The Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events (REPLACE)-2 trial is one of the largest acute randomized controlled trials evaluating the efficacy of two anticoagulant strategies during contemporary urgent or elective percutaneous coronary intervention (PCI). The direct thrombin inhibitor, bivalirudin, with provisional use of glycoprotein IIb/IIIa (GP IIb/IIIa) inhibitor was compared to low-dose unfractionated heparin (UFH) plus planned GP IIb/IIIa inhibitor. At 30-day follow-up, the primary quadruple composite endpoint (death, myocardial infarction (MI), urgent repeat revascularization, or in-hospital major bleeding) occurred in 9.2% of patients in the bivalirudin group versus 10.0% of patients in the UFH plus GP IIb/IIIa inhibitor group. The secondary triple composite endpoint (death, MI, urgent repeat revascularization) occurred in 7.6% of patients in the bivalirudin group compared with 7.1% of patients in the UFH plus GP IIb/IIIa inhibitor group. Both endpoints met formal statistical criteria for noninferiority to UFH plus GP IIb/IIIa inhibitor. By imputed comparison from historic GP IIb/IIIa trials between bivalirudin versus UFH alone, REPLACE-2 demonstrated that bivalirudin was superior to UFH alone with respect to the quadruple and triple composite endpoints. Furthermore, bivalirudin plus provisional GP IIb/IIIa blockade was associated with a significant reduction in in-hospital bleeding (2.4% vs. 4.1%; p < 0.001). At 6 months' follow-up, there was no significant difference in rates of death, MI, or revascularization between the two groups. Furthermore, there was no evidence that the early, nonsignificant 0.5% excess non-Q-wave MI in the bivalirudin group translated into later mortality. There was a trend toward decreased mortality at 6 months in the bivalirudin arm (0.95% vs. 1.35%; p = 0.148). The relative efficacy of bivalirudin versus UFH plus GP IIb/IIIa inhibitor was similar in several high-risk subgroups, including patients with diabetes mellitus or prior MI, women, the elderly (age > 65 years), and patients undergoing PCI of bypass grafts. Bivalirudin represents an exciting alternative to UFH plus GP IIb/IIIa inhibitor in patients undergoing urgent and elective PCI with similar suppression of ischemic events, fewer bleeding complications, and the potential for greater cost savings and ease of administration.