Influence Of Metformin On Contrast-Induced Acute Kidney Injury In Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Objective:This study was designed to analyze the association between metformin treatment and the development of contrast-induced acute kidney injury(CI-AKI)after primary percutaneous coronary intervention(PCI)in patients with ST segment elevation myocardial infarction(STEMI),furthermore,to analyze the risk factors of contrast-induced acute kidney injury in patients with acute ST segment elevation myocardial infarction combined with type2 diabetes mellitus.Methods:A retrospective study was conducted on patients hospitalized in the department of cardiology and CCU in our hospital form January 2015 to December 2017 diagnosised as acute ST segment elevation myocardial infarction combined with type 2 diabetes.There were238 patients recieved primary percutaneous coronary intervention.According to whether taking oral metformin,they were divide into two groups,that is,metformin group(MET,n=84)and non-metformin group(non-MET n=154).The general clinical data of the two groups were recorded,including age,sex,height,weight,smoking,history of basic diseases, preoperative medications.Electrocardiography and UCG were performed for all patients preoperatively in order to evaluate left ventricular diameter and ejection fraction(LVEF).Preoperative blood test includs blood routine analyses,BNP,serum creatinine C measurements.eGFR was calculated by MDRD formula.The number of implanted stent and the dosage of contrast agent were recorded.Serum creatinine C measurement and eGFR calculation were repeated 48 to 72 hours after PCI.All patients were given loading dose of aspirin(300mg)and clopidogrel(600mg)at emergency room.Laboratory tests were performed 48 hours after the procedure,patients with normal renal function continued oral administration of metformin.Basic clinical data comparison between the two groups,and the level of serum creatinine,eGFR before and after the procedure,procedure related parameters such as contrast volume,coronary lesions,number of stents,hemodynamical fearures such as heart rate,blood pressure,TIMI flow grade and major adverse cardiac events during hospitalization include cadiac deathe,recurrent angina,re-AMI,intrastent thrombus,heart falure,fatal arrhythmia etc,were observed.To analyze the effect of metformin on the occurrence of CI-AKI in patients with different renal function,subgroup analysis was performed on patients with eGFR<60 ml/min/1.73m~2 in order to compare the kidney function of metformin group and non-metformin group and the occurrence of CI-AKI.To explore the risk factors of acute kidney injury in STEMI patients with diabetes mellitus,all patients were divided into two groups,CI-AKI group and non CI-AKI group,multivariate logistic regression analysis was performed.Major adverse cardiac events were also recorded during hospitalization and within 30 days after hospital.Results:Of the 238 patients,baseline data between the two groups were not statistically significant.There was no statistically significant difference in serum creatinine level and eGFR between the two groups before PCI.Thirty five cases(22.73%)developed CI-AKI after the procedure in non-metformin group while 22 cases(26.19%)in metformin group.The incidence in metformin groups was slightly higher,but there was no statistical difference between the two groups.There were 65 patients with eGFR less than 60 ml/min/1.73m~2.and27 cases(41.53%)developed CI-AKI.Among them,there were 23 cases in metformin group and 13 cases(56.52%)developed CI-AKI,the other 42 cases come form non-metformin,and14 cases(33.33%)developed CI-AKI.The incidence rate of metformin group was higher than that of non-metformin group(P=0.040).Logistic regression analysis was performed to screen out the risk factors of CI-AKI.Regression analyses showed that preoperative eGFR<60 ml/min/1.73 m2,age>65 years old,contrast agent>200 ml,left ventricular ejection fraction<40%were independent risk factors for CI-AKI in patients with acute ST segment elevation myocardial infarction patients combined with diabetes mellitus.The incidence rate of reperfusion arrhythmia,heart failure after myocardial infarction,cardiogenic shock, mortality,CI-AKI group was significantly higher in CI-AKI group than in non-CI-AKI group.Conclusions:In this retrospective study,long term metformin treatment prior to primary PCI had no significant impact on the incidence of CI-AKI.However,for patients with renal dysfunction(eGFR<60 ml/min/1.73 m2),metformin increases the risk of CI-AKI.The independent risk factor of CI-AKI after primary PCI in diabetic patients with acute ST segment elevation myocardial infarction is the older age,contrast volume,renal function,heart function.Carefully assessing the preoperative situation of each patients,and minimizing the dose of contrast agent during PCI are needed in order to reduce the occurrence of CI-AKI.