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.     

Five decades of the Fontan operation: A systematic review of international reports on outcomes after univentricular palliation

Almost fifty years after its first clinical application, the modified Fontan operation is among the most frequently performed procedures in congenital heart disease surgery in children today. The objective of this review is to systematically summarize the international evolution of outcomes in regard to morbidity and mortality of patients with Fontan palliation. All studies published over the past five decades with more than 100 Fontan patients included were screened. In eligible studies, information concerning preoperative patients' characteristics, Fontan modifications employed, early mortality, long‐term survival and frequency of relevant complications was extracted. Ultimately, thirty‐one studies published by the largest surgical centers with an overall number of 9390 patients were included in this review. The extracardiac total cavopulmonary anastomosis is the most frequently used Fontan modification. Hemodynamic data demonstrate a rigorous overall adherence to suggested Fontan selection criteria. The analysis showed a clear trend toward improved early and long‐term survival over the time period covered. Although inconsistently reported, severe complications such as arrhythmias, thromboembolic events and protein‐losing enteropathy as well as reoperations and reinterventions were frequent. In conclusion, patients palliated for complex univentricular heart malformations nowadays benefit from the experience and technical developments of the past decades and have a significantly improved long‐term prognosis. However, important issues concerning postoperative long‐term morbidity and mortality are still unsolved and clear intrinsic limitations of the Fontan circulation are becoming evident as the population of Fontan patients ages.     

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.     

Entwicklung der Fontan-Prozedur als Behandlungskonzept für Kinder mit angeborenen komplexen Herzfehlern

The spectrum of congenital heart defects reaches from very simple to extremely complex anomalies. 3 decades earlier, the prognosis of children with univentricular heart defects was poor. The Fontan procedure has been offered to patients with a variety of complex cyanotic heart diseases and has resulted in decreased mortality. This review summarizes the development and modifications of the Fontan procedure. The advances in preoperative, intraoperative und postoperative patient management have resulted in greatly improved survivals for even the most complex congenital defects. Over the past 3 decades, the survival of infants with critical congenital heart defects has increased to 90%.     

Somatic Growth after Fontan and Mustard Palliation

Objective. Patients with complex congenital heart disease frequently develop early growth failure; however, the long‐term outcome for growth after surgery for single ventricle or anatomic right ventricle as systemic ventricle is not clear. This study was designed to determine long‐term growth in patients following the Fontan and Mustard operations. Method. We retrospectively reviewed the growth parameters of children who had previously undergone the Fontan (n = 80) or Mustard (n = 66) palliation at the Riley Hospital for Children, Indiana. Results. Both the Fontan and Mustard groups had normal height and weight at birth. At the time of their Fontan or Mustard palliation, there was a significant retardation in weight (Z‐score: ?0.98 and ?1.79, respectively) and height (Z‐score: ?0.96 and ?1.03, respectively). Both cohorts postoperatively demonstrated significant catch‐up in their weights. Although the Mustard group normalized their heights, the Fontan patients continued to demonstrate short statures in long‐term follow‐up. Conclusion. Children with single ventricles and those with palliated d‐loop transposition of the great arteries suffer somatic growth delay prior to definitive surgery, despite being of normal size at birth. Catch‐up growth in weight occurs after the Fontan and Mustard operations. In the Mustard population, height also normalizes, whereas in patients with univentricular circulation, height remains abnormally low.     

Bidirectional cavopulmonary anastomosis in congenital heart disease. Functional and clinical outcome.

