Interhemispheric steal syndrome.
A case of acute occlusion of the left common carotid artery is reported. The patient presented with symptoms and signs largely on the left side, ipsilateral to an occluded left carotid artery. Angiography revealed occlusion of the left common carotid artery and ulceration within the lumen of the right internal carotid artery bulb. Computerized tomography showed findings compatible with an old infarct within the right temporal lobe. The diagnosis of interhemispheric steal syndrome was made and the patient was treated successfully with staged surgical procedures on the carotid arteries, beginning with the totally occluded vessel, which was obstructed by fresh clot. The pathophysiology of interhemispheric steal syndrome is reviewed. A policy of operating first on the side of the occluded or more severely stenosed carotid artery is recommended, even though this vessel may be ipsilateral to the patient's symptoms.