Local cardiac wall stabilization influences the reproducibility of regional wall motion during off-pump coronary artery pass surgery.

OBJECTIVE: Myocardial ischemia is a risk factor during off-pump coronary artery bypass procedures. The development of new regional wall motion abnormalities assessed by transesophageal echocardiography (TEE) is a very sensitive sign of myocardial ischemia. To facilitate anastomosis, the epicardial area of the anastomosis site is often immobilized by a "stabilizer." This study was designed to investigate whether cardiac wall stabilization with an epicardial stabilizer could affect the interpretation of wall motion during coronary anastomosis without cardiopulmonary bypass.
METHODS: The TEE videotapes of 15 adult patients were investigated. Left ventricular (LV) transgastric short and long axis views were divided according to a modified 16-segment method. LV wall motion was scored using a 5-grade scale by two independent blinded investigators during pre-occlusion, occlusion, and reperfusion of anastomosed coronary arteries. The wall motion scores of a stabilized segment combined with two adjacent segments were compared with those of non-stabilized segments. Interobserver agreement was assessed using the weighted kappa statistic.
RESULTS: A total of 216 segments were analyzed by two investigators. The interobserver kappa coefficient in pre-occlusion and reperfusion periods was 0.87, 0.87 and 0.86, 0.87, respectively, indicating high agreements without stabilizer. During the occlusion period in stabilized and non-stabilized segments, it was 0.59 and 0.76, respectively, showing significantly less reproducibility in the presence of stabilizer.
CONCLUSION: Cardiac wall stabilization affects the reproducibility in the interpretation of regional wall motion during off-pump coronary artery bypass surgery. Caution should be used when monitoring for myocardial ischemia using TEE during coronary artery bypass surgery with epicardial stabilizer.