Negative-Pressure Ventilation in the Pediatric ICU

Negative-pressure ventilation (NPV) is a form of noninvasive ventilation that has been recently utilized in pediatric acute respiratory failure. Negative-pressure ventilators apply negative pressure onto the chest wall via a cuirass to recruit areas of atelectasis. Continuous negative extrathoracic pressure, the most common mode, is similar to CPAP, where negative pressure is maintained at a constant level throughout the respiratory cycle while patients initiate their own breaths and continue to breathe spontaneously throughout. Control mode, which is similar to bi-level positive airway pressure, alternates negative pressure with positive pressure and controls both phases of breathing at a mandatory frequency set higher than the patient's spontaneous frequency. Supplemental oxygen is provided through a nasal cannula or face mask due of the lack of NPV devices' interface with the mouth or nose. NPV can improve preload to the heart and cardiac output (CO) in patients with restrictive right-ventricular physiology requiring CO augmentation and those with Fontan physiology. The purpose of this article is to review the physiological principles of spontaneous and NPV, examine the evidence supporting the use of NPV, give practical and meaningful guidance on its clinical application in the pediatric ICU, and summarize areas for future studies on its uses.

Experience with SGLT2 Inhibitors in Patients with Single Ventricle Congenital Heart Disease and Fontan Circulatory Failure

Heart failure is the leading cause of morbidity and mortality in patients with Fontan circulation. Sodium-glucose-cotransporter 2 inhibitors (SGLT2i) have become a mainstay of heart failure therapy in adult patients, however, there remains a paucity of literature to describe its use in pediatric heart failure patients, especially those with single ventricle physiology. We describe our early experience using SGLT2i in patients with single ventricle congenital heart disease surgically palliated to the Fontan circulation. We conducted a single-center retrospective chart review of all patients with Fontan circulation who were initiated on an SGLT2i from January 1, 2022 to March 1, 2023. Patient demographics, diagnoses, clinical status, and other therapies were collected from the electronic medical record. During the study period, 14 patients (median age 14.5 years, range 2.0-26.4 years) with Fontan circulation were started on a SGLT2i. Mean weight was 54 kg (range 11.6-80.4 kg). Median follow-up since SGLT2i initiation was 4.1 months (range 13 days-7.7 months). Four patients had a systemic left ventricle and 10 had a systemic right ventricle. Half the patients had Fontan Circulatory Failure with reduced Ejection Fraction (FCFrEF) of the systemic ventricle and the other half had Fontan Circulatory Failure with preserved Ejection Fraction (FCFpEF) of the systemic ventricle. In addition, 3 patients experienced Protein Losing Enteropathy (PLE) and 2 patients had plastic bronchitis, one of whom also was diagnosed with chylothorax. There were no genitourinary infections, hypoglycemia, ketoacidosis, hypotension or other significant adverse effects noted in our patient population. One patient experienced significant diuresis and transient acute kidney injury. Patients with FCFrEF showed a decrease in natriuretic peptide levels. Given the lack of proven therapies, demonstrated benefits of SGLT2i in other populations, and some suggestion of efficacy in Fontan circulation, further study of SGTLT2i in patients with Fontan circulation is warranted.

Long-term follow-up of atrioventricular valve function in Fontan patients: effect of atrioventricular valve surgery

OBJECTIVES

The aim of this study was to evaluate the relationship between atrioventricular valve and ventricular function in Fontan survivors, including the effect of atrioventricular valve surgery.

METHODS

Analysis focused on transplant-free survival and the need for atrioventricular valve surgery in single ventricle patients after Fontan completion. Longitudinal echocardiographic examination of long-term valve and ventricular function was performed.

RESULTS

Fontan completion was performed in 113 patients, having a right univentricular morphology in 33.6%, a left ventricle morphology in 62.8% and ambiguous in 3.6%. Perioperative mortality was 2.7% (n = 3). Within a median follow-up of 16.3 years (interquartile range 10.6-23.6), transplant-free survival was 96.1 ± 1.9% and 90.4 ± 5.8% at 10-25 years. Twenty AV valve procedures were performed in 14 (12.4%) children, respectively, pre-Fontan (n = 10), per-Fontan (n = 8) and post-Fontan (n = 2), resulting in a cumulative incidence of AV valve surgery is 5.7 ± 2.2% and 12.3 ± 3.2% at 1-5 years. Atrio-ventricular valve function deteriorated over time [hazard ratio (HR) 1.112, 95% confidence interval (CI) 1.089-1.138, P < 0.001], without difference for valve morphology (P = 0.736) or ventricular dominance (P = 0.484). AV valve dysfunction was greater in patients requiring AV valve surgery (HR 20.383, 95% CI 6.223-36.762, P < 0.001) but showed a comparable evolution since repair to those without valve surgery (HR 1.070, 95% CI 0.987-1.160, P = 0.099). Progressive time-related ventricular dysfunction was observed (HR 1.141, 95% CI 1.097-1.182, P < 0.001), significantly less in left ventricle-dominance (HR 0.927, 95% CI 0.860-0.999, P = 0.047) but more after AV valve surgery (HR 1.103, 95% CI 1.014-1.167, P = 0.022).

CONCLUSIONS

In a homogeneously treated Fontan population, 25-year transplant-free survival is encouraging. Atrio-ventricular valve surgery was necessary in 12.4%, resulting mostly in a durable valve function. However, a slow time-related decline of atrioventricular valve function as of ventricular function is worrisome, evoking a role for additional heart failure therapy.

