Myocardial infarction: intravenous heparin had an unclear role.

Clinical bottom line (level 1a-)

  1. In patients with myocardial infarction, intravenous heparin had no clear effect on mortality.
  2. In patients with myocardial infarction heparin caused excess bleeding (NNH = 15 at unknown) .
  3. Heparin had no clear effect on stroke.
Mahaffey et al: American Journal of Cardiology 1996; 77: 551-556
Expires March 2003

The study

Systematic review of randomised controlled trials of
  • Patients: acute myocardial infarction treated with thrombolysis
  • Intervention: heparin compared with no heparin
  • Outcome: mortality; reinfarction; stroke; bleeding


Articles found in not stated using MEDLINE, unstated (search terms: thrombolytic therapy , heparin, myocardial infarction ) and bibliographic searches and contact with researches in the area including extra data from published studies

Selection criteria: RCTs comparing heparin to no-heparin
Appraisal criteria: not stated
Articles excluded if: not stated

6 trials with 1735 patients; combined by fixed-effects model
Breslow's test; non-significant.

The evidence

Outcome Time to outcome CER OR
(95% CI)		 NNT
(95% CI)
mortality unknown 48/857
(5.6%)		 0.91
(0.59 to 1.39) 		210
(NNT = 50 to infinity;
NNH = 45 to infinity)
stroke unknown 6/857
(0.7%)		 2.0
(0.75 to 5.22) 		-150
(NNT = 35 to infinity;
NNH = 570 to infinity)
severe bleeding unknown 18/857
(3.3%)		 1.44
(0.76 to 2.65) 		-72
(NNT = 20 to infinity;
NNH = 130 to infinity)
any bleeding unknown 139/857
(16.2%)		 1.55
(1.21 to 1.98) 		-15
(-36 to -9)

  • NNT/H based on pooled control rates from all studies included.

Citation

  1. Mahaffey KW, Granger CB, Collins R, et al: Overview of randomized trials of intravenous heparin in patients with acute myocardial infarction treated with thrombolytic therapy. American Journal of Cardiology 1996; 77: 551-556
Contributor: Bob Phillips and Clare Wotton, November 1999
Reviewer:

Clinical Question.
Patient acute myocardial infarction treated with thrombolysis
Intervention or Exposure intravenous heparin
Comparison no heparin
Outcome mortality; reinfarction; stroke; bleeding problems