Long-term prognostic value of exercise echocardiography compared with exercise ²⁰¹Tl, ECG, and clinical variables in patients evaluated for coronary artery disease

Background - The accuracy of exercise echocardiography and ²⁰¹Tl single photon emission computed tomography (SPECT) is similar in the diagnosis of coronary artery disease (CAD). However, comparative data on long-term prognosis are lacking. Methods and Results - Clinical variables and exercise, echocardiographic, and ²⁰¹Tl tomographic parameters were studied in 248 patients (age, 56±12 years [mean±SD]; 189 men) who underwent simultaneous treadmill exercise ²⁰¹Tl SPECT and echocardiography. Follow- up was obtained in 225 patients (91%) at a mean of 3.7±2.0 years. A total of 64 cardiac events occurred. With the use of stepwise logistic regression, 4 models simulating clinical Stress testing scenarios were evaluated in the prediction of all cardiac events, ischemic events, and/or cardiac death. The best clinical models were exercise echocardiography with exercise ECG and exercise ²⁰¹Tl SPECT with exercise ECG. Both models were comparable in the prediction of cardiac events. For the exercise echocardiography model, exercise wall motion score index and induction of ischemia were the strongest predictors of events with ORs of 2.63 per unit treatment (95% CI, 1.34 to 5.17; P=0.005) and 4.1 (95% CI, 1.32 to 12.79; P=0.015), respectively. For the model with exercise ²⁰¹Tl SPECT, the strongest predictor was ischemic perfusion defect (OR, 4.93; 95% CI, 1.72 to 14.08; P=0.003). The absence of ST changes during exercise decreased the risk of events. For the prediction of ischemic events and/or cardiac death, echocardiographic and ²⁰¹Tl parameters were the only predictive variables. Conclusions - In patients evaluated for CAD, exercise echocardiography and ²⁰¹Tl combined with ECG variables provide comparable prognostic information and can be used interchangeably for risk stratification.