Intracoronary macrothrombus formation during percutaneous coronary intervention despite optimal activated clotting time using bivalirudin--a case report.

The occurrence of intracoronary thrombus during percutaneous coronary intervention (PCI) is a well-known complication. It has been estimated that it complicates approximately 6% of all coronary procedures. Patients at highest risk for this complication include those with acute ischemic syndromes or with angiographically apparent thrombus. Since the development of PCI, intravenous unfractionated heparin (UFH) has remained the primary antithrombotic therapy for the prevention of periprocedural ischemic complications. The availability of a rapid "point of care'' test for dose individualization (the activated clotting time [ACT]) has facilitated this process. Other forms of antithrombotic therapies such as direct thrombin inhibitors or low-molecular-weight heparin have been proposed as more effective anticoagulants during PCI. Bivalirudin is a direct thrombin inhibitor proven to decrease post-PCI ischemic complication rate compared with UFH and have a lower vascular complication rate compared with glycoprotein IIb/IIIa receptor antagonists. We herein report a case of acute macrothrombus formation during PCI despite adequate ACT achieved with bivalirudin.