DOPPLER STUDY OF THE OPHTHALMIC ARTERY IN PATIENTS WITH CAROTID OCCLUSIVE DISEASE

Assessing the adequacy of collateral circulatory pathways has become i ncreasingly important in the investigation of cerebral circulation. Us ing transorbital Doppler ultrasonography (TOD), we examined the ophtha lmic artery (OA) in patients with hemodynamic significant internal car otid artery (ICA) occlusive disease. The velocity and the direction of flow in the OA were studied in 45 patients (occlusion n = 27, stenosi s > 75 % n = 18), and in 30 age matched controls, under baseline condi tions and within 30 minutes after the i.v. administration of Ig acetaz olamide as a vasodilatory stimulus. Based on the direction of how befo re and after acetazolamide, the 45 patients could be separated into fo ur groups with increasing degree of ICA lesions. In group I the OA flo w was anterograde, but the velocity decreased after acetazolamide. In group II the OA direction became retrograde after acetazolamide, indic ating collateral flow to the brain. In patients with retrograde OA flo w following acetazolamide injection (group II-IV), the vessel reacted similarly to an intracranial artery, with marked increase in velocity when vasoreactivity was tested. TOD and the acetazolamide test provide useful information about potential collateral OA flow to the brain in patients with ICA occlusive disease.