Fenestration in the Fontan circulation as a strategy for chronic cardioprotection

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.

Stress imaging in patients with a Fontan circulation: A systematic review

INTRODUCTION

The aims of this study were to provide an overview of the cardiac stress response in Fontan patients and of the use, safety and clinical value of stress imaging in Fontan patients.

METHODS

Studies evaluating cardiac function using stress imaging in Fontan patients published up until 12 December 2021 were included in this review.

RESULTS

From 1603 potential studies, 32 studies met the inclusion criteria. In total, stress imaging tests of 728 Fontan patients were included. Cardiac function was most often measured using physical stress (61%), all other studies used dobutamine-induced stress. Stroke volume (SV) increased in most studies (71%), mean SV at rest ranged from 27 mL/m2 to 60 mL/m2 versus 27 mL/m2 to 101 mL/m2 during stress, and increased with an average of 4%. Ejection fraction increased in almost all studies, whereas both end-systolic volume and end-diastolic volume decreased during stress. Higher heart rates were obtained with physical stress (82-180) compared to dobutamine induced stress (73-128). Compared to controls, increases in heartrate and SV were lower and end-diastolic volume decreased abnormally in 75% of reporting studies. No major adverse events were reported. Poorer cardiac stress response was related to decreased exercise capacity and higher risk for long-term (adverse) outcomes in Fontan patients.

DISCUSSION

Cardiac stress response in Fontan patients differs from healthy subjects, reflected by lower increases in heart rate, diminished preload and decreased cardiac output, especially during higher levels of exercise. Stress imaging is safe, however the added clinical value needs to be investigated in more detail.

Impact of Fontan Fenestration on Long-Term Outcomes: A Propensity Score-Matched Analysis

Background The long-term impact of fenestration at the time of Fontan operation remains unclear. We aimed to review the early and long-term impact of Fontan fenestration in the Australia and New Zealand cohort. Methods and Results We reviewed 1443 patients (621 fenestrated, 822 nonfenestrated) from the Australia and New Zealand Fontan registry. Data were collected on preoperative demographics, operative details, and follow-up. Propensity-score matching was performed to account for the various preoperative and operative differences and risk factors. Primary outcomes were survival and freedom from failure. Median follow-up was 10.6 years. After propensity-score matching (407 matched pairs), there was no difference in survival (87% versus 90% at 20 years; P=0.16) or freedom from failure (73% versus 80% at 20 years; P=0.10) between patients with and without fenestration, respectively. Although patients with fenestration had longer bypass and cross-clamp times (P<0.001), there was no difference in hospital length of stay or prolonged pleural effusions (P=0.80 and P=0.46, respectively). Freedom from systemic and Fontan circuit thromboembolism was higher in the nonfenestrated group (89%; 95% CI, 88%-95%) than the fenestrated group (84%; 95% CI, 77%-89%; P=0.03). There was no difference in incidence of plastic bronchitis, protein-losing enteropathy, New York Heart Association Class III/IV symptoms, or Fontan takedown. Conclusions In the propensity score-matched analysis we have demonstrated no difference in long-term survival or freedom from Fontan failure in patients with and without fenestration. There was a higher incidence of long-term thromboembolic events in patients with fenestration. Overall, it appears that fenestration in Fontan circulation does not bring long-term benefits.

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.

Anesthetic Management of Resection of Metastatic Occipital Malignancy in a Patient With Fontan Physiology

Significant advances in surgical management have allowed patients with congenital heart disease to survive to adulthood. Often, these patients present for non-cardiac surgeries, including patients who have undergone the three-staged Fontan repair for congenital single ventricle. The primary aim in the anesthetic management of adult patients with Fontan physiology is to maintain adequate venous pressure, low pulmonary vascular resistance (PVR) and normal contractility to maintain the cardiac output. We present the case of a 26-year-old female with Fontan physiology following a three-staged Fontan repair for tricuspid atresia who underwent a stealth-guided left occipital craniotomy for the palliative resection of a metastatic brain tumor.

This case highlights the importance of understanding Fontan physiology and its implications in the anesthetic management of a patient undergoing an open craniotomy. These patients require a high central venous pressure and low PVR to maintain optimum venous return to the left atrium. A rise in PVR can result in the shunting of the deoxygenated blood from the Fontan shunt to the systemic circulation. Hence, alpha agonists and high airway pressure are to be avoided. To minimize the risk of perioperative mortality, there is an increased need to optimize systemic to pulmonary blood flow ratios and maintain normal arterial saturation and euvolemic fluid status.

Planned reduction in Fontan fenestration size using the Atrial Flow Regulator

Fontan fenestration allows right-to-left shunting increasing cardiac output and oxygen delivery. Increased shunting occurs as cardiac function and ventricular end-diastolic pressures improve, potentially decreasing oxygen saturation. Complete closure may result in impaired Fontan haemodynamics and low cardiac output; however, there are no dedicated devices to reduce fenestration size. We describe Fontan fenestration size reduction using the Atrial Flow Regulator.

