Rare problems associated with the Fontan circulation

The Fontan operation, originally described for the surgical management of tricuspid atresia, is now the final surgery in the strategy of staged palliation for a number of different forms of congenital cardiac disease with a functionally univentricular heart. Despite the improved technical outcomes of the Fontan operation, staged palliation does not recreate a normal physiology. Without a pumping chamber delivering blood to the lungs, the cardiovascular system is less efficient; cardiac output is generally diminished, and the systemic venous pressure is increased. As a result, patients with "Fontan physiology" may face a number of rare but potentially life-threatening complications including hepatic dysfunction, abnormalities of coagulation, protein-losing enteropathy, and plastic bronchitis. Despite the staged palliation resulting in remarkable survival, the possible complications for this group of patients are complex, involve multiple organ systems, and can be life threatening. Identifying the mechanisms associated with each of the rare complications, and developing strategies to treat them, requires the work of many people at many institutions. Continued collaboration between sub-specialists and between institutions will be required to optimise the care for this group of survivors with functionally univentricular hearts.     

Echocardiographic evaluation of univentricular physiology and cavopulmonary shunts

Since the surgical palliation of a univentricular congenital heart defect was first described in the early 1970s, thousands of lives were saved by this groundbreaking operation. Although initially described for the palliation of tricuspid valve atresia, the Fontan operation is now utilized for many other univentricular heart defects involving either hypoplastic right or left ventricles, and the number of babies who survive the surgery and the postsurgical hospitalization continues to grow. Echocardiography constitutes the mainstay follow‐up imaging modality for patients with a Fontan system. In order to obtain all the needed information from the echocardiographic studies, close familiarity with the native congenital heart defects, the build of the Fontan systems, and the potential long‐term complications is required. Detailed studies provide valuable information on the various components of the Fontan circulation such as the function of the single ventricle and the valves, flow in the Glenn and Fontan pathways, and possible sources of cyanosis and shunts. Three‐dimensional and transesophageal echocardiogram studies can assist in delineating the Fontan anatomy and to evaluate smaller intracardiac structures.     

Relief of an early pulmonary pathway obstruction with stenting after modified Fontan operation in an adult

The prognosis of Tricuspid Atresia, a rare congenital heart disease, has been changed by surgery. The criteria for Fontan operation have been well established in the literature and adult patients rarely fulfil these criteria; however, in very selected cases Fontan operation can be performed also in adults. A 33 year old woman with tricuspid atresia and previous palliation with classical right Glenn and with left modified Blalock-Taussing, underwent modified Fontan operation because increasing cyanosis and moderate exercise intolerance. Three weeks after operation the patient was readmitted with severe heart failure because of a tight obstruction at the anastomosis between right atrium and main-left pulmonary artery. The stenosis was treated with balloon and stenting achieving large pathway. Our experience confirms that after a modified Fontan, if cardiac failure occurs, an immediate full investigation have to be done.     

Laparoscopic colectomy in an adult with single ventricle physiology: Anesthetic implications and management

Increasing numbers of adult patients with complex congenital heart conditions are presenting for noncardiac surgery later in life. These disorders can present challenges for surgical and anesthesia providers. Specifically, single ventricle lesions offer anatomic and physiologic concerns during the perioperative period. Single ventricle physiology represents a delicate balance between systemic and pulmonary blood flow. Any alterations in blood flow through these systems can produce undesirable hemodynamic changes, especially during the perioperative period. We present a case of an adult patient with a single left ventricle who presented for laparoscopic total colectomy due to inflammatory bowel disease. His abnormal anatomy coupled with the hemodynamic disruptions caused by laparoscopy presented significant anesthetic challenges. We highlight the anesthetic concerns of single ventricle physiology, specifically pertaining to laparoscopic surgery. We provide recommendations for safely managing these patients perioperatively. With detailed preoperative evaluation and close hemodynamic monitoring during the perioperative period, these patients can experience successful surgical and anesthetic outcomes.     

