Practical applications in stress echocardiography: Risk stratification and prognosis in patientswith known or suspected ischemic heart disease

Objectives The purpose of this study was to define appropriate parameters for risk stratification and prognosis in patients undergoing stress echocardiography. Background Stress echocardiography is an established technique for the diagnosis of coronary artery disease. However, current data on risk stratification of patients undergoing stress echocardiography are limited. Methods We evaluated 1,500 patients (59 ± 13 years old; 51% male) undergoing stress echocardiography (34% with treadmill exercise and 66% with dobutamine). Resting left ventricular ejection fraction (EF) and regional wall motion were assessed by the consensus of two echocardiographers. Follow-up (mean 2.7 ± 1.0 years) for confirmed non-fatal myocardial infarction (n = 31) and cardiac death (n = 44) were performed. Results By univariate analysis, both the peak wall motion score index (WMSI) (p < 0.0001) and EF (p < 0.0001) were significant predictors of cardiac events. Peak WMSI effectively risk stratified patients into low (0.9%/year), intermediate (3.1%/year), and high (5.2%/year) risk groups (p < 0.0001). A threshold of 45% EF provided further risk stratification of all WMSI groups. By multivariate logistic regression analysis, peak WMSI (relative risk [RR] 2.1, 95% confidence interval [CI] 1.0 to 4.4; p = 0.04) and EF (RR 1.0, 95% CI 0.9 to 1.0; p = 0.01) were both predictors of cardiac events. Conclusions Stress echocardiography yields prognostic information for risk stratification of patients with known or suspected ischemic heart disease. A normal stress echocardiographic study (peak WMSI = 1.0) confers a benign prognosis (0.9%/year cardiac event rate). Peak WMSI >1.7 and EF ≤45% are independent markers of patients at high risk of an adverse clinical outcome.