急性大動脈解離をきたし拡大心筋切除も併施した肥大型心筋症の1例

Ascending Aorta Replacement and Extended Myectomy for Acute Aortic Dissection and Coexistent Hypertrophic Obstructive Cardiomyopathy；Report of a Case

左室流出路（LVOT）障害のある肥大型心筋症は閉塞性肥大型心筋症（HOCM）と分類され，狭窄が高度の場合，僧帽弁前尖の収縮期前方運動（SAM）やそれに伴う僧帽弁閉鎖不全症（MR）を合併する．HOCMの症状は，胸痛・呼吸困難・動悸といった胸部症状と，立ちくらみ・眼前暗黒感・失神などの脳症状に2分される．自覚症状がある場合，薬物療法が行われるが，一般に薬剤抵抗性で安静時に50 mmHg以上のLVOT圧

Emergent ascending aortic replacement and extended myectomy were performed in a woman with acute aortic dissection who was aged 63 years. Preoperative transthoracic echocardiography performed in the intensive care unit showed only slight left ventricular outflow tract （LVOT） obstruction, but intraoperative transesophageal echocardiography after induction of anesthesia revealed pericardial effusion, systolic anterior motion （SAM）, and associated mitral regurgitation （MR）. Perioperative SAM and MR are sometimes facilitated under various hemodynamic conditions, but in this case, the left ventricular wall was thick and LVOT appeared to be obstructive by a hypertrophied septum. Structural hypertrophic obstructive cardiomyopathy （HOCM） was diagnosed, and septal myectomy and aortic replacement were performed. After ascending aortic replacement and simultaneous extended myectomy with resection of abnormal band, weaning from cardiopulmonary bypass was smooth without SAM and MR. The patient was discharged from hospital 24 days postoperatively with no major complications. Extended myectomy should be considered if structural HOCM is diagnosed, even when aortic replacement for the dissected aorta is the primary procedure.