A case of PAGOD syndrome with hypoplastic left heart syndrome

PAGOD syndrome is an extremely rare congenital malformation complex involving multiple organs. These include pulmonary artery and lung hypoplasia, diaphragm defects, omphalocele, sex reversal or ambiguous genitalia, and complex cardiac defects. Eight cases have been reported to date. We report a case of PAGOD syndrome that is manifested by right diaphragm eventration, horseshoe lung with right lung hypoplasia, hypoplastic left heart syndrome (mitral atresia, aortic atresia), scimitar syndrome, agonadism with ambiguous genitalia. A karyotype revealed normal 46-XY. This patient received a modified Norwood procedure for hypoplastic left heart syndrome as an initial palliation and bidirectional cavopulmonary anastomosis as a second stage of operation. The postoperative courses were uneventful. This patient is waiting for Fontan operation.     

Course of tricuspid atresia in the Fontan era

Tricuspid atresia is an uncommon form of congenital heart disease and long-term survival was rare before the Fontan era. It was thought that the long-term survival of patients with tricuspid atresia would be improved by the introduction of the Fontan procedure and its subsequent modifications. This study reviews the clinical course of 84 patients with tricuspid atresia identified in the first year of life in the Fontan era. Prior palliative operations, their results and their ultimate application for the Fontan procedure were considered. Eleven patients died before surgical intervention and 5 did not undergo catheterization or echocardiographic confirmation before death. Five children underwent the Fontan procedure without prior palliation and 1 child does not require palliation at the present time. Sixty-seven patients (80%) had surgical procedures before evaluation for the suitability of a Fontan operation. Thirty-four patients had a second surgical palliation and 9 patients had a third palliation. The surgical mortalities for the first, second and third palliative surgery were 17.9, 17.6 and 0%, respectively. Thirty-two patients (38%) underwent the Fontan procedure and 2 deaths occurred (6%). An estimate of the probability of surviving for 1 year was 64% (95% confidence limits 54 to 74%) and that of 8 years was 55% (95% confidence limits 44 to 66%).     

The utility of cardiac magnetic resonance imaging in post‐Fontan surveillance

Objective: Gated cardiac MRI offers the most detailed and accurate noninvasive method of assessing cardiac anatomy, particularly in patients with complex congenital heart disease. The proposed benefits of using cMRI as a routine screening tool in the Fontan population include early recognition of asymptomatic, postoperative anatomic and physiologic changes. In 2011, we therefore instituted at our center a recommended practice of cMRI screening in patients with Fontan physiology at 3 and 8 years postFontan operation. The purpose of this study was to determine the impact of this standardized practice of cMRI screening on the clinical management of a Fontan population.
Design: We retrospectively reviewed charts from our institutional Fontan database to determine which patients were eligible for cMRI under the current guidelines and who underwent imaging from November 2002 to June 2015. We reviewed the frequency of cMRI and number of changes in management based on the results. Statistical significance was determined using a chi-square test.
Results: There were 141 cMRIs performed on 121 patients who met inclusion criteria. The odds of a change in management were significantly greater after clinically indicated cMRI compared to screening cMRI (OR = 3.79, 95% CI: 1.48-9.66, P = .004). There were near significant odds of change in management if the cMRI occurred <8 years after Fontan regardless of whether it was for screening or clinically indicated purposes (OR = 2.43, 95% CI: 0.97-6.08, P = .052). The most frequent change in management was referral for catheterization with pulmonary artery angioplasty.
Conclusions: There is an important role for cMRI in routine surveillance of post-Fontan patients. Screening cMRI performed less than 8 years after Fontan palliation offers increased utility compared to studies performed later. The optimal timing of such imaging after Fontan palliation remains unclear.     

