Purpose: Considerations in selecting antithrombotic and antiplatelet therapy for patients with non-ST-segment elevation (NSTE) acute coronary syndrome (ACS), including patients undergoing percutaneous coronary intervention (PCI), are discussed, and case studies are used to illustrate.
Summary: Patients with NSTE ACS for whom a conservative treatment strategy is selected should receive enoxaparin, fondaparinux, or unfractionated heparin (UFH) as anticoagulant therapy. In high-risk patients with NSTE ACS for whom an early invasive strategy is planned, enoxaparin and UFH are the agents with the highest level of evidence (evidence level A). Fondaparinux and bivalirudin can also be used, but they have a lower level of evidence (evidence level B). Since fondaparinux use in patients undergoing PCI has been associated with an increased risk for catheter-related thrombosis, the use of fondaparinux in PCI patients should be limited. The use of bivalirudin alone is as effective and has been associated with less bleeding than the use of UFH or enoxaparin plus a glycoprotein (GP) IIb/ IIIa inhibitor in patients with NSTE ACS who undergo PCI. No benefit has been shown from adding bivalirudin to a GP IIb/ IIIa inhibitor. The role of GP IIb/IIIa inhibitors in patients with NSTE ACS and elevated troponin levels who are undergoing PCI has been well established, even for patients receiving high-dose clopidogrel. Anti-platelet therapy with clopidogrel has been shown to reduce both acute and chronic events in patients with NSTE ACS, including patients undergoing PCI. A conventional 300-mg clopidogrel loading dose needs to be administered at least six hours before PCI to achieve an adequate antiplatelet effect. A 600-mg loading dose appears to shorten the time to achieve an adequate antiplatelet effect to about two hours.
Conclusion: The choice of anticoagulant and antiplatelet agents, dose, and timing of administration can affect outcomes in patients with NSTE ACS.