[Carotid screening with duplex scanning before coronary artery bypass]

Seventy-one patients undergoing scheduled coronary artery bypass were preoperatively evaluated for the presence of carotid stenosis by duplex scanning. Prevalence of a moderate degree of stenosis (peak systolic flow velocity of internal carotid artery > 130 cm/sec) or a high degree of stenosis (peak systolic flow velocity > 250 or < 25 cm/sec) was 12.7% (nine patients). Predictive risk factors for carotid stenosis were diabetes mellitus and history of stroke. Compared with carotid angiogram, hemodynamically critical stenosis greater than 90% was found in three patients, severe stenosis (75-90%) in four, moderate stenosis (50-75%) in two. Bilateral carotid occlusion, complete occlusion of an internal carotid artery with contralateral 99% stenosis, was found in one patient. In the critical stenosis group (n = 3), simultaneous carotid endarterectomy and coronary artery bypass were performed in two and coronary artery bypass alone in one patient with unilateral complete occlusion of the internal carotid artery. There was neither operative death nor postoperative stroke in this series of patients. In conclusion, carotid screening with a duplex scan is very helpful to evaluate the presence of carotid occlusive disease in coronary artery bypass candidates. When significant carotid stenosis is detected, further examination should be done to clarify the carotid hemodynamics and brain protection during the operation should be employed.