Myocardial infarction: fibrinolytic therapy decreases mortality.

Clinical bottom line (level 1a)

  1. Patients with suspected acute myocardial infarction who were given fibrinolytic therapy are less likely to die than those given a control drug (NNT = 55 at unknown) .
  2. Patients who are given fibrinolytic therapy are more likely to have a stroke, than those given a control drug (NNH = 256 at unknown) .
Fibrinolytic Therapy Trialists' (FTT) Collaborative Group : Lancet 1994; 343: 311-322
Expires March 2003

The study

Systematic review of randomised trials of
  • Patients: suspected myocardial infarction
  • Intervention: fibrinolytic therapy compared with control (placebo, another fibrinolytic therapy or no fibrinolytic therapy)
  • Outcome: death and major adverse effects


Articles found in ? language using ? database, ? dates (search terms: not given ) and knowledge of the field. As this was looking at trials >1000 patients, it is unlikely there are any but the included nine which had been performed.

Selection criteria: as above and with 1000 or more patients
Appraisal criteria: detailed in text
Articles excluded if: not stated

Nine trials were included in the study.

  • Individual patient data was used for the study.
  • Trials included the drugs streptokinase (four studies), anistreplase (one) , tissue plasminogen activator (two) or urokinase (one).
  • Six trials were placebo controlled, while three randomised patients between fibrinolytic therapy and 'open' control.
  • Aspirin was given routinely to all patients in four trials and to half of patients in one trial. Heparin was given routinely to all patients in five trials and to half of the patients in one trial (without significant effect).

The evidence

Outcome Time to outcome CEREERRRR
(95% CI)		NNT
(95% CI)
mortality 35 days 3357
(11.5%)		 2820
(9.62%)		 18%
(13% to 23%)		 55
(43 to 76)
any stroke 35 days 224
(0.76%)		 340
(1.16%)		 -51%
(-30% to -73%)		 -256
(-434 to -181)

Comments

  1. This paper also looks at subgroups and effect of time-from-randomisation on NNTs.
  2. The search strategy was not detailed but all trials with more than 1000 patients randomised to fibrinolytic therapy or a control were said to be included.

Citation

  1. Fibrinolytic Therapy Trialists' (FTT) Collaborative Group , : Indications for fibrinolytic therapy in suspected acute myocardial infarction: collaborative overview of early mortality and major morbidity results from all randomised trials of more than 1000 patients. Lancet 1994; 343: 311-322
Contributor: Clare Wotton, December 1999
Reviewer: Chris Ball

Clinical Question.
Patient suspected myocardial infarction
Intervention or Exposure fibrinolytic therapy
Comparison placebo
Outcome death and major adverse effects