The bidirectional cavopulmonary anastomosis is a surgical procedure suitable for patients with cyanotic congenital heart disease and univentricular physiology. This operation is able to increase the effective pulmonary blood flow without any additional load on the cardiac work and without any further distortion on the pulmonary artery branches. The cavopulmonary anastomosis can represent the first stage for patients destined for Fontan repair or a definitive palliative operation in high risk Fontan candidates. In order to test the hypothesis of a definitive palliation by cavopulmonary anastomosis in this kind of patients, we evaluated the hemodynamic data before and after this surgical approach and compared these data with their clinical and functional outcome. We evaluated 74 patients submitted to bidirectional cavopulmonary anastomosis by either hemodynamic or functional evaluation. End-diastolic and end-systolic ventricular volumes were significantly reduced by bidirectional cavopulmonary anastomosis (p less than 0.0005). Despite these data and a normal ambulatory ECG, spirometry and echocardiographic analysis, the stress test showed discouraging results. In fact, mean work time and peak heart rate were significantly different from normal values showing an impaired functional capacity of these children. In conclusion we think that bidirectional cavopulmonary anastomosis can not be considered an adequate definitive palliation but it represents a very good stage to preserve the pulmonary arteries and to prepare the systemic ventricle towards the Fontan repair.     

Pathophysiological aspects after cavopulmonary anastomosis

The ventricle of a functionally univentricular heart is known to be dilated, hypertrophic and hypocontractile before and after completion of a Fontan type of circuit. Ventricular dysfunction can be due to the congenital malformation itself, previous surgical conditions, or the very abnormal working conditions of the ventricle at the various stages of palliation. Because of the very different types of ventricle, it remains difficult to assess size, shape, hypertrophy, stress, strain, contraction and relaxation. The ventricle after birth tries to adapt to different and very abnormal circulations, evolving from overloaded and overstretched while shunted, to underloaded and overgrown after a Fontan type of circulation.     

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.     

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.     

Somatic growth failure after the Fontan operation

Our study was designed to characterize the patterns of growth, in the medium term, of children with functionally univentricular hearts managed with a hemi-Fontan procedure in infancy, followed by a modified Fontan operation in early childhood. Failure of growth is common in patients with congenital cardiac malformations, and may be related to congestive heart failure and hypoxia. Repair of simple lesions appears to reverse the retardation in growth. Palliation of the functionally single ventricular physiology with a staged Fontan operation reduces the adverse effects of hypoxemia and prolonged ventricular volume overload. The impact of this approach on somatic growth is unknown. Retrospectively, we reviewed the parameters of growth of all children with functionally univentricular hearts followed primarily at our institution who had completed a staged construction of the Fontan circulation between January 1990 and December 1995. Measurements were available on all children prior to surgery, and annually for three years following the Fontan operation. Data was obtained on siblings and parents for comparative purposes. The criterions of eligibility for inclusion were satisfied by 65 patients. The mean Z score for weight was -1.5 +/- 1.2 at the time of the hemi-Fontan operation. Weight improved by the time of completion of the Fontan circulation (-0.91 +/- 0.99), and for the first two years following the Fontan operation, but never normalized. The mean Z scores for height at the hemi-Fontan and Fontan operations were -0.67 +/- 1.1 and -0.89 +/- 1.2 respectively. At most recent follow-up, with a mean age of 6.1 +/- 1.3 years, and a mean time from the Fontan operation of 4.4 +/- 1.4 years, the mean Z score for height was -1.15 +/- 1.2, and was significantly less than comparable Z scores for parents and siblings. In our experience, children with functionally univentricular hearts who have been palliated with a Fontan operation are significantly underweight and shorter than the general population and their siblings.     

Three-dimensional echocardiographic evaluation of the Fontan conduit for thrombus

Introduction: Total caval pulmonary connection (Fontan circuit) is the final common pathway for the palliation of single ventricle congenital heart disease. Flow within the Fontan circuit results in an environment that is prone to thrombus formation putting the patient at risk for pulmonary and/or systemic embolus. To prevent these problems, patients are placed on antithrombotic therapy and periodically evaluated for thrombus within the conduit. Two‐dimensional (2D) echocardiography, although commonly used to evaluate these patients, has been shown to have limited ability in accurately identifying thrombi within the Fontan conduit. The diagnosis of intracardiac thrombi has been augmented by three‐dimensional (3D) echocardiography and the patients in this series were evaluated with 3D imaging (3D transthoracic echocardiography and/or 3D transesophageal echocardiography) to determine if thrombi could be detected or excluded within the Fontan conduit. To the author's knowledge, this constitutes the first case series describing the use of 3D echocardiography to evaluate the Fontan conduit for thrombus. Methods: The four patients described in this case series underwent 3D echocardiography to evaluate the Fontan conduit for a suspected or potential thrombus. Results: The Fontan conduit was imaged and thrombi were felt to be documented or excluded in all four patients with 3D echocardiography. Conclusions: Three‐dimensional echocardiography may enhance the ability to detect or exclude thrombi within the Fontan conduit. Further studies are needed to determine if this will prove to be an effective and reliable technique in evaluating the Fontan conduit for thrombus. (Echocardiography 2012;29:363‐368)     

