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Surgical Variations and Flow Dynamics in Cavopulmonary Connections: A Historical Review
Abstract
Cavopulmonary connections (CPC) have been extensively used in the palliation of complex forms of congenital heart disease requiring some form of right heart bypass. The concept has evolved from unilateral CPC to total CPC (TCPC) in an attempt to prolong the palliated state, but the physiological implications remain only partially understood. We summarize some of the modifications and experimental data and their impact on flow distribution after the Fontan procedure. Copyright 1998 by W.B. Saunders Company
... Generalmente se realiza una perforación en el tercio medio del injerto que funciona como fenestración y tiene ventajas en el postoperatorio, especialmente cuando se realiza en pacientes de alto riesgo o en ciudades a grandes alturas. [12][13][14][15] Esta cirugía para la corrección de la patología cardiaca univentricular ha evolucionado enormemente. El principal problema de estos pacientes es la presión que tiene que soportar el ventrículo único, pues maneja el volumen de los dos ventrículos. ...
... El manejo postoperatorio de estos pacientes es un aspecto muy importante para el éxito del procedimiento, pues los cambios hemodinámicos y fi siológicos son difícilmente tolerados y pueden requerir intervención inmediata, como el desmontaje del procedimiento. 15,20,21 Del total de pacientes, solamente uno ameritó el desmontaje por presentar gradiente transpulmonar de 17 mmHg. Cabe destacar que, como en otros centros del mundo, 22 los niños que sobreviven el período postoperatorio con o sin complicaciones, presentan una evolución a mediano y largo plazo satisfactoria. ...
Background. At the present time, the Fontan procedure is indicated for patients with univentricular cardiac pathology. In Mexico, few tertiary centers are performing Fontan surgery in the pediatric population. The objective was to analyze the results of patients with congenital heart disease with univentricular physiology who have undergone Fontan surgery since 1980 in the Hospital Infantil de Mexico Federico Gomez. Methods. We present a retrospective analysis of pediatric patients undergoing Fontan surgery. We included variables related to preoperative mortality and morbidity, those related to surgery and to the postoperative period. A bivariate analysis with the comparison of averages and odds ratio was performed. Kaplan-Meier survival curves were constructed. Results. From 1983 to 2012, 53 Fontan surgeries have been performed. Of the total, comprehensive data of 32 patients were gathered. The most common congenital heart disease was tricuspid atresia IB (39.4%); according to type of surgery, in 48% of patients extracardiac Fontan was performed more frequently (48%) followed by intracardiac Fontan (24%). In 87% of patients fenestration was performed. The most common complications were acute renal failure, neurological problems and pleural effusion. Overall survival was 65.6%; 90.9% of patients died within the first month of surgery. Some patients have survived >20 years (average actuarial survival 14.5 years). Variables associated with mortality were younger age at surgery, type of Fontan performed, surgical technique complications, lack of fenestration and acute renal failure. Conclusions. Evolution of Fontan surgery during the past 30 years has been satisfactory. In patients undergoing this procedure, mortality and quality of life have shown improvements.
... Most (n = 17) showed a similar pressure increase at the pre-cardiac and pre-pulmonary sites (increase MVP = VEDP (with a range of ± 2 mmHg)). Some 12.3 ± 3.5 [7][8][9][10][11][12][13][14][15][16][17][18][19] 14.6 ± 1.6 [13][14][15][16][17][18] 9.9 ± 4.5 [4][5][6][7][8][9][10][11][12][13][14][15][16] 16.0 ± 6.2 [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] 13.6 ± 1.5 [12][13][14][15][16] 17 The mean ± standard deviation and range in measured pressure and oxygen saturation before (pre) and after (post) volume challenge are shown for the different locations. The mean of calculated arterio-venous oxygen gradient and transpulmonary gradient are noted. ...
... A patient whose circulation functions at its limits will respond to the volume challenge with pressure increase prior to the limiting factor. Nowadays the connection itself, such as the current cavo-pulmonary connection, is no longer a limiting factor; stenosis and energy loss by flow disturbance have become rare complications 22,23 . The patients included in this study had good ventricular functions, so the limiting factor will most likely be found within the pulmonary vasculature. ...
Objective It is diffi cult to indicate whether the limitation in a failing Fontan circulation lies within the pulmonary vasculature or the heart. Such diff erentiation is crucial to direct adequate therapy. This study was set out to determine if a volume challenge could identify the limiting factor.
Methods and study population Thirty-two catheterizations in 28 patients with a Fontan circulation were included. Pressures and oxygen saturations were measured before and after volume challenge (NaCl 0.9%; 15 cc/Kg). The changes in data were grouped based on the location of the major pressure increase. Ventricular function was measured in the resting state.
Results The majority of the patients showed an increase in aortic oxygen saturation, mixed venous oxygen saturation, systolic, pulmonary and systemic venous pressures. The arterio-venous oxygen gradient decreased, suggesting an increase in cardiac output. Diff erent patterns in pressure changes were observed. Most (n = 17) showed a similar increase of ventricular end-diastolic pressure and mean venous pressure (MVP); some (n = 7) showed a lower increase of MVP, suggesting pulmonary reserve and recruitment; others (n = 8) showed a signifi cant higher increase in MVP, suggesting increased pulmonary vascular resistance. All volume challenge was well tolerated.
