真島 康雄

Yasuo MAJIMA

真島消化器クリニック

Majima Digestive Organ Clinic

キーワード : cerebral infarction, coronary disease, subclavian artery, carotid arteries, ultrasonics

背景：頸動脈のIMT（内膜中膜肥厚）計測は，脳梗塞や冠動脈イベントのリスクを判定する“窓”として用いられている．しかし，頸動脈の動脈硬化所見が無くてもイベントが少なからず発生している．目的：イベント予知のために，新たな“窓”を発見すること．対象および方法：当院に通院中の30歳以上の連続628名を対象とし，イベント歴有り26名，無し602名の右鎖骨下動脈と頸動脈の最も厚いIMTを計測し，それぞれS-max，C-maxとした．無イベント例ではLDL，HDL，TG，食の好み，糖尿病や高血圧と，S-maxおよびC-maxとの関連を調査した．イベント例のS-max，C-maxの所見から，対象を5群のリスクレベルに分類した．結果：S-maxを97.1％（610/628）に検出した．60歳以上の症例でのS-maxは，LDLやTGの高値，高血圧，肉類や糖分の摂取過多，および野菜不足を，C-maxはLDL高値，HDL低値，高血圧，肉類の摂取過多の程度を反映していると考えられた．レベル0‐4までのイベント歴率を計算すると，それぞれ0％（0/182），1.2％（2/164），2.0％（2/100），11.4％（9/79），14.1％（12/85）であった．結語：S-max は動脈硬化の定量診断や，経過観察のための新しい明瞭な“窓”と言える．S-max とC-maxで分類したカテゴリーは，脳梗塞や冠動脈疾患のイベントのリスクレベルを判定するのに非常に有用である．

Background: Carotid arteries have been used as “windows” to or indicator sites for cerebral and coronary arteriosclerosis. However, there are many cases of cerebral or myocardial infarction without atherosclerosis in carotid arteries. Purpose: To find a new “window” and to determine whether subclavian and carotid arterial intima-media thickness (IMT) predicts cerebral infarction and coronary events. Subjects and Method: Maximal IMT of the right subclavian artery (S-max) and maximal IMT of carotid arteries (C-max) were measured by high-resolution (10 MHz) ultrasonography in 628 consecutive patients (26 patients with a history of cerebral infarction or coronary events and 602 patients without events) at Majima Digestive Organ Clinic. LDL, HDL, TG, taste in food, diabetes, and hypertension were examined in the patients without events. Taking the cases with events into consideration, the ultrasonographic findings in all cases were classified into five categories. Results: S-max was detected in 610 (97.1%) of 628 patients. The degree of thickening of S-max was correlated with LDL and TG levels, taste in food (meats, sweets, vegetables), and hypertension in the elderly (≥60 years old). The degree of thickening of C-max was correlated with LDL and HDL levels, taste in food (meats), and hypertension in the elderly (≥60 years old). The event history rate in the five categories was as follows: Level 0: 0.0% (0/182); Level 1: 1.2% (2/164); Level 2: 2.0% (2/100); Level 3: 11.4% (9/79); Level 4: 14.1% (12/85). Conclusions: S-max is a new clear “window” for the quantitation and follow-up of preclinical atherosclerosis. The categories employing the combination of S-max and C-max measurements are very useful for determining the risk levels of cerebral infarction and coronary events.