Considerations in Critical-Care and Anesthetic Management of Adult Patients Living With Fontan Circulation

The Fontan procedure is a staged palliation for various complex congenital cardiac lesions, including tricuspid atresia, pulmonary atresia, hypoplastic left heart syndrome, and double-inlet left ventricle, all of which involve a functional single-ventricle physiology. The complexity of the patients’ original anatomy combined with the anatomic and physiologic consequences of the Fontan circulation creates challenges. Teens and adults living with Fontan palliation will need perioperative support for noncardiac surgery, peripartum management for labour and delivery, interventions related to their structural heart disease, electrophysiology procedures, pacemakers, cardioversions, cardiac surgery, transplantation, and advanced mechanical support. This review focuses on the anesthetic and intensive care unit (ICU) management of these patients during their perioperative journey, with an emphasis on the continuity of preintervention planning, referral pathways, and postintervention ICU management. Requests for recipes and doses of medications are frequent; however, as in normal anesthesia and ICU practice, the method of anesthesia and dosing are dependent on the presenting medical/surgical conditions and the underlying anatomy and physiologic reserve. A patient with Fontan palliation in their early 20s attending school full-time with a cavopulmonary connection is likely to have more reserve than a patient in their late 40s with an atriopulmonary Fontan at home waiting for a heart transplant. Each case will require an anesthetic and critical care plan tailored to the situation. The critical care environment is a natural extension of the anesthetic management of a patient, with complex considerations for a patient with Fontan palliation.     

Novel approaches to direct atrial access after extracardiac fontan palliation

• Catheter access to the “native” atria is limited after extra‐cardiac Fontan palliation of univentricular cardiac defects
• Catheter access to the atria is necessary to percutaneously treat acquired abnormalities after extra‐cardiac Fontan palliation
• Direct trans‐thoracic atrial access and extra‐cardiac conduit puncture is technically straightforward and allows for novel catheter interventions

     

Acute Dyspnea in a Young Man With an Old Sternotomy

Described is a 42‐year‐old man with complex congenital heart disease with single‐ventricle physiology who underwent a Fontan operation at 27 years of age. He presented with sudden‐onset chest pain and dyspnea and was initially misdiagnosed with a pulmonary embolism. This case is described in order to highlight the challenges in the evaluation of common presentations in adults with congenital heart disease.     

Single-stage Fontan procedure: early and late outcome in 124 patients

INTRODUCTION AND OBJECTIVES: The Fontan procedure was designed to palliate complex congenital heart disease with univentricular physiology. A retrospective study was made to document the determinants of early (/= 31 days) mortality with the modified Fontan procedure performed in one-stage over a 22-year period. MATERIAL AND METHODS: Between 1978 and 2000, 102 atriopulmonary, 16 cavopulmonary, and 6 Kawashima type anastomoses were performed to palliate complex congenital heart defects in 124 patients with a mean age of 7.3 4.7 years. Forty-five patient and procedure-related variables were analyzed in relation to mortality. All events were verified. RESULTS: There were 29 early (23%) and 20 late (16%) deaths. Estimated survival at 30 days, 2 years, 5 years, and 20 years was 78, 75, 66, and 50%, respectively. Subaortic stenosis, protein-losing enteropathy, and arrythmia were observed in 8, 5 and 33 patients, respectively, after surgery. Univariate and multivariable analysis indicated that left ventricular end-diastolic pressure (>/= 13 mmHg), mean pulmonary pressure (>/= 19 mmHg), mitral stenosis/atresia, atrioventricular valve regurgitation, visceral heterotaxia, absence of fenestration, risk factors criteria, duration of extracorporeal circulation, and operative technique were associated with early mortality. Reoperation, arrhythmia, and pacemaker implantation were predictors of late death. Forty percent remained free from surgical or catheter reintervention after Fontan operation at 20 years. CONCLUSIONS: The outcome of Fontan procedure is profoundly affected by patient-related variables (ventricular function and pulmonary circulation). Postoperative arrhythmia and reoperation shortened the lifespan of the Fontan circulation model in patients with atriopulmonary connections. Total cavopulmonary anastomosis improves the physiology of univentricular circulation. In the light of our findings, the modified Fontan procedure (one or two stages) should be performed early in life to better preserve ventricular and pulmonary vascular function.     

