Deep vein thrombosis: silent pulmonary embolism was common.

Clinical bottom line (level 2c)

  1. About a half of patients with a deep vein thrombosis have a silent pulmonary embolism.
  2. The clinical signifcance of silent PE is uncertain
Nielsen et al: Journal of Internal Medicine 1994; 235: 457-461
Expires August 2003

The study

Outcome study with objective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: teaching hospital, Denmark

87 patients (aged range 17 to 84 years; mean 55, 63% male) with deep vein thrombosis symptoms < 6 days long, confirmed by venogram within 24 hours of admission, and no symptoms of PE
Patients received TEDS and anticoagulation or TEDS and phenylbutazone.


Outcomes studied:
  • silent pulmonary embolism

    • All patients had ventilation-perfusion scan at day 10 and day 60. Interpreted twice by two independent observers.

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    silent pulmonary embolism ? 43/87 49%
    (39% to 60%)

    Comments

    1. Phenylbutazone is a powerful NSAID. Anticoagulation was not significantly better than phenylbutazone at causing regression of PE, but study was far too small to demonstrate efficacy or safety of therapeutic NSAID use
    2. Do silent PEs matter? How many go on to be fatal?
    3. Data was taken from a randomised controlled trial.

    Citation

    1. Nielsen HK, Husted SE, Krusell LR, et al: Silent pulmonary embolism in patients with deep venous thrombosis: incidence and fate in a randomized, controlled trial of anticoagulation versus no anticoagulation. Journal of Internal Medicine 1994; 235: 457-461
    Contributor: Chris Ball and Clare Wotton, August 2000
    Reviewer: Alex Gallus

    Clinical Question.
    Patient DVT
    Intervention or Exposure prevalence
    Outcome silent PE