Prognostic values of lipoprotein(a) levels for secondary prevention of acute coronary syndrome among patients who underwent primary percutaneous coronary intervention

Abstract Background Lipoprotein(a) [Lp(a)] is known to be a residual risk factor for acute coronary syndrome(ACS). However, in the current era where primary percutaneous coronary intervention (PCI) and lipid-lowering therapies have advanced, the role of Lp(a) levels in secondary prevention among ACS patients remains unclear. Purpose The purpose of this study is to determine whether Lp(a) levels play a role in secondary prevention by studying patients with ACS who underwent primary PCI and survived discharge. Methods Consecutive ACS patients who were admitted to our institution between December 2016 and March 2021, requiring primary PCI and were discharged alive were enrolled for the current study (n = 471). Of these patients, those with the following circumstances were excluded: (1) multidisciplinary treatment such as mechanical ventilation management and percutaneous cardiopulmonary support (n = 74), (2) incomplete clinical data (n = 34), (3) ACS classified as other than type 1 in the universal definition (n = 6), and (4) unknown prognosis at 6 months after discharge (n = 8). A total of 349 consecutive patients were included in the current study. They were divided into two groups according to Lp(a) levels: Lower Lp(a) group (Lp(a) < 30 mg/dL, n = 277) and Higher Lp(a) group (Lp(a) ≥ 30 mg/dL, n = 72). The primary endpoints were major adverse cardiac events (MACEs), composite of all cause death, nonfatal myocardial infarction, nonfatal stroke and congestive heart failure requiring admission. Event-free survival curves were estimated using Kaplan-Meier method and log-rank test was used to detect statistically significant differences. In addition, influence of Lp(a) levels on MACE was examined using three cox regression analyses. Model 1 was adjusted for age, gender and body mass index, model 2 was adjusted for hypertension, diabetes and chronic kidney disease (CKD), model 3 was adjusted for old myocardial infarction (OMI), smoking and multivessel disease, respectively. Results The mean age was 67.0 ± 12.8 years, and 70.5% were male. The median serum Lp(a) levels of the entire population was 14 mg/dL (interquartile range, 7 to 26). There were no significant differences about baseline patient’s characteristics, laboratory findings, and medications at discharge including statin treatment. The MACE was observed in 15.5% of the Lower Lp(a) group and 20.8% of the Higher Lp(a) group (p=0.29). No difference was observed about MACE between the two groups (log-rank p=0.45). After adjusting for cardiovascular risk factors, Lp(a) levels were not associated with MACEs in all three models. However, in model 2 and model 3, CKD and OMI were associated with MACEs (hazard ratio 4.29, 95% confidence interval 2.17 to 8.46, p < 0.001, hazard ratio 3.02, 95% confidence interval 1.39 to 6.51, p = 0.005, respectively). Conclusions In the current era, Lp(a) levels are not associated with secondary prevention among ACS patients who underwent primary PCI.