[The diagnostic exercise test in coronary disease. Proposal for a more rigorous and efficacious interpretation]

Although exercise stress testing does not allow certain diagnosis of coronary artery disease, its interpretation should not necessarily be vague. By using the Bayes theorem and the many studies available we can now quantify the probability of a correct result for each individual case. Three parameters need to be known to undertake this calculation; the prevalence of the disease and the sensitivity and specificity of the investigation. The prevalence of the disease is beginning to be recognised taking into account the character of the pain. Four groups of increasing prevalence can thereby be defined: absence of chest pain, non-anginal pain, atypical pain and typical pain. Within each of these groups the prevalence of coronary disease is higher in men and increases with age. Information about the prevalence of multivessel disease after infarction is more limited. Only two groups can be distinguished which do not take symptoms, age or sex into consideration. The prevalence is 57% after anterior and 65% after inferior infarction. The sensitivity and specificity of stress testing can be determined by comparison with coronary angiography or, when this is available, by following up the patients. These parameters depend mainly on the methodology which should be strictly defined. When only significant ST depression is considered, the overall sensitivity and specificity of exercise stress testing is 70% and 80% respectively. These results vary according to the particular context; in women, the sensitivity and specificity are 72% and 75% respectively; in asymptomatic subjects the sensitivity and specificity are 50% and 85% respectively. With regards to the detection of multivessel disease after anterior infarction, the sensitivity and specificity are 58 and 85% respectively and after inferior infarction, 85 and 84% respectively. The use of diagnostic probability based on these parameters should lead to unambiguous practical management of patients related to the degrees of probability obtained. The underlying principles of this diagnostic approach cannot be questioned as they are based on a well established mathematical formula. However, much work remains to be done, on the one hand to determine the exact prevalence of coronary disease, and on the other hand to improve the sensitivity of exercise stress testing.