Persistent fenestration may be a marker for physiologic intolerance after Fontan completion

Impact of Fontan Fenestration on Adverse Cardiovascular Outcomes: A Multicentre Study

BACKGROUND

Fenestrating a Fontan baffle has been associated with improved perioperative outcomes in patients with univentricular hearts. However, longer-term potential adverse effects remain debated. We sought to assess the impact of a fenestrated Fontan baffle on adverse cardiovascular events including all-cause mortality, cardiac transplantation, atrial arrhythmias, and thromboemboli.

METHODS

A multicentre North American retrospective cohort study was conducted on patients with total cavopulmonary connection Fontan baffle, with and without fenestration. All components of the composite outcome were independently adjudicated. Potential static and time-varying confounders were taken into consideration, along with competing risks.

RESULTS

A total of 407 patients were followed for 10.4 (7.1-14.4) years; 70.0% had fenestration of their Fontan baffle. The fenestration spontaneously closed or was deliberately sealed in 79.9% of patients a median of 2.0 years after Fontan completion. In multivariable analysis in which a persistent fenestration was modelled as a time-dependent variable, an open fenestration did not confer a higher risk of the composite outcome (hazard ratio, 1.18; 95% confidence interval, 0.71-1.97; P = 0.521). In secondary analyses, an open fenestration was not significantly associated with components of the primary outcome: that is, mortality or transplantation, atrial arrhythmias, or thromboemboli. However, sensitivity analyses to assess the possible range of error resulting from imprecise dates for spontaneous fenestration closures could not rule out significant associations between an open fenestration and atrial arrhythmias or thromboemboli.

CONCLUSIONS

In this multicentre study, no significant association was identified between an open fenestration in the Fontan baffle and major adverse cardiovascular events.

Impact of Optimal Fenestration Size on Outcomes of High-Risk Fontan Patients

BACKGROUND

We aimed to analyze mid-term outcomes of the fenestrated Fontan procedure, focusing on the fenestration size.

METHODS

We retrospectively reviewed the outcomes of the fenestrated Fontan procedure. Among 165 patients who underwent the Fontan procedure from 2011 to 2021, fenestration was created in 27 patients with the highest risks, including those with hypoplastic left heart syndrome, hypoplastic pulmonary arteries, heterotaxy syndrome with high pulmonary vascular resistance, and pulmonary arterial pressure >15 mm Hg. The patients underwent the procedure at a median age of three years (body weight, 11.4 kg; body surface area, 0.54 m2). Fenestration sizes were 3.5 to 5 mm.

RESULTS

Spontaneous fenestration closure occurred within one year postoperatively in nine patients. Among them, three experienced Fontan failure, necessitating refenestration. Although fenestration size did not differ, the size corrected by body surface area at the time of surgery was smaller in patients with fenestration closure (6.4 mm/m2 vs 8.3 mm/m2, P < .05). Patients with a fenestration <7 mm/m2 were more likely to have fenestration closure within one year postoperatively, and those with a fenestration >9 mm/m2 were more likely to have severe desaturation and require home oxygen therapy following discharge.

CONCLUSIONS

Spontaneous fenestration closure affected the frequency of Fontan complications. A very small fenestration size corrected by body surface area was a significant risk factor for spontaneous closure. Conversely, a very large fenestration size corrected by body surface area resulted in severe desaturation. The optimal fenestration size to prevent early spontaneous closure and severe desaturation is approximately 8 mm/m2.

Influence of fenestration on long-term Fontan survival

INTRODUCTION

Fenestration in the total cavopulmonary connection system may improve the outcome of patients with significant risk factors for Fontan haemodynamics. Our study aims to analyse the difference in long-term survival between non-fenestrated and fenestrated patients.

METHODS

All consecutive patients (n = 351) who underwent total cavopulmonary connection between 1992 and 2016 were identified. Six early deaths were excluded resulting in a group of 345 patients. Median (interquartile range,) length of follow-up was 14.4 (7.1-19.7) years. Freedom from the composite endpoint of death, total cavopulmonary connection take-down or indication for a heart transplant was analysed.

RESULTS

Fenestration was absent in 237 patients (68.7%, Group 1), was created and closed later in 79 patients (22.9%, Group 2), and remained open in 29 patients (8.4%, Group 3). Mean survival probability until composite endpoint was 97.1 and 92.9% at 10 and 20 years, respectively. Patients with patent fenestration had worse survival (p < 0.001) as compared to both the non-fenestrated and fenestration closure groups. Despite a similar outcome, exercise capacity was lower in Group 2 than 1 (p = 0.013). In 58 patients with interventional fenestration closure, Nakata index was lower at the time of closure than pre-operatively, and both the pressure in the circuit and oxygen saturation in the aorta increased significantly (p < 0.001).

