Z Kardiol 94: Suppl 2 (2005)

Impact of bivalirudin on ACT monitoring and platelet function in patients undergoing PCI
V. Klauss1, J. Omary2, M. Spannagl2
1, München; 2Med. Klinik und Poliklinik - Abt. Kardiologie, Klinikum der Universität München, München;
Introduction: The direct thrombin inhibitor bivalirudin has been approved as new anticoagulant in patients undergoing PCI. Its use resulted in lower rates of bleeding and ischaemic complications compared to heparin. Bivalirudin has effects both on coagulation as well as on platelet aggregation. There are only few data assessing the interindividual variability in aggregation time and platelet function during PCI with bivalirudin. Methods:  27 patients undergoing PCI were pretreated with ASS (100 mg/die) and clopidogrel (75 mg/die) for at least 3 days before intervention. All patients received bivalirudin as a single bolus of 0.75 mg/kg after sheath insertion followed by an intravenous infusion of 1.75 mg/kg/h during PCI. Activated Clotting Time, ACT (Hemochron 401®) was monitored at fixed timepoints: before bivalirudin application, 5 min, 10 min, 15 min, 30 min after bivalirudin application, and after completion of PCI. Minimal ACT time was defined as 250 sec.  Platelet function was tested by using the Platelet Function Analyser  PFA-100 ® (PFA-ADP) before and 10 min after bivalirudin, and at the end of PCI. Results: There was a considerable individual variability of ACT-times. After receiving bivalirudin 19 patients (70 %) had ACT-times between 250-600 sec, 8 patients (30%) had levels of > 600 sec, and no patient was below 250 sec. The median ACT`s  were 150 ± 24 sec before PCI, 530 ± 205 after 10 min, and 487 ± 214 sec at the end of PCI. Furthermore, 24/27 patients (89 %) had an additional significant inhibition in platelet function during bivalirudin infusion. Conclusion: In patients undergoing PCI with bivalirudin as anticoagulant a large interindividual variability of ACT-values was observed. However, no patient had ACT times below 250 sec. Bivalirudin had an additional beneficial effect on platelet function.