Conclusion Most patients were preload-responsive. The pressure changes following volume load showed patterns with a potential of diff erentiating between patients with a major pulmonary or cardiac limiting factor.
... In this setting, the most studied procedure is most likely the Fontan surgery [17][18][19]. Enhancing the flow conditions after treatment, computational models of the Fontan technique have led to the improvement of previous surgical intervention strategies [20,21]. In a similar way, application of computational patient specific models in the context of aortic coarctation can enhance perception of long-term morbidity, improve current treatment strategies and facilitate the assessment of coarctation severity by providing a quantification of hemodynamic parameters throughout the entire aorta. ...
... • In order to be physiological, a time point of zero imbalance (which is the inflow reduced by the outflow) should be selected as the starting point for our simulations. These time points are indicated with a red dot in Figure 4. 20. This approach allows the actual FSI simulation to start from a physiological equilibrium state and will result in a nearly periodic simulation from the first cycle on. ...
... Most (n = 17) showed a similar pressure increase at the pre-cardiac and pre-pulmonary sites (increase MVP = VEDP (with a range of ± 2 mmHg)). Some 12.3 ± 3.5 [7][8][9][10][11][12][13][14][15][16][17][18][19] 14.6 ± 1.6 [13][14][15][16][17][18] 9.9 ± 4.5 [4][5][6][7][8][9][10][11][12][13][14][15][16] 16.0 ± 6.2 [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] 13.6 ± 1.5 [12][13][14][15][16] 17 The mean ± standard deviation and range in measured pressure and oxygen saturation before (pre) and after (post) volume challenge are shown for the different locations. The mean of calculated arterio-venous oxygen gradient and transpulmonary gradient are noted. ...
... A patient whose circulation functions at its limits will respond to the volume challenge with pressure increase prior to the limiting factor. Nowadays the connection itself, such as the current cavo-pulmonary connection, is no longer a limiting factor; stenosis and energy loss by flow disturbance have become rare complications 22,23 . The patients included in this study had good ventricular functions, so the limiting factor will most likely be found within the pulmonary vasculature. ...
Objective:
It is difficult to indicate whether the limitation in a failing Fontan circulation lies within the pulmonary vasculature or the heart. Such differentiation is crucial to direct adequate therapy. This study was set out to determine if a volume challenge could identify the limiting factor.
Methods and study population:
Thirty-two catheterizations in 28 patients with a Fontan circulation were included. Pressures and oxygen saturations were measured before and after volume challenge (NaCl 0.9%; 15 cc/Kg). The changes in data were grouped based on the location of the major pressure increase. Ventricular function was measured in the resting state.
Results:
The majority of the patients showed an increase in aortic oxygen saturation, mixed venous oxygen saturation, systolic, pulmonary and systemic venous pressures. The arterio-venous oxygen gradient decreased, suggesting an increase in cardiac output. Different patterns in pressure changes were observed. Most (n=17) showed a similar increase of ventricular end-diastolic pressure and mean venous pressure (MVP); some (n=7) showed a lower increase of MVP, suggesting pulmonary reserve and recruitment; others (n=8) showed a significant higher increase in MVP, suggesting increased pulmonary vascular resistance. All volume challenge was well tolerated.
Conclusion:
Most patients were preload-responsive. The pressure changes following volume load showed patterns with a potential of differentiating between patients with a major pulmonary or cardiac limiting factor.
... Diese Methode der Kreislauftrennung wurde im weiteren Verlauf für die chirurgische Behandlung von verschiedenen komplexen Herzfehlern bis hin zum hypoplastischen Linksherzsyndrom (HLHS) angenommen. Die Entwicklung der chirurgischen Behandlung von diesen früher nicht korrigierbaren Herzfehlern wurde von mehreren Autoren verfolgt und beschrieben [17][18][19][20] . Zur Verbesserung der frühen und späten postoperativen Ergebnisse wurden viele Modifikationen der ursprünglichen Fontan-Operation vorgeschlagen, wie z. ...
... Um die beschriebene Problematik zu umgehen, wurde vorgeschlagen, einen extrakardialen Rechtsherzbypass durchzuführen. Nach klinisch nicht erfolgreichen Versuchen [32,33] berichteten Marceletti und Mitarbeiter über die erfolgreiche klinische Durchführung der extrakardialen Modifikation der Fontan-Operation (ECFO, Abbildung 3,7,20) [34] . ...
