Pulmonary embolism: vena caval filters reduced PE in trauma patients.

Clinical bottom line (level 4)

  1. Vena caval filters may have reduced pulmonary embolisms in multiple trauma patients (NNT = 7 at unknown) .
  2. Vena caval filters may have reduced mortality from pulmonary embolism (NNT = 10 at unknown) .
  3. Overall mortality was noted to be reduced (NNT = 9 at unknown) .
Rodriguez et al: Journal of Trauma: Injury, Infection, and Critical Care 1996; 40 (5): 797-804
Expires September 2003

The study

Case-control study with objective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.
Setting: tertiary centre, USA

120 patients (aged mean 42 years, 63% male) 40 patients with multiple injuries who survived > 48 hours, with three or more risk factors for pulmonary embolism, compared with 80 retrospective matched controls.

Excluded if
  • <56 years old
  • injury score <16


    • Control Group: (n = 80, 80 analysed): controls- no vena cava filters
    Experimental Group: (n = 40, 40 analysed): multiple injuries- given vena cava filters
    All patients had venous thromboembolism prophylaxis: TEDS +/- heparin.
    100% followed for ?

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    pulmonary embolism unknown 14
    (17.5%)    		 1
    (2.5%)    		 86%
    (-5% to 98%)    		 15.0%
    (5.37% to 24.6%)    		 7
    (4 to 19)
    lower extremity DVT unknown 15
    (18.8%)    		 6
    (15.0%)    		 20%
    (-90% to 66%)    		 3.75%
    (-10.2% to 17.7%)    		 27
    (NNT = 6 to infinity;
    NNH = 10 to infinity)
    pulmonary embolism mortality unknown 8
    (10.0%)    		 0
    (0.00%)    		 100%
    (% to %)    		 10.0%
    (3.43% to 16.6%)    		 10
    (6 to 29)
    overall mortality unknown 13
    (16.3%)    		 2
    (5.00%)    		 69%
    (-30% to 93%)    		 11.3%
    (0.72% to 21.8%)    		 9
    (5 to 140)

    Comments

    1. Not a randomised trial: more likely to overestimate benefit of vena caval filters. Was management of retrospective group different in some way? Note high PE mortality rate - ~60% of PE cases (normally ~ 2.5%).
    2. Vena cava group were older, had less severe injuries, and were immobilised for longer (35 days +/-3 v. 28 days +/- 3: mean difference: 7 (95% CI: 6 to 8): i.e. all would make PE more likely.
    3. No complications noted on placement of vena caval filters. Venacavagram taken to check position.
    4. Technically complicated procedure: how practical? Unlikely that complication rate is nothing. How do filters compare with a set of trauma patients on LMWH and TEDS?

    Citation

    1. Rodriguez JL, Lopez JM, Proctor MC, et al: early placement of prophylactic vena caval filters in injured patients at high risk for pulmonary embolism. Journal of Trauma: Injury, Infection, and Critical Care 1996; 40 (5): 797-804
    Contributor: Chris Ball and Clare Wotton, Unknown Month 2000
    Reviewer:

    Clinical Question.
    Patient multiple trauma patients
    Intervention or Exposure vena caval filters
    Outcome PE, mortality