Clinical decision-making with treadmill testing and thallium 201.

Abstract

Fifty patients were prospectively evaluated for myocardial ischemia utilizing treadmill testing and thallium-201 imaging. By coronary angiography, 43 had significant coronary stenosis and seven were normal. The sensitivity, specificity, accuracy and predictive value of treadmill testing alone (81 per cent, 71 per cent, 80 per cent and 95 per cent) did not statistically differ from that of thallium-201 imaging (70 per cent, 86 per cent, 72 per cent and 97 per cent). Combined treadmill testing and thallium-201 imaging (84 per cent, 71 per cent, 80 per cent and 98 per cent) did not significantly affect the results of treadmill testing alone. Thallium-201 imaging failed to identify a number of patients with high risk lesions. The high prevalence of disease, the presentation of typical angina, preselection bias, multiple lead monitoring and exclusion of patients with abnormalities on the resting electrocardiogram probably accounted for failure of thallium-201 imaging to improve the results obtained with treadmill testing. The use of thallium-201 imaging in certain subsets of patient (resting electrocardiographic abnormalities, nondiagnostic treadmill testing, atypical chest pain or asymptomatic patients with abnormalities on treadmill testing) may be of value. However, the use of thallium-201 imaging as a routine screening procedure for myocardial ischemia in patients with typical angina, without due consideration of the prevalence of the disease in the population, is not justified.