Measurement of oxidized lipoprotein (a) in patients with acute coronary syndromes and stable coronary artery disease by 2 ELISAs: using different capture antibody against oxidized lipoprotein (a) or oxidized LDL.

OBJECTIVE To evaluate clinical value of oxidized lipoprotein(a) [ox-Lp(a)] levels. DESIGN AND METHODS Ox-Lp(a) were measured by 2 ELISAs using antibodies against ox-Lp(a) [ox-Lp(a)1] or oxidized low-density lipoprotein [ox-Lp(a)2], and studied in 161 acute coronary syndromes (ACS) patients, 114 stable coronary artery disease (CAD) and 100 control subjects. RESULTS Ox-Lp(a)1 was found related with ox-Lp(a)2 (r=0.864, P=0.000). Controlling for plasma lipids, Lp(a) and clinical characteristics, odds ratios of ox-Lp(a)1 on ACS and stable CAD were 5.06 (95% confidence interval 1.82-14.04) and 2.20 (0.78-6.22); those of ox-Lp(a)2 were 3.37 (1.07-10.63) and 1.35 (0.41-4.48), respectively. Receiver-operating characteristic curve analysis confirmed that performances of ox-Lp(a)1 were significantly superior to those for ox-Lp(a)2 in ACS (area: 0.803 vs. 0.723, P<0.001) and stable CAD (area: 0.670 vs. 0.607, P<0.01). CONCLUSION Ox-Lp(a) levels using antibodies against ox-Lp(a) may represent a better risk marker than those using antibodies against oxidized low-density lipoprotein for ACS and stable CAD.