Recurrent retinal ischemia beyond cervical carotid occlusions: clinical-angiographic correlations and therapeutic implications.

Seventeen patients with persistent amaurosis fugax ipsilateral to angiographically documented internal carotid artery (ICA) occlusions in the neck have been treated by the authors over the past 5 years. Complete cerebral arteriography in each case demonstrated that the symptomatic ophthalmic artery was perfused exclusively by the ipsilateral external carotid artery (ECA), which invariably had an obstructive and/or ulcerative lesion and its origin, and/or an adjacent residual "stump" of the occluded ICA. In nine patients, retinal artery branch emboli were visible on funduscopy. One patient had angiographic evidence of intracranial embolization via the ophthalmic artery from the ECA. Although ipsilateral superficial temporal-muscle cerebral artery anastomosis in one patient, and endarterectomy of a contralateral carotid stenosis in another patient, failed to relieve symptoms, endarterectomy of the ECA with resection of the "stump" of the occluded ICA effectively terminated symptoms in 10 of 11 patients. Anticoagulant drug therapy promptly abolished symptoms in four nonsurgical patients as well as in two patients with failed operations. It is concluded that recurrent retinal ischemia beyond cervical carotid occlusions frequently results from microembolism via the ipsilateral ECA. Patients with this mechanism of postocclusion recurrent ischemia can be identified on the basis of clinical history, ophthalmological examinations, and complete cerebral arteriography. Termination of embolic phenomena should be the major treatment goal in these individuals, and ECA endarterectomy is recommended. Anticoagulant drugs are an effective alternative treatment in patients who are poor surgical risks.