Aim To investigate the incidence, clinical characteristics and risk factors of intraprocedural thrombotic events (IPTE) during percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) and analyse the influences of IPTE on heart function and major adverse cardiac events (MACE). Methods From January 2013 to December 2014, a total of 836 consecutive AMI patients from Hainan General Hospital who underwent PCI were enrolled in this study (708 male, aged 61.05±11.96 years; 128 female, aged 68.18±10.42 years). The patients with thrombotic events occurred during PCI were enrolled in IPTE group. The patients without thrombotic events were enrolled in non intraprocedural thrombotic events (NIPTE) group. Blood routine test, biochemical test and coagulation test were obtained before PCI. Risk stratification were noted by the GRACE scores, CURSADE scores, SYNTAX scores and thrombus burden scores. Independent sample t test, multiple Logistic regression analysis and other testing methods were applied. Results IPTE occurred in 166 cases (19.86%) during PCI, 670 cases were enrolled in NIPTE group. There was no significant difference between the two groups in SYNTAX scores. Thrombus burden scores were higher in IPTE group than those in NIPTE group (1.11±0.78 vs. 0.57±0.70, P＜0.001). The level of admission CK-MB (127.20±138.36 U/L vs. 89.67±139.25 U/L, P＜0.01), admission TNT (2.30±3.04 μg/L vs. 1.81±2.59 μg/L, P＜0.05), hs-CRP (28.90±43.97 mg/L vs. 22.96±30.92 mg/L, P＜0.05), counts of white blood cell (11.50±3.94 10⁹/L vs. 10.43±3.63 10⁹/L, P＝0.001) and Hcy (17.26±15.28 μmol/L vs. 14.41±8.33 μmol/L, P＜0.05) were higher in IPTE group than those in NIPTE group. The incidence of heart failure was higher in IPTE group than that in NIPTE group (30.1% vs. 22.2%, P＜0.05). There were no significant difference of cardiovascular death, reinfarction, cardiac shock, sudden death and MACE between the two groups. Multiple Logistic regression analysis showed age (OR＝1.9,5%CI was 1.017～1.062, P＜0.001), GLU (OR＝1.7,5%CI was 1.023～1.197, P＜0.05), reduced FIB (OR＝0.8,5%CI was 0.644～0.893, P＜0.05), shortened TT (OR＝0.4,5%CI was 0.990～0.998, P＜0.01), Hcy (OR＝1.3,5%CI was 1.010～1.058, P＜0.01), RBC (OR＝2.8,5%CI was 1.357～3.183, P＜0.01) and thrombus burden scores (OR＝2.3,5%CI was 2.067～3.719, P＜0.001) were independent risk factors associated with IPTE. ConclusionsThe incidence of IPTE during PCI in AMI patients was 19.86% in our study. The patients with IPTE presented higher incidence of heart failure. Age, GLU, FIB, TT, Hcy, RBC and thrombus burden scores were independent risk factors associated with IPTE.