Abstract 4373221: Clinical Implications of Elevated Lipoprotein(a) in the Absence of Significant Coronary Artery Stenosis

Background: Lipoprotein(a) [Lp(a)] has recently re-emerged as a biomarker of growing interest in the prognostic assessment of cardiovascular disease. However, prognostic evidence remains limited in patients without significant coronary artery stenosis confirmed by coronary angiography (CAG), and who therefore did not undergo percutaneous coronary intervention (PCI). Methods: A total of 2,342 patients with chest pain who underwent CAG and acetylcholine provocation test and were confirmed to have no significant coronary artery stenosis, were analyzed and categorized into two groups based on Lp(a) levels: the high Lp(a) group (≥50 mg/dL) and the low Lp(a) group (<50 mg/dL). The primary endpoint was major adverse cardiovascular events (MACE); secondary endpoints included major adverse cardiovascular and cerebrovascular events (MACCE1) and MACCE1 with recurrent angina (MACCE2). Multiple imputation was followed by inverse probability of treatment weighting (IPTW), and Cox regression analysis was used to analyze 10-year clinical outcomes. Results: Atherosclerotic plaque burden appeared to be higher in the high Lp(a) group. However, there was no difference in the incidence of coronary artery spasm between the two groups. In addition, there was no significant difference in MACE, MACCE1, or MACCE2. Before IPTW adjustment, the high Lp(a) group showed a higher incidence of revascularization (2.5% vs. 1.0%; p = 0.033), but this difference was no longer statistically significant after adjustment (p = 0.085). Conclusion: Although Lp(a) is an established independent risk factor, it did not show prognostic significance in patients with the absence of significant coronary artery stenosis and PCI.