Fondaparinux is a selective factor Xa inhibitor. Benefits of fodaparinux vs. heparin when anticoagulants are used in ACS: 1. It is not associated with heparin induced thrombocytopenia. 2. Significant reduction in 30-day and 6-month mortality vs. enoxaparin. 3. Significant reduction in bleeding complications. 4. Safer in patients with renal insufficiency vs. enoxaparin. Unfractionated heparin should be continued while the patient goes for PCI.