Prediction of severe coronary artery disease and long-term outcome in patients undergoing vasodilator SPECT

Background. Vasodilator perfusion imaging has not been extensively evaluate d for predicting severe coronary artery disease (CAD) or long-term prognosi s. Methods and Results. The goals of this study were to develop a model to pre dict left main/3-vessel CAD in patients undergoing vasodilator thallium 201 imaging and coronary angiography (angiographic population) and to test the long-term prognostic value of this model in a separate cohort of patients who were not referred for angiography (prognostic population). In the angio graphic population (n = 653) the chi (2) value of the clinical model (conta ining the variables age, sex, and prior myocardial infarction) in the predi ction of severe CAD was 32. The addition of 3 vasodilator TI-201 variables (magnitude of ST-segment depression, summed reversibility score, and increa sed lung uptake) increased the model chi (2) value to 114 (P < .001). Only 9% of predicted low-risk patients versus 57% of predicted high-risk patient s had severe CAD. In the prognostic population (n = 521) survival rates fre e of cardiac death or myocardial infarction at 7 years were 91%, 73%, and 5 1%, respectively, for patient groups predicted to be at low, intermediate, and high risk of severe CAD (P < .001). Conclusions. Clinical and vasodilator TI-201 variables can accurately predi ct the risk of severe CAD. Stress TI-201 variables add incremental informat ion to clinical variables. The same model also predicts patient outcome.