Impact of Thymectomy on Immunity in Infants After Cardiac Surgery

Summary

Heart surgery in infants typically involves complete removal of the thymus gland to improve access to the heart. However, the thymus plays a key role in developing the immune system in early childhood, especially in the production and maturation of T lymphocytes, which help the body defend itself against infections. The THYMIC study tests the hypothesis that partial removal of the thymus (partial thymectomy) during heart surgery may better preserve the child's immune function compared to total removal (complete thymectomy). The goal is to determine whether this conservative surgical approach could reduce the risk of immune system impairment and infections in the months following surgery. This is a prospective, interventional, single-center study conducted at CHU de Nantes, involving 3 groups of infants: * One group undergoing heart surgery with complete thymectomy; * One group undergoing heart surgery with partial thymectomy; * One control group undergoing heart or non-heart surgery without thymus removal. All infants enrolled will have two blood tests: one taken during their surgery and one taken one year later. These blood tests will quantify immune cells (T, B, NK cells), levels of antibodies, and vaccine responses. Parents will also be asked to fill out a questionnaire to record any infections their child experiences during the year after surgery. By comparing the immune responses and infection rates among the groups, the researchers hope to better understand the long-term effects of thymectomy in infants. The results could support future recommendations to preserve part of the thymus when possible during heart surgery. Participation in the study does not change the medical or surgical care of the child. The decision to perform a partial or complete thymectomy is made by the surgeon based on the child's anatomy. The additional blood samples are small in volume and follow current safety regulations.

Eligibility

Inclusion Criteria:

* \- Children aged between 0 and 6 months;
* Born at a gestational age \> 37 weeks' gestation;
* With an indication for cardiac surgery under CEC at Nantes University Hospital;
* Cardiopediatric follow-up planned at Nantes University Hospital;
* Written agreement signed by legal guardians to participate in the study.

For the control groups:

* Control group A (cardiac surgery without thymectomy):

  * Children aged between 0 and 6 months of age;
  * Born at a gestational age \> 37 SA;
  * Indicated for thoracotomy cardiac surgery at Nantes University Hospital;
  * Cardiopediatric follow-up planned at Nantes University Hospital;
  * Written agreement signed by legal guardians to participate in the study.
* Control group B (non-cardiac surgery)

  * Children aged between 0 and 6 months;
  * Born at a gestational age \> 37 SA;
  * Indicated for non-cardiac surgery (ENT or visceral surgery at Nantes University Hospital);
  * Planned follow-up surgery at Nantes University Hospital;
  * Written agreement signed by legal guardians to participate in the study.

Exclusion Criteria :

* Gestational age \< 37 SA;
* With a history of cardiac surgery under ECG;
* And/or with heart disease requiring further surgery within 12 months of the 1st surgery (e.g. pulmonary cerclage, systemic pulmonary anastomosis).
* And/or a history of partial or complete thymectomy;
* Receiving long-term immunosuppressive treatment;
* Post-operative follow-up planned in a hospital other than Nantes University Hospital, or moving house planned during the follow-up period;
* parental refusal.

Exclusion Criteria:

* \- Gestational age \< 37 SA;
* With a history of cardiac surgery under ECG;
* And/or with heart disease requiring further surgery within 12 months of the 1st surgery (e.g. pulmonary cerclage, systemic pulmonary anastomosis).
* And/or a history of partial or complete thymectomy;
* Receiving long-term immunosuppressive treatment;
* Post-operative follow-up planned in a hospital other than Nantes University Hospital, or moving house planned during the follow-up period;
* parental refusal.

Conditions4

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