Spyropoulos Alex C, Bauersachs Rupert M, Omran Heyder, Cohen Marc
Clinical Thrombosis Center, Lovelace Medical Center, Albuquerque, NM 87108, USA.
Curr Med Res Opin. 2006 Jun;22(6):1109-22. doi: 10.1185/030079906X104858.
In patients receiving chronic oral anticoagulation with vitamin K antagonists (VKAs) it may be necessary to temporarily discontinue VKA therapy to allow surgery or other invasive procedures to be performed, as maintaining treatment may increase the risk of bleeding during the procedure. This, however, creates a clinical dilemma, since discontinuing VKAs may place the patient at risk of thromboembolism.
We undertook a systematic narrative review of patients on chronic oral anticoagulation, requiring a periprocedural bridging therapy with heparin during invasive procedures.
For patients requiring temporary discontinuation of VKA, current guidelines recommend the use of 'bridging' therapy with unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) in patients considered to be at intermediate-to-high risk of thromboembolism, such as those with prosthetic heart valves or atrial fibrillation. Recent studies show that LMWHs are associated with low rates of thromboembolism and, when compared with UFH, are as effective and safe as UFH when used as periprocedural bridging therapy in such patients. LMWHs also offer advantages such as ease of administration and predictable anticoagulant effects. Moreover, outpatient-based periprocedural bridging therapy with LMWH has been shown to result in significant cost savings compared with in-hospital UFH.
The decision to provide bridging therapy requires careful consideration of the relative risks of thromboembolism and bleeding in each patient. Based upon the studies reviewed we recommend a therapeutic dose of UFH or LMWH for patients at intermediate-to-high thromboembolic risk requiring interruption of VKA, especially for low bleeding risk procedures. We would like to propose upgrading the American College of Chest Physicians (ACCP) guideline recommendations from 2C to 1C. However, there is still a need for a randomized controlled trial on the efficacy and safety of the available bridging strategies, including heparin and placebo comparators, in preventing thromboembolism for specific patients and procedures.
在接受维生素K拮抗剂（VKA）长期口服抗凝治疗的患者中，可能有必要暂时停用VKA治疗，以便进行手术或其他侵入性操作，因为维持治疗可能会增加操作过程中出血的风险。然而，这会造成临床困境，因为停用VKA可能使患者面临血栓栓塞的风险。
我们对接受长期口服抗凝治疗、在侵入性操作期间需要肝素进行围手术期桥接治疗的患者进行了系统的叙述性综述。
对于需要暂时停用VKA的患者，当前指南建议，对于被认为血栓栓塞风险为中到高的患者，如有人工心脏瓣膜或心房颤动的患者，使用普通肝素（UFH）或低分子量肝素（LMWH）进行“桥接”治疗。最近的研究表明，LMWH与低血栓栓塞发生率相关，并且与UFH相比，在这类患者中用作围手术期桥接治疗时，其有效性和安全性与UFH相当。LMWH还具有给药方便和抗凝效果可预测等优点。此外，与住院使用UFH相比，门诊使用LMWH进行围手术期桥接治疗已被证明可显著节省费用。
决定是否提供桥接治疗需要仔细考虑每位患者血栓栓塞和出血的相对风险。基于所综述的研究，我们建议对于血栓栓塞风险为中到高且需要中断VKA的患者，给予治疗剂量的UFH或LMWH，特别是对于出血风险低的操作。我们建议将美国胸科医师学会（ACCP）指南建议从2C级提升至1C级。然而，仍需要进行一项随机对照试验，以研究现有桥接策略（包括肝素和安慰剂对照）在预防特定患者和操作的血栓栓塞方面的有效性和安全性。
