A Serial Study On Coronary Microvascular Obstruction In Patients With STEMI: Risk Prediction And Function Evaluation

For patients with STEMI,the basic principle is performing reperfusion therapy as soon as possible.By reopening IRA,restoring effective myocardial tissue perfusion,inhibiting infarction extension and saving the ischemic myocardium are the goals of primary percutaneous intervention.However,an urgent need is addressing the significance of coronary microvascular functional and structural obstruction(CMVO),which occurs even after epicardial recanalization.In clinical practice,quite a number of patients developed CMVO,which is also known as No-Reflow or Slow-Reflow Phenomenon.Once happens,the ischemia and anoxia of tissue worsen without efficient treatment,which increasing the incidence of major adverse cardiac events during follow-up.Therefore,identifying patients at high risk before procedure plays an important part in decreasing MACEs and improving patients' life quality,which is also a hot spot in clinical filed recently.Quantity of papers and evidence have discussed and analyzed the possible independent risk predictors of CMVO.Since multiple factors are thought to contribute to the occurrence of it,including ischemic injury,distal embolization,reperfusion injury and susceptibility,it is unreasonable to estimate whether CMVO happens or not according to just one specific single element.As a result,selecting a series of risk factors and developing a risk model are beneficial to predict and recognize patients with high hazard of developing CMVO,which may guide preventive therapy.In order to evaluate microcirculation perfusion status accurately,the Index of Microcirculatory Resistance has been applied in the field of coronary intervention gradually.IMR shares the advantages of specificity and reproducibility.It can not only reflect the coronary microcirculation dysfunction,but associate with heart function and long-term prognosis of STEMI patients.Based on the previous research,this serial study is mainly about risk prediction and function evaluation of coronary microvascular obstruction in patient with STEMI.There are three parts,part one was designed to predict and evaluate the risk of coronary microvascular obstruction in STEMI patients undergoing primary percutaneous coronary intervention by developing and validating the nomogram model,part two is aimed to compare the predicting values of two risk scores of coronary microvascular obstruction,part three is designed to evaluate the efficacy and safety of thrombus aspiration and intracoronary targeted thrombolysis with the assistance of the index of microciculatory resistance,comparing their protective effects on myocardial microcirculation perfusion in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.Part one Development and validation of risk nomogram model predicting coronary microvascular obstruction in patients with STEMI undergoing primary percutaneous catherization.Objective:This study was designed to predict and evaluate the risk of coronary microvascular obstruction in STEMI patients undergoing primary percutaneous coronary intervention by developing and validating the nomogram model.Methods:Patients admitted from January 2014 to December 2016 who were diagnosed of STEMI and receiving primary percutaneous intervention were collected.Demographic characteristics,vital signs,past medical history,baseline laboratory data,interventional parameters and data were recorded.All patients were numbered according to admission time sequence and divided into training database group and validation database goup.The groups were divided into MO group(TMPG 3 grade)and NMO group(TMPG 0-2 grade).The data of training database were analyzed,and the independent risk factors of CMVO after primary PCI were analyzed by binary Logistic regression analysis.The risk factors were drawn wo develop the nomogram model with the application of R language.Internal and external validation of the nomogram was done by determining the validity and stability of the model.Moreover,the occurance of MACEs in-hospital and 30 days after procedure were assessed,which were defined as cardiac death,heart failure,malignat arrhythmia,revascularization of target vessel revascularization and recurrence of angina pectoris.Results:Totally 446 patients were enrolled into training group.Among them,319 cases were classified into NMO group,while 127 cases in MO group(CMVO incidence was 28.48%).99 patients were enrolled into validation group,74 cases in NMO group and 25 in MO group(CMVO incidence was 28.48%).In training group,the average age of MO group was significantly higher than that of NMO group,and the proportion of patients with Killip 3 grade was higher.The two goups exist diffrence in a number of laboratory indicators(all P<0.05).In NMO group,patients had a shorter reperfusion time comapared with patients in MO group.After intervention,coronary perfusion paramter in MO group was inferior,including TIMI 3 grade flow and CTFC(ALL P<0.05).By binary Logsitic regression analysis,Age>65(X1),admission Killip grade(X2)?SO-B time(x3)?ACT(X4)?NLR >7.0(X5)?random blood glucose level(X6)were independent predictors of CMVO in traning database.Regression equation was Logit P =-7.580 + 1.055 * X1 + 1.461 * X2 + 0.278 * X3-0.734 * X4 + 1.423 * X5 + 0.893 * X6.The regression prediction accuracy of the model was 86.3%.The internal model ROC curve AUC is 0.925(95%CI: 0.9-0.949).After 50 percent off cross validation to the model,the final average AUC is 0.902.The data of the verification group were similar to those of the modeling group,and the AUC of external validation was 0.939(95%CI: 0.894-0.984).There was a significant difference in the LVEF level between the two subgroups in both databases.Patients with CMVO had a higher rate of MACEs during follow-up(ALL P < 0.05).Summary:1.Symptom onset to Balloon time is the most important predicting factor of CMVO in STEMI patients undergoing primary percutaneous catheterization.2.The baseline ACT level of admission is an independent predictor of CMVO in STEMI patients undergoing emergency intervention.3.Nomogram model with age,SO-B time,Killip grade,admission ACT level,N/L ratio and