Heart Rate Responses During Exercise by Dominant Ventricle in Pediatric and Young Adult Patients With a Fontan Circulation

BackgroundPatients with univentricular physiology palliated with the Fontan operation have multiple late cardiovascular and extracardiac complications, including autonomic dysfunction. Despite the observation, little is known about autonomic function driving exercise-related heart rate responses in Fontan patients and whether dominant ventricle subtype or underlying cardiac anatomy affects heart rate responses during exercise.MethodsWe performed a retrospective chart review of all single ventricle patients palliated with a Fontan operation who underwent a maximal effort cardiopulmonary exercise test at Cincinnati Children’s Hospital Medical Center from 2013 to 2018.ResultsOne hundred and three Fontan patients aged 16.7 ± 5.5 years were included in this study. Although both the systemic right (n = 38) and systemic left (n = 65) ventricle groups demonstrated chronotropic incompetence, there were no differences between the groups in maximal heart rate (167.5 ± 17.4 vs 169.6 ± 20.9 bpm, P = 0.59), heart rate reserve (87.3 ± 22.6 vs 96.8 ± 25.7, P = 0.06) nor chronotropic index (70 ± 13% vs 74 ± 20%, P = 0.19). In addition, there were no differences between the groups in heart rate recovery at 1, 3, 5, and 10 minutes. Interestingly, patients with hypoplastic left heart syndrome (n = 34) had lower heart rate reserve (84.76 ± 22.8 vs 96.38 ± 26.75, P = 0.04) and chronotropic index (70.5 ± 12.5% vs 76.3 ± 13.2%, P = 0.04) compared with patients with tricuspid atresia (n = 42).ConclusionsFontan patients commonly have chronotropic incompetence, diminished heart rate reserve but with preserved heart rate recovery. Although there is overall no difference in chronotropy in Fontan patients based on dominant systemic ventricle, there is a difference between patients with hypoplastic left heart syndrome and those with tricuspid atresia.     

Special problems in Fontan-type operations for complex cardiac lesions

Four patients with complex cardiac lesions, who underwent successfully a Fontan type of operation are presented, each case representing a particular problem in surgical management. The first exhibited displacement of a trileaflet straddling and overriding left atrioventricular valve in addition to tricuspid atresia, while the second one had unilateral lung perfusion. In the third case, a stenosis had developed near the origin of the right pulmonary artery, and pulmonary vascular resistance could not be determined prior to the definite palliation procedure, whereas the fourth patient presented with stenosis of the left atrioventricular valve. Surgery was planned after detailed evaluation of the morphologic and hemodynamic features by means of echocardiography and cardiac catheterization. Our results illustrate the common tendency to extend the limits for modified Fontan procedures, which also includes revision of the original criteria for selection.     

Orthotopic heart transplantation in patients with univentricular physiology

Parallel advancements in surgical technique, preoperative and postoperative care, as well as a better understanding of physiology in patients with duct-dependent pulmonary or systemic circulation and a functional single ventricle, have led to superb results in staged palliation of most complex congenital heart disease (CHD) [1]. The Fontan procedure and its technical modifications have resulted in markedly improved outcomes of patients with single ventricle anatomy [2,3,4]. The improved early survival has led to an exponential increase of the proportion of Fontan patients surviving long into adolescence and young adulthood [5]. Improved early and late survival has not yet abolished late mortality secondary to myocardial failure, therefore increasing the referrals for cardiac transplantation [6]. Interstage attrition [7] is moreover expected in staged palliation towards completion of a Fontan-type circulation, while Fontan failure represents a growing indication for heart transplantation [8]. Heart transplantation has therefore become the potential "fourth stage" [9] or a possible alternative to a high-risk Fontan operation [10] in a strategy of staged palliation for single ventricle physiology. Heart transplant barely accounts for 16% of pediatric solid organ transplants [11]. The thirteenth official pediatric heart transplantation report- 2010 [11] indicates that pediatric recipients received only 12.5% of the total reported heart transplants worldwide. Congenital heart disease is not only the most common recipient diagnosis, but also the most powerful predictor of 1-year mortality after OHT. Results of orthotopic heart transplantations (OHT) for failing single ventricle physiology are mixed. Some authors advocate excellent early and mid-term survival after OHT for failing Fontan [9], while others suggest that rescue-OHT after failing Fontan seems unwarranted [10]. Moreover, OHT outcome appears to be different according to the surgical staging towards the Fontan operation and surgical technique of Fontan completion [12].The focus of this report is a complete review of the recent literature on OHT for failing single ventricles, outlining the clinical issues affecting Fontan failure, OHT listing and OHT outcome. These data are endorsed reporting our experience with OHT for failing single ventricle physiology in recent years.     

