Stress echocardiography for the risk stratification of patients following coronary bypass surgery

Abstract

Objectives: The aim of the study was to assess the prognostic value of stress echocardiography after surgical revascularization.

Methods: We evaluated 500 (100 women) patients who had undergone exercise or pharmacological SE after a median of 69 months after coronary artery by-pass grafting (CABG). Of these, 351 (70%) complained of symptoms suggestive of ischemic origin while 149 (30%) were tested for asymptomatic progression of the disease.

Results: SE was positive for ischemia in 196 (39%) patients. During a median follow-up of 25 months, 61 patients died, 33 had a nonfatal myocardial infarction, and 112 underwent late (>3 months) revascularization. Multivariable Cox' regression analysis indicated age (HR=1.04; 95% CI 1.01-1.06; p<0.003), and peak WMSI (HR=3.07; 95% CI 1.96-4.81; p=0.0001) as independent predictors of hard (total mortality and myocardial infarction) events. SE information provided a significant improvement in predictive power of the statistical model (chi-square increase 34%, p<0.0001 for hard and 91%, p<0.0001 for major events, respectively). Survival analysis showed ischemia at SE to be associated with significantly higher hard and major event rate in both symptomatic and asymptomatic patients.

Discussion: SE represents an effective tool for the risk stratification of patients with previous CABG independently of the presence of symptoms suggestive of ischemic origin.