Use of aspirin in cardiovascular prophylaxis.

The value of prophylatic low-dose aspirin in patients who have experienced a myocardial infarction (MI), stroke or transient ischaemic attack (TIA) has been established beyond all reasonable doubt in a number of major overviews of randomised controlled trials. The value of aspirin in so-called 'primary prevention' is debated, but discussions are based on a misunderstanding. The terms 'primary' and 'secondary' relate to past vascular events and the occurrence of a prior event is only one factor in the estimation of the risk of a future event. Trials have confirmed that patients at high risk, who have not already had a clinical event, do benefit from aspirin. The estimation of risk, and the balancing of this against the chance of undesirable side-effects from aspirin, constitutes a clinical judgement. Although there is only limited evidence from trials, it is reasonable to assume that the earlier aspirin is given in infarction, the greater the benefit is likely to be. This assumption underlies advice from a number of bodies that aspirin should be given by a doctor, nurse or paramedic on first contact with a patient experiencing sudden severe chest pain. Again, although there is no direct evidence from trials, it would seem reasonable to advise patients who have been judged to be at increased risk of infarction to carry aspirin tablets and to chew and swallow one or two immediately if they experience sudden severe chest pain. Aspirin has a fascinating history. The new uses now being suggested, namely in the management of dementia, cancer and other conditions, make it likely that it will have an even more fascinating future.