Oran Betul, Lee-Parritz Aviva, Ansell Jack
Department of Medicine, Boston University Medical Center, 650 Albany Street, Boston, MA 02118, USA.
Thromb Haemost. 2004 Oct;92(4):747-51. doi: 10.1160/TH04-06-0337.
Increased thromboembolic events occur in women with mechanical prosthetic valves during pregnancy, and selecting an effective and safe anticoagulant is still a challenge. Low molecular weight heparin (LMWH) is a promising alternative, but a recent warning and label change about its use in patients with mechanical prosthetic valves has caused confusion among physicians. The aim of the present study was to review the risks of maternal and fetal complications with mechanical heart valves treated with LMWH during pregnancy. We performed a review of the current medical literature through MEDLINE and EMBASE (1989 to 2004). Additional data sources included abstract proceedings, and reference lists of selected articles. Among 81 pregnancies in 75 women, the proportion of valve thrombosis was 8.64% (7/81; 95% CI, 2.52%-14.76%). The frequency of overall thromboembolic complication (TEC) was 12.35% (10/81; 95% CI, 5.19%-19.51%). Nine of ten patients with TEC received a fixed dose of LMWH and two of these received a fixed low dose of LMWH. Among 51 pregnancies whose anti-factor Xa levels were monitored, only one patient was reported to have a thromboembolic complication. The frequency of live births with LMWH was 87.65% (95%CI, 80.49%-94.81%). In pregnant women with mechanical heart valves, LMWH appears to be a suitable option to a vitamin K antagonist. The use of LMWH warrants monitoring and appropriate dose adjustments to maintain a 4-6 hr post-injection anti-factor Xa level at a minimum of 1.0 U/ml to decrease the incidence of TEC.
机械人工瓣膜置换术后的女性在孕期发生血栓栓塞事件的风险增加，选择一种有效且安全的抗凝剂仍是一项挑战。低分子量肝素（LMWH）是一种有前景的替代药物，但最近关于其在机械人工瓣膜置换患者中应用的警告和标签变更在医生中引起了困惑。本研究的目的是回顾孕期使用LMWH治疗的机械心脏瓣膜患者发生母婴并发症的风险。我们通过MEDLINE和EMBASE（1989年至2004年）对当前医学文献进行了综述。其他数据来源包括摘要汇编以及所选文章的参考文献列表。75名女性的81次妊娠中，瓣膜血栓形成的比例为8.64%（7/81；95%CI，2.52%-14.76%）。总体血栓栓塞并发症（TEC）的发生率为12.35%（(10/81；95%CI，5.19%-19.51%）。10例TEC患者中有9例接受了固定剂量的LMWH，其中2例接受了固定低剂量的LMWH。在51次监测了抗Xa因子水平的妊娠中，仅有1例患者发生血栓栓塞并发症。LMWH治疗的活产率为87.65%（95%CI，80.49%-94.81%）。对于患有机械心脏瓣膜的孕妇，LMWH似乎是维生素K拮抗剂的合适替代品。使用LMWH需要进行监测并适当调整剂量，以使注射后4-6小时的抗Xa因子水平维持在至少1.0 U/ml，以降低TEC的发生率。
