Free malondialdehyde (F-MDA): a plasmatic marker of clinical instability in coronary artery disease

Background: Macrophage derived proteolytic enzymes induce collagen catabolism, resulting in a weakened fibrous cap of coronary atherosclerotic plaques. The subsequent ulceration and endoluminal thrombosis may lead to unstable angina and myocardial infarction. Futhermore, macrophage activation is followed by the release of oxigen free radicals whose activity may be monitored by plasmatic concentration of free-malondialdehyde (F-MDA). Elevated F-MDA values are considered suggestive of a rising rate of macrophage-mediated lipid peroxidation. v Aim: To evaluate F-MDA as a marker of macrophage activation and, then, of plaque and clinical instability. Methods: We enrolled 15 pts with stable angina (SA), 22 with unstable angina (UA) and 12 with myocardial infarction (AMI). Patients were well-matched for age, sex and coronary risk factors. F-MDA was assessed by gas chromatography-mass spectrometry Data were analysed using Wilcoxon test and χ2 test. Results: F-MDA was significantly higher in patients with UA and AMI when compared with SA group (0.58μM and 0.65μM vs 0.31μM, as median values p<0.01). F-MDA was over the normal range (0-0.35μM) in 4 pts with SA (26%), 17 with UA (77%) and 9 with AMI (75%) (p<0.02). No relation was found between F-MDA concentration and lipids, CRP and ESR. (Graph Presented) Conclusions: Our study shows the "in vivo" role of activated macrophages in acute coronary syndromes. F-MDA might be useful to identify patients at risk of instabilisation.