Noncardiac surgery in the elderly patient with cardiovascular disease

The elderly patient with cardiovascular disease who undergoes noncardiac surgery presents a challenge to the medical-surgical team. A high prevalence of cardiac disease necessitates a preoperative in-depth search for the presence of cardiovascular risk factors and their reversal if possible. Aging is associated with an altered physiologic response to the stress of surgery as well as to anesthetic agents and perioperative medications, requiring that the elderly patient often be treated quite differently than the younger surgical patient. This article provides guidelines for the estimation of the risk of cardiac complication due to noncardiac surgery and discusses the identification and management of acute and chronic cardiovascular problems in the perioperative period.     

The impact of electroencephalography, pressure, and pO2 monitoring on the risk of stroke during cardiopulmonary bypass

Currently it is possible to account for an incidence of perfusion-related perioperative stroke of about 1%. The sources of stroke over which cardiac surgeons have some control relate to the perfusion circuit, the conducting of coronary pulmonary bypass, the operative approach to the patient with intracardiac clot, maneuvers that eliminate air during left heart procedures, control of biochemical factors such as hyperglycemia, and to the choice of anesthetic agents and drugs given during the procedure. The availability of equipment that allows in-line continuous monitoring of arterial and venous O2 saturations, control of physiologic parameters within certain limits, selective use of encephalographic monitoring for high-risk patients, along with careful attention to the details of the procedure, may allow the surgeon to alter favorably the numbers of patients suffering neurologic complications as a consequence of cardiac surgery. We have limited our investigation in this study to those neurologic events occurring from the onset of anesthesia through the recovery from anesthesia when the patient can be neurologically examined.     

Anaesthetic management of a patient undergoing reoperation for pathway obstruction after fontan operation

Since 1968, the Fontan operation, or its various modifications, have provided a functional correction in an increasingly complex spectrum of congenital heart malformations.1.2 These procedures have gained wide acceptance because of very good intermediate and longterm results2. However, as survival increases, follow up of these patients has shown more prevalent reoperations for obstruction of the surgically created corrective pathway.3 perioperative management of these patients requires an understanding of the unique anatomic and physiologic changes occurring in this condition. In this report, we review our anaesthetic management of a patient who underwent reoperation for thrombotic occlusion of the conduit from a previous Fontan procedure.     

Cardiac Implantable Electronic Devices in the Fontan Patient

As a result of remarkable progress in operative techniques and cardiology care during childhood, Fontan patients continue to age and require team-based multidisciplinary expertise to manage complications encountered in adulthood. They face particular challenges in terms of altered hemodynamic stressors, cardiac and hepatic failure, and arrhythmias. Arrhythmias in Fontan patients are highly prevalent and associated with underlying anatomy, surgical technique, and postoperative sequelae. Diagnostic tools, treatments, and device strategies for arrhythmias in Fontan patients should be adapted to the specific anatomy, type of surgical repair, and clinical status. Great strides in our understanding of arrhythmia mechanisms, options and techniques to obtain access to relevant cardiac structures, and application of both old and new technologies have contributed to improving cardiac implantable electronic device (CIED) therapies for this unique population. In this state-of-the-art review, we discuss the various arrhythmias encountered in Fontan patients, their diagnosis, and options for treatment and prevention, with a focus on CIEDs. Throughout, access challenges particular to the Fontan circulation are considered. Recently developed technologies, such as the subcutaneous implantable cardioverter defibrillator, carry the potential to be transformative but require awareness of Fontan-specific issues. Moreover, new leadless pacing technology represents a promising strategy that may soon become applicable to Fontan patients with sinus-node dysfunction. CIEDs are essential tools in managing Fontan patients, but the complex clinical scenarios that arise in this patient population are among the most challenging for the electrophysiologist treating patients with congenital heart disease.     

Transcatheter occlusion of aortopulmonary shunts during single-ventricle surgical palliation.

