Elevated lipoprotein (a) levels are associated with the acute myocardial infarction in patients with normal low-density lipoprotein cholesterol levels.

Gaojun Cai,Li Li,Lei Yu,Zhiying Huang,Bifeng Zhang

doi:10.1042/bsr20182096

Abstract

Elevated lipoprotein (a) [Lp(a)] and coronary artery disease (CAD) risk has been renewed interested in recent years. However, the association between Lp(a) and acute myocardial infarction (AMI) risk in patients with normal low-density lipoprotein cholesterol (LDL-C) levels has yet to been established. A hospital-based observational study including 558 AMI patients and 1959 controls was conducted. Lp(a) level was significantly higher in AMI patients with normal LDL-C levels than that in non-CAD group (median: 134.5 mg/l vs 108 mg/l, P<0.001). According to Lp(a) quartiles (Q1, <51 mg/l; Q2, 51–108 mg/l; Q3, 108–215 mg/l; Q4, ≥215 mg/l), the incidence of AMI increased with the elevated Lp(a) quartiles (P<0.001 and P for trend<0.001). Logistic regression analysis suggested that patients with Q3 and Q4 of Lp(a) values had 1.666 (95%CI = 1.230–2.257, P<0.001) and 1.769 (95%CI = 1.305–2.398, P< 0.001) folds of AMI risk compared with patients with Q1, after adjusting for traditional confounders. Subgroup analyses stratified by gender and age showed that the association only existed in male and late-onset subgroups. In addition, we analyzed the association of Lp(a) with AMI risk in different cut-off values (cut-off 1 = 170 mg/l, cut-off 2 = 300 mg/l). A total of 873 (34.68%) and 432 (17.16%) participants were measured to have higher Lp(a) levels according to cut-off 1 and cut-off 2, respectively. Participants with high Lp(a) levels had 1.418- (cut-off1, 95%CI = 1.150–1.748, P<0.001) and 1.521- (cut-off 2, 95%CI = 1.179–1.963, P< 0.001) folds of AMI risk compared with patients with low Lp(a) levels. The present large-scale study revealed that elevated Lp(a) levels were associated with increased AMI risk in Chinese population with normal LDL-C levels.

Highlights

Acute myocardial infarction (AMI), including ST segment elevated AMI and non-ST segment elevated AMI, is the most severe type of coronary artery disease (CAD), which results in the disability and sudden death due to the occlusion of coronary arteries
The present large-scale study revealed that elevated Lp(a) levels were associated with increased AMI risk in Chinese population with normal Low-density lipoprotein cholesterol (LDL-C) levels
The levels of Lp(a), high-density lipoprotein cholesterol (HDL-C) and apoprotein A (ApoA) were significantly lower in the AMI patients than those in the non-CAD participants

Summary

Introduction

Acute myocardial infarction (AMI), including ST segment elevated AMI and non-ST segment elevated AMI, is the most severe type of coronary artery disease (CAD), which results in the disability and sudden death due to the occlusion of coronary arteries. Low-density lipoprotein cholesterol (LDL-C) is known to play a crucial role in the occurrence and development of CAD, and therapeutics for decreasing LDL-C levels can reduce the risk of major adverse cardiovascular events (MACEs) in patients with CAD. Some patients who have achieved the guideline recommended LDL-C levels may have high residual cardiovascular risk [2]. Lipoprotein (a) [Lp(a)], firstly described in 1963 by Berg K, is a LDL-like particle consisting of one apolipoprotein B100 (ApoB100) linked covalently to one molecule of apolipoprotein a [apo(a)] via a single disulfide bond [3]. Apo(a) is a hydrophilic glycoprotein secreted by hepatocyte, which is highly homologous to plasminogen. Differed from plasminogen, apo(a) only has multiple repeats of KIV and one License 4.0 (CC BY)

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