Management of venous thromboembolism: A systematic review for a practice guideline

Background: New treatments are available for treatment of venous thromboembolism. Purpose: To review the evidence on the efficacy of interventions for treatment of deep venous thrombosis (DVT) and pulmonary embolism. Data Sources: MEDLINE, MICROMEDEX, the Cochrane Controlled Trials Register, and Cochrane Database of Systematic Reviews from the 1950s through June 2006. Study Selection: Randomized, controlled trials; systematic reviews of trials; and observational studies; all restricted to English-language articles. Data Extraction: Paired reviewers assessed study quality and abstracted data. The authors pooled results about optimal duration of anticoagulation. Data Synthesis: This review includes 101 articles. Low-molecular-weight heparin (LMWH) is modestly superior to unfractionated heparin at preventing recurrent DVT and is at least as effective as unfractionated heparin for treatment of pulmonary embolism. Outpatient treatment of venous thromboembolism is likely to be effective and safe in carefully chosen patients, with appropriate services available. Inpatient or outpatient use of LMWH is cost-saving or cost-effective compared with unfractionated heparin. In observational studies, catheter-directed thrombolysis safely restored vein patency in select patients. Moderately strong evidence supports early use of compression stockings to reduce postthrombotic syndrome. Limited evidence suggests that vena cava filters are only modestly efficacious for prevention of pulmonary embolism. Conve ntional-intensity oral anticoagulation beyond 12 months may be optimal for patients with unprovoked venous thromboembolism, although patients with transient risk factors benefit little from more than 3 months of therapy. High-quality trials support use of LMWH in place of oral anticoagulation, particularly in patients with cancer. Little evidence is available to guide treatment of venous thromboembolism during pregnancy. Limitations: The authors could not address all management questions, and excluded non-English-language literature. Conclusions: The strength of evidence varies across the study questions but generally is strong.