Heparin-induced antibodies create vexing problems during cardiac surgery. Although alternative medications have been used for intraoperative anticoagulation, the results have been sufficiently variable that no one medication is recommended. In our case, due to the poor reversibility of the antithrombin agents, argatroban was chosen as a heparin substitute due to its short half-life and its anticoagulation assessment using the activated clotting time (ACT). Unfortunately, our experience was that argatroban does not provide adequate anticoagulation during off-pump coronary bypass surgery, even when the ACT is maintained at more than 380 sec. (C) 2004 by The Society of Thoracic Surgeons.