Incremental diagnostic and prognostic value of contemporary stress echocardiography in a chest pain unit: mortality and morbidity outcomes from a real-world setting.

BACKGROUND: Clinical assessment often cannot reliably or rapidly risk stratify patients hospitalized with suspected acute coronary syndrome. The real-world clinical value of stress echocardiography (SE) in these patients is unknown. Thus, we undertook this study to assess the feasibility, safety, ability for early triaging, and prediction of hard events of SE incorporated into a chest pain unit for patients admitted with acute chest pain, nondiagnostic ECG, and negative 12-hour troponin. METHODS AND RESULTS: Accordingly, 839 consecutive patients who underwent clinical, ECG, and SE assessments within 24 hours of admission were assessed for feasibility, safety, impact on triaging and discharge, and 30-day readmission rate and were followed up for hard events (all-cause mortality and acute myocardial infarction). Of the 839 patients, 811 (96.7%) had diagnostic SE results. Median time to SE and median length of stay for normal SE patients (77%) were both 1 day. The 30-day readmission rate was 0.5%. During long-term follow-up of 27±11 months, 39 hard events (30 deaths and 9 acute myocardial infarctions) occurred. Kaplan-Meier estimates of hard events were 0.5% versus 6.6% in the normal versus abnormal SE groups, respectively, in the first year of follow-up (15 events in the first year). Among all prognostic variables, only abnormal SE (hazard ratio, 4.08; 95% confidence interval, 2.15-7.72; P<0.001) and advancing age (hazard ratio, 1.78; 95% confidence interval, 1.39-2.37; P<0.001) predicted hard events in multivariable regression analysis. CONCLUSIONS: SE incorporated into a chest pain unit has excellent feasibility and provides rapid assessment and discharge with accurate risk stratification of patients with suspected acute coronary syndrome but nondiagnostic ECG and negative 12-hour troponin.