Fontan Heart: Insight Into the Physiological Role of the Right Heart

BACKGROUND

Cardiac output (CO) is almost normal in children born without a functional right ventricle (RV), and a Fontan repair, so why is RV dysfunction such a clinical problem? We tested the hypotheses that increased pulmonary vascular resistance (PVR) is the dominant factor and volume expansion by any means is of limited benefit.

METHODS

We removed the RV from a previously used MATLAB model and altered vascular volume, venous compliance (Cv), PVR, and measures of left ventricular (LV) systolic and diastolic function. CO and regional vascular pressures were the primary outcome measures.

RESULTS

RV removal decreased CO by 25%, and raised mean systemic filling pressure (MSFP). A 10 mL/kg increase in stressed volume only moderately increased CO with or without the RV. Decreasing systemic Cv increased CO but also markedly increased pulmonary venous pressure. With no RV, increasing PVR had the greatest effect on CO. Increasing LV function had little benefit.

CONCLUSIONS

Model data indicate that increasing PVR dominates the decrease in CO in Fontan physiology. Increasing stressed volume by any means only moderately increased CO and increasing LV function had little effect. Decreasing systemic Cv unexpectedly markedly increased pulmonary venous pressures even with the RV intact.

"Laparoscopic pyeloplasty for treating ureteropelvic junction obstruction in a patient with Fontan physiology: The first case described in literature"

The Fontan procedure is a palliative operation for patients with single ventricle congenital heart disease. In this case-report, we present the case of a 36-years-old man, with Fontan physiology and ureteropelvic junction obstruction, undergoing laparoscopic pyeloplasty. He presented with right flank pain and mild hydronephrosis of his right kidney. Although few laparoscopic operations have been described in the literature, this, to our knowledge, is the first laparoscopic urological procedure described in a patient with Fontan physiology. Laparoscopic pyeloplasty in patients with Fontan physiology, is an efficient and safe technique when performed in centers with extensive experience in laparoscopic procedures.

Considerations for Biventricular Conversion of Fontan Circulation

Despite significant improvements in the management of Fontan circulation in patients with single ventricle physiology, long-term outcomes continue to be suboptimal. Conversion to biventricular circulation is increasingly gaining popularity, particularly in the subset of patients who are not ideal Fontan candidates. Meticulous image-guided planning, extensive preoperative discussions, and a team-based approach are required for successful execution of complex biventricular conversion. A segmental approach to the anatomy of the heart defect allows methodical planning of the technique of biventricular conversion. Ventricular size and function continue to be the Achilles heel of successful biventricular repair. Long-term studies comparing outcomes in patients converted to biventricular circulation to those in patients with Fontan physiology are required to appropriately tailor management approaches to an individual patient.

Adolescents and adults with Fontan circulation: insights from the PREpArE-Fontan registry

The Patient Registry for Adolescents and Adults with Stable Fontan Circulation aims to describe a contemporary cohort of Fontan patients who could be eligible for a clinical trial investigating macitentan, an endothelin receptor antagonist. This international, non-interventional, multicentre, cross-sectional, observational registry enrolled patients with "stable" Fontan circulation ≥10 years following extra-cardiac conduit or lateral tunnel procedure. Main exclusion criteria were NYHA functional class IV, reoperation of Fontan circulation, or signs of disease worsening. Patient characteristics at enrolment are described; available data were collected during a single registration visit. Of the 266 screened patients, 254 were included in this analysis. At enrolment, median (interquartile range) age was 24 (20;30) years, 37%/63% of patients were from the USA/Europe, 54% were male, 54%/47% had undergone extra-cardiac conduit/lateral tunnel procedures, and 95% were in NYHA functional class I or II. History of arrhythmia was more common in older patients and patients with lateral tunnel; overall prevalence was 19%. Most laboratory values were within the normal range but mean creatinine clearance was abnormally low (87.7 ml/min). Angiotensin-converting enzyme inhibitors were used by 48% of patients and their use was associated with creatinine clearance <90 ml/min (p = 0.007), as was Fontan completion at an older age (p = 0.007). 53.4% of patients had clinical characteristics that could potentially meet an endothelin receptor antagonist trial's eligibility criteria. The PREpArE-Fontan registry describes a cohort of patients who could potentially participate in an endothelin receptor antagonist trial and identified early subtle signs of Fontan failure, even in "stable" patients.

Management considerations of Hodgkin lymphoma for patients with Fontan physiology

While treatment protocols for Hodgkin lymphoma (HL) are well established, there is no literature available to guide therapy or estimate prognosis for patients with Fontan physiology who develop HL. The physiology of a Fontan procedure can result in the inability to tolerate chemotherapy toxicities, supportive care, and infection. We present a series of three patients with Fontan physiology who were treated for HL and discuss their clinical course and treatment.

A Decision Rule for Determining the Optimal Transplant Listing Window for Patients With a Fontan Physiology

The Fontan is a complex surgical procedure used as a palliative treatment for children with univentricular hearts. In the past, the mortality rate was high and the associated comorbidities as a result of the Fontan circulation were many. However, as research into the condition developed, better understanding has led to a massive reduction in early mortality and a rapidly increasing population of such patients surviving well into adulthood. This has led to a large surge in patients with congenital heart disease being referred for cardiac transplant assessment. According to research, listing these patients at the optimal time is the key to improving transplant outcomes. However, determining that optimal time is unclear and controversial. In this article, I address this issue by developing an optimal timing rule that accounts for the factors faced by specialist cardiologists in determining when transplant ought to be considered for this cohort of patients.

