OBJECTIVE Intracoronary thrombus is a source of active lipid mediators including eicosanoids that play a critical role in the pathogenesis of acute myocardial infarction (AMI). Eicosanoids are derived from arachidonic acid generated by phospholipase A(2) (PLA(2)). This study examined whether PLA(2) is expressed in the aspirated coronary thrombus and whether PLA(2) expression in the thrombus may be related to recurrence of cardiac events and development of atherosclerosis in the culprit coronary artery after AMI. METHODS Intracoronary thrombus was obtained using an aspiration catheter from 48 patients with AMI, who had successful emergent treatment with percutaneous coronary intervention (PCI). Repeated intravascular ultrasound in the culprit coronary artery was performed at emergent PCI and 6 months later in a subgroup of 20 patients. RESULTS There was a higher prevalence of cells in the thrombus that were immunopositive to group IIA, IVA, V and X PLA2s in patients with (n = 11) than without (n = 37) cardiac events during 6 months of follow-up (P < 0.05 for all). The prevalence of the cells that were immunopositive to group IIA, IVA and V PLA2s in the thrombus was significantly associated with the percent increase in atheroma volume (r = 0.60, 0.55 and 0.45, respectively, P < 0.05 for all) after 6 months in the native coronary segment distal to the culprit coronary lesion. CONCLUSIONS PLA(2) expression in coronary thrombus is associated with recurrence of cardiac events and development of atherosclerosis in the culprit coronary artery in AMI survivors.