心筋梗塞発症における冠動脈攣縮の意義（I）—寒冷刺激に対する冠血管反応性異常

A case of myocardial infarction induced by cold stimulation:Provocation of coronary vasospasm by the cold pressor test

　冠動脈spasmが異型狭心症のみならず，ST降下型安静時狭心症や心筋梗塞の発症成因としても重要な役割を演じている可能性が明らかにされ^1,2,3），さらに冠動脈造影上有意な器質的狭窄を証明しえない冠動脈にも，spasmが生じうる^4）ことより，いわゆる正常冠動脈像を示す心筋梗症例^5）においても発症メカニズムとして冠動脈のspasm役割が注目されてきた。著者らは非発作時，正常冠動脈造影像を呈し，狭心痛出現に際してのみ冠動脈spasmを認めたことより冠攣縮性狭心症vasospastic angina^6）と診断し，経過中に心筋梗塞を発症した症例について，梗塞発症前後の冠動脈造影像を検討し，心筋梗塞発症における冠動脈spasmの関与について興味ある所見を得た。

A 48-year-old man admitted our clinic, com-plaining of anterior chest pain. He had been already diagnosed as the vasospastic angina with normal coronary arteriogram (right coronary-artery), and treated with Ca²⁺antagonist. The electrocardiogram on admission revealed acute inferior infarction. On the 60 th day, we per-formed coronary arteriography again. The pro-ximal portion of the right coronary artery was almost normal visualization, but 75% or 90% stenosis appeared at the same position as docu-mented as before arteriogram during cold pressor test. From this findings of the coronary arterio-grams and the history of the onset of myocardial infarction, we concluded that the cold stimulation provoked coronary vasospasm and its could play a great important part as an intiating factor of acute myocardial infarction.