Abstract:Objective To investigate the changes in neutrophil-to-lymphocyte ratio（NLR）before and after percutaneous coronary intervention（PCI）in patients with acute myocardial infarction（AMI）and its impact on the development of major adverse cardiovascular and cerebrovascular events（MACCE）, and to analyze the influencing factors for MACCE within one year after PCI in AMI patients. Methods A retrospective analysis was conducted on 225 AMI patients admitted to the Department of Cardiology, Northern Jiangsu People’s Hospital from January 2021 to April 2023, all of whom presented within 24 hours of symptom onset and underwent PCI within 24 hours of admission. Based on follow-up outcomes, patients were divided into a non-MACCE group and a MACCE group. General data, laboratory parameters, cardiac function indicators, Gensini score, and reperfusion time were compared between the two groups. Risk factors for MACCE within one year after PCI were analyzed, using Cox multivariate regression model. Results All patients completed one year of follow-up and were divided into the non-MACCE group（n=144）and the MACCE group（n=81）.NLR levels at 1 day and 2 days after PCI were significantly lower than those at admission in both groups, and the levels at 2 days were lower than those at 1 day（P＜0.05）. Compared with the non-MACCE group, patients in the MACCE group had higher neutrophil-to-lymphocyte ratio（NLR）levels at 1 day and 2 days after PCI（P＜0.05）. Cox regression analysis showed that risk factors for MACCE within one year after PCI in AMI patients included age>65 years（HR=1.038, 95%CI：1.003-1.075, P=0.034）, atrial fibrillation（HR=3.133, 95%CI：1.052-9.329, P=0.040）, and NLR>3.54 on postoperative day 2（HR=1.080, 95%CI：1.021-1.141, P=0.007）. Conclusion Peripheral blood NLR level is closely associated with the prognosis of AMI patients. NLR levels and their changes at different time points have predictive value for the prognosis of AMI patients undergoing PCI.