The Effects Of Ischemic Postconditioning On Cardiac Structure And Function In Patients With Acute STEMI:A Meta Analysis

Background:Rapid,complete,sustained reperfusion of infarct-related coronary artery is a cornerstone in the treatment of acute ST-elevation myocardial infarction(STEMI).Paradoxically,reperfusion itself can enlarge the damage to ischemic myocardium by complex mechanisms termed ischemic/reperfusion injury.Some published experimental studies demonstrated ischemic postconditioning can reduce ischemic reperfusion injury considerably,but some others observed negtive results.Objective:This meta analysis is aimed to summarize the evidence from randomized controlled clinical trails studies examining the effcacy of ischemic postconditioning in acute ST elevation myocardial infarction.Methods:We systematically searched Medline,Embase,the Cochrane Central Register of Controlled Trials,CBM,China National Knowledge Infrastructure(CNKI),WanFang database,VIP database from onset to April 2018.Final ischemic size(IS),left ventricular ejection fraction(LVEF)were selected as the primary outcomes.myocardial salvage index(MSI),the extent of myocardial edema(ME),LV-end diastolic volume(LVEDV),the incidence of microvascular obstruction(MVO)were the secondary outcomes.All of the outcomes were estimated and quantified by cardiac magnetic resonance.Results:Twelve randomized controlled trails were included in our meta analysis.Compared with conventional PCI,ischemic postconditoning obtained better results in terms of IS(SMD-0.192;95%CI[-0.383,-0.002];P=0.048),LVEF(WMD1.62;95%CI[0.392,2.848];P=0.01),MSI(WMD3.69;95%CI[0.25,7.13];P=0.035).There was a trend toward decreased myocardial edema in the ischemic postconditioning group,which was not of statistical significance(SMD-0.18;95%CI[-0.38,0.01];P=0.057).NO significant difference was found in the two groups in terms of the incidence of MVO(RR0.98;95%CI[0.84,1.14];P>0.05),and LVEDV(WMD-0.15;95%CI[-3.05,2.74];P>0.05).Conclusion:Ischemic postconditioning yielded favorable outcomes in terms of cardioprotection as evidenced by decreased IS,the extent of myocardial edema,and improved LVEF,MSI without affecting the incidence of MVO,LVEDV in patients with STEMI.