Epicardial atrial pacing after the extracardiac Fontan operation: Feasibility of an entirely transvenous approach

This series describes an innovative technique for pacing in patients with sinus node dysfunction after extracardiac Fontan surgery. This transpulmonary approach to the left atrial epi-myocardium has been successfully applied to three patients at two centers and resulted in excellent acute and midterm pacing characteristics without known complications. The principal advantage of this procedure in comparison to prior iterations is the absence of pacing material within the pulmonary venous atrium, so that future systemic thromboembolism risk is minimized. The transpulmonary approach for permanent atrial pacing offers a novel solution to the unique challenges for patients after extracardiac Fontan operation.

Bleeding and thrombotic risk in pregnant women with Fontan physiology

BACKGROUND/OBJECTIVES

Pregnancy may potentiate the inherent hypercoagulability of the Fontan circulation, thereby amplifying adverse events. This study sought to evaluate thrombosis and bleeding risk in pregnant women with a Fontan.

METHODS

We performed a retrospective observational cohort study across 13 international centres and recorded data on thrombotic and bleeding events, antithrombotic therapies and pre-pregnancy thrombotic risk factors.

RESULTS

We analysed 84 women with Fontan physiology undergoing 108 pregnancies, average gestation 33±5 weeks. The most common antithrombotic therapy in pregnancy was aspirin (ASA, 47 pregnancies (43.5%)). Heparin (unfractionated (UFH) or low molecular weight (LMWH)) was prescribed in 32 pregnancies (30%) and vitamin K antagonist (VKA) in 10 pregnancies (9%). Three pregnancies were complicated by thrombotic events (2.8%). Thirty-eight pregnancies (35%) were complicated by bleeding, of which 5 (13%) were severe. Most bleeds were obstetric, occurring antepartum (45%) and postpartum (42%). The use of therapeutic heparin (OR 15.6, 95% CI 1.88 to 129, p=0.006), VKA (OR 11.7, 95% CI 1.06 to 130, p=0.032) or any combination of anticoagulation medication (OR 13.0, 95% CI 1.13 to 150, p=0.032) were significantly associated with bleeding events, while ASA (OR 5.41, 95% CI 0.73 to 40.4, p=0.067) and prophylactic heparin were not (OR 4.68, 95% CI 0.488 to 44.9, p=0.096).

CONCLUSIONS

Current antithrombotic strategies appear effective at attenuating thrombotic risk in pregnant women with a Fontan. However, this comes with high (>30%) bleeding risk, of which 13% are life threatening. Achieving haemostatic balance is challenging in pregnant women with a Fontan, necessitating individualised risk-adjusted counselling and therapeutic approaches that are monitored during the course of pregnancy.

Acute neurological injury in pediatric patients with single-ventricle congenital heart disease

OBJECTIVE

Single-ventricle congenital heart disease (CHD) in pediatric patients with Glenn and Fontan physiology represents a unique physiology requiring the surgical diversion of the systemic venous return from the superior vena cava (Glenn) and then the inferior vena cava (Fontan) directly to the pulmonary arteries. Because many of these patients are on chronic anticoagulation therapy and may have right-to-left shunts, arrhythmias, or lymphatic disorders that predispose them to bleeding and/or clotting, they are at risk of experiencing neurological injury requiring intubation and positive pressure ventilation, which can significantly hamper pulmonary blood flow and cardiac output. The aim of this study was to describe the complex neurological and cardiopulmonary interactions of these pediatric patients after acute central nervous system (CNS) injury.

METHODS

The authors retrospectively analyzed the records of pediatric patients who had been admitted to a quaternary children's hospital with CHD palliated to bidirectional Glenn (BDG) or Fontan circulation and acute CNS injury and who had undergone intubation and mechanical ventilation. Patients who had been admitted from 2005 to 2019 were included in the study. Clinical characteristics, surgical outcomes, cardiovascular and pulmonary data, and intracranial pressure data were collected and analyzed.

RESULTS

Nine pediatric single-ventricle patients met the study inclusion criteria. All had undergone the BDG procedure, and the majority (78%) were status post Fontan palliation. The mean age was 7.4 years (range 1.3-17.3 years). At the time of acute CNS injury, which included traumatic brain injury, intracranial hemorrhage, and cerebral infarct, the median time interval from the most recent cardiac surgical procedure was 3 years (range 2 weeks-11 years). Maintaining normocarbia to mild hypercarbia for most patients during intubation periods did not cause neurological deterioration, and hemodynamic profiles were more favorable as compared to periods of hypocarbia. Hypocarbia was associated with unfavorable hemodynamics but was necessary to decrease intracranial hypertension. Most patients were managed using low mean airway pressure (MAWP) in order to minimize the impact on preload and cardiac output.

CONCLUSIONS

The authors highlight the complex neurological and cardiopulmonary interactions with respect to partial pressure of arterial CO2 (PaCO2) and MAWP when pediatric CHD patients with single-ventricle physiology require mechanical ventilation. The study data demonstrated that tight control of PaCO2 and minimizing MAWP with the goal of early extubation may be beneficial in this population. A multidisciplinary team of pediatric critical care intensivists, cardiac intensivists and anesthesiologists, and pediatric neurosurgeons and neurologists are recommended to ensure the best possible outcomes.

Hemodynamic and Clinical Implications of Impaired Pulmonary Vascular Reserve in the Fontan Circulation

BACKGROUND

Pulmonary vascular disease, pulmonary endothelial dysfunction, liver fibrosis, renal disease, and exercise intolerance are common in adults with Fontan physiology. Although the pathophysiologic mechanisms linking these phenomena have been studied, certain aspects are not well understood.

