Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-leg immobilization.
BACKGROUND
Immobilization of the lower leg is associated with venous thromboembolism. Low molecular weight heparin (LMWH) is an anticoagulant treatment which might be used in adult patients with lower-leg immobilization to prevent deep venous thrombosis and its complications.


OBJECTIVE
To investigate the current literature on thromboprophylactic practice for patients with lower-limb injuries who are immobilized in plaster casts or braces, to assess the need for concrete guidelines, and to assess whether it is possible to come to an evidence-based conclusion.


METHODS
The Cochrane Peripheral Vascular Disease Group searched their Specialized Register (last searched 20 May 2008) and the Central Register of Controlled Trials (CENTRAL) (last searched The Cochrane Library 2008, Issue 2). We searched MEDLINE (until May 2008) and EMBASE (until May 2008) and reference lists of articles. We contacted pharmaceutical companies of LMWHs for relevant studies.


METHODS
Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-leg immobilization. Immobilization was by means of a plaster cast or brace.


METHODS
Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager (RevMan 5).


RESULTS
We included six RCTs fulfilling the above criteria with a total of 1490 patients. We found an incidence of venous thromboembolism ranging from 4.3% to 40%, in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization (event rates ranging from 0% to 37%; odds ratio (OR) 0.49; fixed 95% confidence interval (CI) 0.34 to 0.72; with minimal evidence of heterogeneity with an I(2) of 20%, P = 0. 29). Comparable results were seen in the following subcategories: operated patients, conservatively treated patients, patients with fractures, patients with soft-tissue injuries, patients with proximal thrombosis, patients with distal thrombosis and patients with below-knee casts. Complications of major bleeding events were extremely rare (0.3%) and there were no reports of heparin-induced thrombocytopenia.


CONCLUSIONS
Use of LMWH in outpatients significantly reduces VTE when immobilization of the lower leg is required.
Testroote
Mark
M
Department of Surgery and Orthopaedic Surgery, Viecuri Medical Centre of Northern Limburg, Tegelseweg 210, Venlo, Limburg, Netherlands, 5912 BL. marktestroote@yahoo.com
Stigter
Willem
W
de Visser
Dianne C
DC
Janzing
Heinrich
H
D000328:Adult; D000925:Anticoagulants / Q000627:therapeutic use*; D006495:Heparin, Low-Molecular-Weight / Q000627:therapeutic use*; D006801:Humans; D007103:Immobilization / Q000009:adverse effects*; D007869:Leg Injuries / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D054556:Venous Thromboembolism / Q000517:prevention & control*
D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight