Abstract: Objective To study the value of clinical features and laboratory indicators in predicting the risk of spontaneous recanalization of infarct-related artery(IRA) in patients with acute ST-segment elevation myocardial infarction(STEMI). 
Methods In total, 375 patients with acute STEMI treated in our hospital were selected as the research subjects. After admission, patients underwent emergency coronary angiography. Patients with IRA TIMI grade 2-3 were included in spontaneous recanalization group(n=114), and patients with IRA TIMI grade 0-1 were included in non-spontaneous recanalization group(n=261). Clinical data of patients were collected, including age, sex, body mass index(BMI), smoking, hypertension or diabetes, and preinfarction angina. Heart rate, number of lesions and infarct sites were recorded. Serum fasting blood glucose(FBG), fibrinogen(FIB), albumin(Alb), creatine kinase isoenzyme(CK-MB), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C), lipoprotein α［Lp(α)］ levels were detected, and FAR values were calculated. ROC curve was used to analyze the value of FIB, CK-MB, FAR and Lp(α) in predicting the risk of spontaneous recanalization of IRA in patients with acute STEMI. Unconditional Logistic stepwise regression analysis was used to analyze the independent predictors of spontaneous recanalization of IRA in patients with acute STEMI. Consistency analysis was used to evaluate the value of multiple predictors in predicting the risk of spontaneous recanalization of IRA in patients with acute STEMI. 
Results Univariate analysis showed that compared with non-spontaneous recanalization group, the proportion of smoking patients in spontaneous recanalization group was lower, the proportion of patients with preinfarction angina was higher, and the levels of FIB, CK-MB，FAR and Lp(α) in spontaneous recanalization group were lower(all P＜0.05). ROC analysis confirmed that FIB level ≤ 359.440 mg/L, CK-MB level ≤73.460 U/L, FAR value ≤ 9.585, and Lp（α）≤150.947 nmol/L were the optimal cut-off values of IRA spontaneous recanalization in patients with acute STEMI(all P＜0.05). The results of multivariate Logistic regression analysis showed that smoking, preinfarction angina, FIB level ≤359.440 mg/L, CK MB level ≤73.460 U/L, FAR value ≤9.585, and Lp（α）≤150.947 nmol/L were independent predictors of spontaneous recanalization of IRA in patients with acute STEMI(all P＜0.05). By consistency analysis, the sensitivity, specificity, accuracy and Kappa of multiple predictors in predicting spontaneous recanalization of IRA in patients with acute STEMI were 0.930, 0.931, 0.931 and 0.840, respectively. 
Conclusion The FIB level ≤ 359.440 mg/L, CK-MB level ≤73.460 U/L, FAR value ≤9.585, and Lp（α）≤150.947 nmol/L were the optimal cut-off values of IRA spontaneous recanalization in patients with acute STEMI. Smoking and preinfarction angina may be the influencing factors of IRA spontaneous recanalization. Multiple factors combined to predict the risk of IRA spontaneous recanalization in patients with acute STEMI has a higher accuracy.

Key words: myocardial infarction, coronary stenosis, forecasting