Prediction of mortality in patients without angina: Use of an exercise score and exercise echocardiography

Background: Exercise testing has limited efficacy for identifying coronary artery disease (CAD) in the absence of anginal symptoms. Exercise echocardiography is more accurate than standard exercise testing, but its efficacy in this situation has not been defined. We sought to identify whether the Duke treadmill score or exercise echocardiography (ExE) could be used to identify risk in patients without anginal symptoms. Methods: We studied 1859 patients without typical or atypical angina, heart failure, or a history or ECG evidence of infarction or CAD, who were referred for ExE, of whom 1832 (age 51±15 years, 944 men) were followed for up to 10 years. The presence and extent of ischaemia and scar were interpreted by expert reviewers at the time of the original study. Results: Exercise provoked significant (>0.1 mV) ST segment depression in 215 patients (12%), and wall motion abnormalities in 137 (8%). Seventy-eight patients (4%) died before revascularization, only 17 from known cardiac causes. The independent predictors of death were age (RR 1.1, p<0.0001), smoking, Duke treadmill score (RR 0.9, p<0.0001) and resting LV dysfunction (RR 1.9, p"0.04, but did not include ischaemia at ExE. Echocardiography was not predictive of outcome in subgroups with an intermediate or high risk Duke score, nor in patients with two or more risk factors. Conclusions: Patients without anginal symptoms have a low mortality, especially from cardiac causes. If such individuals undergo exercise testing and a resting echocardiogram, exercise echocardiography does not offer additional prognostic information.