The long-term effects of the fenestration in patients with extracardiac Fontan circulation-a multicenter Korean cohort study based on national Fontan registry

Introduction

The long-term effects of fenestration in patients with Fontan circulation remain unclear. We aim to evaluate the fenestration impact on early and late outcomes in patients with extracardiac Fontan (ECF) using a propensity score matching analysis.

Methods

We performed an extensive retrospective multicenter clinical data review of the Korean Fontan registry and included 1,233 patients with surgical ECF (779 fenestrated, 454 non-fenestrated). Demographics, baseline, and follow-up data were collected and comprehensively analyzed. Patients were divided into two groups according to the baseline presence or absence of surgical fenestration. Subsequently, patients were sub-divided according to the fenestration status at the last follow-up. Propensity-score matching was performed to account for collected data between the 2 groups using a multistep approach. The primary outcomes were survival and freedom from Fontan failure (FFF). We also looked at postoperative hemodynamics, cardiopulmonary exercise test results, oxygen saturations, and functional status.

Results

After propensity-score matching (454 matched pairs), there was no difference in survival or FFF between the 2 groups. However, ECF patients with baseline fenestration had significantly lower oxygen saturation (p = 0.001) and lower functional status (p < 0.001). Patients with fenestration had significantly longer bypass times, higher postoperative central venous pressure, higher postoperative left atrial pressure, and less prolonged pleural effusion in the early postoperative period. The propensity score matching according to the fenestration status at the last follow-up (148 matched pairs) showed that patients with a persistent fenestration had significantly lower oxygen saturation levels (p < 0.001). However there were no intergroup differences in the functional status, survival and FFF.

Conclusions

Our results showed no long-term benefits of the Fenestration in terms of survival and FFF. Patients with persistent fenestration showed oxygen desaturation but no difference in exercise intolerance was shown between the 2 groups.

Long-term outcomes of hypoplastic left heart syndrome with analysis of the Norwood procedure in infants following bilateral pulmonary artery banding

Objective

To investigate the early and long-term outcomes of the deferred Norwood procedure by bilateral pulmonary artery banding (BPAB) versus the neonatal Norwood procedure.

Methods

This retrospective study examined 46 patients with hypoplastic left heart syndrome and its variants undergoing the Norwood procedure for single ventricle physiology between 2004 and 2022 at 3 institutions. The patients were divided into 2 groups: neonatal Norwood procedure (group N; n = 23) and staged Norwood procedure in infants following BPAB (group I; n = 23). Preoperative risk factors, surgical results, survival rates, Fontan candidacy, and long-term complications were compared.

Results

Early survival rates after the Norwood procedure were 91.3% (21 of 23) in both groups. Late survival rates after the Norwood procedure were similar at the 10-year follow-up (group N, 76.3%; group I, 68.7%; P = .63). Fontan completion rates also were comparable in the 2 groups (group N, 77.8%; group I, 85.7%; P = .67). Group N showed a higher median pulmonary artery (PA) index before bidirectional cavopulmonary connection (group N, 177 [interquartile range (IQR), 147-243] mm2/m2; group I, 152 [IQR, 146-163] mm2/m2; P = .03); this trend continued until 5 years after Fontan completion (P = .01). Group N also had a lower rate of freedom from protein-losing enteropathy (PLE) at 9.0 years after the Fontan operation (90.0% vs 52.5% for group I; P = .04), although the incidences of other Fontan-associated events were not significantly different.

Conclusions

Fontan candidacy and survival rates were similar regardless of the timing of the Norwood procedure. Early performance of the Norwood procedure may lead to lower rates of late Fontan-associated events, such as PLE.

Are dynamic measurements of central venous pressure in Fontan circulation during exercise or volume loading superior to resting measurements?

BACKGROUND

The main objective measure to assess the health of the Fontan circulation is the pressure measurement of the superior vena cava or pulmonary arteries. We reviewed the literature for benefits of measuring resting pressure in the Fontan circuit and explored whether dynamic measurement by volume loading or exercise has the potential to refine this diagnostic tool.

METHODS

PubMed was searched for articles showing a relationship between resting post-operative central venous pressure or pulmonary artery pressure and Fontan failure. Relationships between post-operative central venous pressure or pulmonary artery pressure and volume loading changes, such as during exercise or volume loading during cardiac catheterization, were also queried.

RESULTS

A total of 44 articles mentioned relationships between resting central venous pressure or pulmonary artery pressure and Fontan failure. Only 26 included an analysis between the variables and only seven of those articles found pressure to be predictive of Fontan failure. Ten articles examined the relationship between exercise or volume loading and outcomes and demonstrated a large individual variation of pressures under these dynamic conditions.

CONCLUSIONS

Based on current literature, there is not a lot of strong evidence to show that elevated resting central venous pressure or pulmonary artery pressure is predictive of Fontan failure. Some individuals experience dramatic increases in central venous pressure or pulmonary artery pressure under increased loading conditions with exercise or bolus fluid infusion, while others experience increases closer to that of a healthy control population. Further studies are needed to examine whether more dynamic and continuous monitoring of systemic venous pressures might better predict outcomes in patients with Fontan circulation.

EASL-ERN position paper on liver involvement in patients with Fontan-type circulation

Fontan-type surgery is the final step in the sequential palliative surgical treatment of infants born with a univentricular heart. The resulting long-term haemodynamic changes promote liver damage, leading to Fontan-associated liver disease (FALD), in virtually all patients with Fontan circulation. Owing to the lack of a uniform definition of FALD and the competitive risk of other complications developed by Fontan patients, the impact of FALD on the prognosis of these patients is currently debatable. However, based on the increasing number of adult Fontan patients and recent research interest, the European Association for The Study of the Liver and the European Reference Network on Rare Liver Diseases thought a position paper timely. The aims of the current paper are: (1) to provide a clear definition and description of FALD, including clinical, analytical, radiological, haemodynamic, and histological features; (2) to facilitate guidance for staging the liver disease; and (3) to provide evidence- and experience-based recommendations for the management of different clinical scenarios.