Development of aortopulmonary collaterals during the course of surgical palliation for single-ventricular anatomy has been linked to adverse outcomes following Fontan palliation. We investigated the hemodynamic significance of aortopulmonary collaterals during presurgical cardiac catheterization of patients with single-ventricle surgically palliated anatomy. Thermal indicator dilution studies were performed to determine degree of shunt. A total of 52 patients were studied and the data were analyzed. Measurements by thermal indicator dilution correlated significantly with qualitative angiographic grading of aortopulmonary collaterals. However, the hemodynamic significance of these aortopulmonary collaterals, as measured by thermal indicator dilution, did not correlate with postoperative outcome variables. This study demonstrated that thermal indicator dilution measurement holds promise for hemodynamically quantifying the significance of aortopulmonary shunts in surgically palliated single-ventricular patients. However, the degree of recirculation from aortopulmonary collaterals does not correlate with outcome after Fontan surgery in this patient cohort.     

Reoperations in adults with congenital heart disease: analysis of early outcome

BACKGROUND: Grown-ups with congenital heart disease (GUCH) are an increasingly important group of patients, with many requiring reoperations because of late complications or residual defects, correction after palliation, further palliation or heart transplantation. METHODS: In order to identify perioperative risk factors, we have retrospectively analysed perioperative mortality and morbidity of 66 consecutive GUCH patients needing reoperations between July 1987 and December 2000 with a mean age of 28+/-12 (14.2-63.5) years and preoperative ejection fraction of 57+/-21%. Primary cardiac defects were LVOT pathology (17 patients), coarctation (10), Tetralogy of Fallot (TOF) (9), VSD (9), transposition of the great arteries (TGA) (7), Marfan syndrome (6), ASD (5) and others (3). RESULTS: Reoperations included various aortic valve procedures (28), aortic replacements (16), ASD/VSD closures (16), conduits (11), RVOT procedures (8), coarctation repair (5), cardiac transplantation (3) or others (8). Early mortality was 7.6%. Serious postoperative complications occurred in 24%. Presence of cyanosis, heart failure, VSD, TGA, pulmonary atresia, correction after palliative surgery and number of previous operations were preoperative risk factors and duration of operation, cardiopulmonary bypass and aortic cross-clamp, core temperature, low output syndrome, use of epinephrine, pneumonia and ARDS, renal failure, dialysis and stroke perioperative risk factors for fatal outcome. CONCLUSIONS: Reoperations in GUCH patients are mostly due to outflow tract lesions, coarctations and TOF. Perioperative risks remain important especially with cyanosis, TGA, pulmonary atresia and poor ventricular function. Therefore, close follow-up, timely referral for re-intervention and adequate perioperative management are mandatory to reduce perioperative risks and improve results.     

Spontaneous Obstruction of Interatrial Communication in Infants with Atrioventricular Valve Atresia or Stenosis in the Neonatal Period: Serial Echocardiographic-Doppler Study

BACKGROUND AND METHODS: The objective of this serial echocardiographic study was to document the critical size of the interatrial communication in infants with atrioventricular valve atresia, with which spontaneous obstruction is most likely to occur. Spontaneous obstruction of interatrial communication (patent foramen ovale) has been reported to occur in infants with atrioventricular valve atresia or severe stenosis. Atrial septostomy or septectomy therefore may be considered during initial palliation of these infants. Serial two-dimensional Doppler echocardiographic examinations were performed on 11 newborn infants with complex cyanotic congenital cardiac lesions for whom Fontan procedure was contemplated. These newborn infants had either mitral or tricuspid valve atresia or severe stenosis other than hypoplastic left heart syndrome. The size of the foramen ovale was measured from the subcostal frontal, long-axis oblique, and parasagittal views. Conventional Doppler and color flow mapping of the interatrial shunt also was obtained on each patient. RESULTS: The size of the foramen ovale was 5 mm in nine patients at birth. Five of these patients underwent Blalock-Taussig shunt in the neonatal period for severely restricted pulmonary blood flow. In three patients, surgery was postponed due to severe systemic (noncardiac) disease. One patient underwent the hemi-Fontan procedure without a previous shunt. In all nine patients, the foramen ovale remained the same size or became progressively smaller beyond the neonatal period, and atrial septectomy was performed in five patients after initial palliation. In the remaining two patients (who underwent Blalock-Taussig shunt as initial palliation), the foramen ovale measured >/=10 mm at birth and became progressively larger on subsequent follow-up studies. Atrial septectomy was not necessary in these patients. In the first nine patients, Doppler technique did not detect any obstructive pattern during the first 2-4 weeks of life, after which it became progressively obstructive (i.e., >2 m/sec and nonphasic). CONCLUSIONS: In newborn infants with either atrioventricular valve atresia or severe stenosis, the interatrial communication, which may not appear restrictive by Doppler at birth, becomes progressively obstructed beyond the neonatal period. If the size of the communication is <10 mm in diameter, as measured by two-dimensional echocardiography, atrial septectomy should be performed as an integral part of any initial palliation to protect the pulmonary vascular bed for subsequent successful Fontan repair.     

