Objective To compare the perioperative efficacy and safety of bivalirudin and unfractionated heparin in ST-segment elevation myocardial infarction (STEMI) patients with different bleeding risks undergoing emergency percutaneous coronary intervention (PCI).

Methods A total of 615 STEMI patients who underwent emergency PCI were enrolled in the study. According to CRUSADE bleeding risk score, they were divided into low risk bleeding group(CRUSADE score ≤30, 421 patients) and medium and high risk bleeding group(CRUSADE score >30, 194 patients). Patients in the low risk bleeding group were divided into low-risk heparin group(n=203) and low-risk bivalirudin group(n=218)according to the anticoagulant treatment plan, while the patients in the medium and high risk bleeding group were divided into medium and high risk heparin group (n=95) and medium and high risk bivalirudin group (n=99). The blood flow grade, major adverse cardiovascular events (MACE) and occurrence of bleeding events 30 days after operation in patients with thrombolysis in myocardial infarction (TIMI) were observed and compared in different groups.

Results Of STEMI patients in moderate and high risk of bleeding group, there were no significant differences in postoperative TIMI blood flow grading and MACE events between the medium and high risk bivalirudin group and the medium and high risk heparin group(P>0.05). The incidence of European and American Hemorrhage Research Committee(BARC)type 2 to 5 bleeding events and total bleeding events in the medium-high risk bivalirudin group were 13.13% and 15.15%, respectively, which were lower than 24.21% and 29.47% in the medium and high risk heparin group (P < 0.05). The incidence of BARC type 3 to 5 bleeding in the medium and high risk bivalirudin group was lower than that in the medium and high risk heparin group, but the difference was not statistically significant (P>0.05). Among STEMI patients in the low risk bleeding group, there were no significant differences in TIMI blood flow grade, MACE and bleeding events between the low risk bivalirudin group and the low risk heparin group (P>0.05).

Conclusion Compared with unfractionated heparin, perioperative application of bivalirudin anticoagulant therapy can reduce the risk of bleeding in STEMI patients with moderate and high risk of bleeding during emergency PCI, but it does not bring the ultimate benefit including all-cause death. In STEMI patients with low risk of bleeding, there are no significant differences in the incidence of bleeding and ischemic events between bivalirudin and unfractionated heparin. Patients with STEMI should undergo CRUSADE bleeding risk assessment before PCI, and select appropriate anticoagulants according to bleeding risk.