OBJECTIVES

This study hypothesized that impaired pulmonary vascular reserve (VR) plays a central role linking these abnormalities, and that patients with abnormal pulmonary VR with exercise, compared with patients with normal VR, would display poorer pulmonary endothelial function, greater liver stiffness, more renal dysfunction, and poorer exercise capacity.

METHODS

Symptomatic adults with the Fontan palliation (n = 29) underwent invasive cardiopulmonary exercise testing, echocardiography, and assessment of microvascular function. Abnormal pulmonary VR was defined by the slope of increase in pulmonary pressure relative to cardiac output with exercise >3 mm Hg/l/min. Pulmonary endothelial function was assessed using reactive hyperemia index. End-organ function was assessed using magnetic resonance elastography-derived liver stiffness, glomerular filtration rate, N-terminal pro-B-type natriuretic peptide, and peak oxygen consumption (Vo₂).

RESULTS

Compared with individuals with normal VR (n = 8), those with abnormal VR (n = 21) displayed higher central and pulmonary venous pressures, and more severely impaired cardiac output and stroke volume responses to exertion, but similar pulmonary vascular resistance at rest. Patients with abnormal VR displayed more severely impaired reactive hyperemia index, increased liver stiffness, lower glomerular filtration rate, higher N-terminal pro-B-type natriuretic peptide, and lower peak Vo₂. As compared to pulmonary vascular resistance at rest, slope of increase in pulmonary pressure relative to cardiac output displayed stronger correlations with reactive hyperemia index (r = -0.63 vs. r = -0.31; Meng test p = 0.009), magnetic resonance elastography-derived liver stiffness (r = 0.47 vs. r = 0.29; Meng test p = 0.07), glomerular filtration rate (r = -0.52 vs. r = -0.24; Meng test p = 0.03), N-terminal pro-B-type natriuretic peptide (r = 0.56 vs. r = 0.17; Meng test p = 0.02), and peak Vo₂ (r = -0.63 vs. r = -0.26; Meng test p = 0.02).

CONCLUSIONS

Pulmonary vascular limitations in Fontan physiology are related to pulmonary endothelial and end-organ dysfunction, suggesting a mechanistic link between these commonly observed findings, and these abnormalities are more apparent during exercise testing, with little relationship at rest.

Path ahead for 'low risk' adolescents living with a Fontan circulation

OBJECTIVE

A high risk of morbidity and mortality is well documented in adults with a Fontan circulation. The difference in outcomes between those with and without significant morbidity at the time of transition to adult care has not been well characterised.

METHODS

We analysed clinical outcomes in patients enrolled in the Australian and New Zealand Fontan Registry ≥16 years of age. Low risk (LR) Fontan patients were defined as those without history of sustained arrhythmia, thromboembolic event, transplantation, Fontan conversion, protein-losing enteropathy, plastic bronchitis, New York Heart Association class III/IV and/or moderate/severe atrioventricular valve regurgitation or ventricular dysfunction. Increased risk (IR) patients had one or more risk factor.

RESULTS

Inclusion criteria were met in 822 patients; mean age 26±8 years, median follow-up from age 16 was 9 years, 203 had atriopulmonary connection (APC) and 619 had total cavopulmonary connection (TCPC). Survival at 30 years was higher in the LR versus IR; 94% versus 82% (p=0.005), 89% versus 77% (p=0.07) for APC and 96% versus 89% (p=0.05) for TCPC. LR patients experienced less Fontan failure (HR 0.34, 95% CI 0.23 to 0.49, p<0.001) and ventricular dysfunction (HR 0.46, 95% CI 0.29 to 0.71, p=0.001) compared with IR patients. For LR TCPC patients, modelled survival projections at 60 years were 49%-67%.

CONCLUSIONS

Clinical outcomes for adolescents LR at transition to adult care are markedly superior to those who have established risk factors for Fontan failure, which is an important consideration when formulating individualised long-term risk estimates and counselling patients.

Focused Update on Pulmonary Hypertension in Children-Selected Topics of Interest for the Adult Cardiologist

Pulmonary hypertensive vascular disease (PHVD), and pulmonary hypertension (PH), which is a broader term, are severe conditions associated with high morbidity and mortality at all ages. Treatment guidelines in childhood are widely adopted from adult data and experience, though big differences may exist regarding aetiology, concomitant conditions and presentation. Over the past few years, paediatric aspects have been incorporated into the common guidelines, which currently address both children and adults with pulmonary hypertension (PH). There are multiple facets of PH in the context of cardiac conditions in childhood. Apart from Eisenmenger syndrome (ES), the broad spectrum of congenital heart disease (CHD) comprises PH in failing Fontan physiology, as well as segmental PH. In this review we provide current data and novel aspects on the pathophysiological background and individual management concepts of these conditions. Moreover, we focus on paediatric left heart failure with PH and its challenging issues, including end stage treatment options, such as mechanical support and paediatric transplantation. PH in the context of rare congenital disorders, such as Scimitar Syndrome and sickle cell disease is discussed. Based on current data, we provide an overview on multiple underlying mechanisms of PH involved in these conditions, and different management strategies in children and adulthood. In addition, we summarize the paediatric aspects and the pros and cons of the recently updated definitions of PH. This review provides deeper insights into some challenging conditions of paediatric PH in order to improve current knowledge and care for children and young adults.

The Adult Patient with a Fontan

The authors summarize the most important anatomic and physiologic substrates of Fontan circulation. Common anatomic substrates include hypoplastic left heart syndrome, tricuspid atresia, double inlet left ventricle, and unbalanced atrioventricular septal defects. After the Fontan operation exercise capacity is limited and the key hemodynamic drivers is limited preload due to a relatively fixed pulmonary vascular resistance. The authors provide contemporary data on survival, morbidity, and need for reintervention. Operative morality is now expected to be less than 1% and 30 year survival approximately 89%. The authors delineate potential therapeutic approaches for the potential late complications.

