Unità Operativa di Medicina Interna II, Dipartimento di Scienze Cliniche L Sacco, Ospedale L Sacco, Università degli Studi di Milano, Milan, Italy.
PLoS One. 2012;7(9):e44553. doi: 10.1371/journal.pone.0044553. Epub 2012 Sep 11.
Low Molecular Weight Heparins (LMWH) are at least as effective antithrombotic drugs as Unfractionated Heparin (UFH). However, it is still unclear whether the safety profiles of LMWH and UFH differ. We performed a systematic review to compare the bleeding risk of fixed dose subcutaneous LMWH and adjusted dose UFH for treatment of venous thromboembolism (VTE) or acute coronary syndromes (ACS). Major bleeding was the primary end point.
Electronic databases (MEDLINE, EMBASE, and the Cochrane Library) were searched up to May 2010 with no language restrictions. Randomized controlled trials in which subcutaneous LMWH were compared to intravenous UFH for the treatment of acute thrombotic events were selected. Two reviewers independently screened studies and extracted data on study design, study quality, incidence of major bleeding, patients' characteristics, type, dose and number of daily administrations of LMWH, co-treatments, study end points and efficacy outcome. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated using the random effects model.
Twenty-seven studies were included. A total of 14,002 patients received UFH and 14,635 patients LMWH. Overall, no difference in major bleeding was observed between LMWH patients and UFH (OR = 0.79, 95% CI 0.60-1.04). In patients with VTE LMWH appeared safer than UFH, (OR = 0.68, 95% CI 0.47-1.00).
The results of our systematic review suggest that the use of LMWH in the treatment of VTE might be associated with a reduction in major bleeding compared with UFH. The choice of which heparin to use to minimize bleeding risk must be based on the single patient, taking into account the bleeding profile of different heparins in different settings.
低分子肝素（LMWH）与未分级肝素（UFH）一样有效抗血栓药物。然而，LMWH 和 UFH 的安全性是否不同仍不清楚。我们进行了一项系统评价，比较了固定剂量皮下 LMWH 和调整剂量 UFH 在治疗静脉血栓栓塞症（VTE）或急性冠状动脉综合征（ACS）中的出血风险。主要出血是主要终点。
电子数据库（MEDLINE、EMBASE 和 Cochrane 图书馆）进行了检索，截至 2010 年 5 月，无语言限制。选择了将皮下 LMWH 与静脉 UFH 比较治疗急性血栓形成事件的随机对照试验。两名评审员独立筛选研究，并提取研究设计、研究质量、大出血发生率、患者特征、LMWH 的类型、剂量和每日给药次数、联合治疗、研究终点和疗效结果的数据。使用随机效应模型计算合并优势比（OR）和 95%置信区间（CI）。
共纳入 27 项研究。共 14002 例患者接受 UFH 治疗，14635 例患者接受 LMWH 治疗。总体而言，LMWH 组和 UFH 组之间主要出血无差异（OR = 0.79，95% CI 0.60-1.04）。在 VTE 患者中，LMWH 似乎比 UFH 更安全（OR = 0.68，95% CI 0.47-1.00）。
我们的系统评价结果表明，与 UFH 相比，在治疗 VTE 时使用 LMWH 可能与减少大出血相关。为了尽量减少出血风险，选择使用哪种肝素必须基于单个患者，考虑不同肝素在不同情况下的出血情况。
