Oxidative stress as a predictor of cardiovascular events in coronary artery disease patients

Background: Enhanced oxidative stress has been associated with atherosclerosis and coronary artery disease (CAD). However, the predictive value of circulating oxidative stress biomarkers for cardiovascular events (CE) in patients with CAD has remained poorly understood. Aim: To assess the prognostic significance of reactive oxygen metabolites, estimated as index of oxidative stress in serum samples by means of a commercial kit (ROMs, Diacron, Italy) on the rate of mortality and major adverse CE (MACE) in CAD. Methods: A study of 93 consecutive patients with angiographically documented CAD (75 males, age: 68 +/- 10 years, mean +/- SD) was made during a mean follow-up of 66 months until the occurrence of one of the following CE: cardiac and all cause death, non-fatal myocardial infarction and coronary revascularization [percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG)]. Patient data were retrospectively collected from the Institute's electronic databank that saves demographic, clinical, instrumental and follow-up data of all patients admitted to our department. Results: The Kaplan-Meier survival estimates showed a significantly worst outcome in patients presenting elevated ROM level (>75th percentile, corresponding to 481 AU) (log rank=11, 7.5, 5.1; p<0.001, p<0.01, p<0.05 for cardiac and all cause death and MACEs, respectively). In a multivariate Cox regression model, elevated oxidative stress remained a significant predictor of cardiac and all cause death [hazard ratio (HR) 3.9, 95% confidence interval, 95% (CI) 1.4-11.1, p=0.01; HR=2.6, 95% CI 1.1-6.2, p=0.02) and MACE (EIR=1.8, 95% CI 1.1-3.1, p=0.03)]. Conclusions: The estimation of ROMs may represent an additional prognostic tool in the assessment of CE in CAD patients.