國原 孝

Takashi KUNIHARA

心臓血管研究所付属病院心臓血管外科

Department of Cardiovascular Surgery, The Cardiovascular Institute

キーワード : aortic valve repair, aortic regurgitation, annuloplasty, valve-sparing root replacement, echocardiography

大動脈弁閉鎖不全症や基部拡張病変に対する外科的治療のガイドラインは大動脈弁置換術を想定しているが，形成を目指すならより早い時期が望ましく，心エコー実施医は重要な役割を占める．全ての病態で理論的には形成可能である．Type Iaは上行大動脈置換の適応だが他病変の併存に注意が必要である．Type Ibは弁温存基部置換術の適応確定のため，大動脈基部サイズの正確な測定が必須である．Type Icはannuloplastyの良い適応であるが，各々一長一短がある．External suture annuloplastyは簡便だがventriculo-aortic junctionを縫縮し，external ring annuloplastyは煩雑だがbasal ringを縫縮する．Internal rigid ring annuloplastyは簡便にbasal ringの縫縮が可能だが，硬いリングが近接するデリケートな弁尖に及ぼす影響に懸念が残る．Type Idはパッチ形成術の成績が良好だが，他のジェットが混在すると術前診断は困難である．Type IIは最もポピュラーでcentral plicationが標準術式と言って良く，eccentric jet，effective heightの低下，弁尖のbendingなどで容易に診断可能である．Type IIIは心膜による弁尖延長を要し，心膜自体が再発のリスク因子であり，最もエコー診断が重要であるが，弁尖長は過小評価されやすい．二尖弁では狭窄回避，交連角度調整，cusp bulging回避などにおいて，心エコー実施医が最も活躍すべき場であろう．今後大動脈弁形成が標準化され，ガイドラインが改訂され，より多くの大動脈弁が温存されることが望まれる．

The guideline on surgical intervention for aortic regurgitation or aortic root disease is formulated supposing that aortic valve replacement is the only alternative. As early intervention is advantageous in the case of aortic valve repair, echocardiographers play an important role. Each type can theoretically be repaired. Type Ia can be treated by ascending aortic replacement, but other types can often be combined. Accurate measurement of the root dimension is essential for use of valve-sparing root replacement in type Ib disease. Type Ic is appropriately treated by annuloplasty, but each one has both advantages and disadvantages. External suture annuloplasty is a simple procedure that entails plication of a ventriculo-aortic junction, whereas external ring annuloplasty is technically demanding but involves plication of a basal ring. Internal rigid ring annuloplasty allows simple plication of a basal ring, but the concern remains with regard to the effect of a rigid ring in close proximity to the delicate aortic cusps. The clinical outcomes of patch repair for type Id lesions is favorable; however, their preoperative diagnosis is difficult in the presence of multiple jets. Type II, the most common type, can easily be repaired by central plication of the cusp. It can easily be diagnosed by eccentric jet, lower effective height, and cusp bending. Type III requires cusp extension with the pericardium. However, use of the pericardium has emerged as a risk of failure. Thus, echocardiographic diagnosis is very important; however, cusp height tends to be underestimated. In the diagnosis of bicuspid valve, echocardiographers play the most important role in avoiding stenosis, arranging commissure orientation, and avoiding cusp bulging. We hope that as many aortic valves as possible will be preserved by standardizing aortic valve repair and revising the guideline.