室内リモジリングへのミトラルパンフレット適応: 缺血性ミトラル吐のモデルにおける将来の変化
Miguel Chaput1, Mark D Handschumacher, J Luis Guerrero
1Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Circulation
|September 16, 2009
まとめ
心臓発作後,ミトラル弁の面積は増加しますが,この適応が完全に漏れを防ぐことはできません. この弁の改造を理解することで,不全性ミトラル吐症の新たな治療目標の可能性が生まれます.
科学分野:
- 心臓病学 心臓病学
- 心臓のメカニズム 心臓のメカニズム
- エコーカルディオグラフィー エコーカルディオグラフィー
背景:
- 発血性ミトラル反吐 (IMR) は,心室の歪みから生じ,ミトラル小葉のシストリック・テザリングを引き起こします.
- IMRにおけるリーフレット面積の適応は,測定上の課題のため,十分に理解されていません.
- 以前の研究では,IMR患者における小葉の面積が増加し,反発が少ないと相関していることが示されています.
研究 の 目的:
- IMRを経験する同じ心臓内のミトラ弁領域の縦方向の変化を調査する.
- 時間の経過とともにミトラルバルブ領域の適応が,IMRにおける心室の改造を補償するかどうかを判断する.
主な方法:
- 3Dエコーカルディオグラフィーを利用して,ベースラインの12頭の羊と,下心筋梗塞の3ヵ月後の羊のミトラリーフレット面積を測定しました.
- 治療を受けていない羊 (n=6) と,左心室の膨張を制限する上心部パッチ (n=6) で治療を受けた羊を比較した.
主要な成果:
- 未治療の羊は,左心房の有意な膨張,全身機能不全,および中程度のIMRを示した.
- 治療を受けていない羊では,ダイアストリックミトラル小葉片の総面積が有意に増加した (13.1〜18.1cm2).
- パッチされた羊は,ベースラインと同様の小葉片面積を維持し,心室機能が保たれ,再吐きが最小限に抑えられました.
結論:
- ミトラ弁の面積は,心筋梗塞後の左心室改造とともに増加し,シストリックストレッチとは無関係です.
- このパンフレット面積の増加は,テザリングを完全に相殺し,IMRを防ぐには不十分です.
- 溶解弁の適応メカニズムは,IMRの新たな治療戦略を明らかにする可能性があります.
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