Bivalirudin, with provisional GP IIb/IIIa inhibitor use allows the same protection against ischemic complications while reducing the hemorrhagic complications compared with the systematic association of a GP IIb/IIIa inhibitor plus heparin (The Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events-2 [Replace-2]). In clinical practice, the use of heparin is not systematically associated with a GP IIb/IIIa inhibitor. That's why we studied the clinical and economic interest of bivalirudin only versus heparin (UFH) only. Opened pragmatic monocentric study carried out in 2007. We made a chronological matching: for each patient treated with bivalirudin, we included the next patient with the same clinical presentation treated with unfractionated heparin. Ninety-two patients were included (46 in each group). The need for a GP IIb/IIIa inhibitor during the PCI was not significantly different between the two groups (p=0.11). No major hemorrhagic complications were observed in the two groups. Prevalence of ecchymosis was not significantly different: 22 % in the UFH group versus 13 % in the bivalirudin group (p=0.27). The average troponin level the next day was significantly higher in the bivalirudin group (p=0,049), although the change in troponin levels before and after the procedure was similar in the two groups. The average cost by patient of anticoagulation by bivalirudin and HNF is very different, respectively 473+/-150 and 51+/-146 euro (p=0.0001). Bivalirudin can be an interesting alternative for patients with a high risk of having complications. But considering its cost this therapy must be used only for selected patients.