Carotid ligation for recurrent ischemia due to inaccessible carotid obstruction. Examination of the rationale of this treatment.

Experiences with a patient with symptomatic obstruction to the carotid artery in its petrous segment are described. In spite of the severe stenosis of this vessel, complete arteriography demonstrated excellent perfusion of the symptomatic eye and hemisphere and an ample collateral reserve. Funduscopy confirmed the clinical impression that recurrent retinal and hemispheric ischemia in this patient was the result of microembolism rather than intracranial hemodynamic insufficiency. Consequently, extracranial-intracranial (EC-IC) bypass was believed to offer little benefit to this patient. Abrupt ligation of the internal carotid artery in the neck proved to be an effective method for arresting the embolic discharge from this vessel's inaccessible obstruction, and resulted in prompt and complete relief of ischemic symptoms. It is concluded that identifying the mechanism(s) responsible for recurrent ischemia past uncorrectable carotid obstructions is of paramount importance in order to establish the most appropriate treatment(s). Carotid occlusion is an effective surgical remedy for terminating microembolism from this vessel when it is diseased and incompletely obstructed, and should be considered in selected patients. The importance of angiographic evaluation of naturally occurring EC-IC anastomotic connections in addition to the assessment of intracranial collateral reserves in cases of carotid occlusion is also emphasized.