収縮性心膜炎様の血行動態を呈した重症三尖弁閉鎖不全症の一例

A Case of the Severe Tricuspid Regurgitation Showing the Hemodynamics Resembling Constrictive Pericarditis

要旨　症例は62歳女性．52歳時に子宮筋腫の手術をした際に心房細動を指摘され，近医にて経過観察されていた．61歳時に下肢の浮腫が出現し，ダイアート(Azosemide)を開始され，浮腫は軽減したが，翌年に再び下肢の浮腫が著明となり，労作時の呼吸苦も強くなったため，精査目的にて2010年11月7日当院入院となった．

　胸部CTでは明らかな心膜の石灰化は認めなかったが，肥厚を認めた．また，心臓カテーテル検査では，冠動脈に有意狭窄はなく，右心カテーテルにて，dip and plateau所見を認めた．拡張期心腔内圧は5mg以内，右室内圧は最大で30mmHg程度，奇脈を認め，収縮性心膜炎を疑わせる所見を認めた．血液データ上も，BNPは比較的低く，ノルアドレナリンの上昇を認めた．しかし，肺動脈圧は29/14(23)とやや高い程度であったにもかかわらず，エコーにて左室より右室が拡大していること，心室中隔の特徴的な運動がないことより，収縮性心膜炎としては典型的ではなかった．心臓MRIでは，心臓周囲全周性に1cm以上の脂肪組織が認められた．典型的ではないが，収縮性心膜炎と診断し，心膜剥離術＋TAP(tricuspid annuloplasty)の方針となった．しかし，術中所見では心膜肥厚は認めず，TAP＋左心耳切断を行った．

　重症三尖弁閉鎖不全症(TR)が収縮性心膜炎類似の血行動態となる興味深い症例であり，その成因につき，文献的考察を加え報告する．

　A 62-year-old woman with a 10-year history of chronic atrial fibrillation developed edema in both lower limbs in 2009. She was treated with an oral diuretic agent, azosemide, but the edema worsened, despite a dose increase. The patient then developed exertional dyspnea, and was therefore admitted for examination in November 2010.

　Echocardiography revealed respiratory variation in the mitral E wave by more than 25%, and cardiac catheterization indicated normal right systolic pressure and similar diastolic pressures, with a dip and plateau pattern, in both ventricles. Although no calcification was observed in the pericardium, a 1-cm thick layer of adipose tissue surrounded the heart. The findings of coronary angiography were unremarkable. The brain natriuretic peptide level was relatively low at 219pg/ml, and the noradrenaline level was elevated at 864pg/ml.

　These data suggested possible constrictive pericarditis complicated with tricuspid regurgitation, despite the atypical manifestations of constrictive pericarditis. Decortication of the pericardium and tricuspid valvuloplasty were planned. During surgery, we confirmed the absence of abnormality in the pericardium and therefore only performed tricuspid valvuloplasty.

　Interestingly, severe tricuspid regurgitation resembles constrictive pericarditis in terms of hemodynamics, and therefore, we describe this case and review the relevant literature.