The Fontan procedure

The Fontan procedure has afforded improved surgical repair for several complex congenital cardiac defects, including tricuspid atresia and single ventricle. Through surgical creation of a connection between the RA and the RV or PA, adequate pulmonary perfusion can be achieved without an RV. Although it is not an anatomic connection, the Fontan procedure is a more physiologic approach than the previously used shunt procedures. Systemic venous return and PVR are effectively separated within the heart, pulmonary blood flow is assured through an RA-to-PA connection, and ventricular volume overload is avoided. The procedure has been effective in relieving cyanosis and has resulted in improved levels of exercise tolerance after surgery.     

Fontan Circulation: Success or Failure?

Fontan surgery represents a milestone in the evolution of congenital heart disease management. It achieved the seemingly improbable (ie, restoration of a noncyanotic state by entirely bypassing the subpulmonary ventricle). In so doing, it has allowed a generation of children who may have otherwise succumbed to their severe congenital heart defect to survive to adulthood. Perfect univentricular physiology is, however, an elusive goal. The Fontan circulation inherently represents a hemodynamic compromise that results in a catalog of potential multiorgan complications. In this review, we explore current knowledge regarding pathophysiology of the failing Fontan, its varied clinical manifestations, and potential therapeutic options. Failure of the Fontan circulation is broadly divided into 3 overlapping categories: ventricular dysfunction, systemic complications of Fontan physiology, and chronic Fontan failure. As long as the Fontan operation continues to serve as the paradigm of care for patients with univentricular hearts, efforts must be directed toward supporting this dynamic circulation that progressively declines in efficiency with age. Continued research in therapies is needed for univentricular dysfunction and systemic complications of Fontan palliation, including potential uses of mechanical support as a bridge to transplantation or as a neosubpulmonary ventricle. Fontan patients remain a major challenge to the medical and surgical community as a whole. Multicentre and multidisciplinary efforts to improve the density and depth of experiences might lead to a better appreciation for, and management of, Fontan failure and its ramifications.     

Fetal and Neonatal Imaging and Strategy of Primary Neonatal Heart Transplantation in Hypoplastic Left Heart with Ebstein's Anomaly

We present the anatomic constellation of mitral stenosis/aortic atresia variant of hypoplastic left heart syndrome, Ebstein's anomaly, and partial anomalous pulmonary venous return, an exceeding rare congenital heart defect. Prenatal echocardiography led to concern about the capacity of the right ventricle to increase cardiac output with lung expansion and pulmonary arterial runoff at birth, prompting the precaution of extracorporeal membrane oxygenator standby at delivery. Stage I palliation was not attempted, and control of pulmonary arterial blood flow was achieved with pulmonary artery banding, allowing sufficient ongoing hemodynamic stability. Orthotopic cardiac transplantation, repair of hypoplastic aortic arch, and primary sutureless repair of left pulmonary veins was performed, using dual‐site arterial cannulation and continuous mild hypothermic cardiopulmonary bypass. We discuss how this unique echocardiographic anatomy influenced the surgical decision and point out how it guided therapy toward a strategy of primary transplantation rather than standard staged surgical palliation.