Association of Parenteral Anticoagulation Therapy With Outcomes in Chinese Patients Undergoing Percutaneous Coronary Intervention for Non–ST-Segment Elevation Acute Coronary Syndrome

Importance: The association of parenteral anticoagulation therapy with improved outcomes in patients with non-ST-segment elevation acute coronary syndrome was previously established. This benefit has not been evaluated in the era of dual antiplatelet therapy and percutaneous coronary intervention. Objective: To evaluate the association between parenteral anticoagulation therapy and clinical outcomes in patients with non-ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention. Design, Setting, and Participants: This cohort study included 8197 adults who underwent percutaneous coronary intervention for non-ST-segment elevation acute coronary syndrome from January 1, 2010, to December 31, 2014, at 5 medical centers in China. Patients receiving parenteral anticoagulation therapy only after percutaneous coronary intervention were excluded. Exposures: Parenteral anticoagulation therapy. Main Outcomes and Measures: The primary outcome was in-hospital all-cause death and in-hospital major bleeding as defined by the Bleeding Academic Research Consortium definition (grades 3-5). Results: Of 6804 patients who met the final criteria, 5104 (75.0%) were male, with a mean (SD) age of 64.2 (10.4) years. The incidence of in-hospital death was not significantly different between the patients who received and did not receive parenteral anticoagulation therapy (0.3% vs 0.1%; P = .13) (adjusted odds ratio, 1.27; 95% CI, 0.38-4.27; P = .70). A similar result was found for myocardial infarction (0.3% vs 0.3%; P = .82) (adjusted odds ratio, 0.77; 95% CI, 0.29-2.07; P = .61). In-hospital major bleeding was more frequent in the parenteral anticoagulation group (2.5% vs 1.0%; P < .001) (adjusted odds ratio, 1.94; 95% CI, 1.24-3.03; P = .004). At a median (interquartile range) follow-up of 2.96 years (1.93-4.46 years), all-cause death was not significantly different between the 2 groups (adjusted hazards ratio, 0.87; 95% CI, 0.71-1.07; P = .19), but the incidence of major bleeding was higher in the parenteral anticoagulation group (adjusted hazards ratio, 1.43; 95% CI, 1.01-2.02; P = .04). The propensity score analysis confirmed these primary analyses. Conclusions and Relevance: In the patients undergoing percutaneous coronary intervention for non-ST-segment elevation acute coronary syndrome, parenteral anticoagulation therapy was not associated with a lower risk of all-cause death or myocardial infarction but was significantly associated with a higher risk of major bleeding. These findings raise important safety questions about the current practice of routine parenteral anticoagulation therapy while we await randomized trials of this practice.