Augmentation of pulmonary blood flow and cardiac output by non-invasive external ventilation late after Fontan palliation

Objectives

Although a life-preserving surgery for children with single ventricle physiology, the Fontan palliation is associated with striking morbidity and mortality with advancing age. Our primary objective was to evaluate the impact of non-invasive, external, thoraco-abdominal ventilation on pulmonary blood flow (PBF) and cardiac output (CO) as measured by cardiovascular magnetic resonance (CMR) imaging in adult Fontan subjects.

Methods

Adults with a dominant left ventricle post-Fontan palliation (lateral tunnel or extracardiac connections) and healthy controls matched by sex and age were studied. We evaluated vascular flows using phase-contrast CMR imaging during unassisted breathing, negative pressure ventilation (NPV) and biphasic ventilation (BPV). Measurements were made within target vessels (aorta, pulmonary arteries, vena cavae and Fontan circuit) at baseline and during each ventilation mode.

Results

Ten Fontan subjects (50% male, 24.5 years (IQR 20.8–34.0)) and 10 matched controls were studied. Changes in PBF and CO, respectively, were greater following BPV as compared with NPV. In subjects during NPV, PBF increased by 8% (Δ0.20 L/min/m² (0.10–0.53), p=0.011) while CO did not change significantly (Δ0.17 L/min/m² (−0.11–0.23), p=0.432); during BPV, PBF increased by 25% (Δ0.61 L/min/m² (0.20–0.84), p=0.002) and CO increased by 16% (Δ0.47 L/min/m² (0.21–0.71), p=0.010). Following BPV, change in PBF and CO were both significantly higher in subjects versus controls (0.61 L/min/m² (0.2–0.84) vs −0.27 L/min/m² (−0.55–0.13), p=0.001; and 0.47 L/min/m² (0.21–0.71) vs 0.07 L/min/m² (−0.47–0.33), p=0.034, respectively).

Conclusion

External ventilation acutely augments PBF and CO in adult Fontan subjects. Confirmation of these findings in larger populations with longer duration of ventilation and extended follow-up will be required to determine sustainability of haemodynamic effects.

N-terminal pro-brain natriuretic peptide serum levels reflect attrition of the Fontan circulation

OBJECTIVE

N-terminal pro-brain natriuretic peptide has an established role in the diagnosis and prognosis of heart failure. In Fontan patients, this peptide is often increased, but its diagnostic value in this particular non-physiologic, univentricular circulation is unclear. We investigated whether N-terminal pro-brain natriuretic peptide represents ventricular function or other key variables in Fontan patients.

METHODS AND RESULTS

Ninety-five consecutive Fontan patients ≥10 years old who attended the outpatient clinic of the Center for Congenital Heart Diseases in 2012-2013 were included. Time since Fontan completion was 16 ± 9 years. Median N-terminal pro-brain natriuretic peptide was 114 (61-264) ng/l and was higher than gender-and age-dependent normal values in 54% of the patients. Peptide Z-scores were higher in patients in NYHA class III/IV compared to those in class I/II, but did not correlate with ventricular function assessed by MRI and echocardiography, nor with peak exercise capacity. Instead, peptide Z-scores significantly correlated with follow-up duration after Fontan completion (p < 0.001), right ventricular morphology (p = 0.004), indexed ventricular mass (p = 0.001), and inferior caval vein diameter (p < 0.001) (adjusted R2 = 0.615).

CONCLUSIONS

N-terminal pro-brain natriuretic peptide levels in Fontan patients correlate with functional class, but do not necessarily indicate ventricular dysfunction. Increased peptide levels were associated with a longer existence of the Fontan circulation, morphologic ventricular characteristics, and signs of increased systemic venous congestion. Since the latter are known to be key determinants of the performance of the Fontan circulation, these findings suggest increase in N-terminal pro-brain natriuretic peptide levels to indicate attrition of the Fontan circulation, independent of ventricular function.

Human Deoxyribonuclease (rhDNase) Nebulization as an Alternative Treatment for Refractory Plastic Bronchitis After Fontan Surgery

We report the case of a 5-year-old boy who developed chronic plastic bronchitis after Fontan surgery for a complex congenital heart disease. During a new admission for acute exacerbation of plastic bronchitis, he started on a mucolytic treatment with inhaled rhDNAse instead of inhaled fibrinolytics because of the potential bleeding risk in a patient on combined coumarin and aspirin treatment. Respiratory symptoms resolved promptly, and the patient was discharged home on rhDNAse treatment. He remained clinically stable on rhDNAse treatment without further hospitalization until definitive treatment with dynamic lymphangiography and percutaneous embolization.

