The importance of age and statin therapy in the interpretation of Lp-PLA(2) in ACS patients, and relation to CRP.

C-reactive protein (CRP) is a marker of arterial inflammation while lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is related to plaque instability. The aim of this study was to evaluate the correlation between the risk of unstable plaque presenting as acute coronary syndrome (ACS) and Lp-PLA(2), and to assess the influence of statins on interpretation of Lp-PLA(2). A total of 362 consecutive patients presenting to the emergency department (ED) with acute chest pain suggestive of ACS were evaluated by cardiologists as STEMI, NSTEMI, or unstable angina, and non-ACS. Serum biomarkers measured on admission: troponin I, C-reactive protein (Abbott), and Lp-PLA(2) (DiaDexus). Four groups were defined according to the final diagnosis and history of statin medication: ACS/statin-; ACS/statin+; non-ACS/statin-; non-ACS/statin+. Lp-PLA(2) was highest in ACS/statin- group; statins decreased Lp-PLA(2) both in ACS and non-ACS of about 20 %. Lp-PLA(2) was higher in ACS patients in comparison with non-ACS patients group without respect to statin therapy (p<0.001). Lp-PLA(2) predicted worse outcome (in terms of acute coronary syndrome) effectively in patients up to 62 years; limited prediction was found in older patients. C-reactive protein (CRP) failed to discriminate four groups of patients. Statin therapy and age should be taken into consideration while interpreting Lp-PLA(2) concentrations and lower cut-off values should be used for statin-treated persons.