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Evidence summaries

Indications for Fibrinolytic Therapy in Suspected Myocardial Infarction

Fibrinolytic therapy is beneficial in patients of all ages with suspected acute myocardial infarction presenting within 12 hours with ST elevation or bundle branch block. Level of evidence: "A"

A systematic review 1 including 9 RCTs with a total of 58,600 subjects was abstracted in DARE. Effects were analysed in 8 subgroups, as defined by entry ECG, hours from onset of symptoms, age, sex, systolic blood pressure, heart rate, history of AMI and presence of diabetes.

The overall mortality was 9.6% for those receiving fibrinolytic therapy, and 11.5% for the controls, representing the avoidance of 18 deaths per 1000 patients allocated to treatment.

The mortality reduction was 26% in patients presenting in < 3 hours, 18% in patients presenting in 4 - 6 hours, and 14% in patients presenting at 7 - 12 hours. Though older patients are a higher absolute risk of death from AMI, absolute mortality reductions see much the same among older and younger patients. The benefit of fibrinolytic therapy is highest among patients with bundle branch block or ST elevation. Patients with ST depression or other ECG abnormalities showed no conclusive evidence of benefit. Fibrinolytic therapy was associated with a small but significant excess of 3.9 (SD 0.8) strokes per 1000 patients. All of this excess appeared on days 0 - 1. Fibrinolytic therapy was associated with a 7.3 (SD 0.7) per 1000 excess of nonfatal major bleeds.

    References

    • 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. Fibrinolytic Therapy Trialists' (FTT) Collaborative Group. Lancet 1994 Feb 5;343(8893):311-22. [PubMed] [DARE]

Primary/Secondary Keywords