Fontan circulation has improved life expectancy for infants born with complex heart disease over the last 50 years but has also resulted in significant morbidity

Liver Imaging in Fontan Patients: How Does Ultrasound Compare to Cross-Sectional Imaging?

Background

Fontan patients frequently develop liver cirrhosis (LC); however, the diagnostic accuracy of ultrasound (US) for detecting LC and the clinical implications of such diagnoses have not been clearly established.

Objectives

This study aims to evaluate the diagnostic performance of US for detecting LC in an adult population with Fontan circulation and to determine the correlation between LC and mortality/transplantation.

Methods

This was a retrospective study. Data on cross-sectional imaging, liver USs, and clinical visits that occurred within 12 months of the cross-sectional imaging were collected. Liver US diagnostic accuracy was evaluated against cross-sectional imaging. Kappa agreement between methods was assessed. Univariate Cox proportional hazards regression analysis was employed to compare mortality and transplant outcomes.

Results

Overall, 131 patients were included. Liver US and cross-sectional imaging (computed tomography 74, magnetic resonance imaging 57) was performed in all patients. Liver US reported heterogeneous parenchyma, lobar redistribution, and surface nodularity in 85.4%, 72.5%, and 65.6% of cases. Cross-sectional imaging reported these features in 60.3%, 87.0%, and 84.9% of cases, respectively. US sensitivity was greater than 0.75 for all variables, while specificity was 0.21, 0.58, and 0.85, respectively. LC was diagnosed in 78% of cases by US and in 90% by cross-sectional imaging, with a kappa agreement of 0.21 between techniques. There was no significant correlation between the presence of hepatic parenchymal changes or cirrhosis and mortality/transplantation.

Conclusions

Liver US is effective for screening and monitoring liver cirrhotic features in the adult Fontan population. In a univariate analysis, there was no association between LC and mortality or transplantation.

Efficacy and safety of macitentan in Fontan-palliated patients: 52-week randomized, placebo-controlled RUBATO Phase 3 trial and open-label extension

OBJECTIVES

The efficacy and safety of macitentan, an endothelin receptor antagonist, were assessed in a 52-week, prospective, multicenter, double-blind, randomized, placebo-controlled, parallel-group study assessing the efficacy and safety of macitentan in Fontan-palliated adult and adolescent patients (RUBATO-DB) and an open-label extension trial (RUBATO-OL).

METHODS

Patients aged 12 years and older with New York Heart Association functional class II or III underwent total cavopulmonary connection more than 1 year before screening and showed no signs of Fontan failure/clinical deterioration. In RUBATO-DB, the primary efficacy end point was change in peak oxygen consumption from baseline to week 16; secondary end points were change from baseline over 52 weeks in peak oxygen consumption and change in mean count/minute of daily physical activity via accelerometer from baseline to week 16. Safety was assessed throughout both studies.

RESULTS

In RUBATO-DB, 137 patients were randomized to macitentan 10 mg (n = 68) or placebo (n = 69); 92.7% completed 52-week double-blind treatment. At week 16, mean ± SD change in peak oxygen consumption was -0.16 ± 2.86 versus -0.67 ± 2.66 mL/kg/minute with macitentan versus placebo (median unbiased treatment difference estimate, 0.62 mL/kg/minute [99% repeated CI, -0.62 to 1.85]; P = .19). No treatment effect was observed in either of the secondary end points. During RUBATO-DB, most common adverse events with macitentan were headache, nasopharyngitis, and pyrexia. Across RUBATO-DB and RUBATO-OL, most common adverse events were COVID-19, headache, and fatigue. RUBATO-OL was prematurely discontinued because RUBATO-DB did not meet its primary or secondary end point.

CONCLUSIONS

The primary end point of RUBATO-DB was not met; macitentan did not improve exercise capacity versus placebo in patients with Fontan palliation. Macitentan was generally well tolerated over long-term treatment.

A Meta-Analysis of Cumulative Incidence of Hepatocellular Carcinoma After the Fontan Operation

BACKGROUND

Hepatic complications are increasingly recognized after the Fontan operation. The development of hepatocellular carcinoma (HCC) is associated with high mortality when diagnosed, but its incidence and risk factors are poorly understood. We conducted a systematic review and meta-analysis of the cumulative incidence of HCC after Fontan and associated risk factors.

METHODS

We searched PubMed, CINAHL, and MEDLINE databases for articles reporting the cumulative incidence of HCC after Fontan operation on March 21, 2023. A single-arm random effects meta-analysis was conducted to assess cumulative incidence at 10, 20, and 30 years after Fontan. Meta-analysis of the difference of the medians was used to assess the influence of risk factors on the development of HCC.

