Efficacy and safety of low molecular weight heparin in patients with mechanical heart valves: systematic review and meta-analysis.
J Thromb Haemost. 2014 Mar 4;
Authors: Caldeira D, David C, Santos AT, Costa J, Pinto FJ, Ferreira JJ
BACKGROUND: Low molecular weight heparins (LMWH) are not approved for patients with mechanical heart valves (MHV). However, temporary LMWH off-label use in this clinical setting is considered in several guidelines as a valid treatment option. Therefore we reviewed the efficacy and safety of LMWH in patients with MHV.
METHODS: MEDLINE and CENTRAL databases were searched from inception to June 2013. Review articles and references also searched. We included experimental and observational studies that compared LMWH with unfractionated heparin (UFH) or Vitamin K Antagonists (VKA). Data was analysed and pooled to estimate odds ratio (OR) with 95% confidence intervals (95%CI) for thromboembolic and major bleeding events. Statistical heterogeneity was evaluated with I(2) test.
RESULTS: Nine studies were included: one randomized controlled trial (RCT) and 8 observational studies, with a total of 1042 patients. No differences were found between LMWH and UFH/VKA in the risk of thromboembolic (OR 0.67; 95%CI: 0.27 to 1.68; I(2) =9%) or major bleeding events (OR 0.66; 95%CI: 0.36 to 1.19; I(2) =0%).
CONCLUSIONS: The best evidence available might support the temporary use of LMWH as a prophylactic treatment option in patients with MHV. However, conclusions are mostly based from observational data (with large confidence intervals) and an adequately powered RCT is urgently needed in this clinical setting. This article is protected by copyright. All rights reserved.
PMID: 24593838 [PubMed - as supplied by publisher]