Author Affiliations: Department of Emergency Services, Sunnybrook and Women's College Health Science Centre, University of Toronto, Toronto, Ontario (Drs Morrison, Verbeek, McDonald, and Sawadsky); and Department of Clinical Epidemiology and Biostatistics, McMaster University Health Science Center, Hamilton, Ontario (Dr Cook).
Context Early administration of thrombolysis for acute myocardial infarction
(AMI) may improve survival if safely and appropriately delivered. No systematic
reviews that have comprehensively examined this topic exist in the literature.
Objective To perform a meta-analysis of randomized controlled trials of prehospital
vs in-hospital thrombolysis for AMI measuring in-hospital mortality.
Data Sources The Cochrane search strategy was used to search MEDLINE, EMBASE, and
the Science Citation Index (1982-1999); Dissertation Abstracts (1987-1999);
and Current Contents (1994-1999) for the terms thrombolysis, thrombolysis therapy, prehospital, and acute myocardial infarction.
In addition, text and journal article bibliographies were hand searched, the
National Institutes of Health Web site was reviewed, and primary authors and
thrombolytic drug manufacturers were contacted for unpublished studies.
Study Selection Randomized controlled trials of prehospital vs in-hospital thrombolysis
for AMI measuring all-cause hospital mortality were included. Two authors
independently reviewed 175 citations by title, abstract, or complete article.
After exclusion of 30 duplicate citations, 145 studies remained, of which
6 studies and 3 follow-up studies met the inclusion criteria.
Data Extraction Independent data abstraction by 2 reviewers blinded to the journal,
title, and author was confirmed by consensus. Trial quality was independently
assessed by 2 other coauthors, blinded to the author, title, journal, introduction,
Data Synthesis The results of the 6 randomized trials (n=6434) were pooled and indicated
significantly decreased all-cause hospital mortality among patients treated
with prehospital thrombolysis compared with in-hospital thrombolysis (odds
ratio, 0.83; 95% confidence interval, 0.70-0.98). Results were similar regardless
of trial quality or training and experience of the provider. Estimated (SE)
time to thrombolysis was 104 (7) minutes for the prehospital group and 162
(16) minutes for the in-hospital thrombolysis group (P=.007).
Conclusions Our meta-analysis suggests that prehospital thrombolysis for AMI significantly
decreases the time to thrombolysis and all-cause hospital mortality.
Morrison LJ, Verbeek PR, McDonald AC, Sawadsky BV, Cook DJ. Mortality and Prehospital Thrombolysis for Acute Myocardial InfarctionA Meta-analysis. JAMA. 2000;283(20):2686-2692. doi:10.1001/jama.283.20.2686