Abstract: Objective To investigate the clinical value of proprotein convertase subtilisin/kexin type 9 (PCSK9) level in predicting the short-term major adverse cardiovascular events (MACEs) in patients with acute ST-segment elevation myocardial infarction (STEMI). 
 Methods A total of 90 STEMI patients were recruited consecutively. All patients received percutaneous coronary intervention (PCI) after admission. Venous blood was obtained and PCSK9 levels in peripheral blood were determined by enzyme-related immunosorbent assay (ELISA). In the meantime, patients were divided into high PCSK9 group (n=45) and low PCSK9 group (n=45) according to the median PCSK9. All patients were regularly followed up after discharge, and MACEs of patients were recorded. The maximum duration of follow-up was 30 d. 
 Results Age, low-density lipoprotein cholesterol (LDL-C) and cardiac troponin Ⅰ （cTnⅠ） levels, and incidence of MACEs in high PCSK9 group were higher than those in low PCSK9 group, while the event-free survival (EFS) was shorter than that in low PCSK9 group (P＜0.05). PCSK9 level was positively correlated with LDL-C and negatively correlated with EFS (P＜0.05). The area under curve (AUC) of PCSK9 in predicting MACEs in STEMI patients was 0.843 (95%CI: 0.722-0.964). High PCSK9 level was an independent risk factor for MACEs within 30 days in STEMI patients (P＜0.05). 
 Conclusion Patients with high levels of PCSK9 have a high incidence of MACEs and a short EFS, and PCSK9 is related to inflammatory indicators and lipid disorders, which is a potential marker for predicting MACEs within 30 days after intervention in STEMI patients, and is also an independent risk factor for the occurrence of MACEs. 

Key words: ST-segment elevation myocardial infarction, proprotein convertase subtilisin/kexin type 9, major adverse cardiovascular events