CONCLUSIONS

Patients with persisting risk factors preventing fenestration closure are at higher risk of reaching the composite endpoint. Patients after fenestration closure have the worse functional outcome; their survival is, however, not different from the non-fenestrated group.

Long-Term Outcomes After Fenestration Closure in High-Risk Fontan Candidates

The study aimed to assess the long-term outcomes after fenestration closure in patients at risk for Fontan failure. Of 119 patients who underwent Fontan operation between 1995 and 2004, fenestration was not created in 89 patients (NF group) and created in 30 patients with hypoplastic left heart syndrome, heterotaxy syndrome, high pulmonary arterial pressure, high systemic ventricular end-diastolic pressure, low ventricular ejection fraction, or atrioventricular valve regurgitation. All fenestrations were closed spontaneously or by catheter/surgical interventions, excepting two patients, and therefore, they were excluded. In fenestration group, patients with pre-Fontan mean pulmonary arterial pressure ≥ 15 mmHg or systemic atrioventricular valve regurgitation ≥ moderate were classified as high-risk Fontan candidates (F-HR group, n = 16), and the remaining patients were as standard-risk (F-SR group, n = 12). Protein-losing enteropathy-free survival rates did not differ among the three groups (p = 0.72). Serial follow-up catheter examinations after Fontan operation were completed in 69 patients in NF group and 11 patients in both F-SR and F-HR groups. Cardiac index and pulmonary vascular resistance significantly and similarly decreased over time in all groups, though the F-HR group showed lowest arterial oxygen saturation, lowest cardiac index, and highest pulmonary vascular resistance. The F-HR group also showed much veno-venous collaterals (p = 0.049), low peak oxygen consumption (p = 0.019), and low anaerobic threshold (p = 0.023) as compared to those in the F-SR group. In F-HR group, cyanosis remained after fenestration closure due to transformation from fenestration to veno-venous collaterals, which resulted in elevation of pulmonary vascular resistance, low cardiac index, and deterioration of exercise tolerance.

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.

Optimal criteria for transcatheter closure of Fontan fenestration: a single-center experience with a review of literature

Fenestration closure is considered to remove the persistent right-to-left shunt after the Fontan operation. However, the criteria for effective transcatheter closure of fenestration to avoid both acute and chronic Fontan failure have not been clarified. The objective of this study was to describe the hemodynamic data with test occlusion of the Fontan fenestration for patients who underwent a closure and those who did not, along with subsequent development of Fontan-associated diseases (FAD) at follow-up. This was a retrospective study conducted to assess the outcome of Fontan fenestration closure at Children's Hospital of Michigan over 27 years (1993-2019). The inclusion criteria were patients undergoing cardiac catheterization indicated for Fontan fenestration closure. Data were compared between the two groups: closure and non-closure patients. Baseline characteristics and hemodynamic variables with the fenestration occlusion test were analyzed. The primary outcome was the development of composite events of death/transplant, deteriorated New York Heart Association class symptoms, or FAD. Among the 38 patients who were brought to the catheterization laboratory, 33 received fenestration closure and 5 did not. On a median follow-up of 3.4 years (range, 1 month-12.6 years), the incidence of primary adverse outcomes was 13% (5/38). The incidence of primary outcome was significantly higher in the non-closure group (60% vs. 6%, p < 0.01). The non-closure group had a higher incidence of moderate or severe atrioventricular valve regurgitation, New York Heart Association class III symptoms, use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, furosemide use, and sildenafil use. The multivariable logistic regression model showed that the hemodynamic variables associated with the non-closure group were mean left atrial pressure (odds ratio 1.74, p < 0.05) and change of mean Fontan pressure at the balloon occlusion (odds ratio 2.2, p < 0.05). The judgment of fenestration closure appeared appropriate in our cohort. Fontan fenestration closure may not be advisable in cases with a high baseline left atrial pressure or a significant increase in Fontan pressure on balloon occlusion testing.

Does routine fenestration improve early and late postoperative outcomes in patients undergoing Fontan palliation?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: 'In [patients undergoing Fontan palliation] does [fenestration] affect [early and late postoperative outcomes]?' Altogether 509 papers were found using the reported search, of which 11 papers represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Current data suggest that the use of fenestration has advantages in the immediate postoperative course, with fewer complications such as pleural effusions, shorter hospitalization and decreased early Fontan failure, but comparable long-term outcomes to a non-fenestrated approach. Fenestration should be used in high-risk patients or based on the haemodynamic parameters measured before weaning from cardiopulmonary bypass. Routine use may potentially lead to additional late fenestration closure procedures in some patients, without improving long-term outcomes.

Modes of late mortality in patients with a Fontan circulation

OBJECTIVES

The mechanisms of attrition of the Fontan population have been poorly characterised and it is unclear whether some of the deaths are potentially preventable. We analysed the circumstances of late death in patients with a Fontan circulation, with a special focus on identifying lesions amenable to intervention that may have contributed to the decline of their circulation.

