Clinical and pathophysiological features of amaurosis fugax in Japanese stroke patients

Objective It has been emphasized that amaurosis fugax (AmF) is caused by th romboembolism due to atheromatous lesions of the extracranial carotid arter y (EC-CA) in Caucasian populations. However, there have been few studies of AmF in Japan. We analyzed the clinical and pathophysiologic features of Am F in 43 Japanese AmF patients. Subjects and Methods Forty-three patients presented with AmF from a group o f 2,056 Japanese patients with acute ischemic stroke. We investigated angio graphic and transcranial Doppler findings, precipitating factors, medical t reatment and prognosis, to elucidate the pathogenetic mechanism of AmF. Results Angiographic findings revealed an intracranial lesion in 22 patient s (51%), extracranial lesion in 16 (37%), and no abnormality in 5 (12%), Bl ood flow in the ophthalmic artery (OA) examined by the transcranial Doppler ultrasonography (TCD) showed normal antegrade flow in 24 patients and reve rsed flow in 7, Precipitating factors for AmF were seen in 7 out of 43 pati ents. Regarding the pathogenesis of AmF, the micro-thromboembolism originat ed from the internal carotid artery (ICA) in 25 patients, the thromboemboli sm was via the external carotid artery (ECA) in 7, the hemodynamic retinal vascular insufficiency in 6 patients showed various atheromatous changes in the intracranial carotid artery (IC-CA) or EC-CA, and the cause was unknow n in 5. Conclusion In this series of patients, AmF was mainly caused by thromboembo lism from IC-CA atheromatous lesions. Micro-thromboemboli from the ECA or h emodynamic retinal vascular insufficiency, although less frequent, should a lso be considered as possible etiologies for AmF.