Hemodynamic role of ophthalmic artery collateral in internal carotid artery occlusion in aged patients

Objective To explore hemodynamic role of ophthalmic artery collateral in internal carotid artery occlusion in aged patients.Methods In 110 aged patients(occlusion group) with unilateral internal carotid artery occlusion determined by MR angiography or digital subtraction,the collateral circulation pathway in circle of Willis and ophthalmic artery was measured by transcranial Doppler.The occlusion group was divided into ophthalmic artery collateral group(40 cases) and a group(70 cases) without ophthalmic artery collateral.Eighty patients without disease of cerebral and carotid artery were selected to serve as controls.Results The pulsatile index of Doppler signal in the ipsilateral middle cerebral artery,a measure of both inflow pressure and distal vascular resistance,did not differ between the groups with and without ophthalmic artery collateral.However,the presence of circle of Willis collateral pathways(anterior communicating and/or posterior communicating artery) did appear to have a significant effect on pulsatile index.Resistance index in ipsilateral common carotid artery was significantly lower in the group with ophthalmic artery collateral than in the group without ophthalmic artery collateral.Conclusions The ophthalmic artery collateral has a marginal effect on vascular resistance in arterial bed distal to internal carotid artery occlusion,while Willis circle collaterals appear to have a more important role in cerebral perfusion.