三浦 崇, 江石 清行

Takashi MIURA, Kiyoyuki EISHI

長崎大学大学院医歯薬総合研究科　循環制御外科学

Division of Cardiovascular Surgery, Nagasaki University Hospital

キーワード : mitral regurgitation, mitral valve repair, pre-operative echocardiography

僧帽弁形成術は対象疾患が幅広く，その効果と意義が弁置換よりも明白であり，また経験と技術が求められることなどから，患者，外科医の双方にとって魅力的な手技の一つである．その反面，再手術のリスクと責任を背負った手術であることも事実である．再手術は術後1～3年以内の比較的早期に集中し，早期再手術率は5～8％が一般的である．その後は安定し10年後の再手術非発生率は80～95％である．再手術を惹起しやすい病態として活動期感染性心内膜炎，前尖広範囲逸脱があり，原因は不完全修復，縫合部の組織損傷，再弁輪拡大，短縮腱索の再延長，溶血などである．良好な成績を得るためには，超音波検査による逆流のメカニズム同定とそれに応じた精緻な形成手技が必要である．形成手技は切除縫合術を基本手技とし，脆弱な縫合部位はパッチ補強を追加し，逸脱の矯正が終了した時点で完全な弁尖接合を得ることを目指す．また，リングを用いた弁輪形成を追加し，人工弁輪の縫着も丁寧に行う必要がある．特に，切除縫合の際のdehiscence予防は重要である．術中の経食道心エコーは専門家に依頼し厳密に行い，ジェット面積2 cm²以上の遺残逆流は再度検索，処置を行うべきである．入院中の再逆流の発生には誠実に対応し，必要であれば引き続き再手術を決断した方が遠隔期の結果は良好である．今回の特集では，上記の内容に加えて，手術前に外科医が必要としている情報についても述べる．

Mitral valve repair is an attractive procedure for both patients and surgeons because there are many target diseases, its effectiveness and significance are clearer than those of valve replacement, and experience and skill are required. However, the risk of re-operation remains an issue. Re-operation is generally performed 1-3 years after surgery, which is relatively early, with the early re-operation rate being 5-8%. The condition stabilizes thereafter, and re-operation-free rate in the subsequent 10 years is 80-95%. The pathology likely to lead to re-operation includes active infective endocarditis and extensive prolapse of the anterior leaflet, and the cause includes incomplete repair, injury of the sutured segment, re-dilatation of the annulus, re-elongation of the shortened chorda tendineae, and hemolysis. To achieve a favorable outcome, identification of the mechanism of mitral regurgitation by means of echocardiography and selection of an appropriate repair procedure for it are necessary. For the repair procedure, resection and suture are the basic procedure, and it is necessary to achieve complete leaflet coaptation at completion of repair, and to implant the annuloplasty ring carefully. Prevention of dehiscence in resection and suture is especially important. Intraoperative transesophageal echocardiography should only be performed by an experienced sonographer, and residual regurgitation of 2 cm² or more should be re-investigated and treated. Re-regurgitation during the hospital stay should be treated, and re-operation should be performed if necessary, which results in a favorable late outcome. In this feature article, we describe information required by surgeons before surgery, in addition to the issues described above.