Direct versus indirect thrombin inhibition in percutaneous coronary intervention

Heparin remains the most widely used anticoagulant in interventional cardiology, but is limited by its inability to inhibit clot-bound thrombin and by its propensity to activate platelets. Furthermore, when attempts are made to overcome these limitations by increasing the dose of heparin, bleeding complications ensue. LMWH represents a theoretic advance in antithrombotic therapy by virtue of its greater pharmacokinetic predictability and reduced propensity to stimulate platelet aggregation. However, with respect to PCI, the extended half-life of LMWH (particularly when administered subcutaneously) relative to UFH represents a major theoretic disadvantage. Direct thrombin inhibitors, such as bivalirudin, that possess shorter half-lives and potentially more potent antithrombotic activity than UFH in a broad range of coronary lesion morphologies may provide interventionalists agents with more desirable pharmacokinetic profiles, particularly in an era characterized by shorter procedure times due to improvements in stent technology.