ABSTRACT
Immediate cessation of, and avoidance of reexposure to, heparin are important principles underlying the management ofpatients with immune-mediated heparin-induced thrombocytopenia (HIT) (Chong and Berndt, 1989; Warkentin et aI., 1998). Because further antithrombotic therapy is often necessary for these patients, several alternative anticoagulant strategies have been developed (see Chaps. 13-17). However, patients with HIT who require cardiac surgery present special problems. Considerable activation of the hemostatic system results when blood is exposed to the artificial surfaces of the cardiopulmonary bypass (CPB) pump used for most heart surgery, making high-dose anticoagulation mandatory (Edmunds, 1993; Slaughter et aI., 1994). Heparin is the current anticoagulant of choice for CPB, and there is relatively little experience with other forms of anticoagulation in this patient setting. Moreover, any alternative anticoagulant considered for HIT patients should ideally meet certain requirements. First, the agent should be effective in minimizing activation of coagulation during CPB. Second, a rapid and simple method ofmonitoring its anticoagulating effects should be available to
avoid inappropriate under-or overanticoagulation. Finally, rapid and complete reversibility of the anticoagulating effects is important to minimize postoperative bleeding complications. Unfortunately, no existing agent meets all of these requirements.
