Prognostic significance of normal quantitative planar thallium-201 stress scintigraphy in patients with chest pain

The prognostic significance of normal quantitative planar thallium-201 stress scintigraphy was evaluated in patients with a chest pain syndrome. The prevalence of cardiac events during follow-up was related to the pretest (that is, before stress scintigraphy) likelihood of coronary artery disease determined on the basis of symptoms, age, sex and stress electrocardiography. In a consecutive series of 344 patients who had adequate thallium-201 stress scintigrams, 95 had unequivocally normal studies by quantitative analysis. The pretest likelihood of coronary artery disease in the 95 patients had a bimodal distribution. During a mean follow-up period of 22 +/- 3 months, no patient died. Three patients (3%) had a cardiac event: two of these patients (pretest likelihood of coronary artery disease 54 and 94%) had a nonfatal myocardial infarction 8 and 22 months, respectively, after stress scintigraphy, and one patient (pretest likelihood 98%) underwent percutaneous transluminal coronary angioplasty 16 months after stress scintigraphy for persisting anginal complaints. Three patients were lost to follow-up; all three had a low pretest likelihood of coronary artery disease. It is concluded that patients with chest pain and normal findings on quantitative thallium-201 scintigraphy have an excellent prognosis. Cardiac events are rare (infarction rate 1% per year) and occur in patients with a moderate to high pretest likelihood of coronary artery disease.