Feasibility and safety of immediate perioperative implantation of intravascular stents in cavopulmonary pathways.

Fontan-type procedures are widely used for palliation of patients with many forms of a functional univentricular heart. An ideal Fontan circuit should be free of any distortion or stenosis. The use of stents for the treatment of stenotic and hypoplastic vessels is well established in pediatric cardiac practice. We report the successful use of endovascular stents during the immediate postoperative period in patients undergoing cavopulmonary anastomoses.     

Recurrent Protein‐losing Enteropathy and Tricuspid Valve Insufficiency in a Transplanted Heart: A Causal Relationship?

This case report describes a toddler who developed a protein‐losing enteropathy (PLE) 4 years after orthotopic heart transplantation (OHT). He was born with a hypoplastic left heart syndrome for which he underwent a successful Norwood procedure, a Hemi–Fontan palliation, and a Fontan palliation at 18 months of age. Fifteen months following the Fontan operation, he developed a PLE and Fontan failure requiring OHT. Four years after OHT, he developed a severe tricuspid regurgitation and a PLE. His PLE improved after tricuspid valve replacement. It is now 2 years since his tricuspid valve replacement and he remains clinically free of ascites and peripheral edema with a normal serum albumin level. His prosthetic tricuspid valve is functioning normally.     

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.     

Evaluation abnormer Myokardwandgeschwindigkeiten des univentrikul?ren Herzens mittels Gewebedoppler-Echokardiographie

INTRODUCTION: Assessment of systolic and diastolic ventricular function in children and adults with morphologically and functionally univentricular heart is difficult using the conventional echocardiographic methods. Quantitative assessment of systolic and diastolic wall motion by TDE may provide information on abnormal systolic and diastolic ventricular function. Thus, the object of this study was to analyze the patterns of anterior and posterior wall motions in children with univentricular heart after palliative Fontan operation in comparison to normal subjects. PATIENTS AND METHODS: We investigated 21 patients of an average age of 10.1 years (range 4.2 to 32 years) with the primary diagnosis of univentricular heart and tricuspid atresia after a median period of 4.3 (range 1.2 to 8) years after cavo-pulmonary anastomosis (Fontan procedure) and in comparison to a normal collective of children without cardiovascular malformations. For investigation we used the novel tissue Doppler echocardiography (TDE) (EchoPack 6.3.6, Vingmed, Norway). Thereby we chose the standardized apical view and evaluated the left and right annular systolic (S(T)), early diastolic (E(T)) and atrial (A(T)) motion. We also registered the acceleration and deceleration time of each obtained curve. RESULTS: In comparison to the posterior myocardial wall the velocities at the anterior wall of the rudimentary ventricle were significantly reduced in all patients with tricuspid atresia and univentricular heart (p<0.0001). Particularly the annular systolic and diastolic wall motions of the rudimentary ventricle as well as their deceleration and acceleration time in patients with univentricular hearts differed significantly from those in healthy persons. CONCLUSION: Abnormal myocardial wall motion is detectable in children and adults with univentricular heart after palliative cardiac procedures using tissue Doppler echocardiography. The hemodynamic value of the measured abnormal wall motions, however, need further comparative studies.