The dose of enoxaparin is 1 mg/kg SC every 12 hours for NSTE-ACS; an initial intravenous loading dose of 30 mg has been used in selected patients. In the presence of impaired renal function (CrCl <30 mL per minute), which is a common finding in older patients, the dose should be reduced to 1 mg/kg SC once daily, and strong consideration should be given to UFH as an alternative. Calculation of CrCl is prudent in patients considered for enoxaparin therapy. In the ESSENCE trial, in patients with UA or non Q-wave MI, the rates of recurrent ischemic events and invasive diagnostic and therapeutic procedures were significantly reduced by enoxaparin therapy in the short term, and benefit was sustained at 1 year.324 In the SYNERGY (Superior Yield of the New Strategy of Enoxaparin, Revascularization and Glycoprotein IIb/IIIa Inhibitors) trial of high-risk patients with NSTE-ACS treated with an early invasive strategy, there was no significant difference in death or MI at 30 days between those randomized to enoxapa- rin versus UFH. There was more TIMI major bleeding in those treated with enoxaparin without statistically significant increase in GUSTO severe bleeding or transfusion. Some of the increased bleeding may have been related to patients randomized to enoxa- parin who received additional UFH at the time of PCI.325,326 The direct thrombin inhibitor bivalirudin is administered intra- venously. Bivalirudin was evaluated in the ACUITY trial, a randomized open-label trial, in 13819 moderate- to high-risk patients with NSTE-ACS with a planned invasive strategy. Three treatment arms were tested, including UFH or LMWH with a GP IIb/IIIa receptor inhibitor, bivalirudin with a GP IIb/IIIa receptor inhibitor, or bivalirudin alone. The majority of patients received clopidogrel (300 mg) before interven- tion, in addition to aspirin, anticoagulants, and GP IIb/IIIa inhibitors. 