ABSTRACT
Introduction: Thymectomy is routine during surgery for congenital heart defects to access to the heart. T cells developed in the thymus play a key role in immunity. Individuals with thymectomy in infancy have altered T cell populations suggesting early immunosenescence. Hypothesis: Adults with Congenital Heart Disease (ACHD) who underwent thymectomy in the first year of life have an altered response to influenza vaccination due to T cell immunosenescence. Methods: We recruited ACHD with early thymectomy ≤ 1 year of age (ACHD-ET;n = 12), ACHD and no thymectomy (ACHD-NT;n = 8), and healthy controls (HC;n = 14). Peripheral blood was collected prior to influenza vaccine and 4 weeks following administration. Flow cytometry of T cell subsets and intracellular cytokine staining of CD4 T cells was done following in vitro stimulation with influenza viral antigen. Results: Subject's mean age was 34 ± 10.6 years with no difference between the groups. At baseline, the median (IQR) frequency of naïve CD4 T cells was 24.7% (15.9) in ACHD-ET vs. 43.6% (16.9) in HC (P=0.01). Similarly, naïve CD8 T cells were lower with 37.5% (25.7) in ACHDET vs 62.8% (22.9) in HC (P=0.02). This also resulted in a reciprocal increase in memory CD4 and CD8 T Cells in the ACHD-ET group. The ACHD-NT was not significantly different than the other groups. The frequencies of influenza antigen-specific memory CD4 T cells expressing IFN-γ and TNF-α were significantly increased in post-vaccine blood samples compared to pre-vaccine samples across all 3 groups (P<0.05). Conclusions: ACHD-ET have a smaller population of naïve T cells, suggestive of immunosenescence. Despite this they have an equivalent cytokine response suggesting that early thymectomy does not inhibit the response to vaccination in young adulthood. Our findings support the recommendation that preventative vaccination against pathogens including influenza virus and the newly emerging SARS-CoV-2 should continue to be routinely performed in ACHD.
ABSTRACT
Background: The SARS-Cov-2 virus and the associated Multi-System Inflammatory Syndrome in Children (MIS-C) can cause myocardial injury, cardiac dysfunction, and coronary dilation. This makes echocardiography a key component during clinical evaluation. To improve technician safety, we implemented a protocol utilizing a tablet-based echocardiography (TBE) system to evaluate patients who had active COVID-19 or whose testing was pending. We hypothesized that appropriate clinical evaluations could be completed with TBE while having a shorter exposure time for personnel. Methods: We retrospectively evaluated 35 patients at a tertiary, pediatric hospital between March 2020 and May 2021 who underwent TBE. We compared the TBE findings and duration to comprehensive echocardiograms done on average two weeks later with a traditional machine. A complete study included evaluation of ventricular function, coronary artery diameter, and pericardial fluid assessment. Pro-brain natriuretic peptide (pro-BNP) and troponin-T levels were reviewed. Subjects were divided into two groups based on an elevation in troponin-T as a surrogate for myocardial injury (Trop and Trop ).Results: Eight subjects had cardiac dysfunction with 6/12 being from the Trop group and 2/23 in the Trop group. The mean troponin-T elevation was 0.32 ng/mL. Pro-BNP levels were elevated in all but 1 of the 35 subjects but were ten times higher in the trop group (mean 18,055 vs 1,888 pg/mL;p = 0.001). Three subjects with MIS-C had coronary dilation noted by TBE (2 in Trop and 1 in Trop ) with one persistently dilated at follow up. TBE findings such as coronary dilation or cardiac dysfunction guided medical therapies and no clinically relevant findings were missed when compared to studies at follow up. TBE was on average 29 minutes shorter (41 ± 18 vs 12 ± 5 min;p < 0.001). One patent ductus arteriosus was found by TBE and this was confirmed on repeat imaging. Conclusions: TBE allows for experienced sonographers to limit exposure time to potentially contagious patients and easier decontamination while not compromising essential clinical information. This study shows TBE is a useful tool to effectively evaluate patients during highly contagious viral respiratory outbreaks.