Prognostic significance of high Lipoprotein(a) levels in patients with coronary artery spasm.

Lipoprotein(a) [Lp(a)] has recently regained attention in prognostic research. However, data remain limited for patients without significant coronary artery stenosis confirmed angiographically and those who do not undergo percutaneous coronary intervention (PCI), and studies focusing specifically on patients with coronary artery spasm (CAS) are even more scarce. In this study, a total of 1,373 patients with positive intracoronary provocation testing with acetylcholine (ACH) and insignificant coronary artery stenosis were divided 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. There was no significant difference in MACE, MACCE1, or MACCE2 between the two groups. Before IPTW adjustment, the high Lp(a) group had a higher incidence of revascularization (0.9% vs. 3.3%; p = 0.033), but this difference was not significant after IPTW adjustment (p = 0.118). Although there was no significant group difference, a notable proportion of patients experienced recurrent angina requiring angiography (25.3% vs. 30.8%; p = 0.615). In conclusion, although Lp(a) is an established independent risk factor, it did not show prognostic significance in CAS patients in the absence of significant coronary artery stenosis and PCI.