Im Rahmen einer vergleichenden retrospektiven Analyse wurden die präoperativen und intraoperativen Einflussfaktoren auf den frühen und mittelfristigen postoperativen Verlauf nach Fontan-Operation untersucht und die Ergebnisse der totalen cavopulmonale Anastomose mit einem intraatrialen lateralen Tunnel (LTFO, n = 25) und mit einem extrakardialen Kunststoff-Konduit (ECFO, n = 25) gegenüber gestellt. Postoperativ wurde nach ECFO ein komplikationsärmerer früher Verlauf mit kürzerer maschineller Beatmung und signifikant geringerer Inzidenz für frühe und mittelfristige Arrhythmien als nach LTFO beobachtet. Im frühen postoperativen Verlauf waren die schnellste Extubation und Entlassung bei den ECFO-Patienten möglich, bei denen keine Kardioplegie verwendet wurde. Unabhängige Risikofaktoren nach multivariater Analyse waren die Dauer der Kardioplegie in Bezug zu den unmittelbaren postoperativen Komplikationen, eine LTFO - sowohl für Tachy- als auch für Bradyarrhythmien - und die Inzision in die cavoatriale Verbindung bei LTFO in Bezug zu Bradyarrhythmien mit der Notwendigkeit einer Schrittmacherimplantation. Durch Vermeidung von Kardioplegie und chirurgischer Schaffung eines lateralen Tunnels sowie Verkürzung des kardiopulmonalen Bypasses bei ECFO werden vor allem die postoperativen Arrhythmien reduziert und es ist wahrscheinlich möglich, den postoperativen Verlauf bei Patienten mit einem durch eine langwierige Zyanose und durch Volumenbelastung vorbeschädigten singulären Ventrikel zu verbessern. Eine prospektive langfristige Vergleichsstudie mit einer größeren Patientenzahl ist notwendig, um die Frage zu beantworten, ob eine signifikante Minderung der spätpostoperativen Komplikationen und eine Verbesserung der Lebenserwartung der Patienten mit univentrikulärer Physiologie durch eine korrekt geplante und optimal durchgeführte extrakardiale Modifikationen der Fontan-Operation erreicht werden kann.
... The use of optimization in stent design and model selection for patients is intriguing, given the idealized CFD findings reviewed above. The use of optimization in CFD is not new; Marsden and colleagues applied an optimization algorithm to surgically reconstruct vessels of children with a single functioning ventricle [109], while other notable work has also been conducted [110]. However, the application of optimization theory to stenting has so far been limited. ...
The success of drug-eluting stents (DES) is limited by restenosis and, to a lesser extent, late stent thrombosis. Mechanical stimuli have been implicated in these outcomes, with indices of wall shear stress (WSS) determined from computational simulations being reported most frequently. The current work summarizes state-of-the-art computational approaches applicable to patient-specific models aimed at further understanding changes in WSS indexes imposed by stent implantation. We begin with a review of best practices involved in the process and then summarize the literature related to stent-induced WSS alterations. Image-based reconstruction methods are also discussed, along with the latest generation boundary conditions that replicate cardiac physiology and downstream vasculature in the setting of coronary artery disease. The influence of existing material property data on WSS results obtained with geometries reconstructed from finite element modeling and fluid structure interaction (FSI) simulations is reviewed, along with the novel approaches being used to provide coronary artery plaque data that are currently missing from the literature. We also consider the use of machine learning tools that have the potential for impact when assessing the role of adverse stent-induced WSS in suboptimal clinical outcomes. We conclude by focusing on challenging cases that involve DES implantation, which may benefit from recent advancements in patient-specific computational modeling.
... In the BDG, the SVC is divided and separated from the right atrium (RA) and an end-to-side anastomosis is made between the SVC and the right PA. In the HF, an anastomosis is created from the SVC/RA junction to the surgically augmented right PA and an intracardiac dam is placed at the SVC/RA junction, separating the SCPC from the RA [9,10]. Importantly, the choice of procedure at the second stage of palliation sets the stage for the choice of the procedure at Fontan completion. ...
Patients with single ventricle (SV) heart defects have two primary surgical options for superior cavopulmonary connection (SCPC): bidirectional Glenn (BDG) and hemi-Fontan (HF). Outcomes based on type of SCPC have not been assessed in a multi-center cohort. This retrospective cohort study uses the Single Ventricle Reconstruction (SVR) Trial public use dataset. Infants who survived to SCPC were evaluated through 1 year of age, based on type of SCPC. The primary outcome was transplant-free survival at 1 year. The cohort included 343 patients undergoing SCPC across 15 centers in North America; 250 (73%) underwent the BDG. There was no difference between the groups in pre-SCPC clinical characteristics. Cardiopulmonary bypass times were longer [99 min (IQR 76, 126) vs 81 min (IQR 59, 116), p < 0.001] and use of deep hypothermic circulatory arrest (DHCA) more prevalent (51% vs 19%, p < 0.001) with HF. Patients who underwent HF had a higher likelihood of experiencing more than one post-operative complication (54% vs 41%, p = 0.05). There were no other differences including the rate of post-operative interventional cardiac catheterizations, length of stay, or survival at discharge, and there was no difference in transplant-free survival out to 1 year of age. Mortality after SCPC is low and there is no difference in mortality at 1 year of age based on type of SCPC. Differences in support time and post-operative complications support the preferential use of the BDG, but additional longitudinal follow-up is necessary to understand whether these differences have implications for long-term outcomes.
... The Fontan operation, intended to provide pulmonary blood flow without a pulmonary ventricle, was first described by Fontan and Baudet in 1971 as a palliation for a patient with tricuspid atresia [1]. The procedure became expanded to include other single ventricle defects by the early 1980s with many important modifications since then [2][3][4]. In the current era, the total cavopulmonary shunt employing either an extracardiac conduit or less commonly an intracardiac lateral tunnel (LT) is the preferred procedure [5][6][7][8][9]. ...
