寒冷凝集素陽性患者の重症大動脈弁閉鎖不全症に対する大動脈弁置換術の1例

Aortic Valve Replacement in a Patient with Cold Agglutinins：Report of a Case

はじめに　寒冷凝集素はIgMを基本とした冷式自己抗体であり，寒冷曝露により赤血球に結合し補体を介した溶血を生じうる．人工心肺下手術では低体温に伴う赤血球凝集，溶血リスクが問題となる．われわれは寒冷凝集素陽性患者の重症大動脈弁閉鎖不全症に対する開心術を経験したので報告する．

Cold agglutinins are a rare autoimmune hemolytic disorder in which immunogloburin （Ig） M antibodies bind to red blood cells at low temperatures, potentially causing hemagglutination and complement-mediated hemolysis during cardiac surgery under hypothermic cardiopulmonary bypass （CPB）. We report a 73-year-old woman with severe aortic regurgitation and positive cold agglutinin （titer 1：512, critical temperature 30 ℃）. To avoid intraoperative hemagglutination, normothermic CPB was performed with a minimum rectal temperature of 34.7 ℃. Warm blood cardioplegia （34 ℃） with increased potassium concentration was used for myocardial protection. The postoperative course was uneventful without hemolytic or thrombotic complications. This case demonstrates that normothermic CPB with warm cardioplegia can be safely applied in patients with cold agglutinin positivity when the critical temperature is above the target intraoperative temperature.