Parametric investigation of an injection-jet self-powered Fontan circulation

Approximately \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1/2500$$\end{document}1/2500 babies are born with only one functioning ventricle and the Fontan is the third and, ideally final staged palliative operation for these patients. This altered circulation is prone to failure with survival rates below \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$50\%$$\end{document}50% into adulthood. Chronically elevated inferior vena cava (IVC) pressure is implicated as one cause of the mortality and morbidity in this population. An injection jet shunt (IJS) drawing blood-flow directly from the aortic arch to significantly lower IVC pressure is proposed. A computer-generated 3D model of a 2–4 year old patient with a fenestrated Fontan and a cardiac output of 2.3 L/min was generated. The detailed 3D pulsatile hemodynamics are resolved in a zero-dimensional lumped parameter network tightly-coupled to a 3D computational fluid dynamics model accounting for non-Newtonian blood rheology and resolving turbulence using large eddy simulation. IVC pressure and systemic oxygen saturation were tracked for various IJS-assisted Fontan configurations, altering design parameters such as shunt and fenestration diameters and locations. A baseline “failing” Fontan with a 4 mm fenestration was tuned to have an elevated IVC pressure (+ 17.8 mmHg). Enlargement of the fenestration to 8 mm resulted in a 3 mmHg IVC pressure drop but an unacceptable reduction in systemic oxygen saturation below 80%. Addition of an IJS with a 2 mm nozzle and minor volume load to the ventricle improved the IVC pressure drop to 3.2 mmHg while increasing systemic oxygen saturation above 80%. The salutary effects of the IJS to effectively lower IVC pressure while retaining acceptable levels of oxygen saturation are successfully demonstrated.

Venous Properties in a Fontan Patient with Successful Remission of Protein-Losing Enteropathy

We present the case of a 1-year-old boy who developed protein-losing enteropathy (PLE) within 2 months of a fenestrated Fontan procedure. His fenestration rapidly closed despite bilateral pulmonary stenosis (BPS). Subsequent to PLE onset, both fenestration and the bilateral pulmonary artery were reconstructed, and the patient's PLE had been in remission, with additive use of medications, for more than 2 years. Notably, although fenestration closed again and central venous pressure (CVP) reduction was minimal, the surrogates of venous return resistance were markedly suppressed as shown by increased blood volume, reduced estimated mean circulatory filling pressure, and suppressed CVP augmentation against a contrast agent. Taken together, dynamic characteristics of venous stagnation, rather than the absolute value of CVP, were ameliorated by the pulmonary reconstruction and use of medications, suggesting a significant role of venous property in the physiology of PLE. In addition, simultaneous measures of CVP and ventricular end-diastolic pressure during the abdominal compression procedure suggested a limited therapeutic role of fenestration against PLE in this patient.

Fontan-associated liver disease and total cavopulmonary anatomical flow effectors

OBJECTIVE

We investigated a relationship between a composite index comprised of Fontan-circuit anatomical features and hepatic fibrosis scores from biopsy.

METHODS

We identified living extracardiac Fontan patients, ≥7 years old and ≥5 but <20 years postoperative, that underwent cardiac catheterization and transvenous liver biopsy between March 2012 and September 2020. We divided patients into anatomical groups and applied a risk score to each patient. We compared average anatomical risk scores with average hepatic total fibrosis scores by group.

RESULTS

We identified 111 patients that met inclusion criteria. After excluding four patients, we assigned 107 to one of 12 anatomical variant groups (n ≥ 3). For the 107, the average age at liver biopsy was 14 ± 6 years old. Of the 107, 105 (98%) were New York Heart Association Class 1. We found average anatomical risk scores by group correlated with average total fibrosis scores by group (R = 0.8; p = .005). An average Fontan duration to biopsy of 10 ± 1 years was similar for all 12 anatomical groups. We found no other clinical variables, laboratory, or hemodynamic values that trended with anatomical risk scores or hepatic total fibrosis scores.

CONCLUSIONS

In a cohort of relatively young, stable extracardiac Fontan patients, average composite anatomical risk scores strongly correlated with average hepatic total fibrosis scores by anatomical group. These findings suggest that some anatomical variants in extracardiac Fontan patients are associated with higher Fontan-associated liver disease (FALD)-related hepatic total fibrosis scores than others, despite similar Fontan durations.

Echocardiogram Unmasked Hemodynamic Advantage of Atrial Pacing in Securing Ventricular Preload in a Fontan Patient with Junctional Rhythm

While the advancement of perioperative management has expanded Fontan candidacy, not all patients have a successful postoperative course. Our case was a right isomerism patient who could not leave the ICU due to high central venous pressure and low output syndrome. Initial observation of the monitor ECG showed his rhythm to be supraventricular, however, an echocardiogram indicated simultaneous contraction of the atrium and ventricle, implying a junctional rhythm. While neither central venous pressure nor blood pressure improved with temporary pacing, better central venous and pulmonary venous blood flow patterns during pacing unraveled its positive impact. The patient successfully left the ICU after permanent pacing implantation. Hemodynamic study revealed a beneficial impact of atrial pacing in securing cardiac output and ventricular preload, lowering central venous pressure, and shortening blood transit time, which is partly attributed to the optimization of the fenestration function in reservation of the preload. Our case emphasizes the significant advantage of atrial pacing in a failing Fontan patient with junctional rhythm by reducing venous congestion and maximizing the benefit of fenestration.