Bivalirudin: a review of its potential place in the management of acute coronary syndromes.

UNLABELLED

Bivalirudin, a synthetic analogue of hirudin, is a specific and reversible inhibitor of thrombin which binds directly with both fluid-phase and clot-bound thrombin. In patients with unstable angina undergoing percutaneous transluminal coronary angioplasty (PTCA), results from a large well designed study and its reanalysis (n = 4312) indicate that bivalirudin is more effective than heparin in the prevention of ischaemic complications for up to 90 days after the start of treatment. In addition, among patients undergoing PTCA for post myocardial infarction (MI) bivalirudin may be more effective than heparin in preventing ischaemic complications for up to 180 days after treatment was started. Data from dose-finding studies indicate bivalirudin has potential in the treatment of patients with unstable angina not undergoing percutaneous coronary intervention (PCI); however, well designed comparative studies are needed before firm conclusions can be made. Among patients with acute ST elevation MI, randomised trials have demonstrated bivalirudin to be significantly more effective than heparin in improving early patency in patients receiving thrombolytic therapy with streptokinase. Data from the Hirulog and Early Reperfusion/Occlusion (HERO)-1 trial (n = 412) indicate that bivalirudin recipients were significantly more likely to have Thrombin Inhibition in Myocardial Ischaemia (TIMI) grade 3 flow at 90 to 120 minutes than heparin recipients. In addition, data from the HERO-2 trial (n = 17 073) show bivalirudin was significantly more effective than heparin in reducing adjudicated 96-hour reinfarction and 30-day investigator-reported death/reinfarction than heparin. Bivalirudin was as effective as heparin in reducing 30-day mortality. Data from a meta-analysis of four randomised trials among patients undergoing PTCA or treatment for acute coronary syndromes indicate that, at after 30 to 50 days of follow-up, bivalirudin was significantly more effective than heparin in reducing the incidence of nonfatal MI and the combined endpoint of death or nonfatal MI. The most significant adverse events associated with bivalirudin are bleeding complications. In individual trials, bivalirudin was as well tolerated as heparin with, in general, a reduced incidence of bleeding complications. Additionally, bivalirudin provides a more consistent, predictable anticoagulant response. In 4312 patients with unstable angina undergoing PTCA the incidence of retroperitoneal bleeding, blood transfusion and major haemorrhage was significantly lower in bivalirudin than heparin recipients. Data from the HERO-2 trial in patients with acute MI indicate that although bivalirudin recipients had a significantly higher incidence of mild or moderate bleeding than heparin recipients, there was no difference in intracranial haemorrhage, severe bleeding or transfusions. Data from a meta-analysis among 5674 patients with ischaemic heart disease show bivalirudin recipients were at a significantly lower risk of haemorrhagic events than heparin recipients.

CONCLUSIONS

Bivalirudin is an effective alternative to heparin in the prevention of ischaemic complications in patients with unstable angina undergoing PTCA. In addition, the drug has shown potential in the treatment of patients with unstable angina not undergoing PCI. For patients with MI, it is clear that bivalirudin can replace heparin in the management of MI where streptokinase is used as the thrombolytic agent. Further data are required on the efficacy of bivalirudin in patients undergoing thrombolysis with newer thrombolytics.