右小開胸アプローチ下僧帽弁形成術における人工腱索長をより簡便に決定する方法

Tips for Use of Chordal Guide System for Easy Adjustment of Appropriate Artificial Chordae Length in Patients Undergoing Minimally Invasive Mitral Valve Repair

僧帽弁形成術において，人工腱索はあらゆる状況に対応でき，広く用いられている．人工腱索再建では，適切な長さや本数の決定，縫着部位の決定にさまざまなバリエーションがあり，種々の工夫や術式が報告されているが，各方法によりさまざまな術式があり1～9），一定の方法はない．特に人工腱索の長さの決定では，リファレンスの同定や長さの測定に熟練を要する．低侵襲心臓手術（MICS）である右小開胸アプローチの僧帽弁形成術においては，限られた視野のため人工腱索の長さや部位の決定に難渋する場合があり，人工腱索の長さが簡便に決定できたら，その汎用性が広がり適応拡大も可能となる．Memo 3D Rechord（LivaNova社，London）は，人工弁輪の後尖側にあらかじめ縫着された黄色い輪となった糸を利用して人工腱索の長さを決定する新しいリングである8）．われわれは，MICS僧帽弁形成術におけるMemo 3D Rechordを用いた人工腱索至適長決定において，簡便かつ再現性のある縫着方法を行っているので供覧する．

Objectives：In patients who require minimally invasive mitral valve repair （MICS-mitral）, it is difficult to determine the appropriate length of artificial chordae, position, and number of artificial chordae. The Memo 3D Rechord, a complete prosthetic ring associated with a temporary chordal guide system comprised of yellow loops that function as a reference guide for automatically determining the height of neo-chordae. We sought to evaluate our tips for use of this system.

Methods：Five patients （1 male, mean 68 years old） who underwent MICS-mitral using artificial chordae with the Memo 3D Rechord were evaluated. Prior to surgery, we assessed the prolapse position using 3-dimensional （3D） echocardiography to decide the number and positions of the artificial chordae. Polytetrafluoroethylene （PTFE） sutures were passed through the papillary muscles and the free margin of the prolapsed leaflet, then appropriate positioning of the PTFE chordae was performed using a saline test. The PTFE chordae were passed through the loops and the free margin of the prolapsed leaflet was brought to the posterior annulus. Then, the PTFE sutures were tied and the temporary loop system removed.

Results：All patients had posterior leaflet prolapse. The number of the artificial chordae was 2 in 3 patients, and 1 in 2. The base of the artificial chordae was attached to the anterior papillary muscle in 3 patients and posterior in 4. Additional indentation closure was required in 1 patient. All mitral valve repairs were performed successfully. Postoperative echocardiography mitral regurgitation （MR） grade was trivial in 5.

Conclusions：Using our technique, it was possible to decide the appropriate length and position of the artificial chordae and MICS-mitral for leaflet prolapse with the Memo 3D Rechord is a simple and reproducible method.