Persisting and reoccurring cyanosis after Fontan operation is associated with increased late mortality

OBJECTIVES

The Fontan operation aims at reducing cyanosis and cardiac volume overload in patients with complex univentricular heart malformations. However, persisting or reoccurring cyanosis is frequently observed. We sought to systematically determine the prevalence and clinical consequences of persisting and secondary cyanosis after Fontan operation.

METHODS

A total of 331 Fontan patients, operated between 1984 and 2016 with a median postoperative follow-up of 7.9 (interquartile range 2.6-15.8) years, were studied retrospectively. Cyanosis was defined as transcutaneous oxygen saturation ≤93% at rest measured by pulse oximetry. Prevalence of cyanosis was analysed at 3 different time points (t1 = post-Fontan operation, t2 = post-Fontan cardiac catheterization, t3 = last follow-up) and the association of cyanosis with mortality was examined.

RESULTS

Prevalence of cyanosis was 50% at t1 and 39% at t3. Fenestration was patent in 71% and 33% of all cyanotic patients at t1 and t3, respectively. In patients with clinical indication for catheterization (t2; n = 178/331), prevalence of cyanosis was 72%. At t2, patent fenestration (33%), veno-venous collaterals (24%) or both (32%) were present. Thirty-six (11%) patients died during follow-up. In a time-varying multivariable Cox regression analysis, cyanosis was the strongest predictor for late mortality (P < 0.001, hazard ratio 12.2, 95% confidence interval 3.7-40.5).

CONCLUSIONS

Prevalence of cyanosis was considerable during long-term follow-up after Fontan operation and-as a surrogate parameter for unfavourable Fontan haemodynamics-is associated with increased late mortality. Accordingly, particular attention should be directed towards the persistence or reoccurrence of cyanosis during follow-up since it may indicate haemodynamic attrition and development of Fontan failure.

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.

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.

Portosystemic shunt with hyperammonemia and high cardiac output as a complication after Fontan surgery

In the late phase after Fontan surgery, organ dysfunction due to high central venous pressure (CVP) is a major clinical problem. We have described the cases of two patients with portosystemic shunts who exhibited hyperammonemia and high cardiac output associated with peripheral vasodilatation after Fontan surgery. A high CVP in these patients may have resulted in the formation of a portosystemic shunt. We performed coil embolization and balloon-occluded retrograde transvenous obliteration for each case. The possibility of a portosystemic shunt as a postoperative complication of Fontan surgery should always be considered. Early detection and therapeutic intervention seem necessary from the viewpoint of stabilizing the Fontan circulation and delaying the progression of liver disorder. <Learning objectives: A portosystemic shunt may develop due to the high central venous pressure after Fontan surgery independent of hepatic disorder and should be considered as a potential cause of unexplained hyperammonemia and high cardiac output status. Transcatheter closure of the portosystemic shunt may improve the clinical status.>.

Transcatheter reduction in size of large undesirable fenestrations following extracardiac conduit Fontan surgery with off-label use of Occlutech atrial flow regulator

Fontan surgery streamlines the systemic venous return through the pulmonary circulation before filling the systemic ventricle in univentricular hearts. The venous congestion leads to effusions, lowers cardiac output, and affects organ perfusion. Fenestrations in the Fontan circuit improve forward flow through the ventricles, lower venous pressures, and reduce perioperative morbidity. When large fenestrations cause profound hypoxia and effort intolerance, there are no current techniques to reduce their size. Atrial flow regulators with a predetermined orifice were used off-label in three borderline patients with large undesirable fenestrations following extracardiac conduit Fontan surgeries. This resulted in improved oxygenation without marked elevation of venous pressures, while retaining the patency of the decompressive fenestration.

Risk Factors for Prolonged Pleural Effusion Following Total Cavopulmonary Connection Surgery: 9 Years' Experience at Fuwai Hospital

Background: Prolonged pleural effusion (PPE) contributes to adverse outcomes after total cavopulmonary connection (TCPC) completion. We aimed to identify risk factors for PPE following TCPC surgery. Methods: We studied a retrospective cohort of 525 who undergoing TCPC surgery from 2010 to 2019. We defined PPE as the duration of pleural effusion exceeding 14 days. Logistic regression was applied to identify risk factors for PPE and Cox regression was used to identify risk factors for predicting the duration of pleural effusion. The impacts of PPE on the short-term outcomes were evaluated. Results: The rate of PPE was 27.4% in our study and independent risk factors for PPE included: young age, no fenestration, low postoperative total protein, prolonged mechanical ventilation and chylothorax. These predictors were also achieved in the Cox regression for predicting the duration of pleural effusion. The applicability of the model was acceptable in different subgroups, which derived from the total cohort. Patients with PPE were associated with more renal replacement treatment, longer length of ICU and hospital stay, more hospitalization costs and a higher rate of in-hospital mortality. Conclusions: PPE in our study occurs at a relatively lower rate than that reported in previous studies and patients with PPE was associated with higher rate of in-hospital mortality when compared to patients without PPE. Young age, no fenestration, low postoperative total protein, prolonged mechanical ventilation, and chylothorax were identified as independent risk factors to predict PPE. A preventive strategy that targets the identified risk factors to reduce the incidence of PPE following TCPC surgery could be beneficial for in-hospital outcomes, and the model needs further validation before its application.