Association between serum Total Antioxidant Status, Malondialdehyde and Coronary Artery Disease severity: A Cross-Sectional Study.

Background: Reduced Total Antioxidant Status (TAS) and elevated Malondialdehyde (MDA) reflect redox imbalance in coronary artery disease (CAD). Their inverse relationship may help assess cardiovascular risk and disease progression. Objectives: To evaluate the association between serum TAS, MDA and the severity of coronary artery damage in CAD patients at Thai Nguyen National Hospital. Results: Serum TAS showed no significant differences by number of stenotic vessels or lesion sites (p > 0.05). TAS was slightly higher in single-vessel disease (1.15 ± 0.38 mmol/L) than in two-vessel (1.08 ± 0.19) and ≥3-vessel groups (1.09 ± 0.18), without statistical significance (p = 0.721). A significant difference was observed only in the right coronary artery (RCA), where TAS peaked in moderate stenosis and decreased in severe stenosis (p = 0.039). In contrast, MDA increased significantly with disease extent: 255.25 ± 48.43 nmol/mL (1-vessel), 281.30 ± 62.56 (2-vessel), and 317.06 ± 54.53 (≥3-vessel) (p = 0.001). MDA also rose markedly with SYNTAX score (low: 239.98 ± 40.96; medium: 271.49 ± 46.53; high: 392.62 ± 90.85 nmol/mL; p < 0.001). ROC analysis showed good diagnostic performance (AUC up to 0.895). TAS did not differ across SYNTAX groups (p = 0.857). Conclusions: TAS is not associated with CAD severity, whereas MDA strongly correlates with disease extent and complexity. MDA may serve as a useful biomarker for oxidative stress and risk stratification in CAD.