Relationship of thymic changes and complications after congenital heart surgery

Background The true role of thymic function in children with congenital heart defects is largely unknown. Aim To study the possible role of thymic CD3 (T-lymphocyte marker) and CD20 (B-lymphocyte marker) expression and thymic histopathological changes in complications after surgery for congenital heart defects. Methods Between January and July 2014, thymic tissue samples were obtained from 13 (69% male, 31% female, mean age 10.9 ± 2 years) of 25 Iraqi patients who underwent open heart surgery with partial thymectomy for correction of congenital heart defects. The samples were evaluated for thymic expression of CD markers (CD3 and CD20) and histopathological changes. For up to 6 months after surgery, data on complications were collected from each patient, including wound infection, cardiac arrhythmias, heart failure, rehospitalization, chest infection, and death. Results The prevalence of thymic hypoplasia was 15% and it occurred more frequently in patients with absent thymic CD3 expression ( p = 0.005). Only wound infection ( n = 2) and atrial fibrillation ( n = 1) comprised the postoperative complications in our patients. Absence of thymic CD20 expression correlated significantly with postoperative complications and obstructive cardiac defects ( p = 0.04), whereas no significant correlations were found between thymic hypoplasia with CD3 expression and postoperative complications ( p > 0.05). Conclusion Patients with absent thymic CD20 expression had significantly more postoperative complications and cardiac obstructive defects than those with positive CD20 expression.