Fluid-structure interaction analysis of a collapsible axial flow blood pump impeller and protective cage for Fontan patients

Limited donor organs and alternative therapies have led to a growing interest in the use of blood pumps as a treatment strategy for patients with single functional ventricle. The present study examines the use of collapsible and flexible impeller, cage, and diffuser designs of an axial blood pump for Fontan patients. Using one-way fluid-structure interaction (FSI) studies, the impact of blade deformation on blood damage and pump performance was investigated for flexible impellers. We evaluated biocompatible materials, including Nitinol, Bionate 80A polyurethane, and silicone for flow rates between 2.0-4.0 L/min and rotational speeds of 3000-9000 rpm. The level of deformation experienced by a cage and diffuser made of surgical stainless steel (control), Nitinol, and Bionate 80A polyurethane was also predicted using one-way FSI. The fluid pressure on the surface of the impeller, cage, and diffuser was determined using computational fluid dynamics (CFD), and then, the surface pressure was exported and used to investigate the impeller, cage, and diffuser deformation using finite element analysis. Finally, deformed impeller geometries were imported into the CFD software to determine the implication of deformation on pressure generation, blood damage index, and fluid streamlines. It was found that rotational speed, and not flow rate, is the largest determinant of impeller deformation, occurring at the blade trailing edges. The models predicted the maximum impeller deformation for Nitinol to be 40 nm, Bionate 80A polyurethane to be 106 μm, and silicone to be 2.8 mm, all occurring at 9000 rpm. The effects of silicone deformation on performance were significant, particularly at speeds above 5000 rpm where a decrease in pressure generation of more than 10% was observed. Despite this loss, the pressure generation at 5000 rpm exceeded the level required to alleviate Fontan complications. A blood damage estimation was performed and levels remained low. The effect of significant impeller deformation on blood damage was inconsistent and requires additional investigation. Cage and diffuser geometries made of steel and Nitinol deformed minimally but Bionate 80A experienced unacceptable levels of deformation, particularly in the free-flow case without a spinning impeller. These results support the continued evaluation of a flexible, pitch-adjusting, axial-flow, mechanical assist device as a clinical therapeutic option for patients with dysfunctional Fontan physiology.

Routine Surveillance Catheterization is Useful in Guiding Management of Stable Fontan Patients

We developed a Fontan surveillance catheterization protocol as part of routine assessment of stable patients 10 years after Fontan completion. The surveillance catherization includes hemodynamic assessment with inhaled nitric oxide, angiography, liver biopsy, and transcatheter intervention if indicated. We aimed to describe hemodynamic and liver biopsy findings, response to pulmonary vasoreactivity testing, rates of transcatheter intervention, and changes in medical therapy following surveillance catheterization in stable Fontan patients. A single-center retrospective review of Fontan patients undergoing surveillance catheterization between November 2014 and May 2019 was performed. Liver biopsies were independently scored by two pathologists. Sixty-three patients underwent surveillance catheterization (mean age 14.6 ± 3.0 years). The mean Fontan pressure was 11.8 ± 2.1 mmHg. The mean cardiac index was 2.9 ± 0.6 L/min/m². In the 51 patients who underwent pulmonary vasoreactivity testing, there was a significant decrease in median pulmonary vascular resistance (1.8 [range 0.8-4.1] vs 1.4 [range 0.7-3.0] Wood units × m²; p < 0.001). The mean cardiac index increased (3.0 ± 0.6 vs 3.2 ± 0.7 L/min/m², p = 0.009). The Fontan pressure did not change significantly. Fifty-seven patients underwent liver biopsy, and all but one showed fibrosis. Nineteen patients (33.3%) demonstrated bridging fibrosis or cirrhosis. Twenty-five patients underwent 34 transcatheter interventions. Pulmonary artery or Fontan stent placement was performed in 19 patients. Phosphodiesterase type 5 inhibitors were initiated in nine patients following surveillance catheterization. Routine surveillance catheterization with liver biopsy in adolescent Fontan patients reveals information that can guide interventional and medical management. Further long-term follow-up and assessment are indicated to assess the benefit of these interventions.

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.

Cost-Effectiveness of Percutaneous Lymphatic Embolization for Management of Plastic Bronchitis

BACKGROUND

Plastic bronchitis is a dreaded complication of single ventricle physiology occurring following palliation via Fontan procedure. Medical management of plastic bronchitis often fails, requiring heart transplantation. Percutaneous lymphatic embolization is an emerging treatment for plastic bronchitis.

METHODS

To determine the cost-effectiveness of competing management strategies, a modified Markov model was constructed with patients transiting through treatments-medical management, lymphatic embolization, or heart transplantation from a hospital system perspective. Health state transitions were modeled using an institutional review board-approved retrospective review of the Children's Hospital of Pennsylvania's plastic bronchitis cohort. Medication pricing data were obtained from the National Inpatient Sample. Differences in costs and quality-adjusted life years (QALYs) over a five-year horizon for each group were determined. The incremental cost-effectiveness ratio was then calculated.

RESULTS

The mean cost of lymphatic embolization from procedure performance was US$340,941, US$385,841 for heart transplantation, and US$594,520 for medical management. The mean quality-adjusted survival of lymphatic embolization yielded an additional 0.66 QALYs (P < .03) relative to heart transplantation and 1.3 (P < .0001) relative to medical management. Orthotopic heart transplantation yielded an additional 0.66 QALYs (P = .06) when comparing heart transplantation to medical management. Compared to medical management, lymphatic embolization generated an incremental cost-effectiveness ratio of US$192,105. Similarly, compared to heart transplantation, lymphatic embolization yielded an incremental cost-effectiveness ratio of US$68,030.

CONCLUSIONS

Of the available plastic bronchitis treatments, with a willingness to pay of US$150,000, lymphatic embolization produces an incremental cost-effectiveness ratio within the bounds considered to be cost-effective, potentially causing financial benefits to the health system.

