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第84回東京女子医科大学学会総会 平成30年9月29日(土) 東京女子医科大学弥生記念講堂

Article, 信州医学雑誌 65(4): 203-210(2017)

Surgical treatment for heart failure includes coronary artery bypass grafting to ischemic heart disease, valvular disease surgery such as mitral valvuloplasty, left ventricular restoration, ventricular assist device (VAD), and heart transplantation. In addition, HeartSheet which is regenerative medicine using autologous skeletal myoblast sheets has been started from the spring of 2016. Formal insurance reimbursement of implantable LVAD was obtained in April 2011, and the life prognosis of patients with severe heart failure improved markedly. However, the indication for implantable LVAD is limited to bridge use for heart transplantation. Implantable LVAD cannot be implanted in patients over 65 years old under health insurance because the adaptive age of heart transplantation in Japan is under 65 years old. It is a problem that the indication of implantable LVAD is identical to that of heart transplantation. Clinical trial of destination therapy is in progress for the purpose of optimizing the implantable LVAD indication. I strongly pray that VAD treatment including destination therapy (DT) and transplant medical treatment based on good intentions will be accepted socially as general treatment.

症例は51歳男性。感冒症状で発症し前医を受診した。心電図所見等から急性心筋梗塞を疑われ緊急冠動脈造影を施行されたが，有意病変を認めず急性心筋炎の診断で同日当院へ緊急搬送された。来院時循環虚脱状態であったため直ちに挿管し，経皮的心肺補助装置（percutaneous cardiopulmonary support:PCPS）と大動脈内バルーンパンピングを導入した。３日間のPCPSによる呼吸循環補助にもかかわらず心不全，多臓器不全が進行したため，両心補助人工心臓（ventricular assist device: VAD）を導入した。以後，状態は安定し術後38日目に右心VADから離脱，術後64日目には血液透析からも離脱したが，左心機能は回復せず左心VADに依存する状態となった。術後７か月目に移植登録を行いVAD装着下での移植待機となったが，術後631日目（入院後634日目）に広範な脳出血で失った。本症例は当院で初めてのVAD導入患者であり，その治療過程で，担当医である心臓外科医，循環器内科医を中心として，CCU/病棟看護師，急性重症患者看護専門看護師，皮膚排泄ケア認定看護師，臨床工学士，理学療法士/理学作業士，精神科医/臨床心理士，社会福祉士，薬剤師，管理栄養士，感染制御部からなる治療チームが形成されてゆき，多業種間の垣根をこえたチーム医療の結果，長期生存を得ることができた。当院における今後の重症心不全治療の方針を具体化したという点で意義があると思われるので報告する。

補助人工心臓（ventricular assist device：以下VAD）は，機能の低下した心臓のポンプ機能の一部もしくは大部分を代行して，心不全患者の全身の循環を維持することを目的とする．本邦では1980 年代初めからVAD の臨床応用が開始され，1994 年には世界に先駆けて保険収載されるに至った．その後，2011 年春からは，日本で開発された植込型左心室補助人工心臓（left ventricular assist device：以下LVAD）であるEVAHEART 等が臨床使用可能になったが，それまでは30 年前に開発された東洋紡製国立循環器病センター（国循）型VAD（現在はニプロVAD）が実質的に唯一長期臨床使用の可能なVAD であった．本邦 での植込型LVAD の適応は心臓移植への橋渡し（bridge to transplantation : BTT）に限定されているが，現在，急速な普及をみている．本邦のLVAD の臨床成績は世界的にも突出して優れており，更なる向上をめざし，心臓移植代替治療としての永久植込み治療（destination therapy : DT）の臨床導入が課題である．

Recently much progress has been made in mechanical support of the failing heart, ventricular assist device （VAD） is the most currently useful technique. In this report, the effect of VAD as a mechanical support system on profound cardiac failure was studied experimentally. Thirty adult mongrel dogs, divided into 3 groups, were prepared for normothermic global is- chemia （NGI）. In groupI （n=10）, no mechanical support was carried out after NGI, groupII （n= 10）, leftVAD was performed for 3 hours, then weaned and observed for 1 hour, groupIII （n=10）, biVAD was performed for 3 hours, then weaned and observed for 1 hour. NGI was induced by aortic cross clamping for 20 minutes under cardiopulmonary bypass （CPB）. After the aorta was undamped, all dogs were weaned from CPB, then VAD was commenced, except for group I. Data sampling was performed at Pre, CPBoff （weaned from CPB）, VAD1h （VAD used for 1 hour）, VAD2h, VAD3h and VADoff1h （weaned from VAD and observed for 1 hour）. In groupI, all dogs died within 1.5 hours after CPB off. The bypass ratio in groupII was 58.9± 10.1% and that in groupIII was 60.2±16.5%L（Left） VAD and 79.6±10.2%R（Right） VAD. LAP （mean left atrial pressure） was significantly reduced during the use of VAD. RAP（mean right atrial pressure） was significantly reduced during VAD, and there was no significant difference between group II and group III. RVSWI（Right ventricular stroke work index） in group III was significantly lower than that in group II. RV%SS（Right ventricular %systolic shortening） in group III was significantly higher than that in groupII. PaO? was moderately diminished during the use of VAD and that in groupIII was significantly lower than that in group II at VAD3h. In these experimental studies, the following conclusions were obtained. Recovery from cardiac failure in the right heart system was better than that in the left heart system. The effect of VAD in treatment of cardiac failure would be to decrease the cardiac performance due to atrial decompres- sion. RVAD was useful for the treatment of right heart failure, however, overflow may cause hypoxemia due to pulmonary capillary leak syndrome. In conclusion, these results indicate that VAD is one of the most useful systems in the treatment of profound cardiac failure.