Long-term Outcomes Of Lipoprotein(a) In Patients With Acute ST-segment Elevation Myocardial Infarction After Percutaneous Coronary Intervention

OBJECTIVE:Lipoprotein(a)levels have gradually gained attention as a new risk factor for coronary heart disease.Recent experimental studies on the relationship between lipoprotein(a)and coronary artery disease are mostly from other countries’population data.There is lack of adequate data about the correlation between lipoprotein(a)and coronary heart disease in Dalian city and China at large.This study was therefore done to investigate the effect of serum lipoprotein(a)levels on long-term prognosis in patients with acute ST-segment elevation myocardial infarction(STEMI)undergoing percutaneous coronary intervention(PCI)in China.METHODS:A prospective analytical study of 892 patients with acute STEMI admitted at the 6th hospital of Dalian city from 1st October 2015 to 30’h October 20x6,who underwent primary PCI and hospitalized was done.415 patients met the inclusion criteria of this study and were followed up for one year.The general inforlation and laboratory examination data of the patients were collected and recorded.The main clinical records included past medical history,personal history,body mass index,blood biochemical lipid index,coronary lesions and medication status.The serum lipoprotein(a)levels of all selected patients at admission was divided into four groups according to the quartile method,from low to high levels Q1,Q2,Q3 and Q4 respectively.Using one-way analysis of variance,Rank sum test,trend analysis and x2 test,the clinical characteristics of the four groups of patients were compared.Multivariate analysis and ROC analysis were used to investigate the association between lipoprotein(a)levels with the occurrence of major adverse cardiovascular and cerebral events(MACCE)during the 2 years period of follow-up after percutaneous coronary intervention.(MACCE events mainly includes cardiogenic shock,sudden death.nonfatal recurrent myocardial infarction,unplanned revascularization and stroke).RESULTS:A total of 415 STEMI patients who underwent primary PCI were included in this study.92 patients were female accounting for 22.2%and 323 patients were males,accounting for 77.8%of total patients.The average age was(61.73±12.62)years old Serum lipoprotein(a)was divided into Q1 group(<4.5 mg/dl,105 patients).Q2 group(4.5-12.6 mg/dl,103 patients),Q3 group(12.7-28.5 mg/dl,104)and group Q4(>28.6 mg/dl,103 patients)by quartile method(1)Comparison of general data of four groups of patients showed that the level of fasting blood glucose and high-density lipoprotein cholesterol(HDL-C)decreased with increase in serum lipoprotein(a)levels.The difference was statistically significant(P value<0.001).ApoB level increased with the increase in serum lipoprotein(a)levels(P value=0.009).There was no statistical significance observed between serum lipoprotein(a)and age,history of hypertension,history of diabetes,triglyceride(TG),total cholesterol(TC),low-density lipoprotein cholesterol(LDL-C)or serum creatinine levels.(P value were>0.05)(2)MACCE single factor analysis of four groups of patients was done.Log-Rank analysis showed statistically significant differences in the occurrence of MACCE in four groups(X2=13.220,P=0.004).Pairwise comparison between groups suggested that when Q4 was compared with Q1,Q2,Q3 the differences of adverse events was statistically significant(P=0.001,0.017 and 0.034 respectively),but when QI,Q2 and Q3,two pairs comparison was not statistically significant(P>0.05).When lipoprotein(a)level increases,the cumulative survival rate decreases significantly(3)Multi-factor COX analysis results showWhen Lp(a)was analyzed as a stratified variable,the incidence of MACCE increased with the increase in Lp(a)level.When Q1 was used as the baseline,the Q2/Q1 HR=1.112.,95%Cl:0.427-2.899;Q3/Q1 HR=1.451,95%CI:0.587-3.585.Q4/Q1 HR=3.585,95%Cl:1.601-8.025)but only Q4 group and QI group end point events of the risk that occurred was statistically significant(P=0.008).There was no significant difference between Q1,Q2 and Q3 groups(P>0.05)When Lp(a)was used as a continuous variable,multivariate COX regression analysis was performed,Lp(a)(mg/dl)(HR=1.016,95%Cl:1.005-1.027,P=0.004),age(HR=1.030,95).%CI:1.007-1.054,P=0.012),coronary multi-vessel disease(HR=2.017,95%Cl:1.121-3.630,P=0.019)and previous stroke history(HR=2.157,95%Cl:1.032-4.508)P=0.041)was an independent risk factor for long-term MACCE in STEMI patients undergoing direct PCI;application of ACEI/ARB drugs(HR=0.511,95%Cl:0.300-0.870,P=0.013)Left ventricular ejection fraction(HR=0.945,95%Cl:0.919-0.972,P<0.001)was a protective factor for long-term MACCE in STEMI patients undergoing direct PCI.(4)According to the ROC curve,the optimal cut-off point of lipoprotein(a)was 27.35mg/dl;that is,when lipoprotein(a)exceeds 27.35mg/dl,the incidence of long-term major adverse cardiovascular and cerebrovascular events MACCE was found to be significantly increased among STEMI patients who underwent emergency PCI.(ROC-AUC:0.620,95%Cl:0.547-0.692,P=0.003);the specificity was 77.60%,and the sensitivity was 43.50%.In Conclusion:(1)Serum Lp(a)level is an independent risk factor for the occurrence of MACCE in patients with STEMI after primary PCI.With increase of Lp(a)level,the incidence of long-term MACCE significantly increased.(2)Serum Lp(a)level>27.35mg/dl predicts that patients will have long-tern MACCE with higher specificity and lower sensitivity.Lp(a)is a certain predictor of long-term prognosis in STEMI patients and has a clinical application value.