Use of Antithrombin Therapy in Patients Undergoing Percutaneous Coronary Intervention

In recent years, several novel approaches to anticoagulation have been developed and tested as adjunctive therapy in patients undergoing percutaneous coronary intervention (PCI). Besides unfractionated heparin, other indirect thrombin inhibitors now available include low molecular weight heparins such as dalteparin and enoxaparin. Direct thrombin inhibitors such as lepirudin, bivalirudin and argatroban have also been introduced. Other emerging therapeutic options that are yet to reach phase III clinical testing in PCI include the pentasaccarides.

Initial studies of glycoprotein IIb/IIIa receptor antagonists used in conjunction with unfractionated heparin have been instrumental in highlighting the key issues surrounding the use of these agents in the catheterization laboratory. As seen within the context of abciximab therapy, an excess bleeding risk associated with high levels of thrombin inhibition can be ameliorated by reducing the heparin dose without compromising overall efficacy |2|. These observations support the need for monitoring and dose individualization in patients undergoing PCI. However, to what extent these observations apply to the newer anticoagulants, or to patients not receiving glycoprotein IIb/IIIa inhibition, requires further clarification. In addition, the evidence supporting pre-treatment with thienopyridines in patients undergoing invasive treatment for acute coronary syndromes suggest that the optimal antithrombin-antiplatelet combination for patients undergoing PCI is likely to differ according to patient acuity. This requires careful re-evaluation. However, compared with the substantial evidence on platelet inhibition for the prevention of periprocedural and late ischaemic events after PCI, studies of anticoagulation have been relatively few in number and of smaller magnitude. While several important large-scale studies addressing these questions are currently in progress, initial studies of these agents have suggested that there is a role for them to be used either alone or possibly in combination with antiplatelet therapies.