Venous thromboembolism: prophylaxis: the benefits of adding aspirin to heparin were unclear.

Clinical bottom line (level 1b-)

  1. In patients who were undergoing hip surgery, the effect of adding aspirin to heparin had no clear effect on overt bleeding, transfusion or death.
Monreal et al: Thrombosis and Haemostasis 1995; 73 (3): 380-385
Expires May 2003

The study

Double-blinded concealed randomised trial with intention-to-treat
Setting: teaching hospital, Spain

305 patients (aged mean 74 years, 61% female) undergoing hip surgery electively or for fracture

Excluded if
  • >24 hours before admission, or surgery >24 hours after admission
  • multiple trauma
  • history of DVT in last six months
  • GI bleeding or active ulcer in last six months
  • known bleeding diathesis
  • impaired hepatic function
  • impaired renal function
  • history of aspirin allergy
  • malignancy


    • Control Group: (n = 154, 154 analysed): heparin 7500 units subcutaneously two hours pre-op, then every 12 hours for 10 days plus placebo
    Experimental Group: (n = 151, 151 analysed): heparin (as above) plus aspirin 200 mg po twice daily for 9 days

    100% followed for 30 days

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    death 30 days 9
    (5.8%)    		 11
    (7.3%)    		 -25%
    (-192% to 47%)    		 -1.44%
    (-7.00% to 4.12%)    		 -69
    (NNT = 24 to infinity;
    NNH = 14 to infinity)
    overt bleeding 30 days 5
    (3.3%)    		 3
    (2.0%)    		 39%
    (-152% to 85%)    		 1.26%
    (-2.32% to 4.84%)    		 79
    (NNT = 21 to infinity;
    NNH = 43 to infinity)
    transfused 30 days 47
    (31%)    		 55
    (36%)    		 -19%
    (-64% to 13%)    		 -5.90%
    (-16.5% to 4.67%)    		 -17
    (NNT = 21 to infinity;
    NNH = 6 to infinity)

    Comments

    1. The study is too small to demonstrate any differences in deaths or bleeding.
    2. What is the effect on venous thromboembolism?

    Citation

    1. Monreal M, Lafoz E, Roca J, et al: Platelet count, antiplatelet therapy and pulmonary embolism- a prospective study in patients with hip surgery. Thrombosis and Haemostasis 1995; 73 (3): 380-385
    Search Terms: bibliographic reference
    Contributor: Chris Ball and Clare Wotton, May 2000
    Reviewer:

    Clinical Question.
    Patient hip surgery
    Intervention or Exposure aspirin and heparin
    Comparison heparin alone
    Outcome death and bleeding