Prognostic implications of stress echocardiography and impact on patient outcomes: An effective gatekeeper for coronary angiography and revascularization

Background: Stress echocardiography is an established technique for diagnosis, risk stratification, and prognosis in patients with known or suspected coronary artery disease. The ability of stress echocardiography to predict clinical outcomes, such as coronary angiography and revascularization, has not been reported previously. The purpose of this study was to evaluate the clinical outcomes of coronary angiography, revascularization, and cardiac events in patients undergoing stress echocardiography. Methods: A total of 3121 patients (mean age, 60 ± 13 years; 48% men) undergoing stress echocardiography (41% treadmill, 59% dobutamine) were assessed. Follow-up (mean, 2.8 ± 1.1 years) for subsequent coronary angiography, revascularization (percutaneous coronary intervention [PCI] or coronary artery bypass grafting [CABG]), and confirmed hard events (nonfatal myocardial infarction or cardiac death) was obtained. Results: Stress echocardiographic results were normal (peak wall motion score index [pWMSI], 1.0) in 66% and abnormal (pWMSI > 1.0) in 34% of patients. The pWMSI effectively risk-stratified patients into low-risk (pWMSI, 1.0; 0.8% per year), intermediate-risk (pWMSI, 1.1-1.7; 2.6% per year), and high-risk (pWMSI >1.7; 5.5% per year) groups for future cardiac events (P < .0001). Early coronary angiography (30 days following stress echocardiography) was performed in only 35 patients (1.7%) with normal stress echocardiographic results and 267 patients (25.5%) with abnormal stress echocardiographic results (P < .0001). Late coronary revascularization (2 years following stress echocardiography) occurred in 80 patients (PCI, 2.8%; CABG, 1.1%) with pWMSI values of 1.0, 123 patients (PCI, 13.5%; CABG, 7.3%) with pWMSI values of 1.1 to 1.7, and 102 patients (PCI, 12.7%; CABG, 9.6%) with pWMSI values > 1.7. Multivariate logistic regression analysis identified pWMSI as a predictor of coronary angiography (relative risk, 2.04; 95% confidence interval, 1.67-2.5), revascularization (relative risk, 1.91; 95% confidence interval, 1.68-2.17), and cardiac events (relative risk, 2.45; 95% confidence interval, 2.09-2.88) (all P values < .0001). Patients with markedly abnormal stress echocardiographic results (pWMSI > 1.7) had a significantly higher cardiac event rate in those who did not undergo coronary revascularization (9.6% per year vs 2.9% per year, P < .05). Conclusions: Stress echocardiography is an effective gatekeeper for coronary angiography and revascularization. Stress echocardiographic results influence clinical decision making in higher risk patients with significantly increased referral to coronary angiography and revascularization. Patients with markedly abnormal stress echocardiographic results (pWMSI > 1.7) were most likely to benefit from coronary revascularization.