Comparative safety profiles of hirulog and heparin in patients undergoing coronary angioplasty

Several new anticoagulants and antiplatelet agents have been developed for use in coronary angioplasty, but almost all have been associated with an increased incidence of bleeding complications. Hirulog, a direct thrombin inhibitor, has several theoretical advantages over heparin. It is unclear, however, whether the use of hirulog as a substitute for heparin in angioplasty would result in a higher incidence of bleeding or other side effects. The safety profile of hirulog was compared with that of heparin in a randomized, double-blind trial in 4312 patients who were scheduled to undergo angioplasty for unstable or postinfarction angina. The goal of anticoagulation was to achieve an activated clotting time of approximately 350 seconds with hirulog (bolus dose of 1.0 mg/kg body weight followed by a 4-hour infusion of 2.5 mg/kg per hour and a 14- to 20-hour infusion of 0.2 mg/kg per hour) or heparin (bolus dose of 175 units/kg followed by an 18- to 24-hour infusion of 15 units/kg per hour). Adverse events were recorded prospectively by study personnel and confirmed independently by clinical monitors blinded to treatment assignment. Compared with heparin in an intention-to-treat analysis, hirulog therapy was associated with either equivalent or lower rates of side effects. Most of the side effects of hirulog and heparin were related to hemorrhagic complications such as intravascular puncture site hemorrhage (29.1% vs 61.6%; p < 0.001), hematuria (16.6% vs 20.6%; p = 0.001), bleeding requiring red cell transfusion (3.7% vs 8.6%; p < 0.001), or hematemesis (0.8% vs 1.9%; p = 0.001). No other adverse events, including death, myocardial infarction, or side effects involving other organ systems occurred more frequently with hirulog treatment than with heparin. In conclusion, hirulog is a new anticoagulant with a better safety profile than heparin. Further analysis is required to determine whether hirulog is a cost-effective and efficacious substitute for heparin for patients undergoing coronary angioplasty for unstable or postinfarction angina.