METHODS

Between 1975 and 2018, a total of 105 patients from a Bi-National Registry died beyond 1 year after Fontan completion, at a median age of 18.6 (IQR 13.8-26.0) years old, 12.7 (IQR 6.0-19.3) years after Fontan completion.

RESULTS

A total of 105 patients died-63 patients (60%) with an atriopulmonary (AP) Fontan, 21 patients (20%) with a lateral tunnel (LT) and 21 patients (20%) with an extracardiac conduit (ECC). 72 patients (69%) were reviewed within 2 years preceding death, with 32% (23/72) deemed to be clinically well. Fontan circulatory failure was the most common cause of death in 42 patients (45%). Other causes of death included sudden death/arrhythmia (19%), perioperative death (12%), neurological complication (7%) and thromboembolism (7%). All patients with an LT or ECC who died from Fontan failure had at least one surgical defect that was amenable to intervention at time of death.

CONCLUSIONS

Conventional clinical surveillance has been insensitive in detecting a significant proportion of patients at risk of late death. Fontan circulatory failure contributes to half of the late deaths. Patients with an LT or ECC Fontan who died with a clinical picture of circulation failure may have potentially correctable lesions.

Outcomes of the Non-fenestrated Fontan Procedure at High Altitude

Background:

Although high altitude has been considered a risk factor for the Fontan operation, and an indication for fenestration, there is a paucity of data to support its routine use. Fenestration, with its necessary right to left induced shunt, together with the lower partial pressure of oxygen found with progressive altitude, can significantly decrease hemoglobin oxygen saturation, and therefore, it would be desirable to avoid it.

Objective:

To analyze immediate and medium-term results of the non-fenestrated, extracardiac, Fontan procedure at high altitude.

Methods:

Retrospective analysis of data from consecutive patients who underwent non-fenestrated, extracardiac, Fontan procedure at two institutions located in Mexico City at 2,312 m (7,585 ft) and 2,691 m (8,828 ft) above sea level. High altitude was not considered a risk factor.

Results:

Thirty-nine patients were included, with a mean age of 6.7 years. Mean preoperative indexed pulmonary vascular resistance was 1.7 Wood units. Seventy-nine percent of the patients extubated in the operating room. There was one in-hospital death (2.56%) and one at follow-up. Median chest tube drainage time was 6.5 and 6 days for the right and left pleural spaces. Median oxygen saturation at discharge was 90%. At a median follow-up of six months, all survivors, except one, had good tolerance to daily life activities.

Conclusions:

The present study shows good short- and medium-term results for the non-fenestrated, extracardiac, Fontan operation at altitudes between 2,300 and 2,700 m and might favor this strategy over fenestration to improve postoperative oxygen saturation. Further studies to examine the long-term outcomes of this approach need to be considered.

Fenestration in the Fontan circulation as a strategy for chronic cardioprotection

Background

Fenestration in the Fontan circulation potentially liberates patients from factors leading to cardiovascular remodelling, through stable haemodynamics with attenuated venous congestion. We hypothesised that a fenestrated Fontan procedure would possess chronic haemodynamic advantages beyond the preload preservation.

Methods

We enrolled 35 patients with fenestrated Fontan with a constructed pressure–volume relationship under dobutamine (DOB) infusion and/or transient fenestration occlusion (TFO). Despite the use of antiplatelets and anticoagulants, natural closure of fenestration was confirmed in 11 patients. Cardiovascular properties in patients with patent fenestration (P-F) were compared with those in patients with naturally closed fenestration (NC-F). To further delineate the roles of fenestration, paired analysis in patients with P-F was performed under DOB or rapid atrial pacing with/without TFO.

Results

As compared with P-F, patients with NC-F had a higher heart rate (HR), smaller ventricular end-diastolic area, better ejection fraction and higher central venous pressure, with higher pulmonary resistance. While this was similarly observed after DOB infusion, DOB markedly augmented diastolic and systolic ventricular stiffness in patients with NC-F compared with patients with P-F. As a mirror image of the relationship between patients with P-F and NC-F, TFO markedly reduced preload, suppressed cardiac output, and augmented afterload and diastolic stiffness. Importantly, rapid atrial pacing compromised these haemodynamic advantages of fenestration.

Conclusions

As compared with patients with NC-F, patients with P-F had robust haemodynamics with secured preload reserve, reduced afterload and a suppressed beta-adrenergic response, along with a lower HR at baseline, although these advantages had been overshadowed, or worsened, by an increased HR.

