12. 左心低形成症候群におけるFontan手術―よりよいFontan循環確立のために

Fontan Procedure in Hypoplastic Left Heart Syndrome：for Better Establishment of Fontan Circulation

左心低形成症候群に対しては，本邦においてこの10年で両側肺動脈絞扼術の概念がより積極的に導入され，新生児早期のNorwood手術を回避し，Blalock-Taussig（BT）シャントより拡張期圧の維持ができる右室肺動脈導管（RV-PAシャント）を用いたNorwood手術を行うことで，Norwood手術の成績が向上した．それにより次のstageⅡであるGlenn手術から最終手術のFontan手術に到達する症例が増加した．本稿では，左心低形成症候群において，段階的治療を行い最終手術のFontan手術に到達する中で，よりよいFontan循環を成立させることを目標として，再手術を含めた治療のポイントについて記す．

Recently, the number of patients with hypoplastic left heart syndrome reaching the final stage of Fontan operation is increasing due to the systematization of staged therapies including bilateral pulmonary artery banding. However, in case, the systemic and pulmonary circulatory pathways initially formed by the Norwood procedure are not always sufficient to obtain a good Fontan circulation. In particular, depending on the method of reconstruction of the aortic arch, aortic re-coarctation may result in increased ventricular afterload. Furthermore, inadequate aortopulmonary space causes pulmonary artery stenosis, which increases the resistance of the pulmonary artery. In addition, tricuspid regurgitation and increased collateral circulation due to the synergistic effects of multiple reoperations and cyanosis can worsen cardiac function due to increased volume load and further increase pulmonary vascular resistance, preventing the establishment of a good Fontan circulation. In order to resolve these factors before Fontan operation and establish a better Fontan circulation, it is important to develop a comprehensive treatment strategy as well as a step-by-step surgical treatment strategy.