Background: The prognostic value of circulating oxidized low-density lipoprotein (OxLDL) in patients with unstable coronary artery disease (CAD) is unknown.
Methods: Plasma levels of OxLDL were measured in 433 patients with unstable CAD included in FRISC-II (Fragmin and fast Revascularisation in Instability in Coronary artery disease trial) and in 233 of these patients at follow-up 4-7 weeks later. Mortality and myocardial infarction (MI) at 2 years of follow-up was related to above (n=226) or below (n=207) the median level of OxLDL (76 U/L) at study entry.
Results: After adjustment for other well-known predictors of risk, OxLDL levels >76 U/L were associated with a higher risk for recurrent MI (Odds Ratio [95% CI]: 1.90 [1.05-3.39]). When patients were divided according to troponin T (TnT) status, the prognostic value of OxLDL was most evident in the TnT negative group with a risk of MI of 16.9% in patients with elevated OxLDL compared to 1.7% (p=0.004) in those without. No association was found between levels of OxLDL and mortality. At follow-up levels of OxLDL were similar to levels during the acute phase unless patients were treated with statins in which levels were significantly lower.
Conclusions: Elevated levels of OxLDL may identify patients with unstable CAD, at increased risk for future MI independent of other risk variables, particularly those without evidence of myocardial damage. OxLDL levels appear to be similar in patients during the unstable and stable phase of CAD unless statin therapy is initiated.