The authors of this study sought to inform their hypothesis that patients with congenital heart disease (CHD) had lower T-cell receptor excision circles (TRECs) than the general population, and low TREC levels in CHD patients are associated with infections leading to hospitalization.

Five hundred and seventy-five patients with a diagnosis of structural CHD born between October 2011 and April 2016 were enrolled in this study. They were recruited from the two major Connecticut children’s hospitals, Connecticut Children’s Medical Center and Yale-New Haven Children’s Hospital, which are the two hospitals in the state that help treat CHD.

This was a retrospective cohort study performed as a collaboration between the two hospitals and the statewide Connecticut Newborn Screening Program. The patients’ corresponding TREC levels were paired with their medical data from a retrospective chart review with a focus on demographics, patient characteristics, and hospitalizations for infections. General population data on TREC level was collected on 37c101 newborns born between January 1, 2016 and December 31, 2016, in Connecticut.

The 575 patients enrolled in the study accounted for 83% of the children with CHD born at one of the two hospitals. Premature births prior to 37 weeks’ gestation occurred in 117 subjects, and 86 subjects had an identified genetic syndrome, with an additional 11 suspected to have a genetic syndrome. The median TREC level for those with CHD was significantly lower than the general population (180.2 copies/µL vs 312.5 copies/µL; P < .001). The levels in preterm patients with CHD were lower than the term patients with CHD (140.8 copies/µL vs 200.4 copies/µL; P < .001). When assessing hospitalization rate, the CHD infants who were hospitalized for infection had a significantly lower median TREC level than those CHD patients who were not admitted (143 copies/µL vs. 186.7 copies/µL; P < .01); however, when the study was controlled for prematurity, the term CHD infants requiring hospitalization did not have significantly lower TREC levels compared with term CHD infants not requiring hospitalizations.

In this study, subjects diagnosed with CHD were found to have significantly lower TREC levels when compared with the general population. In addition, CHD participants with prematurity were significantly lower in TREC level compared with term CHD patients. Finally, the study further solidified that prematurity was a significant factor in not only TREC level but the association in hospitalization of CHD infants.

Infection leading to hospitalization can be detrimental for patients with CHD. This risk stratification by TREC level and prematurity will allow us to identify early at-risk CHD patients and change management leading to improved long-term care and survival.