| Backgroud and Objective:Intra-aortic balloon counterpulsation(IABP)is a circulatory support device,which is deployed transfemorally into the descending aorta after the takeoff of subclavian artery.The balloon inflates and deflates cyclically with the cardiac cycle and thereby reduces the preload,afterload of the heart,increases the coronary perfusion,decreases the myocardial oxygen demand and improves the cardiac output eventually.IABP was introduced into clinical practice at the end of 1960s.It has saved numerous critical patients with coronary heart disease and the recommendation of IABP has been class ? in the ST segment elevation myocardial infarction(STEMI)guidelines made by European society of cardiology(ESC)for long-term.However,the debate on the efficacy of IABP has become more and more as the clinical studies increased.Many studies,such as CRISP AMI,TACTICS,PAMI-?,IABP SHOCK,have found that IABP was unable to reduce the mortality,infarct sizes or left ventricular function of patients with myocardial infarction(MI)with or without cardiogenic shock(CS).IABP SHOCK ? study,which was of the largest scale,found that IABP plus percutaneous coronary intervention(PCI)/coronary artery bypass graft surgery could not decrease the mortality of the patients with CS due to STEMI or non-ST segment elevation myocardial infarction(NSTEMI)at 30 days and 1 year.This finding led to the recommendation degradation of IABP from class ? to class ? in the myocardial infarction guidelines made by ESC and American heart association(AHA)and also made the utilization of IABP decline.Nevertheless,some meta-analyses revealed that IABP was not able to reduce the mortality of MI patients with CS,but was able to decrease the mortality of the MI patients without CS at 6-12 months.Furthermore,a few of retrospective studies suggested that IABP insertion before revascularization could reduce the mortality and major adverse cardiac events(MACE)of the MI patients with CS or high-risk patients with coronary heart disease(CHD)without CS in comparison with IABP insertion after revascularization.Taken all together,we believe that IABP definitely benefits the critical patients with heart diseases.Nontheless,it could not benefit all the patients The effect of IABP on the hemodynamics could probably not offset the disease exacerbation when the patients illed dramatically.Therefore,we speculate that IABP should benefit a subset of the CHD population and prophylactic insertion of IABP probably produces more benefits than rescued insertion.For this purpose,we performed this study in order to identify the CHD population who would benefit from the IABP utilizationMethods:First of all,we retrospectively analyzed the STEMI paients in our center.We compared the clinical feature,angiography and PCI results of the patients accepted primary PCI without IABP versus patients accepted primary PCI with rescued IABP due to CS during the procedure.The risk factors which could predict the hemodynamic collapse in the primary PCI were identified using Logistic multivariate regression and the regression model was optimized with Aakaike information criterion(AIC)and Bayesian information criterion(BIC).Thereafter,we formulated a risk score for definition of non-shock critical STEMI patients(details of risk score in Chapter 3)based on the risk factors acquired from regression analysis as well as the previous studies.The STEMI patients who met the criteria of the risk score were enrolled in a randomized,controlled trial(RCT).The patients were randomized into control group and intervention group with 1:1 ratio.IABP should be inserted before primary PCI in the intervention group,while primary PCI was accomplished without IABP in control group.The cardiac function,mortality and major adverse cardiac and cerebral events(MACCE)at 12 months were analyzed in order to evaluate the efficacy of IABP utilization in the non-shock critical STEMI patients during the primary PCI.Results:(1)Total 691 STEMI patients were enrolled in the retrospective study,658 STEMI patients in the non-IABP group and 33 STEMI patients in the rescued IABP group.Compared with the non-IABP group,there were higher percentage of patients with prior ischemic stroke(P=0.005)and lower percentage of smoking patients(P=0.03)in the rescued IABP group.The patients in the rescued IABP group also had lower left ventricular ejection fraction(LVEF)(P=0.002),longer door-to-balloon(D-to-B)time and higher percentage of D-to-B time more than 90min(P<0.001).Moreover,the patients in the rescued IABP group had lower pre-procedural systolic blood pressure(SBP)(P<0.001)and faster pre-procedural heart rate(HR)(P=0.008)than the non-IABP group.(2)Logistic multivariate regression analysis identified the 5 predictors of impending hemodynamic compromise during primary PCI as follows:LVEF(OR:0.89,95%CI:0.82?0.96,P=0.003),pre-procedural SBP(OR:0.94,95%CI:0.92?0.97,P<0.001),pre-procedural HR(OR:1.03,95%CI:1.02?1.06,P=0.006),multivessel disease(OR:2.26,95%CI:0.90?5.67,P=0.08),D-to-B time(OR:1.0,95%CI:1.0?1.01,P=0.04).(3)In the RCT,29 non-shock critical STEMI patients had been enrolled so far.After randomization,there were 16 patients in the control group and 13 patients in the intervention group.The clinical baselines,angiography results and PCI strategy were matched between two groups.(4)All the patients were followed up with median 213 days.There were 5 cases of' mortality and total 22 MACCE occurred in 13 patients.There were no differences in any MACCE between the two groups.Furthermore,the cumulative survival rate at 12 months estimated by Kaplan-Meier were no different between the two groups(81.3%vs 84.6%,RR:0.82,P=0.87).The cumulative incidence of first MACCE occurrence were also similar between the two groups(37.5%vs 38.5%,RR:1.03,P=0.97).There was 1 case of BARC2 bleeding event and 1 case of BARC3 bleeding event in the intervention group,whereas there was only 1 case of BARC2 bleeding event in control group.No significant difference in the bleeding event was observed between the two groups.(5)Compared with the LVEF at 24 hours after revascularization,there was no improvement of LVEF during the followup period in the control group,while the LVEF presented sigificant improvement during the followup period in the intervention group,which was apparent at 6 month(43.2±5.35 vs 38.1±2.68,P<0.0125)and 12 month(44.9±5.60 vs 38.1±2.68,P<0.0125).More important,the superiority of LVEF in the intervention group over the control group took on significant as time passed by during the followup(P=0.011).Conclusions:The utilization of IABP support during primary PCI in the non-shock critical STEMI patients was safe and feasible.The LVEF in the intervention group was improved significantly at 6 months and 12 months after PCI in comparison with 24 hours after PCI.As time passed by during followup period,the superiority of LVEF in the intervention group over the control group became significant.Nontheless,IABP was not able to reduce the mortality and MACCE at 12 months.Notably,the present results were not decisive because the predetermined sample size was not reached yet.The final evaluation of efficacy for IABP suppport should be done after the finish of recruitment and analysis. |
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