[Methods for evaluating thrombolytic drugs].

There are two conceptually quite separate objectives to be attained in evaluating a new class of therapeutic agents: the establishment of benefit-risk relationships which allow assessment of their clinical utility; the evaluation of the underlying physiopathological concepts. These two distinct objectives overlap; the criteria of assessment of the benefit-risk studies are based on the physiopathological concepts. Similarly, the relationships observed after analysing the results of the benefit-risk studies increase our understanding of the physiopathology of a disease process. With respect to the use of thrombolytic drugs in the acute phase of myocardial infarction: --the usual criteria of evaluation of the benefits of treatment are coronary artery patency, left ventricular ejection fraction and patient mortality; the severity of blood clotting abnormalities and the frequency of haemorrhage are used to assess the risks; --the physiopathological reasoning behind this choice of criteria of assessment is the direct relationship between coronary artery patency, ejection fraction and mortality. Also, the severity of blood clotting abnormalities seems to be related to the frequency of haemorrhagic complications; We have reviewed these criteria of assessment of the benefit-risk ratio of thrombolysis in the acute stage of myocardial infarction. Our analysis indicates that mortality is the only indiscutable criterion of assessment and that the classical physiopathological concepts are not validated by the results of therapeutic trials.