The Fontan operation and its modifications are currently the standard palliation in patients with single ventricle physiology. The advantages of extracardiac conduit Fontan operation (ECF) have previously been described. We evaluated the outcome of patients who underwent ECF operation at our center since the year 2000 to assess morbidity, mortality and New York Heart Association (NYHA) functional class in the current era. Medical records of 97 patients who underwent ECF operation from November 2000 till October 2013 were reviewed to determine the diagnosis, age at surgery, surgical technique, postoperative complications, NYHA class at last follow-up, echocardiographic parameters, and most recent Holter monitor results. The median age at surgery was 3.4 years with 4 total deaths until last follow-up (hospital mortality was 1 %, and mortality after hospital discharge was 3 %). Seventy-eight of the 97 patients (80 %) underwent fenestrated Fontan surgery. Median duration of follow-up was 3.9 years (IQR 0.2–12.2 years). At the latest follow-up, 62 patients (67 %) were determined to be in NYHA class I, 25 patients (27 %) in NYHA class II, and 6 (6 %) patients in NYHA class III, and the median oxygen saturation was 92 % (IQR 86–96). There were 15 patients with history of preoperative arrhythmias and 6 of them required pacemaker placement at the time of surgery. One patient developed ectopic atrial tachycardia, and 1 patient had clinical thromboembolism on follow-up. Systolic function of the single ventricle by transthoracic echocardiogram at the latest follow-up was described as normal in 77 patients (83 %), fair in 15 patients (16 %), and poor in 1 patient (1 %). The results of our study show that patients who undergo extracardiac conduit Fontan operation in the modern era may have significantly less morbidity and mortality when compared to earlier years.
... If specific physiological and structural outcomes are related to adverse hemodynamics, investigation of modifications that restore more favorable flow patterns could be used to design optimal treatments. This approach has been successfully applied to congenital heart defects resulting in single ventricle physiology where CFD simulations of the Fontan procedure have led to several technical modifications demonstrated to be hemodynamically superior to previous surgical techniques (Marsden et al., 2009;Pizarro & De Leval, 1998). ...
... If specific physiological and structural outcomes are related to adverse hemodynamics, investigation of modifications that restore more favorable flow patterns could be used to design optimal treatments. This approach has been successfully applied to congenital heart defects resulting in a single ventricle physiology where CFD simulations of the Fontan procedure have led to several technical modifications demonstrated to be hemodynamically superior to previous surgical techniques [18]. ...
Computational fluid dynamics (CFD) simulations quantifying thoracic aortic flow patterns have not included disturbances from the aortic valve (AoV). 80% of patients with aortic coarctation (CoA) have a bicuspid aortic valve (BAV) which may cause adverse flow patterns contributing to morbidity. Our objectives were to develop a method to account for the AoV in CFD simulations, and quantify its impact on local hemodynamics. The method developed facilitates segmentation of the AoV, spatiotemporal interpolation of segments, and anatomic positioning of segments at the CFD model inlet. The AoV was included in CFD model examples of a normal (tricuspid AoV) and a post-surgical CoA patient (BAV). Velocity, turbulent kinetic energy (TKE), time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) results were compared to equivalent simulations using a plug inlet profile. The plug inlet greatly underestimated TKE for both examples. TAWSS differences extended throughout the thoracic aorta for the CoA BAV, but were limited to the arch for the normal example. OSI differences existed mainly in the ascending aorta for both cases. The impact of AoV can now be included with CFD simulations to identify regions of deleterious hemodynamics thereby advancing simulations of the thoracic aorta one step closer to reality.
... Previous studies have shown that, if carefully used and well-resolved, Computational Fluid Dynamics (CFD) can be an accurate method of predicting in vitro and in vivo hemodynamics (13)(14)(15)(16). Combined CFD and MRI studies of the staged surgical palliation (Fontan) for patients with single ventricle heart diseases have illustrated the importance of local hemodynamics on clinical outcome, and led to several technical suggestions and improvements (17)(18)(19). Of particular relevance to our work, CFD has been applied to resolve the flow dynamics of patient specific aortas (14,15), as well as to characterize the flow patterns and wall shear stresses in coronary artery bypass grafts (CABG) and aneurysm development (16). ...
PURPOSE: Late morbidity of surgically repaired coarctation of the aorta includes early cardiovascular and cerebrovascular disease, shortened life expectancy, abnormal vasomodulator response, hypertension and exercise-induced hypertension in the absence of recurrent coarctation. Observational studies have linked patterns of arch remodeling (Gothic, Crenel, and Romanesque) to late morbidity, with Gothic arches having the highest incidence. We evaluated flow in native and surgically repaired aortic arches to correlate respective hemodynamic indices with incidence of late morbidity. METHODS: Three dimensional reconstructions of each remodeled arch were created from an anatomic stack of magnetic resonance (MR) images. A structured mesh core with a boundary layer was generated. Computational fluid dynamic (CFD) analysis was performed assuming peak flow conditions with a uniform velocity profile and unsteady turbulent flow. Wall shear stress (WSS), pressure and velocity data were extracted. RESULTS: The region of maximum WSS was located in the mid-transverse arch for the Crenel, Romanesque and Native arches. Peak WSS was located in the isthmus of the Gothic model. Variations in descending aorta flow patterns were also observed among the models. CONCLUSION: The location of peak WSS is a primary difference among the models tested, and may have clinical relevance. Specifically, the Gothic arch had a unique location of peak WSS with flow disorganization in the descending aorta. Our results suggest that varied patterns and locations of WSS resulting from abnormal arch remodeling may exhibit a primary effect on clinical vascular dysfunction.
