僧帽弁形成術およびMAZE術後遠隔期に難治性心不全を発症した1例

Refractory Heart Failure due to a Late Complication after Mitral Valvuloplasty and MAZE Surgery：A case report

要旨

　患者は65歳，男性．重症僧帽弁閉鎖不全に伴う心房細動にて加療されていたが，63歳時に度重なる心不全のため僧帽弁形成術を施行，併せて心房細動に対しMAZEの手術も施行した．術後一時的な心機能の改善を認めたが，1年後より徐々に利尿剤を必要とする慢性心不全へと移行．その後心不全の急性増悪にて入院したが，入院時血漿ANP値は比較的低値であった．十分量の利尿剤やカテコラミンの投与に対する反応は悪く，αヒト心房性ナトリウム利尿ペプチド(αhANP)投与後に著しい利尿が得られた．経胸壁心エコーを用いた評価では各弁に臨床上問題となる閉鎖不全はなく，また電気生理学的検査にて洞調律の維持も確認された．安定期ではあるがSwan-Ganzカテーテルを用いた薬剤効果判定でαhANPの有効性が確認できた．これらのことから術式に伴う遠隔期内因性ANPの分泌低下が心不全の発現に関与していたと考えられた．

Summary

　The patient, a 65-year-old male, had been treated for severe mitral valve regurgitation accompanied by chronic atrial fibrillation. He had undergone mitral valvuloplasty and MAZE surgery for atrial fibrillation at the age of 63, because of repeated episodes of acute heart failure. Cardiac function improved transiently immediately after surgery,but it deteriorated gradually. Finally, diuretics were required one year after surgery. The patient was re-hospitalized due to acute deterioration of heart failure, and poor response to large doses of diuretics or catecholamines. However, α human natriuretic peptide (αhANP) proved very effective for diuresis. Echocardiography revealed no regurgitation in the valves including the mitral valve, and sinus rhythm was confirmed by electrophysiological studies. Pharmacological evaluation with Swann-Ganz catheter, which was performed following stabilization of the patient's condition, demonstrated the efficacy of αhANP. These findings suggested that the exhaustion of endogenous ANP may play an important role in the progression of heart failure, even in the chronic phase after MAZE surgery.