DCA（directional coronary atherectomy），冠動脈内エコーで診断したfibromuscular dysplasiaによる労作狭心症の1例

A Case of Effort Angina Pectoris Caused by Fibromuscular Dysplasia, Undergoing Directional Corollary Atherectomy

　症例は37歳，男性，主訴は胸痛．既往歴，家族歴は特記事項なし．生来健康であったが，1992年11月頃より労作時に反復する胸痛が出現するようになった．多段階運動負荷試験にて有意なST下降が認められ，1993年6月に入院した．明らかな冠危険因子はなかった．冠動脈造影で左前下行枝起始部に孤立性の90％の狭窄病変がみられたため，同部位に対してDCAを施行し，狭窄はほぼ0％までに改善した．冠動脈内エコー検査ではDCA施行部に3層構造を認めたが，主幹部および前下行枝末梢部には異常エコーを認めなかった．DCA時に採取した組織では平滑筋細胞を含む硝子様変性所見を認めたが粥状硬化性変化は認められず，冠動脈狭窄の原困としてはFibromuscular dysplasia（FMD）が考えられた．

This report described a 37-year- old man who was admitted to our hospital with exercise-induced chest pain and ischemic ST depression. lie showed no coro-nary risk factors including hyperlipidemia, diabetes or hypertension. On the coronary angiogram, the patient showed discrete and tight stenosis at the proximal portion of the otherwise normal left anterior descending artery. Directional coronary atherectomy (DCA) wasindicated and successfully improved the luminal narr-owing from 90% to 0%. Intravascular ultrasound (IVUS) demonstrated a three layered appearance at the site of the narrowing, but revealed no abnormal echoes in the other parts of coronary arteries. Histological examination of the removed specimen showed fibrous proliferation of the intima and media which, however, lacked the usual characteristics of atheromatous plaques. Based on these observations, clinical diagnosis of fibromuscular dysplasia was established as the coro-nary stenotic lesion of this patient.