Abstract:ObjectiveTo investigate the clinical effects of three route of etibatide administration in percutaneous coronary intervention (PCI) of acute ST-segment elevation myocardial infarction (STEMI) with high thrombotic load. Methods A total of 300 patients with acute STEMI with high thrombus burden treated in Central People's Hospital of Zhanjiang from May 2018 to July 2021 were selected and randomized to grouPA, B and C, with 100 cases in each group. PCI was performed in all three groups, etibatide was injected intravenously in grouPA, etibatide was injected into the coronary artery in grouPB, and etibatide was injected into the lesion site in grouPC. The blood perfusion level of epicardial vessels, myocardial microcirculation index, myocardial injury area index, bleeding during hospitalization and 3-month follow-uPresults were compared among three groups. Results Compared with grouPA, the myocardial color grading, left ventricular ejection fraction (LVEF) in grouPB and grouPC were significantly higher, corrected TIMI frame number(cTFC), creatine kinase isoenzyme(CK-MB),CK-MB peak, troponin I(cTn I), cTn I peak, N-terminal B-type natriuretic peptide precursor(NT-proBNP) level and the total incidence of adverse cardiac events(MACE) in grouPB and grouPC were significantly lower, the degree of ST segment decline in grouPB and grouPC were significantly greater (P<0.05). Compared with grouPB, the myocardial color grading, LVEF in grouPC were significantly higher, cTFC, CK-MB, CK-MB peak, cTn I, cTn I peak, NT-proBNPlevel and the total incidence of MACE in grouPC were significantly lower, the degree of ST segment decline in grouPC were significantly greater(P<0.05). Conclusions In PCI of acute STEMI with high thrombotic load, injection of etibatide into the lesion site has the best effect in improving myocardial microcirculation perfusion, reducing myocardial injury area, cardiac function after PCI, and reducing MACE after PCI, followed by intracoronary injection of etibatide.