左冠状動脈主幹部圧迫による心筋虚血，心タンポナーデを伴う巨大左Valsalva 洞動脈瘤

Left sinus of Valsalva aneurysm（SVAn）is a very rare clinical entity. We present a 68-year-old female with left SVAn, 5 cm in diameter, compressing the left main coronary artery and causing antero-septal asynergy. She also had massive pericardial effusion, moderate to severe（grade Ⅲ）aortic regurgitation, and mitral regurgitation. One month after pericardial drainage, the patient successfully underwent composite graft replacement of the aortic root, reimplantation of the right coronary artery and suture closure of thin friable left main trunk（LMT）orifice, as well as double coronary artery bypass grafting with bilateral internal mammary arteries to the left anterior descending artery and the diagonal branch. Mitral valve repair was also performed. She recovered uneventfully and remains asymptomatic at 2 years after surgery. To our knowledge, only 13 cases undergoing open heart surgery for left SVAn have been reported in Japan.