3．僧帽弁置換術後左室後壁破裂

Left Ventricular Rupture after Mitral Valve Replacement

2018年の日本胸部外科学会の学術集計では，僧帽弁手術は11,000例に施行され，65％において弁形成術，35％において人工弁置換術が行われた．そのうち生体弁は全体の25％，機械弁が全体の10％であり，30日死亡率は単独僧帽弁形成術が1.0％に対して単独僧帽弁置換術が4.3％であった．低侵襲心臓手術（MICS）など技術的な発展も認めるものの，一定頻度で合併症は起こりうる．僧帽弁手術の重大な合併症として左室破裂があげられるが，死亡原因の18％を占めており，その致死率は高く，避けたい合併症である1）．

Ventricular rupture after mitral valve surgery is rare but a serious complication associated with high mortality rate. Of the 2,338 patients who underwent mitral valve surgery, 8 patients （0.7％） suffered from left ventricular rupture in our institution. All developed left ventricular rupture after mitral valve replacement and 3 patients （37.5％） died within 30 days. To prevent left ventricular rupture, preservation of the mitral loop, appropriate valve sizing, and perioperative hemodynamic management to unload ventricular pressure are needed. Surgical repair for left ventricular rupture should be performed under cardiac arrest. Combination of external approach and endoventricular repair is recommended but epicardial tissue sealing may be an only option for patients with friable ventricular muscles and undetermined location of ruptured site. Use of intraaortic balloon pumping （IABP）, percutaneous cardiopulmonary support （PCPS） and Impella are also important technique to unload left ventricular pressure and to maintain systemic hemodynamics.