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

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.