Venous thromboembolism and warfarin contraindication: fewer vertebral fractures on long term LMWH.

Clinical bottom line (level 1b-)

  1. In patients with a venous thromboembolism and a contraindication to warfarin, low molecular weight heparin was as effective as heparin in preventing further VTE.
  2. Patients had fewer vertebral fractures on LMWH (NNT = at years) .
Monreal et al: Thrombosis and Haemostasis 1994; 71 (1): 7-11
Expires May 2003

The study

Unblinded concealed randomised trial without intention-to-treat
Setting: university hospital, Spain

80 patients (aged range 19 to 92 years; mean 68, 50% male) objectively proven venous thromboembolism (deep vein thrombosis by venography or ultrasound; pulmonary embolism by high probability v/q scan) and a contraindication to coumarin therapy (>80, active bleeding, no monitoring possible, active peptic ulcer, chronic alcohol disease, recent neurosurgery, pregnant or dementia)

Excluded if
  • taking NSAIDs, oestrogens or diuretics


    • Control Group: (n = 40, 40 analysed): heparin 10,000 units sc bd for three months (DVT) or six months (PE)
    Experimental Group: (n = 40, 40 analysed): fragmin 5,000 units sc bd for three months (DVT) or six months (PE)
    All patients had iv heparin in hospital. Trial medication was started on discharge.
    100% followed for 6 months
    Outcome notes:
    • recurrent VTE : DVT diagnosed by bilateral venogram; PE by v/q scan

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    recurrent VTE 6 months 5
    (12.5%)    		 2
    (5.0%)    		 60%
    (-94% to 92%)    		 7.50%
    (-4.77% to 19.8%)    		 13
    (NNT = 5 to infinity;
    NNH = 21 to infinity)
    vertebral fracture 6 months 6
    (15%)    		 1
    (2.5%)    		 83%
    (-32% to 98%)    		 12.5%
    (0.42% to 24.6%)    		 8
    (4 to 237)

  • No patients had a major bleed.

    • Comments

    1. It is unclear how old vertebral fractures were distinguished from new ones.

    Citation

    1. Monreal M, Lafoz E, Olive A, et al: Comparison of subcutaneous unfractionated heparin with a low molecular weight heparin (Fragmin) in patients with venous thromboembolism and contraindications to coumarin. Thrombosis and Haemostasis 1994; 71 (1): 7-11
    Contributor: Chris Ball and Clare Wotton, May 2000
    Reviewer:

    Clinical Question.
    Patient venous thromboembolism
    Intervention or Exposure fragmin (LMWH)
    Comparison heparin
    Outcome recurrent VTE