Prognostic value of dual imaging stress echocardiography following coronary bypass surgery

To assess the prognostic value of dual imaging stress echocardiography after coronary artery bypass grafting (CABG). Dual imaging stress echocardiography, combining the evaluation of regional wall motion and Doppler echocardiographic derived coronary flow velocity reserve (CFVR) of the left anterior descending artery (LAD), is the state-of-the-art methodology during vasodilatory stress.

In a prospective, multicenter, observational study, 349 patients (270 men; 69 ± 9 years; 262 symptomatic) with history of CABG underwent high-dose dipyridamole (0.84 mg/kg over 6 min) stress echocardiography with CFVR evaluation of LAD by Doppler. The composite endpoint of death and myocardial infarction was considered in the survival analysis. Positivity rate with either criteria was 13% in the 262 symptomatic patients with appropriate and 6% in the 87 asymptomatic patients with maybe/rarely appropriate indications on the basis of 2014 American College of Cardiology Foundation guidelines. During a median follow-up of 22 months (1st quartile 8, 3rd quartile 44), there were 56 (16%) events: 21 deaths, and 35 nonfatal myocardial infarctions. At Cox analysis, ischemia at stress echo (HR 4.80, 95% CI 2.69-8.55; p < 0.0001), and CFVR of LAD ≤2 (HR 2.28, 95% CI 1.32-3.95; p = 0.003) were multivariable prognostic predictors. Considering the group with no ischemia, patients with CFVR ≤2 showed 2.5 fold higher yearly hard events as compared to those with CFVR >2 (7.5 vs 2.9%; p = 0.002).

Dual imaging stress echocardiography provides useful prognostic information following CABG. Inducible ischemia and abnormal CFVR are strong and independent prognostic indicators in patients with appropriate and rarely/maybe appropriate indications.