Heparin-associated thrombocytopenia and thrombosis: optimal therapy with ancrod.

Heparin-associated thrombocytopenia and thrombosis (HATT) is an infrequent occurrence but may have disastrous consequences. Continued therapy with heparin must be avoided and anticoagulation achieved by alternative means. Among the few alternatives to heparin in critically ill patients, the best is ancrod. Depletion of fibrinogen with ancrod results in anticoagulation comparable to therapy with heparin within 12 hours. In a small series, nine patients with HATT were treated with ancrod; one underwent angiographic assessment, angioplasty and subsequent vascular reconstruction. Ancrod therapy was not associated with bleeding complications. It appears to provide optimal therapy for patients suspected of having HATT.