RESULTS

Four studies including a total of 1320 patients reported cumulative incidence. The cumulative incidence of HCC at 10, 20, and 30 years after Fontan was 0% (95% CI 0.00-0.01), 2% (0.01-0.06), and 7% (0.03-0.17) respectively. Seven studies including 6,250 patients reported overall incidence of HCC and associated risk factors. At a median 18.4 (IQR 11.9-24.9) years of follow-up, incidence of HCC was 2% (0.01-0.04). Only use of anticoagulation was associated with a lower risk of HCC (RR 0.3, 95% CI 0.1-0.88).

DISCUSSION

By 30 years after Fontan, cumulative incidence of HCC is high (7%). Risk of HCC development prior to 10 years post-Fontan is low (0%), though the decision to defer HCC surveillance in this period may require future investigation based on larger studies. Screening with ultrasound every 6 months starting 20 years post-Fontan is reasonable, however, further research regarding timing, cost-effectiveness, additional risk factors associated with HCC risk, and different screening modalities is required.

Ideal chest compression site for cardiopulmonary resuscitation in fontan circulation patients with dextrocardia

BACKGROUND

We aimed to identify the ideal chest compression site for cardiopulmonary resuscitation (CPR) in patients with a single ventricle with dextrocardia corrected by Fontan surgery.

METHODS

The most recent stored chest computed tomography images of all patients with a single ventricle who underwent Fontan surgery were retrospectively analysed. We reported that the ideal chest compression site is the largest part of the compressed single ventricle. To identify the ideal chest compression site, we measured the distance from the midline of the sternum to the point of the maximum sagittal area of the single ventricle as a deviation and calculated the area fraction of the compressed structures.

RESULTS

58 patients (67.2% male) were analysed. The mean right deviation from the midline of the sternum to the ideal compression site was similar to the mean sternum width (32.85 ± 15.61 vs. 31.05 ± 6.75 mm). When chest compression was performed at the ideal site, the area fraction of the single ventricle significantly increased by 7%, which was greater than that of conventional compression (0.15 ± 0.10 vs. 0.22 ± 0.11, P < 0.05).

CONCLUSIONS

When performing CPR on a patient with Fontan circulation with dextrocardia, right-sided chest compression may be better than the conventional location.

Early outcomes of fenestrated intra-extracardiac Fontan procedure: Insights, experiences, and expectations

BACKGROUND

Intraextracardiac Fontan procedure (FP) aimed to combine the advantages of lateral tunnel and extracardiac conduit modifications of the original technique. Herein, we present our early outcomes in patients with intraextracardiac fenestrated FP.

METHODS

A retrospective analysis was performed to evaluate intraextracardiac fenestrated Fontan patients between 2014 and 2021. Seventeen patients were operated on with a mean age and body weight of 9.1 ± 5.5 years and 28.6 ± 14.6 kg.

RESULTS

Sixteen patients (94%) were palliated as univentricular physiology with hypoplasia of one of the ventricles. One patient (6%) with well-developed two ventricles with double outlet right ventricle and complete atrioventricular septal defect had straddling of the chordae prohibiting a biventricular repair. All of the patients had cavopulmonary anastomosis before Fontan completion, except one case. Fenestration was performed in all cases. Postoperative mean pulmonary artery pressures and arterial oxygen saturation levels at follow-up were 10 ± 2.4 mmHg and 91.3 ± 2.7%, respectively. Mean duration of pleural drainage was 5.4 ± 2.3 days. All of the fenestrations are patent at a mean follow-up period of 4.8 ± 7.7 years, except one case. Any morbidity and mortality were not encountered.

CONCLUSIONS

Early outcomes of intraextracardiac fenestrated FP are encouraging. This procedure may improve the results in a patient population who should be palliated as univentricular physiology, especially in cases with complex cardiac anatomy.

Delving into the Molecular World of Single Ventricle Congenital Heart Disease

PURPOSE OF REVIEW

Given a general lack of emphasis on the molecular underpinnings of single ventricle (SV) congenital heart diseases (CHD), our review highlights and summarizes recent advances in uncovering the genetic and molecular mechanisms in SV CHD etiology.

RECENT FINDINGS

While common SV-associated genetic mutations were found in key cardiac transcription factors, other mutations were sporadic. With advances in genetic sequencing technologies and animal models, more disease-associated factors have been identified to act in critical cardiac signaling pathways such as NOTCH, Wnt, and TGF signaling. Recent studies have also revealed that different cardiac lineages play different roles in disease pathogenesis. SV defects are attributed to complex combinations of genetic mutations, indicating that sophisticated spatiotemporal regulation of gene transcription networks and functional cellular pathways govern disease progression. Future studies will warrant in-depth investigations into better understanding how different genetic factors converge to influence common downstream cellular pathways, resulting in SV abnormalities.