In Summary, for those who took the thrombolytics:

Benefits in NNT

    In the best case (given within 6 hours):
  • 97.7% saw no benefit
  • 2.3% were helped by being saved from death
  • 1 in 43 were helped (life saved, given within 6 hours)
  • 1 in 63 were helped (life saved, given between 6-12 hours)
  • 1 in 200 were helped (life saved, given between 12-24 hours)

Harms in NNT

    In the best case (given within 6 hours):
  • 0.7% were harmed by a major bleeding event
  • 0.4% were harmed by a hemorrhagic stroke
  • 1 in 143 were harmed (major bleeding episode)
  • 1 in 250 were harmed (hemorrhagic stroke)

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Source: Indications for fibrinolytic therapy in suspected acute myocardial infarction: collaborative overview of early mortality and major morbidity results from all randomized trials of more than 1000 patients. Lancet 1994; 343:311-22.

Efficacy Endpoints: Death at 1 month following acute heart attack (STEMI)

Harm Endpoints: Major bleeding (brain bleeding or bleeding requiring transfusion).

Narrative: This systematic review includes 9 trials and 58600 patients randomized to receive a fibrinolytic drug or placebo for suspected heart attack. Patients were enrolled based on strong suspicion of heart attack by the treating doctor. Most (76%) were men, and most had ST-elevations on their EKG (68%). There was an overall mortality benefit of 1.9% (9.6 vs. 11.5) in favor of fibrinolytics. There was also a 0.4% increase in hemorrhagic stroke (1.2 vs. 0.8). Benefit was demonstrably greater with earlier treatment, with the most benefit apparent for treatment given within a few hours of symptom onset. Benefits were smaller and less statistically robust in the 12 to 24 hour period. Patients with ST-depressions were harmed rather than helped.

Caveats: There was no gold standard to prove STEMI (e.g. catheterization or biomarkers) and some patients had normal EKG’s (5%). There is heterogeneity between trials, including inconsistency in the use of aspirin. However, groups appear to have been randomized well and treated equally with respect to other interventions.

Author: Joshua Quaas, MD

Published/Updated: January 19, 2010

  1. The Title Bar

    The title bar is color-coded with our overall recommendation.

    • Green: Benefits outweigh risks.
    • Yellow: Unclear risk/benefit profile.
    • Red: Benefits do not outweigh risks.
    • Black: Obvious harms, no clear benefits.
  2. Tip content...