... This anatomic data, together with physiological data such as phase-contrast MRI (PC-MRI) and BP, can be used to create 3D patient-specific representations of hemodynamics that consider vascular properties associated with the current patient state. This paradigm has been applied with single ventricle congenital defects where computational fluid dynamics (CFD) simulations of the Fontan procedure have led to several technical modifications demonstrated to be hemodynamically superior to previous surgical techniques[4]. Similar outcomes may be realized if this approach is applied to CoA, but few studies to date have used CFD for this purpose. ...
Treatments for coarctation of the aorta (CoA) can alleviate blood pressure (BP) gradients (Δ), but long-term morbidity still exists that can be explained by altered indices of hemodynamics and biomechanics. We introduce a technique to increase our understanding of these indices for CoA under resting and nonresting conditions, quantify their contribution to morbidity, and evaluate treatment options. Patient-specific computational fluid dynamics (CFD) models were created from imaging and BP data for one normal and four CoA patients (moderate native CoA: Δ12 mmHg, severe native CoA: Δ25 mmHg and postoperative end-to-end and end-to-side patients: Δ0 mmHg). Simulations incorporated vessel deformation, downstream vascular resistance and compliance. Indices including cyclic strain, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) were quantified. Simulations replicated resting BP and blood flow data. BP during simulated exercise for the normal patient matched reported values. Greatest exercise-induced increases in systolic BP and mean and peak ΔBP occurred for the moderate native CoA patient (SBP: 115 to 154 mmHg; mean and peak ΔBP: 31 and 73 mmHg). Cyclic strain was elevated proximal to the coarctation for native CoA patients, but reduced throughout the aorta after treatment. A greater percentage of vessels was exposed to subnormal TAWSS or elevated OSI for CoA patients. Local patterns of these indices reported to correlate with atherosclerosis in normal patients were accentuated by CoA. These results apply CFD to a range of CoA patients for the first time and provide the foundation for future progress in this area.
... This approach has been successfully applied to other congenital heart defects, specifically malformations resulting in a single ventricle. In these patients, computational fluid dynamics (CFD) simulations of the Fontan procedure has led to widespread acceptance of several technical modifications demonstrated to be hemodynamically superior to previous surgical techniques [25]. If these techniques were applied to CoA, similar studies would likely provide greater understanding of longterm morbidity, preoperative assessment of treatment options, and an additional tool for evaluation of current treatment practices when compared to comparable results from normal patients. ...
Coarctation of the aorta (CoA) is often considered a relatively simple disease, but long-term outcomes suggest otherwise as life expectancies are decades less than in the average population and substantial morbidity often exists. What follows is an expanded version of collective work conducted by the authors' and numerous collaborators that was presented at the 1st International Conference on Computational Simulation in Congenital Heart Disease pertaining to recent advances for CoA. The work begins by focusing on what is known about blood flow, pressure and indices of wall shear stress (WSS) in patients with normal vascular anatomy from both clinical imaging and the use of computational fluid dynamics (CFD) techniques. Hemodynamic alterations observed in CFD studies from untreated CoA patients and those undergoing surgical or interventional treatment are subsequently discussed. The impact of surgical approach, stent design and valve morphology are also presented for these patient populations. Finally, recent work from a representative experimental animal model of CoA that may offer insight into proposed mechanisms of long-term morbidity in CoA is presented.
Coarctation of the aorta (CoA) is a constriction of the proximal descending thoracic aorta and is one of the most common congenital cardiovascular defects. Treatments for CoA can improve life expectancy, but morbidity persists. In this chapter, we review CoA from clinical and engineering perspectives. We start with a review of the anomaly including its natural history, current therapies, and pathophysiology. Particular attention is given to potential factors contributing to hypertension, which is arguably the single most important outcome variable in patients with repaired CoA. We then discuss the application of patient-specific computational modeling to CoA, featuring recent work that has employed heightened levels of realism to foster clinical translation. The application of such methods to the noninvasive estimation of blood pressure gradients is discussed, along with experimental models developed to foster improved mechanistic understanding of CoA from cellular and engineering perspectives. Lastly, we offer perspectives on the potential impact of recent advances related to CoA on the current clinical arena, and what is likely to be expected into the future.
Background:
The Fontan palliation is associated with numerous complications during long-term. The Fontan conversion operation has been advocated as an option to avoid some of these problems by converting classical Fontan types to modern forms of the circulation. Early mortality of Fontan conversion, however, remains unclear as available reports include limited numbers of patients and the results are heterogeneous.
Methods:
We reviewed all original articles from 1994 to 2016 reporting Fontan conversion operations. Reports were analysed with specific reference to patient demographics, patient number, concomitant arrhythmia surgery, pacemaker implantation and early mortality.
