Collateral compensative capacity assessed by transcranial Doppler in aged patients with internal carotid artery occlusion

Objective To assess collateral compensative capacity by transcranial Doppler(TCD) in patients with internal carotid artery occlusion .Method In 80 aged patients with unilateral internal carotid artery occlusion, collateral circulation pathway in circle of Willis and ophthalmic artery was measured by TCD.Results TCD showed collateral patency of anterior communicating artery in 93%,posterior communicating artery in 51%,and ophthalmic artery in 25%.Absence of collateral flow was found in 4 patients(5%) with symptomatic occlusion.Thirty-one patients (39%) had 1 collateral pathway,36 patients(45%) 2 collateral pathways,and 9 patients (11%) 3 collateral pathways.The mean flow velocity of middle cerebral artery in asymptomatic patients was significantly higher than that in symptomatic patients(P0.01).Conclusions TCD can help to know the collateral compensative capacity of patients with internal carotid artery occlusion.