Improvement of diagnosis in the non-invasive assessment of coronary artery disease: enhanced evaluation of quantitative exercise 201thallium imaging by multivariate analysis

Study objective – The aim was to evaluate discriminant analysis, performed in patients without prior myocardial infarction, in enhancing the diagnostic value of quantitative exercise 201thallium scintigraphy. Design – All clinical, electrocardiographic, and scintigraphic variables were first subjected to a univariate analysis. Afterwards a discriminant analysis was done. Patients – 135 patients (104 male) were studied. Age was 24-70 years, mean 55 years. Measurements and main results – Two discriminant analyses were done. In the first analysis, the ability to detect the presence of coronary artery disease was tested. Significant variables were: (1) history of angina, (2) sex, (3) quantitative analysis of 201thallium scintigraphy, (4) age, (5) ischaemic ST response, (6) angina during the test, and (7) the pressure-rate product. The sensitivity, specificity, and accuracy of classification using the discriminant function were 91%, 87%, and 90%, respectively. The sensitivity was higher than when using only visual interpretation (sensitivity 70%; p