Deep vein thrombosis: prophylaxis: knee surgery: LMWH plus compression stockings was better than stockings alone.

Clinical bottom line (level 1b)

  1. Ardeparin plus graduated compression stockings prevented DVT after knee surgery more effectively than stockings alone (NNT = 3 at 14 days) .
  2. There was no clear difference in the number of pulmonary embolisms or major bleeds.
Levine et al: Archives of Internal Medicine 1996; 156: 851-856
Expires July 2003

The study

Double-blinded ?concealed randomised trial with intention-to-treat
Setting: five hospitals, Canada

199 patients (aged mean 68 years, 60% female) having total knee replacement or tibial osteotomy

Excluded if
  • aged <30 years
  • increased risk for bleeding or thrombosis
  • allergy to iodine, radiopaque dye, heparin, pork or fish
  • alcohol or drug abuse
  • uncontrolled hypertension
  • requirement for aspirin therapy
  • bilateral knee surgery
  • inability to wear stockings


    • Control Group: (n = 103, 103 analysed): placebo and compression stockings for 14 days or until discharge
    Experimental Group: (n = 96, 96 analysed): ardeparin 0.005 ml/kg of body weight (50 anti-Xa units/kg) twice daily s/l and graduated compression stockings
    All patients were fitted with graduated compression stockings below the knee immediately after wound closure.
    100% followed for 14 days
    Outcome notes:
    • DVT : bilateral venography before hospital discharge

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    DVT 14 days 60
    (58.3%)    		 28
    (29.2%)    		 50%
    (29% to 65%)    		 29.1%
    (15.9% to 42.3%)    		 3
    (2 to 6)
    pulmonary embolism 14 days 1
    (0.97%)    		 1
    (1.04%)    		 -7%
    (-1592% to 93%)    		 -0.07%
    (-2.85% to 2.71%)    		 -1400
    (NNT = 37 to infinity;
    NNH = 35 to infinity)
    major bleed 14 days 3
    (2.91%)    		 3
    (3.13%)    		 -7%
    (-419% to 78%)    		 -0.21%
    (-4.97% to 4.55%)    		 -470
    (NNT = 22 to infinity;
    NNH = 20 to infinity)

    Comments

    1. Unclear how many DVT cases were symptomatic.

    Citation

    1. Levine MN, Gent M, Hirsh J, et al: Ardeparin (low-molecular-weight heparin) vs graduated compression stockings for the prevention of venous thromboembolism. A randomized trial in patients undergoing knee surgery. Archives of Internal Medicine 1996; 156: 851-856
    Contributor: Chris Ball and Clare Wotton, July 2000
    Reviewer:

    Clinical Question.
    Patient knee surgery
    Intervention or Exposure LMWH and compression stockings
    Comparison placebo and compression stockings
    Outcome DVT, PE, bleeds