AIMSTo assess the link between persistent lipoprotein(a) [Lp(a)] exposure levels and clinical outcomes in patients with acute myocardial infarction (AMI).METHODSThis longitudinal cohort study included 1131 AMI patients, categorizing persistent Lp(a) exposure based on measurements at admission and after 1 year. Patients were segmented into four groups using a 300 mg/L Lp(a) threshold: (1) persistent low Lp(a) (lowon admission - lowat 1 year); (2) fortified Lp(a) (lowon admission - highat 1 year); (3) attenuated Lp(a) (highon admission - lowat 1 year); and (4) persistent high Lp(a) (highon admission - highat 1 year). Multivariate Cox regression, subgroup analysis and sensitivity analysis assessed the association between Lp(a) trajectories and major adverse cardiovascular and cerebrovascular events (MACCE), cardiovascular death, non-fatal MI, non-fatal stroke, unplanned revascularization, and all-cause death.RESULTSOver a median 50-month follow-up, 343 (35.70%) patients encountered MACCE, and 210 (18.70%) died, including 126 (11.20%) from cardiovascular causes. The group with persistent high Lp(a) faced increased risk of MACCE (HRadjusted, 1.871; 95% CI: 1.474-2.374), non-fatal stroke (HRadjusted, 1.647; 95% CI: 1.031-2.632), unplanned revascularization (HRadjusted, 1.571; 95% CI: 1.008-2.449), and both all-cause (HRadjusted, 1.546; 95% CI: 1.134-2.108) and cardiovascular death (HRadjusted, 2.163; 95% CI: 1.405-3.331), compared to the persistent low Lp(a) group.CONCLUSIONSIn AMI patients, sustained high Lp(a) levels were significantly associated with increased risk of MACCE, non-fatal stroke, unplanned revascularization, and both all-cause and cardiovascular death.