緩めの肺動脈絞扼術後にダブルスイッチ手術を行った修正大血管転位症

Double Switch Operation for Congenitally Corrected Transposition of the Great Arteries after the Loose Pulmonary Artery Banding

修正大血管転位症（ccTGA）は先天性心疾患のうち発生頻度が0.5～1％とされる比較的まれな疾患で，心室中隔欠損症や肺動脈弁狭窄症の合併の有無，両心室容量や三尖弁閉鎖不全（TR）の有無，左室機能などを考慮した治療戦略が選択される．左室圧の低下した症例では，肺動脈絞扼術（PAB）を先行することにより左室心筋をトレーニングした後にダブルスイッチ手術（DSO）を行うなど，より計画的な治療戦略が必要となる．左室圧が低い状態が長期に及ぶ年長児の左室トレーニングは効果が不十分で，その後のDSOも低年齢児で行う場合に比して成績は不良とされている1，2）．われわれは，緩めのPAB（loose PAB）後9年の16歳時にDSOを行った症例を経験したので報告する．

Congenitally corrected transposition of the great arteries （ccTGA） is a rare complex cardiac anomaly, where the heart twist and the ventricles are reversed during fetal development. Through a double switch operation （DSO）, the morphologic left ventricle （LV） can be corrected back to pumping blood for systemic circulation. For successful DSO, the morphologic LV may need training with a pulmonary artery banding （PAB） before surgery. There have been reports of early LV failure in patients who underwent PAB training and a DSO, due to rapid pressure loading on the myocardium. We reported a case of DSO in a 16 years old male after prolonged LV training with a loose PAB. He was scheduled for a DSO, due to severe tricuspid regurgitation （TR）. At eight years old, he underwent a loose PAB training with left ventricular pressure to right ventricular pressure ratio （LVp/RVp） of 0.5. After eight years, the LVp/RVp ratio increased to 0.77；he successfully underwent a DSO with good LV function.