AGAINST

Thrombolysis is the established treatment for patients with an acute ST segment elevation myocardial infarction based on large trials in the past two decades.1 Studies show that treatment within an hour after onset of symptoms results in a 6.5% absolute reduction in mortality compared with placebo; this benefit falls quickly with time to 3.7% at 1-2 hours, 2.6% at 2-3 hours, 2.9% at 3-6 hours, 1.8% at 6-12 hours, and 0.9% at 12-24 hours.2 However, thrombolysis also causes an absolute increase in stroke of 0.4% (half of which are fatal), an absolute increase of 0.7% in major non-cerebral bleeds, and a 3% increase in early non-fatal reinfarction.1

Although thrombolysis saves lives in hospital, it has no later benefits; the survival curves of patients given placebo or thrombolysis exactly superimpose after 35 days, or even after discharge from hospital.3 4 The mechanism for the reduction in hospital mortality is unclear since all causes of death are reduced. It is not accounted for by a reduction in infarct size because this effect is small (6% at 4 days and only 2% at 10-28 days),5 and a reduction in infarct size would confer a long term survival advantage, which is not seen.