Neutrophil and T Cell Functions in Patients with Congenital Heart Diseases: A Review

Association Between Postoperative Lymphocyte Count and the Occurrence of Infections After Pediatric Cardiac Surgery With Cardiopulmonary Bypass

OBJECTIVE

The objective of this study was to evaluate the association between the minimal count of lymphocyte (Ly_Min) after cardiac surgery with cardiopulmonary bypass and the occurrence of infections within the first 30 postoperative days (POD).

METHODS

From a local European Congenital Heart Surgeons Association (ECHSA) database, all cardiac surgeries with cardiopulmonary bypass in children under 18 years old between January 2014 and December 2021 were eligible. Infections occurring within 30 POD were prospectively recorded according to ECHSA definitions, and classified into sepsis, pneumonia, wound infection, mediastinitis or endocarditis. For each surgery, Ly_Min was collected during the first 2 POD and the optimal threshold for predicting infection was chosen using receiver operating characteristic curve analysis. Univariate and multivariate logistic regression analyses were performed to identify variables associated with the risk of infection.

RESULTS

Of 1428 surgeries conducted over the 8-year period, 111 (8%) were complicated by at least 1 infection, including pneumonia (n = 45), wound infection (n = 41), sepsis (n = 24), mediastinitis (n = 20) and endocarditis (n = 3). Mean Ly_Min in the first 2 POD was lower in the infected group compared with the noninfected group (1.32 ± 0.81 vs. 1.81 ± 1.05 × 109/L, P < 0.001). After adjusting for confounders, Ly_Min <1.105 × 109/L within the first 1 POD was independently associated with an increased risk of postoperative infections (adjusted odds ratio = 1.75, 95% confidence interval: 1.10-2.79, P = 0.019).

CONCLUSIONS

In this large single-center cohort of pediatric cardiac surgeries, Ly_Min during the first 2 POD was associated with the development of infections within 30 days after cardiopulmonary bypass.

From heart to gut: Exploring the gut microbiome in congenital heart disease

Congenital heart disease (CHD) is a prevalent birth defect and a significant contributor to childhood mortality. The major characteristics of CHD include cardiovascular malformations and hemodynamical disorders. However, the impact of CHD extends beyond the circulatory system. Evidence has identified dysbiosis of the gut microbiome in patients with CHD. Chronic hypoxia and inflammation associated with CHD affect the gut microbiome, leading to alterations in its number, abundance, and composition. The gut microbiome, aside from providing essential nutrients, engages in direct interactions with the host immune system and indirect interactions via metabolites. The abnormal gut microbiome or its products can translocate into the bloodstream through an impaired gut barrier, leading to an inflammatory state. Metabolites of the gut microbiome, such as short-chain fatty acids and trimethylamine N-oxide, also play important roles in the development, treatment, and prognosis of CHD. This review discusses the role of the gut microbiome in immunity, gut barrier, neurodevelopment, and perioperative period in CHD. By fostering a better understanding of the cross-talk between CHD and the gut microbiome, this review aims to contribute to improve clinical management and outcomes for CHD patients.

Immunodeficiency is prevalent in congenital heart disease and associated with increased risk of emergency admissions and death

AIMS

To provide population-based data on the prevalence and clinical significance of immune deficiency syndromes (IDS) associated with congenital heart disease (CHD).

METHODS AND RESULTS

Utilizing administrative German Health System data the prevalence of increased susceptibility to infection (ISI) or confirmed IDS was assessed in CHD patients and compared with an age-matched non-congenital control group. Furthermore, the prognostic significance of IDS was assessed using all-cause mortality and freedom from emergency hospital admission. A total of 54 449 CHD patients were included. Of these 14 998 (27.5%) had ISI and 3034 (5.6%) had a documented IDS (compared with 2.9% of the age-matched general population). During an observation period of 394 289 patient-years, 3824 CHD patients died, and 31 017 patients experienced a combined event of all-cause mortality or emergency admission. On multivariable Cox proportional-hazard analysis, the presence of ISI [hazard ratio (HR): 2.14, P < 0.001] or documented IDS (HR: 1.77, P = 0.035) emerged as independent predictors of all-cause mortality. In addition, ISI and confirmed IDS were associated with a significantly higher risk of emergency hospital admission (P = 0.01 for both on competing risk analysis) during follow-up.

CONCLUSION

Limited immune competence is common in CHD patients and associated with an increased risk of morbidity and mortality. This highlights the need for structured IDS screening and collaboration with immunology specialists as immunodeficiency may be amenable to specific therapy. Furthermore, studies are required to assess whether IDS patients might benefit from intensified antibiotic shielding or tailored prophylaxis.

Hematological indices in pediatric patients with acyanotic congenital heart disease: a cross-sectional study of 248 patients

Background

Congenital heart disease CHD is a significant cause of mortality and morbidity in children worldwide. Patients with congenital heart disease may develop hematological problems, including thrombocytopenia and neutropenia. In addition, several studies indicate the higher frailty of patients with CHDs to infections and malignancies. Nevertheless, the mechanisms of immune system changes in these patients have remained in the shadow of uncertainty. Moreover, very few studies have worked on cytopenia in CHD. This study has assessed the frequency of thrombocytopenia, neutropenia, lymphopenia, and anemia in pediatric patients with acyanotic congenital heart disease ACHD prior to open-heart surgery.

Methods

This cross-sectional study was handled in the Pediatric Cardiology Clinic, Tehran University of Medical Sciences, during pre-operation visits from 2014 till 2019. Two hundred forty-eight children and adolescents with acyanotic congenital heart disease before open-heart surgery met the criteria to enter the study.

Results

A total of 191 (76.7%) patients with Ventricular Septal Defects (VSD), 37 (14.85%) patients with Atrial Septal Defects (ASD), and 20 (8.11%) patients with Patent Ductus Arteriosus (PDA) were enrolled in this study. The median age was 23.87 months. Thrombocytopenia and neutropenia were found, respectively, in 3 (1.2) and 23 (9.2%) patients. Hemoglobin level and lymphocyte count were significantly lower in patients with neutropenia than patients with normal neutrophil count (P value = 0.024 and P value = 0.000). Significant positive correlations were found between neutropenia and anemia. There were no correlations between neutrophil count and Platelets. Also, anemia was found in 48 patients (19.3%). The study also found a statistically significant correlation between the co-existence of VSD and neutropenia in the patients (P value = 0.000).

Conclusion

Although most were mildly neutropenic, there was a significant correlation between neutropenia and Ventricular Septal Defect compared to PDA and ASD groups. Regarding the importance of neutropenia to affect the prognosis of congenital heart defects in infections, it is important to consider further studies on the status of immune system function in these patients.