道倉 雅仁¹, 柏瀬 一路², 平尾 円香³, 佐藤 まり恵³, 黒田 暁生³, 苅田 真子³, 田邊 淳³, 佐藤 秀幸³

Masahito MICHIKURA¹, Kazunori KASHIWASE², Madoka HIRAO³, Marie SATOU³, Akio KURODA³, Michiko KARITA³, Jun TANABE³, Hideyuki SATOU³

¹株式会社関西超音波サービス, ²大阪警察病院心臓センター, ³生登会寺元記念西天満クリニック

¹Kansai Ultrasound Service Corporation, ²Cardiovascular Division, Osaka Police Hospital, ³Teramotokinen Nisitenma Clinic

キーワード : ultrasound, carotid sinus, plaque, diameter, shear stress

目的：粥状動脈硬化病変（Plaque）は，比較的大きな血管の分枝部など特定部位に好発する特性がある．しかし，左右頸動脈洞（CS）の一方のみにPlaque形成を認めることは，臨床現場にてしばしば遭遇する．我々は，血管径などが一方のみにPlaqueを形成させている要因と推測し，それらの因子がPlaque形成に与える影響について研究した．対象と方法：2009年4月から2010年3月までに医療法人生登会寺元記念西天満クリニックにて頸動脈超音波検査を実施した外来患者の内，左右一方のCSのみにPlaque形成を認めた100例（男性68人，女性32人）を対象とした．頸動脈超音波検査にて，左右両側の総頸動脈（CCA）とCSの接合角，各血管径，血管径比（CS/CCA），平均内膜中膜複合体厚及び流速を求めた．Plaque形成を認めた側をP側，認めない側をN側として，各因子を比較検討した．結果と考察：接合角，CS径とCS/CCAは，P側の方がN側に比較して有意に高値を示した．本研究結果より，血管径や接合角は血管内皮へかかるずり応力に影響し，Plaque形成の重要な因子になると推測された．結論：血管径や接合角がPlaque形成の要因であることが示唆された．

Purpose: Generally, atherosclerosis forms in a specific region, e.g., bifurcation of a large artery. Therefore, we often encounter plaque formation in one side of the carotid sinus (CS). Thus, we investigated whether or not the diameter and angle of the carotid artery impact plaque formation in CS using carotid ultrasound. Subjects and Methods: The candidates for this study were 655 subjects who underwent carotid ultrasound at Teramotokinen Nisitenma Clinic between April 2009 and March 2010. Exclusion criteria were plaque formation on both sides of the CS, unclear connection between the common carotid artery (CCA) and the CS, plaque formation or wall thickening of the CCA, and severe stenosis or total occlusion of the internal carotid artery (ICA). Eligible data from 100 subjects were ultimately used for this study. We analyzed relationships between plaque formation and CCA diameter (CCAd), CS diameter (CSd), ratio of CSd to CCAd (CS/CCA), angle between CCA and CS (angle), mean intima-media thickening, and velocity. We defined side with plaque formation as the positive side (P side) and the intact side as the negative side (N side), and compared factors between the two sides. Results and Discussion: We found that angle, CSd, and CS/CCA on the P side were significantly higher as compared with the N side. The present study demonstrated that vessel diameter and angle might influence shear stress, resulting in involvement in plaque formation in the CS. Conclusion: Our findings confirmed that the diameter of the CS and the angle between the CCA and the CS play a role in plaque formation in the CS.