Circulating malondialdehyde-modified low-density lipoprotein levels are associated with the presence of thin-cap fibroatheromas determined by optical coherence tomography in coronary artery disease

AIMS: The importance of oxidized low-density lipoprotein (oxLDL) has been implicated in the process of plaque rupture. However, few previous studies demonstrated the relationship between plaque morphology and oxLDL. We evaluated the relationship between coronary plaque vulnerability assessed by optical coherence tomography (OCT) and circulating malondialdehyde-modified low-density lipoprotein (MDA-LDL). METHODS AND RESULTS: OCT was used to determine plaque vulnerability in 102 patients with acute coronary syndrome (ACS; n = 53) and stable angina pectoris (SAP; n = 49). Circulating levels of MDA-LDL were measured by using enzyme-linked immunosorbent assay. Thin-cap fibroatheromas (TCFAs; defined as lipid-rich with plaque cap thickness <65 μm) were detected more frequently in ACS than in SAP (83% vs. 16%, P < 0.001). The circulating levels of MDA-LDL were significantly higher in patients with ACS compared with SAP (P = 0.008). The levels of MDA-LDL were significantly higher in SAP patients with TCFA than those with non-TCFA (P < 0.001). Although the levels of MDA-LDL were not significant between ACS patients with TCFA and those with non-TCFA, patients with ruptured TCFA had higher levels of MDA-LDL compared with those with morphologically intact TCFA (P = 0.023). MDA-LDL levels were associated with the presence of TCFA (odds ratio, 1.45 per 10-unit increment of MDA-LDL; 95% CI, 1.24-1.68; P< 0.001) in multivariable logistic regression analysis. CONCLUSION: Circulating MDA-LDL levels might be associated with the presence of TCFA in the culprit lesion.