Trials of platelet glycoprotein IIb/IIIa receptor antagonists during percutaneous coronary revascularization

Selective inhibition of the platelet glycoprotein (GP) IIb/ IIIa surface receptor is a potent mechanism to inhibit platelet aggregation and thrombus formation. Over 15,000 patients have been enrolled in pivotal trials of GP IIb/IIIa receptor blockade with the parenteral inhibitors abciximab, eptifibatide, and tirofiban during coronary intervention, unequivocally establishing the clinical efficacy of this class of therapy in this setting. Reductions of up to 50-60% in the risk of important clinical endpoints have been achieved with these agents, a treatment effect that extends to all components of the composite clinical endpoints (death, myocardial infarction, and emergency revascularization). Inhibition of ischemic events by GP IIb/IIIa blockade is achieved early and almost invariably maintained without attenuation over long-term follow-up, although an influence of these agents on the risk of restenosis has not been consistently observed. All patients undergoing intervention appear to benefit from this class of therapy, irrespective of their risk profile or indication for revascularization, and clinical benefit is independent of the device or modality (stent, balloon, atherectomy) used. Patients undergoing coronary revascularization for acute ischemic syndromes such as unstable angina may derive exceptional treatment effect. Excessive bleeding risk associated with these agents may be markedly diminished without loss of efficacy by reduction in conjunctive heparin dosing.