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Low molecular weight heparin is the treatment of choice for deep vein thrombosis (DVT)

Three Part Question

In [patients with deep vein thrombosis] are [low molecular weight heparin as good as unfractionated heparin] at [treating uncomplicated proximal DVT]?

Clinical Scenario

A 60 year old man presents with a three day history of pain in his left calf. You suspect an above knee deep vein thrombosis (DVT) which is later confirmed by ultrasound. You are considering admitting this man for treatment with Unfractionated Heparin (UH), when one of your colleagues mentions that low weight molecular weight heparins (LMWH) have been proven to be as good at treating thromboembolic disease and it's complications. You wonder whether this is true.

Search Strategy

Medline 1966-07/00 using the OVID interface.
(Exp venous thrombosis/ or "deep vein thrombosis"mp) or ( or [(exp thrombosis or and (exp veins or Veins$.map)] and(exp. heparin, low molecular weight or low molecular weight [( or (primary]Limit to human and English language.

Search Outcome

373 papers identified of which 369 were irrelevant or of insufficient quality for inclusion. The remaining 4 papers are shown in the table.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Hull RD et al,
432 patients with proximal DVT.UH (219) vsLMWH (213) Multi centre randomised double blind clinical trialRecurrence of VTE6/213 vs 15/219 (p=0.07; 95% CI for the difference, 0.02% to 8.1%)
Major bleeding 1/ 213 patients (0.5%) vs 11/219 (5%), reduction in risk of 91% (P=0.006)
Death10/ 213 (4.7%) vs 21/ 219 (9.6%) a risk reduction of 51% (P=0.049)
Koopman MM et al,
Multi National
400 patients with symptomaticproximal deep vein thrombosis. UH in hospital (198)LMWH at home(202) PRCTRecurrent VTE (within 6 months)17/198(8.6%) vs 14/202 (6.9%)Unblinded
Major bleeding(within 3 months)4/198 vs 1/202
Quality of life(at 1,12 and 24wks) Physical activity and social functioning better in LMWH group
Average length of stayIn the LMWH group was 2.7 days vs 8.1 in the UH group
Levine M et al,
500 patients with acute proximal deep vein thrombosis - UH in hospital (253) vs - LMWH primarily at home (247) PRCTRecurrent VTE 17/253 (6.7%) vs 13/247 (5.3%)2/3rds of potential patients excluded
Major bleeding3/253 (2%) vs 5/247(2%)
Costs6.5 days in hospital vs 1.1 days. 120 (49%) patients in LWMH were not admitted at all.
Belcaro G et al,
294/ 589 patients with acute proximal - UH in hospital (98) vs- Treatment with LMWH primarily at home or in the hospital (97) vs- Treatment with SCHep given directly at home (99) PRCTRecurrence/ extension of DVT6.2% vs 6.1% vs 7.1%264 (44%) of potential patients excluded
BleedingBleedings were all minor and mostly during hospital stay
Length of stay 5.4 +- 1.2 vs 1.2 +-1.4 days (there was no hospital stay in the SCHep group).
Treatment costsAverage treatment costs in 3 months in the UH group were considered to be 100%. In comparison costs in the LMWH group was 28% of the UH and 8% in the SCHep group.


There are 4 well designed trials in this area. All come to the same conclusion.

Clinical Bottom Line

Low molecular weight heparin is as effective and safe as unfractionated heparin and should be the form of treatment for patients with uncomplicated proximal deep vein thrombosis.


  1. Hull RD, Raskob GE, Pineo GF et al. Subcutaneous low molecular-weight-heparin compared with continuous intravenous heparin in the treatment of proximal-vein thrombosis. The New Eng J Med 1992;326(15):975-82.
  2. Koopman MM, Prandoni P, Piovella F, et al. Treatment of venous thrombosis with intravenous unfractionated heparin administered in the hospital as compared with subcutaneous low-molecular-weight heparin administered at home. The New Eng J Med 1996;334(11):682-7.
  3. Levine M, Gent M, Hirsh J, et al A comparison of low-molecular-weight heparin administered primarily at home with unfractionated heparin administered in the hospital for proximal deep-vein thrombosis. New Eng J Med 1996;334(11):677-681.
  4. Belcaro G, Nicolaides AN, Cesarone MR, et al Comparison of low-molecular-weight heparin, administered primarily at home, with unfractionated heparin, administered in hospital, and subcutaneous heparin administered at home for deep-vein thrombosi Angiol 1999;50(10):781-787.