21 healthy subjects (mean age: 54.86 ± 6.9 years). The high-resolution ultrasound was performed to measure: flow-mediated vasodilatation (FMD), nitroglycerine-mediated vasodilatation (NMD) and intima-media thickness (IMT) of carotid arteries. RESULTS: In CSX patients, significantly lower FMD (9.06 ± 3.2%) and significantly higher IMT (0.667 ± 0.14 mm) values were observed compared to healthy individuals (17.42 ± 8.4%, 0.571 ± 0.2 mm; P < 0.05). Mean total NO serum concentration was significantly higher in the CSX group (48.2 ± 18.2 μmol/L) as compared to controls (32.1 ± 1.4 μmol/L; P < 0.0001). There were no differences in serum ADMA and PDGF levels. In CSX patients, FMD values correlated with NO (r = 0.323; P = 0.039) and ADMA (r = -0.387; P = 0.012) serum levels; however, there were no significant correlations between NO and ADMA concentrations. CONCLUSION: Serum ADMA concentration is the only independent factor determining FMD impairment.