Evidence-based On-call

Deep vein thrombosis

Therapy

Monitor the response using daily INR ^c

and aim for a therapeutic range of 2.0 to 3.0. ^c

Use a set protocol (preferably computerised) ^a

to prescribe the amount of warfarin.

Continue the LMWH for at least 5 days, and until the INR is in range for 2 days. ^d
Seek expert advice if there are problems. ^a

Why?

A therapeutic and stable INR is achieved sooner by using a computer program to predict dosing. Patients are also more likely to have a therapeutic INR after 2 weeks. ^a
Hospital stays are shorter: patients spend on average a week less in hospital. ^a
Fewer patients have anticoagulant-related bleeding if guideline-based consultation is used. ^a
Fewer patients have new or recurrent PE or DVT if guideline-based consultation is used. ^a

Guideline-based anticoagulation reduces bleeding and recurrent PE or DVT

Patient	Treatment	Comparison	Outcome	CER	RRR (95% CI)	NNT (95% CI)
requiring anticoagulation ^a	guideline-based anticoagulation with expert advice	standard care	major or minor bleeding at 3 months	31%	58% (2% to 82%)	6 (3 to 45)
			new or recurrent PE or DVT at 3 months	16%	73% (-17% to 94%)	8 (4 to 160)