LMWH better than UFH for acute DVT

Clinical Question

Which interventions are effective for the treatment of deep venous thrombosis and pulmonary embolism?

Bottom Line

Low-molecular-weight heparin (LMWH) is superior to unfractionated heparin (UFH) for deep venous thrombosis (DVT) and as effective as UFH for pulmonary embolism (PE). Outpatient DVT treatment is safe and cost effective for selected patients. Compression stockings should be provided to patients with DVT at discharge. (LOE = 1a)


Segal JB, Streiff MB, Hofmann LV, Thornton K, Bass EB. Management of venous thromboembolism: a systematic review for a practice guideline. Ann Intern Med 2007;146:211-222.  [PMID:17261856]

Study Design

Meta-analysis (randomized controlled trials)




Inpatient (any location) with outpatient follow-up


This systematic review addressed a number of questions concerning the treatment of venous thromboembolism. The authors conducted thorough literature searches and specified article inclusion criteria, and 2 independent reviewers selected studies that met specified criteria. The researchers included English language studies published after 1995. The criteria for the study methodology varied by the individual question being addressed. Three meta-analyses of the most recently published trials found LMWH superior to UFH for the initial treatment of DVT, with reduced recurrent VTE (odds ratios [ORs] = 0.66 - 0.76), mortality (ORs = 0.56 - 0.67) and risk of major bleeding (ORs = 0.68 - 0.78). LMWH was found to be as effective as UHF for the initial treatment of PE. On the basis of 4 randomized trials and 9 cohort studies, the review found outpatient LMWH for the initial treatment of DVT to be at least as safe as inpatient treatment for selected patients. The outpatient treatment was also cost effective. Strong evidence from 2 trials supports the use of compression stockings for at least 1 year after DVT to prevent postthrombotic syndrome (number needed to treat [NNT] at 2 years = 3; 95% CI, 4.4 - 10.8). Although there may be benefit in certain patients, overall evidence was insufficient to support the use of catheter-directed thrombolysis for DVT (cohort studies and 1 small randomized trial). Only 1 randomized trial compared vena cava filters plus anticoagulation to anticoagulation alone in patients at high risk for PE. Filters reduced symptomatic PE at long-term follow-up (relative risk [RR] at 8 years = 0.41; NNT = 11), but increased DVT at 2 years (RR = 1.8; number needed to treat to harm [NNH] = 11) and 8 years (RR = 1.3; NNH = 12). Mortality and major bleeding rates were not affected. The accompanying guideline based on this review differs from the 2004 American College of Chest Physicians guidelines primarily in the stronger recommendation of LMWH over UFH for initial DVT treatment.