Objective: Risk factors for major adverse events late after Fontan palliation are unknown. Prior studies have suggested ventricular function and morphology as important risk factors. The aim of this study is to (1) characterize the late major adverse event profile in adult Fontan patients and (2) identify additional risk factors that may contribute to adverse outcomes. Design and Setting: A retrospective review of all adult patients >15 years post-Fontan seen at a tertiary academic center was conducted. Clinical, laboratory, cardiac data, and abdominal imaging were collected via chart review. Major adverse events (death, cardiac transplantation, or listing) were identified, and timing of events was plotted using Kaplan-Meier methods. Univariate and multivariate logistic regression was used to determine independent predictors of late-term events. Results: A total of 123 adult Fontan patients were identified (mean time post-Fontan 22.4 years [±4.4]). Major adverse events occurred in 19/123 patients (15%). In this 15-year survivor cohort, transplant-free survival rates were 94.6%, 82.9%, and 59.8% at 20, 25, and 30 years postoperation, respectively. Modes of death were Fontan failure with preserved function (4), congestive heart failure with decreased function (2), sudden death (2), thromboembolic event (1), post-Fontan conversion (2), and posttransplant (2). No differences in adverse outcomes were found based on morphology of the systemic ventricle, Fontan type, or systolic ventricular function. On the other hand, features of portal hypertension (OR 19.0, CI 4.7-77.3, P < .0001), presence of a pacemaker (OR 13.4, CI 2.6-69.8, P=.002), and systemic oxygen desaturation (OR 0.86, CI 0.75-0.98, P=.02) were risk factors for major adverse events in the multivariate analysis. Conclusions: In adult Fontan patients surviving >15 years post-Fontan, portal hypertension, oxygen desaturation, and need for pacemaker were predictive of adverse events. Traditional measures may not predict late-term outcomes in adult survivors; further study of the liver's role in late outcomes is warranted.

Thymectomy is performed routinely in infants undergoing cardiothoracic surgery. Children post-sternotomy have decreased numbers of T lymphocytes, although the mechanisms involved and long-term consequences of this have not been defined. We hypothesized that lymphopenia in patients with adult congenital heart disease (ACHD) would be reflective of premature T cell maturation and exhaustion. Adults with ACHD who had sternotomy to repair congenital heart disease as infants (<1 year) and age-matched ACHD patients without prior sternotomy were studied using polychromatic flow cytometry interrogating markers of lymphocyte maturation, exhaustion and senescence. Group differences were analyzed using Mann–Whitney U and Fisher’s exact tests. Eighteen ACHD patients aged 21–40 years participated: 10 cases and 8 controls. Median age at sternotomy for cases was 52 days. Cases and controls were matched for age (28.9 vs. 29.1 years; p = 0.83), gender (p = 0.15) and race (p = 0.62) and had similar case complexity. Cases had a lower mean percentage of cytotoxic CD8 lymphocytes compared to controls (26.8 vs. 33.9 %; p = 0.016), with fewer naive, undifferentiated CD8 T cells (31.0 vs. 53.6 %; p = 0.027). CD8 cells expressing PD1, a marker of immune exhaustion, trended higher in cases versus controls (25.6 vs. 19.0 %; p = 0.083). Mean percentage of CD4 cells was higher in cases versus controls (65.6 vs. 59.6 %; p = 0.027), without differences in CD4 T cell maturation subtype. In summary, ACHD patients who undergo sternotomy as infants exhibit differences in T lymphocyte composition compared to ACHD controls, suggesting accelerated immunologic exhaustion. Investigation is warranted to assess the progressive nature and clinical impact of this immune phenotypic change.