Association of Elevated Lipoprotein(a) Levels with Major Adverse Cardiovascular Events in Non-Diabetic Patients with Acute Myocardial Infarction: A Cohort Study from Bosnia and Herzegovina

Background/Objectives: Elevated lipoprotein(a) [Lp(a)] is an independent causal risk factor for atherosclerotic cardiovascular disease and may contribute to increased coronary complexity and adverse outcomes after acute myocardial infarction (AMI). Data regarding its prognostic significance in Southeastern Europe remains limited. This study aimed to evaluate the association between elevated Lp(a) levels, coronary artery disease severity, and major adverse cardiovascular events (MACE) at 1 and 6 months after AMI. Methods: This prospective study included 150 consecutive patients with STEMI and NSTEMI enrolled between December 2024 and August 2025. MACE was defined as a composite of overall cardiac death, recurrent myocardial infarction, cerebrovascular insult, heart failure with reduced ejection fraction occurrence, and new revascularization, either PCI or CABG. Results: Patients with elevated Lp(a) had significantly greater coronary disease burden, reflected by higher mean SYNTAX scores (17.3 ± 7.0 vs. 13.8 ± 7.0; p = 0.011) and a greater proportion of intermediate- and high-risk SYNTAX classifications (p = 0.016). Although the number of diseased vessels did not differ significantly, three-vessel disease was more frequent in the elevated Lp(a) group. At 1-month follow-up, overall MACE incidence was numerically higher but not statistically significant between groups. At 6 months, heart failure with reduced ejection fraction was significantly increased in patients with elevated Lp(a) (27.7% vs. 12.2%; p = 0.027). Binary logistic regression demonstrated that elevated Lp(a) independently predicted 6-month MACE (OR 2.768, p = 0.011, 95% CI 1.262–6.072), but not 1-month outcomes. Conclusions: Elevated Lp(a) is associated with increased coronary artery disease severity and higher mid-term MACE risk after AMI.