Long-Term Effects of Percutaneous Fenestration Following the Fontan Procedure in Adult Patients with Congenital Univentricular Heart

Background

The Fontan procedure, performed for univentricular heart, may also include the technique of percutaneous fenestration to create a small atrial septal defect (ASD) and a right-to-left shunt. The aim of this study was to evaluate the long-term effects of fenestration in adult patients who had a Fontan procedure for univentricular heart.

Material/Methods

Fontan surgery was performed in 39 patients, including 19 (49%) patients with fenestration (Group I), and 20 (51%) patients without the fenestration procedure (Group II). Laboratory tests in both groups included echocardiography, plethysmography, cardiopulmonary exercise testing, and 24-hour Holter monitoring.

Results

Compared with patients in Group I, patients in Group II had a significantly increased level of N-terminal pro-brain natriuretic peptide (NT-proBNP) (p=0.04), alkaline phosphatase (ALP) (p=0.01) and a significant increase in frequency of atrial fibrillation (p=0.04). Patients in Group I had a significantly increased systemic ventricular ejection fraction (SVEF) (p=0.05) and increased heart rate (HR) (p=0.006), heart rate reserve (HRR) (p=0.02), ventilatory equivalent (VE) (p=0.01), and VO₂ peak (p=0.05) on cardiopulmonary exercise testing (CPET). Renal, hematologic, and ventilatory parameters, and incidence of thromboembolism showed no significant differences between the groups.

Conclusions

Long-term follow-up of patients who underwent Fontan procedures with percutaneous fenestration had improved single ventricular function, lower NT-proBNP levels, improved exercise capacity, and reduced ALP levels. These findings indicate that percutaneous fenestration closure should be considered for adult patients who have undergone Fontan procedure for univentricular heart.

Chylothorax and pleural effusion in contemporary extracardiac fenestrated fontan completion

BACKGROUND

We hypothesized that chylothorax could be a sign of intolerance to the Fontan physiology, and thus patients who develop chylothorax or pleural effusion have worse medium-term to long-term survival.

METHODS

A total of 324 patients who underwent the Fontan operation between 2000 and 2013 were included. Chylothorax was defined as ≥5 mL/kg/day of chylomicron-positive chest drainage fluid no earlier than postoperative day 5 or drainage with >80% lymphocytes. Outcomes were compared between the chylothorax and non-chylothorax groups by the Kaplan-Meier method and log-rank test. Independent predictors of chylothorax and number of days of any chest drainage were analyzed with multivariable logistic regression and multivariable generalized negative binomial regression for count data, respectively.

RESULTS

Chylothorax occurred in 78 patients (24%). Compared with the non-chylothorax group, the chylothorax group had a longer duration of chest tube requirement (median, 18 days vs 9 days; P < .000) and a longer length of hospital stay (median, 19 days vs 10 days; P < .000). Eight patients (10.3%) required thoracic duct ligation. The chylothorax group had lower freedom from death (P = .013) and from composite adverse events (P = .021). No predictor was found for chylothorax. Pulmonary atresia (P = .031) and pre-Fontan pulmonary artery pressure (P = .01) were predictive of prolonged pleural effusion (>14 days).

CONCLUSIONS

Occurrence of chylothorax following the Fontan operation can be a marker of poorer medium-term clinical outcomes. It is difficult to predict occurrence of chylothorax owing to its multifactorial nature and involvement of lymphatic compensatory capacity that is unmasked only after the Fontan operation.

Effect of Fenestration on Early Postoperative Outcome in Extracardiac Fontan Patients with Different Risk Levels

Although fenestration is used to improve the postoperative course of Fontan patients, the effect of fenestration on the extracardiac Fontan seems controversial especially at early postoperation. One hundred and eighty-three patients from January 2004 to June 2013 undergoing an extracardiac Fontan operation were retrospectively selected for this study. We divided the patients into low risk (93 patients) and high risk (90 patients) groups according to the risk factors recognized by previous studies and then compared the perioperative data between the nonfenestrated and fenestrated patients in each group. In both groups there was no significant difference in preoperative and operative data between the nonfenestrated and fenestrated patients. The postoperative blood oxygen saturation of fenestrated patients was significantly lower (p < 0.01) in each group. In the high risk group the chest tube volume (1153 mL vs. 1739 mL, p = 0.021) and chest tube duration (11.9 days vs. 17.0 days, p = 0.028) of fenestrated patients were lower comparing to nonfenestrated patients, while the chest tube volume and chest tube duration were similar between the nonfenestrated and fenestrated patients in the low risk group. The morbidity and mortality of nonfenestrated and fenestrated patients were similar in both groups (p > 0.05). Although fenestration was associated with lower postoperative oxygen saturation, fenestration showed better postoperative outcomes regarding the chest tube volume and duration for the high-risk patients. Considering the similar early postoperative outcomes of nonfenestrated and fenestrated patients in low risk group, our data indicate that fenestration for the high-risk patients should be performed.