712-6 Detecting Myocardial Stunning During CABG Surgery with Myocardial Contrast Echocardiography (MCE)

Abstract

During cardiac surgery, differentiating between ischemic and non-ischemic LV dysfunction is critical for prognosis and therapeutic strategies. We hypothesized that flow determined with myocardial contrast echo and wall motion analysis would enable identification of stunned myocardium. Twelve patients who received aortic root injections of Albunex R contrast during elective CABG surgery were compared to 14 matched controls for contrast agent safety. CPK enzymes, EKG, and hemodynamics were measured (pre- and post-op) for 72 hr. Baseline wall motion was scored (0–4) in contrast patients from 4 equally divided LV mid-papillary, short-axis regions and after CPB at the following intervals: 15, 30, 60 min.; 12 hr.; 5–8 days; and 30 days. Recorded images were analyzed off-line by 3 observers blinded to outcome. Contrast enhancement of myocardial perfusion at the time of surgery was also assessed in equally divided LV regions from the short-axis, LV echo image. Relationships between flow and function were described based on acute function (AF) (the avg. of scores at 15, 30, and 60 min after CPB). chronic function (CF) (the avg. of scores at 12 hr., 5 days, and 30 days), and intraoperative flow score. There were no significant differences pre- and post-op between control and contrast groups with respect to CPK enzymes, EKG changes, and hemodynamics. When coupled to function, flow was measured 60% of the time (29 of 48) Four relationships of flow and function were defined (function score of 0–2 = abnormal; 3–4 = normal): Normal AF = 3–4 flow normal CF = 3–4 Stunned AF = 0–2 flow nomal CF = 3–4 Hyperdynamic AF = 3–4 flow abnormal CF = 0–2 Other (post-op event) AF = 3–4 flow normal CF = 0–2 Relationship of Flow and Function by Region Region Normal Stunned Hyper Other Anterior 7 6 - - 1 Posterior 9 6 3 - - Septal 7 5 - 2 - Lateral 6 5 - 1 - 76% 10% 10% 4% Differentiation of non-ischemic and ischemic LV dysfunction appears possible with MCE and wall motion analysis. Myocardial stunning occurred 10% of the time after elective CABG surgery. Intraoperative flow and chronic function after CABG surgery are strongly linked (96%).