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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 (dvt.mp) or [(exp thrombosis or thrombosis.mp) and (exp veins or Veins$.map)] and(exp. heparin, low molecular weight or low molecular weight heparin.mp)Not [(prophylaxis.mp) or (primary prevention.mp)]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, 1992, USA	432 patients with proximal DVT.UH (219) vsLMWH (213)	Multi centre randomised double blind clinical trial	Recurrence of VTE	6/213 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)
			Death	10/ 213 (4.7%) vs 21/ 219 (9.6%) a risk reduction of 51% (P=0.049)
Koopman MM et al, 1996, Multi National	400 patients with symptomaticproximal deep vein thrombosis. UH in hospital (198)LMWH at home(202)	PRCT	Recurrent 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 stay	In the LMWH group was 2.7 days vs 8.1 in the UH group
Levine M et al, 1996, Canada	500 patients with acute proximal deep vein thrombosis - UH in hospital (253) vs - LMWH primarily at home (247)	PRCT	Recurrent VTE	17/253 (6.7%) vs 13/247 (5.3%)	2/3rds of potential patients excluded
			Major bleeding	3/253 (2%) vs 5/247(2%)
			Costs	6.5 days in hospital vs 1.1 days. 120 (49%) patients in LWMH were not admitted at all.
Belcaro G et al, 1999, Italy	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)	PRCT	Recurrence/ extension of DVT	6.2% vs 6.1% vs 7.1%	264 (44%) of potential patients excluded
			Bleeding	Bleedings 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 costs	Average 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.

Comment(s)

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.

References

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.