Analysis of Inflammatory Cytokines in Postoperative Fontan Pleural Drainage

Prolonged pleural drainage is a common complication in patients after Fontan palliation and is associated with short- and long- term morbidities. Among many potential etiologies, prolonged drainage has an inflammatory component, but there are no descriptions of cytokines in Fontan pleural drainage to date. This study aimed to examine the inflammatory make-up of Fontan pleural drainage. This prospective age-range-matched cohort study recruited 25 patients undergoing Fontan procedure and 15 bi-ventricular patients undergoing cardiopulmonary bypass (CPB). Chest tube samples were taken on postoperative day (POD) 1-4, 7, and 10. Cytokines were measured using Bio-Plex Assays. Univariate comparisons were made in patient characteristics and cytokine levels. Median age was 3.7 y (IQR 2.8-3.9) for controls and 2.5 y (IQR 2.1-2.9) in Fontan patients (p = 0.02). Median drainage duration and daily volume was higher in Fontan patients (both p < 0.001). Inflammatory cytokines (IL-17A, IFN-y, MIP-1β, and TNF-α) were higher in Fontan patients than controls (all p < 0.02). There was an increase in pro-inflammatory cytokines (IL-8, MIP-1β, and TNF-α) from POD1 to the last chest tube day (LCD) in Fontan patients (all p < 0.0001) and a decrease in the anti-inflammatory cytokine IL-10 (p = 0.001). There was no difference in cytokine concentration from POD1 to LCD among controls. There was a significant association with the cytokine concentration of TNF-α on POD1 and duration of chest tube drainage (p < 0.05). Inflammatory cytokine levels in the pleural fluid of Fontan patients are higher compared to bi-ventricular controls and rise over time where controls do not. This suggests ongoing localized inflammation that is not a result of CPB alone and may be an important contributor to pleural drainage in patients after the Fontan procedure.

Impact of Time Interval Between Glenn and Fontan Procedures on Fontan Operative and Long-Term Follow-up Results

OBJECTIVE

The bidirectional cavopulmonary shunt (BCPS) is an effective palliative procedure which has been widely used to boost outcome of the Fontan procedure. However, there is no standard duration time between these two procedures. Therefore, we investigated whether different time intervals between BCPS and Fontan procedure affects morbidity and mortality of Fontan patients.

METHODS

Between 2004 and 2016, 210 post-BCPS patients underwent Fontan operation at Fuwai Hospital. The median interval between BCPS and Fontan procedure was 3.7 years (range 0.55-11.86 years) and this was used to divide study cohort into Group 1 (< 3.7 years; n = 124) and Group 2 (> 3.7 years; n = 86). We analyzed these patients retrospectively in terms of their preoperative characteristics and post-operative and follow-up results.

RESULTS

Weight z-scores for age at BCPS (- 0.73 ± 1.39 vs - 1.17 ± 1.60, p < 0.05) was significantly higher in Group 2. However, saturation at room air before Fontan (76.42 ± 20.01 vs 82.85 ± 9.69, p < 0.001) was significantly higher in Group 1. The morbidity and mortality were similar between two groups. There were twelve hospital deaths (5.7%): eight (8/124, 6.5%) presented in Group 1 and four (4/86, 4.7%) in Group 2. On multi-variable analysis, risk factors for death were prolonged mechanical ventilation [hazard ratio (HR) 1.02, p = 0.004] and single right ventricle (HR 7.17, p = 0.03). After a mean follow-up of 4.95 years (range 0.74-13.62 years), one patient in Group 1 died of heart failure 13 months after Fontan procedure. The overall Fontan failure in Group 1 was similar to that in Group 2 (2.7% vs 2.6%, p = 0.985). The incidence of arrhythmias and re-intervention were not different between the two groups.

CONCLUSIONS

Fontan procedure could be performed safely in patient who stayed in long duration between Fontan procedure and BCPS without affecting the operative and long-term follow-up results. However, for post-BCPS patients with severe hypoxemia, earlier age at Fontan might be a good choice.

Bronchoscopic and histologic findings during lymphatic intervention for plastic bronchitis

BACKGROUND

Percutaneous lymphatic intervention (PCL) is a promising new therapy for plastic bronchitis (PB). We characterized bronchoalveolar lavage (BAL) and cast morphology in surgically repaired congenital heart disease (CHD) patients with PB during PCL. We quantified respiratory and bronchoscopic characteristics and correlated them with post-intervention respiratory outcomes.

METHODS

We retrospectively reviewed patients with PB and surgically repaired CHD undergoing PCL and bronchoscopy at our institution. Pre-intervention characteristics, bronchoscopy notes, BAL cell counts, virology, and cultures were collected. A pathologist blinded to clinical data reviewed cast specimens. Respiratory outcomes were evaluated through standardized telephone questionnaire.

RESULTS

Sixty-two patients were included with a median follow-up of 20 months. No patients experienced airway bleeding, obstruction, or prolonged intubation related to bronchoscopy. Of BAL infectious studies, the positive results were 4 (8%) fungal, 6 (11%) bacterial, and 6 (14%) viral. Median BAL count per 100 cells for neutrophils, lymphocytes, and eosinophils were 13, 10, and 0, respectively. Of 23 bronchial casts analyzed, all contained lymphocytes, and 19 (83%) were proteinaceous, with 14 containing neutrophils and/or eosinophils. Median BAL neutrophil count was greater in patients with proteinaceous neutrophilic or eosinophilic casts compared to casts without neutrophils or lymphocytes (P = 0.030). Post-intervention, there was a significant reduction in respiratory medications and support and casting frequency.

CONCLUSIONS

The predominance of neutrophilic proteinaceous casts and high percentage of positive BAL infectious studies support short-term fibrinolytic and anti-infective therapies in PB in select patients. Flexible bronchoscopy enables safe assessment of cast burden. PCL effectively treats PB and reduces respiratory therapies.

