Prediction of Mortality and Major Cardiac Events by Exercise Echocardiography in Patients With Normal Exercise Electrocardiographic Testing

Abstract

We sought to assess the value of exercise echocardiography (EE) for predicting outcome in patients with known or suspected coronary artery disease and normal exercise electrocardiogram (ECG) testing. The prognostic value of EE in patients with normal exercise ECG testing has not been characterized. We studied 4,004 consecutive patients (2,358 men, mean age [+/- SD] 59.6 +/- 12.5 years) with interpretable ECG who underwent treadmill EE and did not develop chest pain or ischemic ECG abnormalities during the tests. Wall motion score index (WMSI) was evaluated at rest and with exercise, and the difference (DeltaWMSI) was calculated. Ischemia was defined as the development of new or worsening wall motion abnormalities with exercise. End points were all-cause mortality and major cardiac events (MACE). Overall, 669 patients (16.7%) developed ischemia with exercise. During a mean follow-up of 4.5 +/- 3.4 years, 313 patients died, and 183 patients had a MACE before any revascularization procedure. The 5-year mortality and MACE rates were 6.4% and 4.2% in patients without ischemia versus 12.1% and 10.1% in those with ischemia, respectively (p < 0.001). In the multivariate analysis, DeltaWMSI remained an independent predictor of mortality (hazard ratio [HR]: 2.73, 95% confidence interval [CI]: 1.40 to 5.32, p = 0.003) and MACE (HR: 3.59, 95% CI: 1.42 to 9.07, p = 0.007). The addition of the EE results to the clinical, resting echocardiographic and exercise hemodynamic data significantly increased the global chi-square of the models for the prediction of mortality (p = 0.005) and MACE (p = 0.009). The use of EE provides significant prognostic information for predicting mortality and MACE in patients with interpretable ECG and normal exercise ECG testing.