RESUMEN
BACKGROUND: The objective of this study was to evaluate the serum levels of ischemia modified albumin and oxidative stress parameters in patients with cardiac syndrome X. METHODS: A total of 61 patients, composed of 32 consecutive patients (24 female, 8 male, average age: 47.63 +/- 9.49 years) diagnosed with cardiac syndrome X by coronary angiography (initially performed following the identification of ischemia by exercise stress test or myocardial perfusion scintigraphy) and a control group of 29 consecutive patients (15 female, 14 male, average age: 49.59 +/- 11.68 years) with similar features without cardiac syndrome X were included in the study. The levels of the ischemia modified albumin (IMA), ferric reducing antioxidant power (FRAP), prooxidant-antioxidant balance (PAB), and advanced protein oxidation products (AOPP) were determined by colorimetric methods. RESULTS: Patients have significantly higher PAB, AOPP, and IMA levels in the patient group than in the control group (p < 0.01, p < 0.001, and p < 0.02, respectively). Also, serum triglyceride (p < 0.005) and hs-CRP (p < 0.0001) levels were significantly higher in the patient group (p < 0.01, p < 0.001, and p < 0.02, respectively). We found that there was a significant correlation between hs-CRP, plasma PAB (r: 0.258; p < 0.05), AOPP (r: 0.459; p < 0.001), and triglyceride levels (r: 0.404; p < 0.01). Plasma AOPP levels were also significantly positive correlated with triglyceride levels (r: 0.463; p < 0.001). In addition, during the correlation analysis performed on the patient group, a positive correlation was observed between the levels of IMA with the levels of plasma PAB and plasma AOPP (r: 0,994; p < 0.01 and r: 0.857; p < 0.05, respectively) In a multiple linear regression analysis, AOPP levels were significantly related with hs-CRP and triglyceride (R2: 0.380, p < 0.0001 and p < 0.05). Simple linear regression analysis was performed between plasma PAB (as dependent variable) and hs-CRP levels. Plasma PAB levels were related with hs-CRP (R2: 0.258, p < 0.05). Using the receiver-operator characteristic (ROC) curve, the best cut-off values for predicting cardiac syndrome X of PAD, AOPP, IMA, and hs-CRP levels were 88.1 arbitrary units, 68.5 kloramin T micromol/L, 7.17 U/mL, and 1.09 mg/dL, respectively. CONCLUSIONS: Based on the results of our study, the increase in oxidative stress during cardiac syndrome X appears to be related to elevated levels of IMA. Treatment modalities that decrease oxidative stress might be beneficial for the treatment of cardiac syndrome X.