Aberrant branchにて閉塞部遠位の血流が保たれた内頚動脈閉塞症に対して頚動脈内膜剝離術を施行した1例

Endarterectomy for Internal Carotid Artery Occlusion, with an Aberrant Branch of the Internal Carotid Artery Maintaining Blood Flow Distal to the Complete Occlusion:A Case Report

Ⅰ．はじめに

　通常，内頚動脈（internal carotid artery：ICA）は総頚動脈（common carotid artery：CCA）から分岐した後，眼動脈を分岐するまで分枝血管をもたない．したがって，ICAが閉塞した場合，眼動脈分岐部まで血栓化して閉塞すると考えられるため，頚動脈内膜剝離術（carotid endarterectomy：CEA）の適応はない．内頚動脈閉塞症（internal carotid artery occlusion：ICO）は頚動脈複合超音波診断法（carotid duplex sonography：CDS）にて比較的容易に診断でき，CDSの所見が治療方針に与える影響は大きい．今回われわれは，CDS上ICAが閉塞しているにもかかわらず，閉塞部遠位のICAの血流が確認され，精査によってICAからの破格血管（aberrant branch）の存在により遠位のICAの血流が保たれていることを確認し，CEAを施行した症例を経験したので報告する．

　Doppler sonography accurately identifies occlusion of the internal carotid artery（ICA）and current surgical guidelines do not list an occluded ICA as an indication for carotid endarterectomy（CEA). We encountered an unusual case, for which we performed CEA. The left ICA was occluded by atherosclerosis, and was reconstituted via an aberrant branch of the occipital artery. A 71-year-old man was referred following brain infarction. Carotid duplex sonography（CDS）demonstrated occlusion of his left ICA, with flow in the distal ICA beyond the occlusion（“Sandwich stump sign”). 3D computed tomography angiography and cervical angiography diagnosed ICA occlusion with flow in the distal ICA, and the patient underwent CEA. Careful evaluation is required when apparent occlusion of the ICA is detected to avoid overlooking a flow pattern beyond the occlusion and to determine whether repair is possible.