Symes Jodi
University of Washington, Atlantic Health Sciences Corporation, Saint John, NB, USA.
CANNT J. 2008 Apr-Jun;18(2):55-61.
Low molecular weight heparins (LMWHs) have been evaluated in a large number of randomized clinical trials and have been shown to be safe and effective for the prophylaxis and treatment of thromboembolic disorders, myocardial infarction and unstable angina in patients with normal renal function. Unfortunately moststudies evaluating LMWH have excluded patients with renal insuffciency, -or those that included these patients were exceedingly small. There are limited clinical data to make assumptions about how to offer the same benefits of LMWH in patients with renal insufficiency. Several small pharmacokinetic studies of the LMWH enoxaparin have demonstrated that there is a delay in elimination in patients with renal insufficiency. There are limited data to make the same assumption concerning other LMWH. This accumulation effect could place these patients at an increased risk of bleeding. Monitoring of LMWH by measuring antifactor Xa levels may be an option. However, the ideal therapeutic range for LMWH for which there is proven efficacy and low risk of bleeding has not been clearly defined Empirically adjusted doses or lower doses intended for prophylaxis or for hemodialysis extra-corporeal anticoagulation may not demonstrate the same level of accumulation, however, studies are limited and ofshort duration. The use of measuring antifactor Xa levels remains warranted in patients with CrCl < 30 mL/min treated with empirically adjusted doses and prophylactic doses used for duration of> 4 days. Until there are better data to suggest otherwise, adjusted doses of enoxaparin are not first choice in patients with renal insufficiency when other options exist. Heparin remains the gold standard of treatment in patients with renal insufficiency.
低分子量肝素（LMWHs）已在大量随机临床试验中得到评估，并已证明对肾功能正常的患者预防和治疗血栓栓塞性疾病、心肌梗死和不稳定型心绞痛是安全有效的。不幸的是，大多数评估LMWH的研究都排除了肾功能不全的患者，或者纳入这些患者的研究规模极小。关于如何在肾功能不全的患者中提供与LMWH相同的益处，临床数据有限。几项关于LMWH依诺肝素的小型药代动力学研究表明，肾功能不全患者的药物消除存在延迟。关于其他LMWH，做出同样假设的数据有限。这种蓄积效应可能使这些患者出血风险增加。通过测量抗Xa因子水平监测LMWH可能是一种选择。然而，尚未明确界定LMWH具有已证实疗效和低出血风险的理想治疗范围。经验性调整剂量或用于预防或血液透析体外抗凝的较低剂量可能不会表现出相同程度的蓄积，然而，研究有限且持续时间短。对于肌酐清除率<30 mL/min且接受经验性调整剂量和预防性剂量治疗超过4天的患者，测量抗Xa因子水平仍有必要。在有其他选择的情况下，对于肾功能不全的患者，依诺肝素调整剂量并非首选。肝素仍然是肾功能不全患者治疗的金标准。