Results:
Overall, 37 Fontan conversion studies with a total of 1182 patients were analysed, including 35 single-centre studies and 2 registers. In the 35 single-centre studies the average age at the time of conversion was 21.6years (range 10.2-30.9years). Concomitant arrhythmia operation was performed in 71.6% of patients and concomitant pacemaker implantation procedure was performed in 59.3% of patients. Early mortality varied greatly between publications ranging from 0 to 21%. Based on a random and a fixed effect model mean mortality was 5.3% and 6.2%, respectively. Lower mortality was observed in series including younger patients at the time of conversion (average age<20years, 4.6%) and in the highest volume centre (1.4%).
Conclusion:
Fontan conversion carries a substantial mortality risk. However, results vary between centres. Overall, the combination with arrhythmia surgery seems to be associated with lower early mortality especially when patients are referred at an earlier age and are treated at highly experienced centres.
Background. At the present time, the Fontan procedure is indicated for patients with univentricular cardiac pathology. In Mexico, few tertiary centers are performing Fontan surgery in the pediatric population. The objective was to analyze the results of patients with congenital heart disease with univentricular physiology who have undergone Fontan surgery since 1980 in the Hospital Infantil de Mexico Dr. Federico Gomez. Methods. We present a retrospective analysis of pediatric patients undergoing Fontan surgery. We included variables related to preoperative mortality and morbidity, those related to surgery and to the postoperative period. A bivariate analysis with the comparison of averages and odds ratio was performed. Kaplan-Meier survival curves were constructed. Results. From 1983 to 2012, 53 Fontan surgeries have been performed. Of the total, comprehensive data of 32 patients were gathered. The most common congenital heart anomaly was tricuspid atresia IB (39.4%); according to type of surgery, in 48% of patients extracardiac Fontan was performed followed by intracardiac Fontan (24%). In 87% of patients fenestration was performed. The most common complications were acute renal failure, neurological problems and pleural effusion. Overall survival was 65.6%; 90.9% of patients died within the first month of surgery. Patients have been reported with >20 years of survival (average actuarial survival 14.5 years). Variables associated with mortality were younger age at surgery, type of Fontan performed, surgical technique complications, lack of fenestration and acute renal failure. Conclusions. Evolution of Fontan surgery during the past 30 years has been satisfactory. In patients undergoing this procedure, mortality and quality of life have shown improvements.
Der Komplex der „Ursprungsanomalien der großen Arterien“ umfasst sowohl Herzgefäßfehlbildungen mit abnormer Sequenz zwischen
den Ventrikeln und den großen Arterien, d. h. mit „ventrikuloarterieller Diskordanz“ (Kirklin et al. 1973) bzw. „Transposition der großen Arterien“ (Farre 1814), als auch Fehlbildungen mit normaler Sequenz, also mit „ventrikuloarterieller Konkordanz“, jedoch mit Lageanomalien („Malpositionen“) der großen Arterien und schließlich Fehlbildungen mit Ursprung beider großen Arterien überwiegend aus einem Ventrikel („double outlet ventricle“; Van Praagh 1972; Anderson et al. 1975, 1985; Shinebourne et al. 1976, 1978; Schumacher et al. 1980).
The vast majority of neonates with single ventricle physiology require some form of surgical intervention to realize long term survival. Surgical options are limited as septation of the single ventricle has been described but is an option available for only a small subset of patients with ideal anatomy [1]. Orthotopic cardiac transplant is another approach which because of limited organ availability eliminates many potential candidates by attrition on the waiting list [2]. The most common approach to palliation in the infant with single ventricle is to intervene surgically in a manner that ultimately culminates in an effective, successful Fontan [3]. This typically requires a staged approach of successive operations which optimally preserve pulmonary vasculature and ventricular function while providing a milieu of adequate oxygenation to allow for normal growth and development of the infant.
In a Fontan circuit the mechanisms involved in control of cardiac output at rest and during exercise differ significantly from normal. The classical model presumes an unlimited preload which is not available in the Fontan circuit. This review critically analyses the role of contractility, heart rate, and afterload and highlights the importance of pulmonary vascular resistance (PVR) in determining adequate preload and, therefore, cardiac output in these patients. A conceptual model of the determinants of cardiac output in Fontan patients is presented.
To compare the postoperative outcomes of patients with the diagnostic univentricular heart undergoing lateral tunnel (LT) operation with extracardiac conduit (EC) operation.
From June 1996 to July 2007, 114 consecutive patients with a single ventricle underwent total cavopulmonary connection (TCPC) in Children's Heart Center, University Hospital Giessen and Marburg GmbH, Germany. A LT was performed in 19 (16.7%) patients, and an EC in 95 (83.3%) patients. The mean age of EC group was 50.8 +/- 31.6 (ranging from 22 to 212) months, and that of LT group was 61.5 +/- 41.2 (ranging from 30 to 168) months. Early and midterm outcomes of two groups were analyzed.
One died in LT group (5.3%) and three in EC group (3.2%). The overall mortality was 3.5%. There was no significant difference in mortality between EC and LT groups (P>0.05). The postoperative pulmonary arterial pressure, oxygen saturation, and effusion time of two groups had no significant difference (all P>0.05). No significant difference in the occurrences of complications (arrhythmias, enteropathy, and thrombosis) was found between two groups after operation (P>0.05).
There seems no difference between LT and EC in the clinical results in the early and middle postoperative stage. Glenn anastomosis followed by an EC seems to have some advantages.
To compare outcomes of extracardiac conduit and lateral tunnel Fontan connections in a single institution over a concurrent time period.
