Single anti-clotting agent as efficacious as combination in ACS

Treating acute coronary syndrome (ACS) patients with bivalirudin alone is associated with similar rates of ischemic adverse events and 50% fewer episodes of major bleeding, compared with treatment with heparin plus glycoprotein IIb/IIIa inhibitors (GPI), or with bivalirudin plus GPI.

"Our findings are important because they demonstrate that in high-risk patients with ACS, bivalirudin, the simplest and least expensive regimen, results in the overall best clinical outcomes,” said Gregg W. Stone, MD, during the American College of Cardiology's 56th annual scientific session.

The Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) trial included 13,819 ACS patients randomized on emergency room arrival to standard therapy with unfractionated heparin or enoxaparin plus GPI, bivalirudin plus GPI, or bivalirudin alone before cardiac catheterization. Patients were then treated for ACS with medical management, bypass surgery, or angioplasty.

The aim of the trial was to evaluate the different anti-clotting treatments with three primary endpoints: composite ischemic events (death, myocardial infarction [MI], or unplanned revascularization), major bleeding unrelated to bypass surgery, and net clinical outcomes (a composite of ischemia or major bleeding).

After 1-year follow-up, patients treated with bivalirudin alone showed similar rates of ischemic events to those in other treatment groups. Death occurred in 4.4% of the heparin plus GPI group, in 4.2% of the bivalirudin plus GPI group, and in 3.8% of patients treated with bivalirudin alone. MI occurred in 6.2%, 6.4% and 7.1% of each respective treatment group. There also were no significant differences in revascularizations performed between treatment groups.

"In terms of mortality bivalirudin was not inferior to other treatments," said Dr. Stone, director of cardiovascular research and education, Columbia University Medical Center, New York. He reported that patients having an MI within the first 30 days after treatment had 2.47 times the risk of death during the study period. However, a patient surviving for at least 8 days after an MI was not more likely to die during the remainder of follow-up than patients not having an MI.

Treatment with bivalirudin alone also produced one-half as many major bleeding episodes compared with other treatment groups, and reduced bleeding episodes were associated with better survival, Dr. Stone said. A major bleeding episode was more predictive of death, with 12.5% of patients experiencing major bleeding during the first 30 days after treatment then dying during the trial. Furthermore, 28.9% of patients having an MI and a bleeding episode during the first month died during the trial.

Dr. Stone also reported that there was no difference in in-stent restenosis between treatment groups and no difference in restenosis between patients receiving bare metal and drug-eluting stents. He concluded that bivalirudin alone is an effective and safe treatment alternative for moderate and high-risk ACS patients.