Prediction of Improvement of Hibernating Myocardium after Coronary Artery Bypass Grafting: The role of dobutamine stress echocardiography

Yoo, Kyung Jong; Kang, Myun Sik; Lee, Kyo Joon; Kim, Dae Jun; Lim, Se Joong; Jung, Nam Sik

Abstract

BACKGROUND: In patients with coronary artery disease, dysfunctional hypoperfused myocardium at rest may represent either nonviable or viable hibernating myocardium. Two-dimensional echocardiography can detect regional wall motion abnormalities resulting from myocardial ischemia by dobutamine infusion. The purpose of the present study was to identify the prediction of improvement of regional left ventricular (LV) function after surgical revascularization. MATERIALS AND METHODS: Sixteen patients with chronic regional LV dysfunction underwent dobutamine stress echocardiography (DSE) (dobutamine: baseline, 5, 10, 20microgram/kg/min) before coronary artery bypass grafting (CABG) and underwent echocardiography at least 2 months after CABG. RESULTS: All patients were male with mean age of 58 years ranging from 42 to 73 years. The mean LV ejection fraction was 41.8% with a range from 19% to 55%. During DSE, there were no complications, also, there were no operative morbidities or mortalities. Improvement of wall motion within the dysfunctional myocardium was found in 8 (50%) of 16 patients in DSE. Among them, 6 patients (75%) showed functional recovery after CABG. Another 8 patients did not show improvement of wall motion in DSE. But among them, 3 patients (38%) showed functional recovery after CABG. 84 dysfunctional segments were found in 256 segments of 16 patients. Improvement of wall motion was found in 34 of 84 segments in DSE. Among them, 23 segments (74%) showed functional recovery after CABG. Another 53 segments did not show improvement of wall motion in DSE. But among them, 12 segments (23%) showed functional recovery after CABG. The sensitivity and specificity of DSE for the prediction of postoperative improvement of segmental wall motion were 66% and 84%, respectively. The positive and negative predictive value of DSE were 74% and 77%, respectively. In patients with chronic regional LV dysfunction, think that DSE is a good predictor of the improvement of dysfunctional segments after CABG.