Between January 1994 and September 1998, 60 extracardiac conduit and 47 lateral tunnel total cavopulmonary connections were performed. Age, sex, and weight did not differ between the 2 groups. Compared with the lateral tunnel group (LT group), patients undergoing the extracardiac conduit procedure (EC group) had a trend to a higher incidence of morphologically right ventricle (EC group 48% vs LT group 32%; P <.09), a higher incidence of isomerism/heterotaxy syndrome (EC 22% vs LT 0%; P <.001), worse atrioventricular valve regurgitation (EC 11% moderate-plus vs LT 0%; P <.06), and lower McGoon indices (EC 1.8 +/- 0.5 vs LT 2.1 +/- 0.5; P <.03). Preoperative arrhythmias, transpulmonary gradients, room air oxygen saturations, ejection fractions, ventricular end-diastolic pressure, and pulmonary artery distortion did not differ between groups. Cardiopulmonary bypass times and fenestration usage were similar in both groups.
Overall operative mortality was 5.6% and did not differ between groups. The LT group had a significantly higher incidence of postoperative sinoatrial node dysfunction (45% vs EC group 15%; P <.007), supraventricular tachycardia (33% vs EC group 8%; P <.0009), and need for temporary postoperative pacing (32% vs 12%; P <.01). Median duration of intensive care unit stay (EC 2 days, range 1-10 days, vs LT 2.8 days, range 1-103 days; P <.07) and ventilatory support (EC 1 day, range 0.25-10 days, vs LT 1 day, range 0.25-99 days; P <.03) were all longer in the LT group. Median chest tube drainage (EC 8 days, LT 9 days) was similar in both groups. Follow-up averaged 2.5 +/- 1.4 years in the EC group and 2.8 +/- 1.9 years in the LT group. There were 2 late deaths. Overall survival is 94% at 1 month, 92% at 1 year, and 92% at 5 years. Late ejection fraction or atrioventricular valve function did not differ between groups. Intermediate follow-up Holter analysis showed a higher incidence of atrial arrhythmias in the LT group (23% vs 7%; P <.02). Multivariable analysis showed that (1) prolonged cardiopulmonary bypass time was the only independent predictor for perioperative mortality, prolonged ventilation and intensive care unit length of stay, and increased time to final removal of chest tube drains and (2) lateral tunnel Fontan connection is an independent predictor of early postoperative and intermediate atrial arrhythmias.
Although patients in the EC group were at higher preoperative risk, their outcomes were comparable with those of the LT group. Use of the extracardiac conduit technique for the modified Fontan operation reduces the risk of early and midterm atrial arrhythmia.
Traditionally, all patients undergo cardiac catheterization before bidirectional cavopulmonary anastomosis (BCPA). The purpose of this study was to determine if preoperative catheterization is necessary when echocardiographic parameters appear favorable. A retrospective review was performed of all patients who underwent BCPA (n = 142) between February 1996 and May 2001. Echocardiographic criteria defining a favorable BCPA candidate included good ventricular function, moderate or less atrioventricular and semilunar valve regurgitation, absence of ventricular outflow tract obstruction, normal proximal branch pulmonary artery (PA) size, and low PA pressures estimated by PA band gradient or systemic PA shunt velocity. The median age at operation was 7 months (range: 2-11) and weight was 6.2 kg (range: 2.7-7.1). There were 73 unfavorable candidates. Patients with hypoplastic left heart syndrome (n = 23) and pulmonary atresia with intact septum (n = 15) predominated among the unfavorable group. All patients were catheterized. This provided additional information on PA pressures in 3 patients in the favorable group but did not defer operation or influence outcome (no mortality, prolonged pleural drainage, or longer intensive care department stay). All 3 patients are alive at a mean follow-up of 51 months. The 30-day mortality was 2% (4 of 151 patients), all in the unfavorable group. Overall, 20 patients (13%) required arterioplasty of PAs at the time of BCPA. BCPA can be performed with a low risk of morbidity and mortality in a wide range of patients. By using commonly acquired echocardiographic parameters, a low-risk subgroup of patients can be identified who can safely avoid preoperative cardiac catheterization.
Creation of an extracardiac cavopulmonary connection has been proposed as a superior alternative to the lateral intracardiac tunnel for the completion of total cavopulmonary connection.
We made a retrospective review of our experience with 125 patients undergoing a total cavopulmonary connection between June 1994 and January 2003. Our experience with the extracardiac connection for completion began in 1999. Since 1994, we have constructed an intracardiac tunnel in 50 patients, and an extracardiac connection in 75. Of the total number, 83 had undergone an earlier partial cavopulmonary connection. Additional intracardiac procedures were performed in 43 patients at time of completion, in 25 of those undergoing extracardiac completion, and in 18 of the patients having an intracardiac procedure. The mean size of the tube used for completion was 19 mm. The mean cross-clamp time for placement of the intracardiac tunnel was 77 min, with a median of 80.5 min, and a mean cardiopulmonary bypass time of 139 min, with a median of 131 min. For construction of the extracardiac connection, a mean cross-clamp time in 24 of the 75 patients was 54 min, with a median of 54 min. Mean cardiopulmonary bypass time for all the patients with an extracardiac connection was 100 min, with a median of 88 min. Reoperations were needed in 10 patients, 6 having intracardiac and 4 extracardiac procedures. Of these, 5 were early and 5 late, including one take down. None of the patients died after these interventions. Taken overall, 8 patients died, with 5 early deaths. In the multivariable analysis, cardiopulmonary bypass time of more than 120 min, atrioventricular valvar replacement, and banding of the pulmonary trunk prior to the total cavopulmonary connection, all reached statistical significance for early death, whereas only heterotaxy syndrome remained as the sole risk factor for late death. There was no significant difference in survival between the modifications used.
