Immunologic Aging in Adults with Congenital Heart Disease: Does Infant Sternotomy Matter?

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.

Risk factors for major adverse events late after Fontan palliation.

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.

Hemodynamic phenotype of the failing Fontan in an adult population.

Fontan failure can occur even with normal systolic ventricular function and often in the context of significant liver disease. We hypothesized that Fontan failure is hemodynamically distinct from traditional heart failure and characterized by low systemic vascular resistance (SVR) index and preserved cardiac index. Twenty-seven symptomatic adult Fontan (SAF) patients who underwent catheterization from 2001 to 2011 constituted our study group. Fifty-four predominantly asymptomatic pediatric Fontan (PF) patients who underwent catheterization during the same period were randomly selected to perform a control:case cohort analysis. Clinical comparisons were made between the 2 groups. The adults were more symptomatic than the PF cohort (New York Heart Association classes I and II or III and IV: 48% or 52% [SAF] vs 94% or 6% [PF], respectively, p <0.01). SAF versus PF mean catheterization findings were central venous pressure 18 ± 6 versus 14 ± 3 mm Hg (p <0.01), SVR index 1,680 ± 368 versus 1,960 ± 550 dyn s/cm(5)/m(2) (p = 0.02), and cardiac index 2.7 ± 0.8 versus 2.8 ± 0.7 L/min/m(2) (p = 0.25). By imaging, the SAF cohort demonstrated a greater incidence of abnormal liver texture changes (96% vs 75%, p = 0.04) and nodularity (77% vs 42%, p = 0.02). In conclusion, adult patients with failing Fontan circulation had a lower SVR index and similar cardiac index compared with the pediatric cohort. Liver disease in the adults was more advanced. Our data suggest that Fontan failure is a distinct circulatory derangement with hemodynamic features similar to portal hypertension, albeit with limited ability to augment cardiac output.

Features of portal hypertension are associated with major adverse events in Fontan patients: the VAST study.

BACKGROUND: Chronic congestive hepatopathy is known to cause hepatic fibrosis and portal hypertension in patients post-Fontan operation for single ventricle palliation. The clinical significance of these findings is not clear. We hypothesized that features of portal hypertension would be significantly related to major adverse events. METHODS: A retrospective review of 73 adult and pediatric post-Fontan patients referred for a liver evaluation from 2001 to 2011 was performed. The relationship between features of portal hypertension (VAST score ≥2, 1 point each for Varices, Ascites, Splenomegaly or Thrombocytopenia) and a major adverse event (death, need for transplant, or hepatocellular carcinoma) was examined using logistic regression. RESULTS: 73 post-Fontan patients (30% female, 73% Caucasian, 66% systemic left ventricle (SLV), mean age 24±11 years, mean interval from Fontan 17±6 years) were included in analysis. Features of portal hypertension (VAST score ≥2) were present in 26 (36%), and there were 19 major adverse events: death (n=12), transplant (n=6), and HCC (n=1). A significant relationship was found between VAST score ≥2 and major adverse events (OR=9.8, 95% CI [2.9-32.7]). After adjusting for time since Fontan, SLV, age, hemoglobin and type of failure, VAST score ≥2 remained significant (OR=9.1, 95% CI [1.4-57.6]). CONCLUSION: Fontan patients with features of portal hypertension have a 9-fold increased risk for a major adverse event. Therapies targeted to manage clinical manifestations of portal hypertension, and early referral to heart transplant may help delay major adverse events. Future prospective studies are needed to confirm these findings.