Abstract 9888: Is There Additional Prognostic Value of Stress Echocardiography in Patients Achieving a High Exercise Capacity (≥10 Metabolic Equivalents)?

Abstract

Background: High exercise capacity is a predictor of favorable prognosis in patients with known or suspected coronary artery disease. The purpose of this study was to examine the prognostic value of stress echocardiography (SEcho) in patients achieving high exercise workload. Methods: We evaluated 970 patients (51 ± 11 years; 62% male) achieving nine minutes (≥10 metabolic equivalents) on a Bruce protocol by treadmill SEcho. Resting left ventricular ejection fraction and regional wall motion were assessed. The left ventricle was divided into 16 segments and scored on 5-point scale of wall motion. Abnormal SEcho was defined as stress-induced ischemia (wall-motion score of ≥1 grade). Followup (3.4 ± 1.5 years) for non-fatal myocardial infarction (n = 11) and cardiac death (n = 3) were obtained. Results: By univariate analysis, both peak wall motion score index (p=0.002) and number of new ischemic wall motion abnormalities (p<0.0001) were significant predictors of cardiac events. Cumulative survival in patients achieving nine minutes (≥10 metabolic equivalents) was signficantly worse in patients with abnormal (ischemic) vs. normal (nonischemic) SEcho (1.1%/year vs. 0.2%/year, p=0.001)(Graph). Multivariate logistic regression analysis identified number of new ischemic wall motion abnormalities as the strongest predictor of cardiac events (RR 1.27, 95% CI 1.0-1.6, p=0.01). Conclusions: The ability to achieve nine minutes (≥10 metabolic equivalents) by treadmill stress echocardiography confers a benign prognosis (~1.0%/year). In the setting of high achieved exercise capacity, stress echocardiography (absence or presence of ischemia) is further able to effectively risk stratify a low risk group.