Successful use of fondaparinux early after mechanical aortic valve replacement in a patient with a history of heparin-induced thrombocytopenia.

Thromboembolic complications such as systemic embolization and valve thrombosis are a major concern early after mechanical valve replacement; however, the benefit of anticoagulation must be weighed against the risk of early postoperative bleeding complications. Thromboembolic risk is also higher in the early postoperative period (less than 6 mo) compared with the risk in the late postoperative period. Current evidence supports the use of unfractionated heparin or low-molecular-weight heparin early after valve replacement to prevent valve thrombosis or systemic embolization but provides no recommendations for the management of patients with a history of heparin-induced thrombocytopenia (HIT), in which heparin products are contraindicated. We describe the use of fondaparinux early after aortic mechanical valve replacement in a 63-year-old, 95-kg woman with a history of HIT. Fondaparinux was initiated on postoperative day 2 at a prophylactic dose of 2.5 mg subcutaneously daily; the dose was increased to a therapeutic weight-based dose of 7.5 mg subcutaneously daily on postoperative day 3. Warfarin was initiated on postoperative day 1, and fondaparinux was continued until a therapeutic international normalized ratio was achieved. The patient was discharged from the hospital receiving warfarin alone on postoperative day 6. No signs or symptoms of thrombosis or bleeding were noted during or after fondaparinux therapy or at hospital follow-up visits. To our knowledge, this is the first case report to describe the use of fondaparinux within the first 48 hours after mechanical valve replacement in a patient with a history of HIT. This case suggests that fondaparinux may be a safe and effective option to prevent thromboembolic complications early after mechanical valve replacement when heparin products are contraindicated.