Exercise thallium-201 scintigraphy in the diagnosis and prognosis of coronary artery disease.

OBJECTIVE: To determine the discriminant accuracy of exercise thallium-201 myocardial perfusion scintigraphy for the diagnosis and prognosis of patients with known or suspected coronary artery disease. DATA IDENTIFICATION: A survey of the National Library of Medicine MEDLINE database. STUDY SELECTION: The key medical subject headings used were coronary disease, myocardial infarction, radionuclide imaging, and thallium. A total of 122 retrieved studies were considered relevant and were reviewed in depth. DATA EXTRACTION: Only studies reporting both the sensitivity and specificity of thallium scintigraphy were analyzed. RESULTS: Discriminant accuracy for diagnosis and prognosis was summarized in terms of pooled sensitivity and specificity. CONCLUSIONS: Exercise thallium scintigraphy is useful in the noninvasive diagnosis of coronary artery disease, especially in patients with abnormal resting electrocardiograms, restricted exercise tolerance, and intermediate probability of having disease at the time of testing as well as of defining the prognosis of patients with known or suspected coronary artery disease, especially in those with previous myocardial infarction. Because of various shortcomings in the published record, however, the marginal discriminant accuracy and cost effectiveness of thallium scintigraphy compared with conventional clinical assessment and exercise electrocardiography remain controversial.

Incremental prognostic power of clinical history, exercise electrocardiography and myocardial perfusion scintigraphy in suspected coronary artery disease.

The incremental ability of a clinical history, exercise electrocardiography (ECG) and myocardial perfusion scintigraphy to identify coronary events in the year after testing was assessed in 1,659 patients with symptoms suggestive of coronary artery disease (CAD), 74 of whom suffered a coronary event in the year after testing. Prognostic power was quantified in terms of the area under receiver operating characteristic curves derived from logistic regression. In 1,451 patients with normal rest ECG findings, a clinical history alone provided the most prognostic power (area = 72%). This improved significantly (by 5%) only when both tests were analyzed. In contrast, clinical history had significantly less prognostic power in the 208 patients with abnormal rest ECG findings (area = 58%), but each test then provided a significant incremental improvement in these patients (by 14% for each). A strategic model was thereby developed for prognostic assessment that recognizes the incremental power of these tests in specific patient groups as well as their overall accuracy and monetary cost. This strategy stratified individual patient risk for subsequent coronary events over a full order of magnitude (from 2 to 22%) at a 64% reduction in the cost of testing compared to performing both stress tests in all patients.