Willenborg Katie L
Department of Pharmacy, University of Wisconsin Hospital and Clinics, Madison, Wisconsin.
Pharmacotherapy. 2014 Jun;34(6):e55-9. doi: 10.1002/phar.1416. Epub 2014 Mar 19.
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.
血栓栓塞性并发症，如全身栓塞和瓣膜血栓形成，是机械瓣膜置换术后早期的主要问题；然而，抗凝治疗的益处必须与术后早期出血并发症的风险相权衡。与术后晚期相比，术后早期（小于6个月）的血栓栓塞风险也更高。目前的证据支持在瓣膜置换术后早期使用普通肝素或低分子量肝素以预防瓣膜血栓形成或全身栓塞，但对于有肝素诱导的血小板减少症（HIT）病史的患者的管理没有提供建议，在这种情况下肝素产品是禁忌的。我们描述了在一名63岁、体重95公斤、有HIT病史的女性患者中，主动脉机械瓣膜置换术后早期使用磺达肝癸钠的情况。磺达肝癸钠在术后第2天开始皮下注射，预防剂量为每日2.5毫克；在术后第3天，剂量增加到基于体重的治疗剂量，每日皮下注射7.5毫克。华法林在术后第1天开始使用，磺达肝癸钠持续使用直至达到治疗性国际标准化比值。患者在术后第6天出院，仅接受华法林治疗。在磺达肝癸钠治疗期间或之后以及医院随访期间，未发现血栓形成或出血的迹象或症状。据我们所知，这是第一例描述在有HIT病史的患者机械瓣膜置换术后48小时内使用磺达肝癸钠的病例报告。该病例表明，当肝素产品禁忌时，磺达肝癸钠可能是预防机械瓣膜置换术后早期血栓栓塞性并发症的一种安全有效的选择。
