Prospective randomized trial of azathioprine in cryopreserved valved allografts in children

Background. The purpose of this study was to prospectively assess the effec ts of azathioprine on the humoral immune response to HLA alloantigens and a llograft function in children receiving cryopreserved valved allografts. Methods. We randomized 13 children to receive azathioprine or not to receiv e azathioprine (controls) after receiving a cryopreserved valved allograft. Azathioprine patients received intraoperatively 4 mg/kg of azathioprine an d 2.0 +/- 0.5 mg/kg once daily for 3 months after operation. Panel reactive antibodies against HLA class I and class II alloantigens were measured bef ore, 1 month, and 3 months after operation. Results. Panel reactive antibodies were not significantly different between the azathioprine and control groups before (0.0% +/- 0% versus 1.6% +/- 1% ), 1 month (59% +/- 17% versus 71% +/- 12%), or 3 months (84% +/- 15% versu s 96% +/- 1.3%) after operation. There were no differences in degree of all ograft valve stenosis between azathioprine (31.5 +/- 26 mm Hg, 13.4 +/- 7 m onths postoperatively) and control groups (25.4 +/- 11 mm Hg, 17.2 +/- 10 m onths postoperatively) or allograft valve insufficiency. Conclusions. Azathioprine does not significantly decrease the immune respon se to HLA alloantigens or affect the function of cryopreserved valved allog rafts used in children to repair congenital heart defects. (Ann Thorac Surg 2001;71:43-8) (C) 2001 by The Society of Thoracic Surgeons.