非外傷性前大脳動脈解離―自験6症例の検討

Nontraumatic Arterial Dissection of the Anterior Cerebral Artery : Six Cases Report

要旨　比較的稀な病態と考えられる非外傷性前大脳動脈解離について，1996年1月～2003年12月に仙台医療センター脳卒中センターにて加療した6症例を対象に検討した。男性3例，女性3例，平均年齢57.7歳，高血圧症の既往が5例にあり，3例に囊状動脈瘤，3例に他部位脳動脈解離の合併が認められ，高血圧および血管構造の異常が原因となっている可能性が示唆された。解離部はA2部からのものが5例，A1からのものが1例で，全例多様な経時的変化を認めた。全例虚血発症（1例は出血性梗塞）で保存的治療を行ったが，結果（Glasgow Outcome Scale）はGood Recoveryが5例，経過中出血をきたしDeadとなったものが1例であった。虚血発症例は保存的治療にて良好な経過をとるが，重篤な出血をきたす可能性があるので，特に発症1カ月以内は，脳血管撮影を中心とした厳重な経過観察が必要で，出血が危惧される場合には外科的治療の必要性があると考えられた。

Abstract

　Nontraumatic arterial dissection of the anterior cerebral artery （NAD-ACA） is a relatively rare disease entity, although case reports have recently been increased. We treated 6 patients suffering from NAD-ACA from January 1996 to December 2003, and the neuroradiological findings together with the clinical courses were reviewed. There were 3 males and 3 females with a mean age of 57.7-year-old, ranging from 41 to 65. Five patients had a past history of hypertension and one diabetes mellitus. At the onset, all patients presented with clinical manifestations of cerebral ischemia. Among them, all exhibited contralateral hemiparesis with greater weakness of the lower extremity, and two patients exhibited headache. Initial angiography revealed the pearl and string sign in four patients and string sign, tapered occlusion in each one. Follow-up angiographies revealed sequential changes in all patients ; four improved and two progressed. Main anatomic site of the lesion was as follows ; five in the A2 and one in the A1 portion, in addition, one patient was complicated by saccular aneurysm, one by PCA dissection, and two had with saccular aneurysm contralateral ACA ＆ MCA and VA dissection each other. Four patients were treated conservatively by intravenous administration of argatroban, one by intravenous administration of Dextrane and one by anti-platelet agent in the acute stage. All patients were treated by anti-platelet agents in the chronic stage. Good recovery was achieved in five patients, but one who suffered from severe subarachnoid hemorrhage in the chronic stage died. Our experience suggests that hypertension and/or the succeeding abnormal structural changes in the arterial wall may contribute to the occurrence of this disease. NAD-ACA showing clinical manifestations of cerebral ischemia could result in a relatively good prognosis ; however, attention should be paid to patients treated conservatively with a very closed follow-up angiography to prevent a possibility of severe hemorrhage.

（Received : March 24, 2005）