The Protective Effect Of Ticagrelor On Coronary Microvascular Injury In Primary PCI For Patients With ST-segment Elevation Myocardial Infarction

Objective To investigate the protective effect of ticagrelor on coronary microvascular injury in primary PCI for patients with ST-segment elevation myocardial infarction(STEMI).Methods This study was a prospective,single-center,randomized controlled study.Patients were randomly assigned to recieve either clopidogrel or ticagrelor using a random number table.115 patients in our hospital from March 2014 to August 2016 with STEMI undergoing emergency PCI were selcected.Inclusion criteria:(1)persistent chest pain is greater than 30min;(2)the electrocardiogram(ECG)between two or more than two lead ST segment elevation;(3)positive troponin(c Tn)or at least two measurements of creatine kinase isoenzyme(CK-MB)is greater than the upper limit of normal(two times);(4)ECG showed that the formation of pathological Q wave.Reasons for exclusion:(1)age < 18 years or ?75 years;(2)history of undergoing coronary artery bypass grafting,previous cerebrovascular accident or myocardial infarction;(3)congestive heart failure,left ventricular ejection fraction <35%;(4)serious liver and kidney dysfunction;(5)hemorrhagic disease or congenital coagulation dysfunction;(6)contraindication or allergy to aspirin,ticagrelor,clopidogrel or adenosine;(7)cardiogenic shock;(8)unprotected left main coronary artery disease;(9)follow-up time less than 3 months or failed to carry out regular follow-up.These patients were randomized divided into two groups: ticagrelor group(n=60)andclopidogrel group(n=55).Patients who were not eligible for primary PCI were excluded,including 16 patients in the ticagrelor group(6 cases of Cardiogenic shock;5 cases of distal lesion;one case of left main;2 cases of variant angina;one case of previous MI;one case of AV block)and 14 patients in the clopidogrel group(5 cases of Cardiogenic shock;3 cases of distal lesion;2 cases of left main;one case of variant angina;one case of previous MI;2 cases of AV block).Finally,the patients of two groups were 44 cases and 41 cases,respectively.Ticagrelor group: patients underwent primary PCI treatment,preoperative aspirin loading dose of 300 mg,after the maintenance dose of 100 mg,one time daily;preoperative administration of oral ticagrelor 180 mg loading dose,given after 90 mg,2 times daily maintenance dose;hospital routine use of atorvastatin,beta blockers,angiotensin converting enzyme inhibitors / angiotensin receptor antagonist.Clopidogrel group: clopidogrel 600 mg was given before operation,and clopidogrel 75 mg was given one time daily.The remainder were treated with the same of ticagrelor group.The microvascular injury were assessed using IMR measured at the infarct-related artery immediately after reperfusion therapy.The Pa(hyp),Pd(hyp),Rest Tmn),Hyper Tmn),FFR,CFR and IMR were recorded.Echocardiographic assessment were obtained less than 24 hours after primary PCI,again seven days and three months later.The EDV,ESV,LVEF and WMSI were recorded.The differences of coronary physiologic assessment and infarct size measurements in two groups were observed.The differences of main adverse cardiovascular events(MACE)and hemorrhage complication in 3 months of patients in two groups were observed.Results1.Compared with clopidogrel group,the Hyper Tmn and IMR in ticagrelor group was significantly decreased(0.31±0.23 s VS 0.48±0.24 s;21.62±14.36 U VS 35.12±15.63 U;P<0.05),and there was no difference of the Pa(hyp),Pd(hyp),Rest Tmn,FFR and CFR of coronary physiologic assessment between these two group(P>0.05).2.There were no difference of EDV,ESV,LVEF and WMSI in baseline,postoperative 7days and postoperative 3 months between these two groups(P> 0.05).3.Compared with clopidogrel group,the major adverse cardiovascular events in ticagrelor group was significantly decreased(P< 0.05).The total rate of hemorrhage complication was no significant difference between these two groups(P> 0.05).Conclusion Compared with clopidogrel,IMR in the preoperativeapplication of ticagrelor in the treatment of STMEI by primary PCI was decreased,which suggest that ticagrelor display more effective in reducing microvascular injury than clopidogrelin primary PCI for patients with STEMI.