前方循環の塞栓源不明脳塞栓症における非狭窄性頸動脈プラーク

Nonstenotic Carotid Plaque in Patients with Anterior Circulation Embolic Stroke of Undetermined Source

塞栓源不明脳塞栓症（embolic stroke of undetermined source：ESUS）において，潜在的な塞栓源となる非狭窄性（狭窄率50％未満）頸動脈プラークの特徴は明らかでない。今回，前方循環のESUS患者連続17例の頸動脈超音波検査を後方視的に調査し，病巣側と対側の頸動脈プラークを比較した。平均プラークサイズは病巣側と対側に差を認めなかったが（2.13mm vs. 1.86mm，P＝0.54），非石灰化プラークの平均プラークサイズは病巣側で有意に大きかった（1.15mm vs. 0.23mm，P＝0.025）。2.5mm以上の非石灰化プラークは病巣側で17例中5例に認めたが，対側では1例も認めず，ESUSの塞栓源となっている可能性が示唆された。

Abstract

Characteristics of nonstenotic (＜50%) carotid plaque in embolic stroke of undetermined source (ESUS) are unclear. This study aimed to clarify the size and properties of carotid plaque in patients with ESUS. We retrospectively analyzed the results of carotid ultrasonography in 17 consecutive patients with anterior circulation ESUS and compared the size and morphology of carotid plaque on the ipsilateral and contralateral sides of the stroke lesion. The mean plaque thickness did not significantly differ between both sides (2.13 vs 1.86 mm, p ＝ 0.54), but the mean noncalcified plaque thickness was greater on the ipsilateral side than on the contralateral side (1.15 vs 0.23mm, p ＝ 0.025). Noncalcified plaque with thickness≥2.5mm was observed on the ipsilateral side in five of 17 patients, but not on the contralateral side, suggesting that noncalcified plaque with thickness≥2.5mm is a potential source of ESUS.

(Received January 29, 2018; Accepted July 21, 2018; Published November 1, 2018)