Plasma-modified ACT can be used to monitor bivalirudin (Angiomax) anticoagulation for on-pump cardiopulmonary bypass surgery in a patient with heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is a problem of growing significance and concern, affecting an estimated 1-3% of patients among those receiving an estimated 10 million heparin exposures annually in the United States. The prevalence of heparin antibodies has been reported as at least 12.7% in the general cardiac surgery population before surgery and 42% following surgery. Various management techniques for anticoagulation in these patients have been proposed. Many of these alternative agents present additional risks for bleeding and efficacy and, furthermore, require the use of nonconventional monitoring assays to assess the level of anticoagulation achieved adequately. We report here the successful use of bivalirudin anticoagulation on pump, with no additional morbidity, and the first reported use of the plasma-modified ACT (activated clotting time) test, a simple modification of the standard ACT assay, to monitor the anticoagulant effect of bivalirudin.