[Primary prevention of coronary thrombosis by antithrombotic agents].

At the start of the eighties, in the wake of the good results obtained with aspirin in secondary prevention, two studies were launched aimed at testing the effect of aspirin on the primary prevention of myocardial infarction. The results published in 1988 and 1989 were divergent: the study conducted by British doctors showed no benefit with aspirin, that conducted by American doctors showed a very distinct benefit concerning myocardial infarction but no advantage for cerebral vascular accidents. Besides, in both studies an additional risk of haemorrhagic cerebral vascular accident was described. Methodological reasons were the origin of these facts, but it resulted in a certain confusion as to the practical conduct to adopt. Ten years later it is much more clear after the publication of three supplementary trials. The benefits of aspirin in terms of prevention of myocardial infarction are certain and considerable, at the price of a haemorrhagic risk equally certain but moderate. On the other hand, questions remain concerning the preventive effect of aspirin on cerebral vascular accidents and also on the expected benefits in the female sex. In practice, the prescription of aspirin with the objective of primary prevention must take into account the absolute benefit which can be expected. This is a function of the individual absolute risk before treatment which therefore signifies an evaluation based on the risk factors. Only subjects exposed to a substantial risk before treatment are likely to benefit from aspirin. For the others, the risks linked with aspirin could counterbalance its preventive advantages.