乳児特発性僧帽弁腱索断裂に対するsupra-annular僧帽弁置換術

Supra-annular Mitral Valve Replacement Using a Composite Valve for an Infant with Acute Rupture of Chordae Tendineae

特発性僧帽弁腱索断裂は，咳や発熱などの前駆症状後に急性循環呼吸不全を引き起こす，高い死亡率と重篤な合併症をきたしうる疾患である1）．広範な急性腱索断裂による重度僧帽弁機能不全に対して弁形成術が困難な場合でも，弁輪-人工弁サイズミスマッチのため，乳児期の僧帽弁置換術（MVR）は容易ではない2～5）．われわれは，特発性僧帽弁および三尖弁腱索断裂により急性循環虚脱をきたした6ヵ月児に，短い18 mm径ePTFEに機械弁（17 mm SJM Regent：St. Jude Medical社）を縫着したcomposite弁を用いてsupra-annular MVRを施行し救命できたので報告する．

Acute rupture of the chordae tendineae of the mitral valve could lead to severe mitral regurgitation and circulatory collapse in infants. Mitral valve replacement may be often challenging because of the valve-annulus size mismatch in small infants when mitral valve repair cannot be accomplished. We present an infant with acute massive rupture of the chordae tendineae of the mitral valve who successfully underwent supra-annular mitral valve replacement using the short composite valve of an expanded polytetrafluoroethylene （ePTFE） graft and a mechanical valve. His mechanical valve has been functioning without complications such as thrombosis and pulmonary venous obstruction for 20 months after surgery. This technique could be helpful even infants with acute rupture of the chordae tendineae of the mitral valve whose left atrium may not be dilated.