STEMI直接PCI术后合并超常射血分数患者LVEF临界值及其可能机制初探

Critical Left Ventricular Ejection Fraction and Its Possible Pathogenesis in STEMI Patients with Supra-normal Ejection Fraction after Primary PCI

背景左心室射血分数(LVEF)在临床评估左心室收缩功能时被广泛应用,在仍有部分射血分数保留的患者出现了不良事件,因此在射血分数≥50%的人群中可能仍存在其他表型,影响患者的预后。目的探索急性心肌梗死直接经皮冠状动脉介入术(PCI)术后超常射血分数患者LVEF临界值及其可能机制。方法选取2016年11月至2018年6月就诊于河北省人民医院心脏中心的急性ST段抬高性心肌梗死接受直接PCI且术后首次经胸超声测量LVEF≥50%的患者272例,患者均在直接PCI术后入住河北省人民医院心血管监护病房(CCU),收集患者基线资料(性别、吸烟史、饮酒史、心血管疾病家族史、1个月内心绞痛发作史、糖尿病史、高血压史、脑卒中史、陈旧性心肌梗死病史、年龄、体质指数、脉率、平均动脉压)、胸痛时间节点(发病至首次医疗接触时间、发病至首次抗血小板时间、发病至首次抗凝时间、发病至球囊时间、门-球时间)、术中资料〔术前血流、侧支循环、同期处理非罪犯血管(NIRA)、血栓抽吸、主动脉内球囊反搏(IABP)应用、抗凝用药、术后血流、术中替罗非班及普佑克应用〕、术前用药情况〔β-受体阻滞剂、肾素-血管紧张素-醛固酮系统抑制剂(RASI)、他汀类〕及实验室检查结果〔白细胞计数、中性粒细胞计数、淋巴细胞计数、血红蛋白、血细胞比容、血小板计数、钾离子、尿素氮、肌酐、随机血糖、估算肾小球滤过率(eGFR)、总胆固醇、三酰甘油、高密度脂蛋白、低密度脂蛋白、极低密度脂蛋白、非高密度脂蛋白、肌酸激酶、肌酸激酶同工酶〕以及经胸超声数据;分析LVEF与院内死亡的相关性,绘制LVEF预测患者院内死亡的ROC曲线,获取LVEF预测院内死亡的临界值并根据临界值分为LVEF>临界值组和LVEF<临界值组,比较临床指标差异。结果LVEF预测院内死亡ROC曲线下面积为0.846〔95%CI(0.628,1.000),P=0.018〕,最佳临界值为67.5%,灵敏度为75.0%,特异度为95.1%。LVEF>临界值组(n=16)和LVEF<临界值组(n=256)院内死亡率分别为18.8%(3/16)和0.4%(1/256),差异有统计学意义(P<0.05)。两组生存曲线比较,差异有统计学意义(χ^(2)=36.526,P<0.001)。LVEF>临界值组女性比例高于LVEF<临界值组、脉率低于LVEF<临界值组,IABP应用高于LVEF<临界值组、术后血流2~3级比例低于LVEF<临界值组、左心室收缩末期内径小于LVEF<临界值组(P<0.05)。结论急性ST段抬高型心肌梗死直接PCI术后射血分数保留的患者存在着超常射血分数的亚组人群,其死亡率较射血分数正常者高,临界值为67.5%。性别差异和冠状动脉微循环障碍可能是其发生和发展的促进因素。

Background Left ventricular ejection fraction(LVEF)is often used as an assessment indicator for left ventricular systolic function.As adverse events occur in some patients with preserved LVEF,other phenotypes based on LVEF may exist in the population with LVEF≥50%,affecting the prognosis.Objective To explore the critical LVEF and possible pathogenesis in acute ST-elevation myocardial infarction(STEMI)patients with supra-normal ejection fraction after primary PCI.Methods A total of 272 STEMI patients with initial LVEF≥50%by transthoracic echocardiographic measurement after being treated with primary PCI were selected from Heart Center,Hebei General Hospital from November 2016 to June 2018.All patients were admitted to the cardiovascular care unit following primary PCI.Data were collected,including baseline characteristics(gender,smoking history,drinking history,family history of cardiovascular disease,angina in the past one month,diabetes history,hypertension history,stroke history,old myocardial infarction,age,body mass index,pulse rate,and mean arterial pressure),time of onset of chest pain〔including time from symptom onset to first medical contact,time from symptom onset to first antiplatelet therapy,time from symptom onset to first anticoagulation,symptom onset to balloon time(SBT),door-to-balloon(D-to-B)time〕,periprocedural data〔pre-procedural TIMI flow grade,collateral circulation,treatment of non-infarct related artery(NIRA),thrombus aspiration,IABP application,anticoagulant medication,pre-procedural use ofβ-blockers,renin-angiotensin-aldosterone system inhibitors(RAASi),or statins,intra-procedural application of tirofiban and prourokinase,post-procedure TIMI flow grade〕,laboratory test results(leukocyte count,Neutrophil count,lymphocyte count,hemoglobin,hematocrit,platelet count,potassium ion,urea nitrogen,creatinine,random blood glucose,eGFR,total cholesterol,triacylglycerol,high-density lipoprotein,low-density lipoprotein,very low-density lipoprotein,non-high density lipoprotein,creatine kinase,creatine kinase isozyme)and transthoracic echocardiographic data.The correlation between LVEF and in-hospital death was analyzed.By ROC analysis,the optimal threshold of LVEF predicting in-hospital death was obtained,and patients with LVEF greater and less than the optimal threshold were compared in terms of clinical indictors.Results The area under the ROC curve of LVEF predicting in-hospital death was 0.846〔95%CI(0.628,1.000),P=0.018〕,and the optimal threshold was 67.5%with a sensitivity of 75.0%and a specificity of 95.1%.Compared with those with LVEF<67.5%,patients with LVEF>67.5%had higher in-hospital mortality〔18.8%(3/16)vs 0.4%(1/256)〕,with a statistical difference(P<0.05).Moreover,they also showed a statistical difference in Kaplan-Meier survival curve(χ^(2)=36.526,P<0.001).Furthermore,patients with LVEF>67.5%showed higher female ratio and rate of IABP application,lower mean pulse rate as well as lower rate of post-procedure TIMI grade 2-3 flow(P<0.05).They also demonstrated lower mean left ventricular end-systolic diameter(P<0.001).Conclusion There may be a subgroup in STEMI patients with preserved ejection fraction after primary PCI,who presented higher LVEF(supra-normal LVEF)and higher in-hospital mortality than those with normal LVEF.The optimal threshold of LVEF for predicting in-hospital death in these STEMI patients was 67.5%.Being female and coronary microcirculation disorder may contribute to the development of supra-normal ejection fraction.