random glucose can accurately predict the risk of CMVO in STEMI patients undergoing emergency PCI.4.Coronary microvascular obstruction is related to the occurrence of cardiac adverse events,which need physicians' attention.Part two The predictive values and comparison of SAK and ATI scores on coronary microvascular obstruction during primary intervention for STEMI patients.Objective:The predictive values of SAThis study is aimed to assess the predictive ability of two risk scoring systems on coronary microvascular obstruction during primary intervention for STEMI patients.Methods:All STEMI patients recieving emergency PCI and IMR from January 2018 to April 2018 were enrolled.Before and after the stent implantation,the IMR examination was respectively performed.On the basis of the IMR value after the stent implantation,the patients with IMR > 40 were classified as group MO,and IMR < 40 was defined as group NMO.According to the two risk systems,all the selected patients were scored.Compare the clinical parameters of two groups,draw the ROC curve of two scores,get the Cut-off value of ROC curve and the corresponding Youden Index.Compare two AUC with the non-parametric test.Results:Totally 65 patients were enrolled with 17 cases in NMO group and 48 cases in MO group.The incidence of CMVO was 26.15%.The average age of group MO was significantly higher than that of group NMO,and the proportion of patients with Killip 3 level was significantly higher.There was a significant difference in a number of laboratory indicators.Related coronary flow index after intervention in the MO group were inferior to the NMO group,including the proportion of TIMI 3 grade,CTFC and the proportion of TMPG 3(ALL P<0.05).Two scoring systems were used to draw ROC curves for patients.For SAK score,AUC was 0.855(95%CI: 0.746-0.930),Cut-off was 15,Youden Index was 0.6078;for ATI score,AUC was 0.907(95%CI: 0.809-0.965),Cut-off value was 3,Youden Index was 0.6875.Two AUC were tested by nonparametric test and result was Z=1.001,P < 0.317.There was a significant difference between the NMO and MO group in the LVEF values in-hospital(P<0.05).Summary:1.ATI score can predict the risk of coronary microvascular obstruction in STEMI patients accurately and reliably.2.When IMR was not available,SAK score was an alternative to predict the occurrence of coronary microvascular obstruction in patients undergoing primary percutaneous coronary intervention.3.The index of microcirculation resistance after primary PCI can be used as a standard to determine the occurrence of coronary microvascular obstruction.Part three Protective effects of different strategy on myocardial microcirculation perfusion in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary interventionObjective: To evaluate the efficancy and safety of thrombus aspiration and intracoronary targeted thrombolysis with the assistance of the index of microciculatory resistance,comparing their protective effects on myocardial microcirculation perfusion in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.Methods: From January 2017 to January 2018,STEMI patients undergoing emergent angiography with high thrombus burden were enrolled.All eligible paitents were randomly divided into two groups,which were IT group and TA group.Patients in IT group received intracoronary targeted thrombolysis therapy with a new specific plasminogen activator,Recombinant Human Prourokinase for intracoronary injection via finercross microcatheter.TA group patients received thrombus aspiration.After reperfusion thrapy,IMR was performed immediately.Infarct size was measured by resting SPECT after a week of operation.All patients were followed-up for 90 days postoperation,including MACES,major bleeding events and cereral stroke.Results:There were 38 patients in IT group and 33 patients in TA group respsctively.There was no significant difference between the two groups in the baseline data,reperfusion treatment period and the basic parameters of intervention(ALL P > 0.05).There was no difference between the two groups in final TIMI blood flow,while patients in IT group had a lower intracoronary thrombus score(P=0.022),a lower CTFC(23.05±5.35 vs.26.51±4.95,P=0.043),and a higher rate of TMPG 3 grade(92.11% vs.72.73%,P=0.030).After intervention,IMR was measured with pressure wire.The average level of IMR in IT group was lower than that in TA group(28.19±7.26 vs.33.56±8.47,P= 0.005).From the results of SPECT,the ROI(%)was lower in TA group,while difference between two groups was not significant(21.29±9.65 vs.24.82±8.87,P=0.115).After 90 days,LVEF and WMSI values in each group was significantly higher than that on admission(BOTH P > 0.05).There was no significant difference in MACEs between the two groups(ALL P > 0.05).No patient had cerebral stroke,hemorrhage and blood transfusion during the follow-up period.There was no statistical significance in the incidence of small bleeding(P>0.05).Summary:1.Intracoronary targeted thrombolysis and thrombus aspiration are effective and safe strategy in dealing with high coronary thrombus burden and restoring epicardial flow.2.Compared with intracoronary thrombus aspiration,intracoronary targeted thrombolysis is more beneficial in improving myocardial microcirculation perfusion and protecting myocardium.3.The Index of microcirculatory resistance is an effective indicator to evaluate the coronary microcirculation perfusion state.Conclusions:1.Nomogram model with age,SO-B time,Killip grade,admission ACT level,N/L ratio and random glucose can accurately predict the risk of CMVO in STEMI patients undergoing emergency PCI.2.SAK score and ATI score can predict the risk of coronary microvascular obstruction in STEMI patients accurately and reliably.3.The Index of microcirculatory resistance is an effective indicator to evaluate the coronary microcirculation perfusion state.4.With optimal anticoagulating and antithrombotic therapy,intracoronary targeted thrombolysis and thrombus aspiration are effective and safe strategy in dealing with high coronary thrombus burden and restoring epicardial flow.5.Coronary microvascular obstruction is related to the occurrence of cardiac adverse events,which needs physicians' attention.