Seshadri Niranjan, Goldhaber Samuel Z, Elkayam Uri, Grimm Richard A, Groce James B, Heit John A, Spinler Sarah A, Turpie Alexander G G, Bosker Gideon, Klein Allan L
Department of Cardiovascular Medicine, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Am Heart J. 2005 Jul;150(1):27-34. doi: 10.1016/j.ahj.2004.11.018.
Recent labeling changes for enoxaparin, a low-molecular-weight heparin (LMWH), have prompted a reexamination of its role in patients with mechanical prosthetic heart valves (MPHVs). Healthcare providers are faced with the challenge of weighing favorable trial results with LMWHs and balancing their clinical experiences with these agents as a bridge to oral anticoagulation in patients with prosthetic heart valves. This review will provide evidence-based guidance on issues surrounding the use of LMWH that require bridging anticoagulant therapy in the setting of cardiac surgery (MPHVs), cardiovascular disease, and during temporary interruption of oral anticoagulants in patients requiring periprocedural bridging therapy.
A Medline search was conducted of articles appearing in the medical literature published in English between 1992 and 2004. Approximately 120 clinical trials, case reports, editorials, and/or guideline statements were retrieved and reviewed by the authors as to their relevance for the subject under review, ie, bridging anticoagulation in patients with MPHVs. Approximately 80 of these publications were selected for detailed review, analysis, and discussion in a consensus format.
This review addresses the controversy surrounding the divergence between the new labeling recommending against the use of LMWH in patients with MPHVs as well as the ongoing clinical experience and evidence in the medical literature. The clinical challenges in the use of LMWH and unfractioned heparin (UFH) in pregnant patients with MPHVs are presented; the evidence for LMWHs in nonpregnant patients with prosthetic valves is described; and the role of LMWH for bridging immediately after mechanical valve surgery and its periprocedural and perioperative uses are discussed. Based on an expert consensus panel, clinical algorithms for the use of LMWH in pregnant and nonpregnant patients with MPHVs are also illustrated.
Based on the available data sets, clinical trials, reviews, and registry data, the evidence suggests that LMWH compared to UFH may be a safe and effective agent in patients with MPHVs. Future large-scale, randomized trials are warranted.
低分子量肝素（LMWH）依诺肝素最近的标签变更促使人们重新审视其在机械人工心脏瓣膜（MPHV）患者中的作用。医疗保健提供者面临着权衡LMWH有利的试验结果以及平衡他们在这些药物方面的临床经验的挑战，这些药物可作为人工心脏瓣膜患者口服抗凝治疗的过渡。本综述将针对LMWH使用中围绕心脏手术（MPHV）、心血管疾病背景下需要桥接抗凝治疗以及在需要围手术期桥接治疗的患者口服抗凝剂暂时中断期间的相关问题提供循证指导。
对1992年至2004年期间以英文发表在医学文献中的文章进行了Medline检索。作者检索并审查了大约120项临床试验、病例报告、社论和/或指南声明与所审查主题（即MPHV患者的桥接抗凝）的相关性。其中约80篇出版物被选出来以共识形式进行详细审查、分析和讨论。
本综述解决了围绕新标签建议不使用LMWH治疗MPHV患者之间的分歧以及医学文献中持续的临床经验和证据的争议。介绍了在患有MPHV的孕妇中使用LMWH和普通肝素（UFH）的临床挑战；描述了LMWH在非妊娠人工瓣膜患者中的证据；并讨论了LMWH在机械瓣膜手术后立即桥接的作用及其围手术期和术中的用途。基于专家共识小组，还说明了在患有MPHV的孕妇和非孕妇中使用LMWH的临床算法。
基于现有数据集、临床试验、综述和登记数据，证据表明与UFH相比，LMWH在MPHV患者中可能是一种安全有效的药物。未来有必要进行大规模随机试验。