Acute-onset abdominal pain in a woman in her 30s

CLINICAL INTRODUCTION

A woman in her 30s presented to the emergency department with sudden-onset abdominal pain with hypotension and tachycardia. She gave a history of congenital heart disease for which she had previously undergone multiple operations. On examination she demonstrated right upper quadrant tenderness. She underwent an urgent multiphase CT (figure 1A-C).heartjnl;105/4/275/F1F1F1Figure 1(A) Arterial phase coronal CT. (B) Arterial phase axial CT. (C) Portal venous phase axial CT.

QUESTION

What is the underlying liver pathology?Hepatocellular adenomaCholangiocarcinomaHepatocellular carcinomaFocal nodular hyperplasiaHepatoblastoma.

Quality of life and sexual well-being in patients with a Fontan circulation: An explorative pilot study with a mixed method design

OBJECTIVE

To get an impression of the quality of life (QOL) and sexual well-being in the Fontan population, and to generate hypotheses for future research.

METHODS

For this cross-sectional pilot study, questionnaires regarding health-related QOL, sexual function and fertility/pregnancy were completed by 21 patients with a Fontan circulation >16 years old, followed at the University Medical Center Groningen, the Netherlands. Semi-structured qualitative interviews were conducted in 8 patients.

RESULTS

Fontan patients scored significantly lower on general health than their healthy peers (t(19)=-3.0, P = .008), whereas their scores on other QOL domains and sexual well-being were comparable to normal values. During childhood, most patients experienced physical limitations and the feeling of being an outsider, and frequently faced bullying. Regarding sexual well-being, large interindividual differences were noted. Four interviewed patients (25-30 years) reported a good sexual well-being, whereas the other interviewed patients (33-47 years) reported erectile dysfunction, low self-esteem and avoidance of sexual intercourse. Both the QOL domains mental health and role restrictions due to emotional problems were associated with female avoidance (P = .083, respectively, P = .089) and dyspareunia (P = ns respectively P = .094). In males, role restrictions due to physical problems and health change were related to sexual dissatisfaction (P = .056) respectively nonsensuality (P = .025).

CONCLUSIONS

Overall, Fontan patients have a relatively preserved quality of life and sexual wellbeing but face more social isolation and bullying during childhood/adolescence than their healthy peers. Sexual problems were mainly associated with physical limitations in males and with psychosocial limitations in females. Finally, sexual dysfunction was more common in older Fontan patients, and future research has to clarify whether progressive attrition of the Fontan circulation affects the patients' QOL and sexual well-being.

The respiratory system in pediatric chronic heart disease

Cardiovascular disease in the pediatric population closely affects the respiratory system inducing water retention in the lungs and pulmonary edema, airway compression by cardiovascular structures, restrictive pulmonary physiology as a result of hemodynamic changes and surgical repair, susceptibility to respiratory infections, development of pulmonary hypertension, thrombosis, or hemorrhage. Chronic heart failure and congenital heart disease are characterized by various respiratory manifestations and symptoms mimicking lung disease, which are frequently difficult to diagnose and treat. Pulmonary function is multiply affected in pediatric heart disease with mostly restrictive but also obstructive and diffusion abnormalities. Patients with Fontan circulation represent a separate group with slow, passive pulmonary blood flow and distinct pathophysiology with low cardiac output heart failure, restrictive lung pattern, increased thromboembolic complications and rare conditions such as protein losing enteropathy and plastic bronchitis. Distinguishing between cardiovascular and pulmonary symptoms may be challenging in the growing population of pediatric and adult survivors of congenital heart disease and understanding of the relationship of the two systems in heart disease is crucial for the optimal management of these patients.

Congenital heart diseases and anaesthesia

Patients with congenital heart diseases (CHDs) are at increased risk of developing complications during anaesthesia. Improvements in medical and surgical management in recent decades have resulted in significantly more children with CHD surviving to adulthood. The aim of this article is to focus on broad classification of CHD and to provide an updated review on the current perioperative anaesthetic management of CHD patients in different settings such as (a) interventional cardiac procedures that have dominated the field, (b) uncorrected patients for non-cardiac surgery and (c) corrected patients for non-cardiac surgery. The complexity of the defects along with a variety of non-cardiac surgery makes it impossible to have one single-anaesthesia technique. Search on Ovid, PubMed, Google Scholar and Medline were done with MeSH terms such as 'congenital heart disease', 'cardiac catheterisation', 'anaesthetic management' and 'non-cardiac surgery' mainly focusing on review articles and controlled studies for preparing the article.

Successful one-lung ventilation in a patient with the Fontan circulation undergoing thoracoscopic procedure

Over the course of the past 4 decades, the survival of patients with the Fontan circulation has improved and today they often present for noncardiac surgery anesthesia care. In patients with the Fontan circulation, pulmonary blood flow is passive and anesthetic management is directed at reducing pulmonary vascular resistance and maintaining adequate cardiac output. One-lung ventilation can have unfavorable effects on the Fontan circulation due to hypoxia, hypercarbia, and increased airway pressure. We present a case of successful one-lung ventilation in a patient with the Fontan circulation and describe the perioperative anesthetic management.

CT demonstration of the extracardiac anastomoses of the coronary veins in superior vena cava or left brachiocephalic vein obstruction

CT scans in four cases of chronic superior vena cava or left brachiocephalic vein obstruction demonstrate a systemic-to-cardiac collateral venous pathway through anastomoses between the pericardial branches of systemic veins and the presumed adventitial veins of the ascending aorta and pulmonary trunk. These adventitial veins then drain into tributaries of the anterior cardiac veins or ventricular coronary veins.