Lipoprotein (a) levels and vulnerable characteristics in nonculprit plaque in patients with acute coronary syndrome()

BACKGROUND: High plasma levels of Lp(a) are associated with a worse prognosis in patients with coronary artery disease. The aim of the present study is to clarify the association between high lipoprotein a [Lp(a)] levels and vulnerable characteristics of nonculprit plaques in patients with acute coronary syndrome (ACS). METHODS: A total of 185 consecutive patients with ACS who underwent optical coherence tomography imaging of nonculprit plaques in the culprit vessels were enrolled. Patients were divided into the high Lp(a) group (≥30 mg/dL; 50 nonculprit plaques in 49 patients) or the low Lp(a) group (<30 mg/dL; 139 nonculprit plaques in 136 patients). RESULTS: The prevalence of thin-cap fibroatheroma (TCFA) was significantly higher in the high Lp(a) group than in the low Lp(a) group (38.0 vs. 21.6%, p = 0.034). Multivariate logistic analysis demonstrated that a high Lp(a) level was independently associated with the prevalence of TCFA (odds ratio, 1.18; 95% confidence interval, 1.01–1.36; p = 0.033). The prevalence of TCFA was significantly higher in the high Lp(a) group than in the low Lp(a) group among patients with plaque erosion (50.0 vs. 9.4%, respectively; p = 0.027), although the difference was not statistically significant between the two groups in patients with plaque rupture. CONCLUSIONS: High Lp(a) levels were associated with a high prevalence of TCFA in nonculprit plaques among patients with ACS, particularly in patients with plaque erosion. The present results may partly explain the pathogenesis of worse clinical outcomes in patients with ACS and a high Lp(a) level as shown in clinical studies.