血管内エコーで冠動脈の炎症の関与が示唆された冠攣縮による急性心筋梗塞の1例

A Case of Acute Myocardial Infarction due to Vasospasm Related to Marked Coronary Inflammation

要旨

　患者は60歳，女性．主訴は胸痛．原発性胆汁性肝硬変で通院中であった．1999年2月3日，胸痛が出現，心電図上，Ⅱ，Ⅲ，aV_F誘導でST上昇を認め，急性心筋梗塞を疑い，緊急冠動脈造影を施行したが，冠動脈に有意狭窄を認めなかった．しかし，左室造影で下壁運動低下と心筋逸脱酵素の上昇を認め，冠攣縮による急性心筋梗塞と思われた．2月13日，再度胸痛が出現，心電図上，V₃からV₆でT波の先鋭化を認め，左前下行枝の攣縮が考えられた．多枝攣縮の診断のため，3月2日アセチルコリン負荷冠動脈造影を施行，左右冠動脈ともに攣縮を認めた．右冠動脈に対して血管内エコーを施行，echolucent areaを伴ったintima-media complexの著明な増加を認めた．2002年3月12日，再度，右冠動脈に対して血管内エコーを施行したが，急性期にみられた異常所見は完全に消失していた．急性心筋梗塞の原因として冠動脈の高度の炎症による冠攣縮の可能性が示唆された．

Summary

　A 60-year-old female with primary biliary cirrhosis was admitted due to anterior chest pain. Electrocardiography revealed ST segments elevation in Ⅱ, Ⅲ, aV_F leads and CPK and CPK-MB were both elevated. We suspected acute myocardial infarction and performed an emergency coronary angiogram. However, significant coronary stenosis was not detected, so we thought that vasospasm was the main cause of the acute myocardial infarction and we administered nitrate and calcium antagonist. Ten days later, the patient had a second vasospasm attack. After stabilization due to full medication, we performed acetylcholine provocated coronary angiography to prove vasospasm. Severe vasoconstriction occurred both in the right and left coronary arteries. We tried intravascular ultrasound to observe vessel morphology in the right coronary artery. Eccentric plaque with a large echolucent area was found in the middle portion of the right coronary artery. Three years later, we again used intravascular ultrasound to observe plaque morphology. Surprisingly, the increased intima-media complex in the right coronary artery had completely disappeared. We thought that this phenomenon seemed to be due to reversible coronary inflammation. In conclusion ,local inflammation in the coronary artery, which was proved by intravascular ultrasound, was the main cause of vasospasm in this patient.