Bivalirudin Compared with Abciximab plus Heparin for Non-STEMI

High-risk patients who have an acute coronary syndrome are often treated with an invasive strategy of coronary angiography. Identifying the most appropriate adjunctive antithrombotic therapy prior to, during, and following percutaneous coronary intervention (PCI) has been the subject of research for the past 30 years. The use of abciximab, a glycoprotein IIb/IIIa inhibitor with potent platelet-antiaggregative effects, has not been shown to have a clinical benefit in patients in stable condition who received a loading dose of clopidogrel prior to PCI; it did, however, reduce the risk of ischemic events in patients with acute coronary syndrome, particularly in patients with non–ST-segment elevation myocardial infarction (non-STEMI). The risk of bleeding is increased with potent antiplatelet drugs, leading physicians to prescribe a direct thrombin inhibitor such as bivalirudin in patients undergoing PCI. According to researchers, the combination of glycoprotein IIb/IIIa inhibitors such as abciximab and heparin has not been compared with bivalirudin in studies specifically involving patients with non-STEMI undergoing PCI. They recently conducted a study to determine whether the combination of abciximab with unfractionated heparin, as compared with bivalirudin, improves clinical outcomes in patients with acute non-STEMI who are undergoing PCI. They reported study results online in the New England Journal of Medicine [10.1056/NEJMoa1109596]. The primary end point was a composite of death, large recurrent myocardial infarction, urgent target-vessel revascularization, or major bleeding with 30 days of randomization. The researchers defined 2 secondary end points prospectively: a composite efficacy end point of death, any recurrent myocardial infarction, or urgent target-vessel revascularization and a safety end point of major bleeding (both within 30 days of randomization). There were 1721 patients enrolled in the study; of those, 861 were randomized to receive abciximab plus unfractionated heparin and 860 were randomized to receive bivalirudin. No patient in the bivalirudin group received provisional abciximab. Baseline characteristics were similar between the 2 groups. Of the original 1721 study subjects, 4 did not undergo the intended PCI, and the infusion of the study drug was discontinued in all of them. Of the 1717 patients who did undergo PCI, 55.6% in the abciximab group and 54.9% in the bivalirudin group underwent the intervention for >1 lesion. The primary end point occurred in 10.9% (n=94) of the patients in the abciximab group and 11.0% (n=95) in the bivalirudin group (relative risk with abciximab, 0.99; 95% confidence interval [CI], 0.74-1.32; P=.94). The secondary efficacy end point occurred in 12.8% (n=118) of the abciximab group and 13.4% (n=115) of the bivalirudin group (relative risk with abciximab, 0.96; 95% CI, 0.74-1.25; P=.76). Major bleeding occurred in 4.6% (n=40) of the abciximab group and 2.6% (n=22) of the bivalirudin group (relative risk with abciximab, 1.84; 95% CI, 1.10-3.07; P=.02). Profound thrombocytopenia developed in 1.2% (n=10) of patients in the abciximab group and in none of the bivalirudin group (P=.002). The researchers noted that “in this double-blind, randomized study, abciximab plus unfractionated heparin, as compared with bivalirudin, was not associated with a reduction in the risk of death, large recurrent myocardial infarction, urgent target-vessel revascularization, or major bleeding in 30 days.… An analysis of the secondary efficacy end point of death, any recurrent myocardial infarction, or urgent target-vessel revascularization also failed to suggest a benefit with abciximab.”