植込み型補助人工心臓治療後の右心不全の現状

Current State of Right Heart Failure after Implantable Ventricular Assist Device

植込み型補助人工心臓（implantable ventricular assist device：iVAD）の日本国内での成績に関して，Japanese registry for Mechanically Assisted Circulatory Support（J-MACS）からの報告では生存率が1年93％，2年90％，4年81％と安定してきている．しかし，三大合併症である神経機能障害，出血，感染の発生率は減少しているものの解決されていない1，2）．また右心不全は，術前両心不全例に対して植込み型左室補助人工心臓（implantable left ventricular assist device：iLVAD）を行うことで右心不全も改善することが多いが，iLVAD後も遷延する例はある．J-MACSの報告からは右心不全回避率は90日95％，1年92％，2年90％，4年84％と報告されている1）．多くがiLVAD後急性期のもので，一酸化窒素（NO）吸入や薬物療法，一時的な右室補助人工心臓（right ventricular assist device：RVAD）で改善する例が多い．

Japanese registry for Mechanically Assisted Circulatory Support （J-MACS） reports on the results of implantable ventricular assist devices （VADs） in Japan show that the survival rates have stabilized at 93％ at one year, 90％ at two years and 81％ at four years. However, the incidence of neurological dysfunction, hemorrhage and infection, the three major complications, has not been resolved, although it has decreased. Right heart failure has also been improved by implantable left VAD （iLVAD） in patients with preoperative biventricular failure. The J-MACS reported right heart failure free rates of 95％ at 90 days, 92％ at one year, 90％ at two years and 84％ at four years. Most cases are in the acute phase after iLVAD and often improve with nitric oxide （NO）, drugs or a temporary right VAD （RVAD）. In Japan, the waiting period for heart transplantation is long due to the shortage of donors, and the period of RVAD support is much longer than in the West. Right heart failure is sometimes observed in the remote period after iLVAD. Severe cases requiring RVAD and biventricular assist device （BiVAD） are treated with early cardiac transplantation in Europe and the United States of America （USA）, while cases requiring long-term BiVAD therapy are extremely rare. Therefore, there are currently no clear standards for the indications and management of RVAD. In this report, we discuss domestic and foreign reports on right heart failure after left VAD （LVAD） and report a valuable case in which RVAD was performed three and a half years after iLVAD in our department, and BiVAD management was required for more than one year for heart transplantation.