Whereas we could not identify any clinical superiority for the extracardiac approach in the short-term, the concept of extracardiac completion has helped to simplify the overall procedure. Longer follow-up will be required to elucidate any potential advantages.
To understand better the contribution of a right atrium in a valveless atriopulmonary connection, we performed some basic hydrodynamic studies. Pulsation of a valveless chamber in a simple continuous flow circuit was found to generate turbulence and thereby to increase resistance to net forward flow. Visualization of flow through cavities and around corners and measurements of energy losses across nonpulsatile cavities, corners, and stenoses indicated the importance of streamlining. These studies suggested ways in which hydrodynamic designs of the Fontan circulation might be improved. In parallel with these in vitro studies, we have developed a modified approach to Fontan reconstruction that entails exclusion of most or all of the right atrium (total cavopulmonary connection). The operation consists of three parts: (1) end-to-side anastomosis of the superior vena cava to the undivided right pulmonary artery; (2) construction of a composite intraatrial tunnel with the use of the posterior wall of the right atrium; and (3) use of a prosthetic patch to channel the inferior vena cava to the enlarged orifice of the transected superior vena cava that is anastomosed to the main pulmonary artery. The operation was performed in 20 patients between March 1987 and March 1988. The diagnoses were double-inlet ventricle (11 patients), hypoplastic systemic or pulmonary ventricle (seven patients), and absent right atrioventricular connection (two patients). There were two early deaths and one late death. None of the deaths was related to the actual procedure but rather to increased pulmonary vascular resistance (two patients) or systemic ventricular failure (one patient). Total cavopulmonary connections have the following advantages: (1) They are technically simple and reproducible in any atrioventricular arrangement and are away from the atrioventricular node; (2) most of the right atrial chamber remains at low pressure, which reduces the risk of early or late arrhythmias; (3) reduction of turbulence prevents energy losses and should minimize the risk of atrial thrombosis; (4) postoperative cardiac catheterization performed in 10 patients confirmed these favorable flow patterns with minimal gradients throughout the connections. These encouraging early results support the continuing use of total cavopulmonary connection, at least for patients with a nonhypertrophied right atrium.
Four patients with presently uncorrectable cyanotic cardiac anomalies underwent a new operation, "total cavopulmonary shunt operation" or "total right heart bypass operation." These anomalies included single ventricle, single atrium, common atrioventricular valve with or without regurgitation, pulmonary stenosis, and most important, absent inferior vena cava with azygos or hemiazygos continuation. All patients had had previous systemic-pulmonary shunts. The new operation consisted of end-to-side anastomosis between the superior vena cava with azygos or hemiazygos continuation and the confluent pulmonary artery, division or ligation of the pulmonary artery trunk, and replacement of the common atrioventricular valve when regurgitation was present. Thus total venous return, except for hepatocardiac venous and coronary sinus flow, drains directly into the pulmonary artery, bypassing the right atrium and ventricle. Three patients survived the operation, and two of the three patients are now alive 4 years, 8 months and 2 years, 6 months after the operation. The two long-term survivors are in significantly improved condition, both clinically and hemodynamically. We believe that this new operation is promising in the treatment of the otherwise uncorrectable complex cardiac anomalies associated with azygos or hemiazygos continuation of the inferior vena cava. A longer follow-up is certainly mandatory before final conclusions can be reached.
A laboratory study designed to investigate the independent pump-like function of the right ventricle of the dog heart is presented. Systolic and diastolic pulmonary arterial pressure fluctuations were used as the definitive criterion for pumping efficiency. Control pressure levels are compared with those recorded after complete damage, by electrosurgical coagulation, of the free right ventricular myocardium. The degree of damage so produced was ascertained from an analysis of electrocardiographic, physiologic and histologic observations. The results are discussed and explained in terms of a postulated mechanism based upon the architecture of the individual ventricular muscle bands.
After modified Fontan procedures with atriopulmonary anastomoses or right atrium–right ventricle conduits, some patients have progressive exercise intolerance, effusions, arrhythmias, or protein-losing enteropathy. Theoretic advantages of a lateral atrial tunnel cavopulmonary anastomosis and published clinical results suggest that conversion of other Fontan procedures to the lateral atrial tunnel may afford clinical improvement for some patients. Eight patients (8 to 25 years old) with tricuspid atresia ( n = 4), double-inlet left ventricle ( n = 3), and double-outlet right ventricle ( n = 1) underwent conversion to a lateral tunnel procedure between December 1990 and November 1994. An arbitrary clinical score was assigned before the lateral tunnel procedure and at follow-up. Before conversion, patients had decreased exercise tolerance ( n = 8), arrhythmias ( n = 6), effusions ( n = 4), and protein-losing enteropathy ( n = 8). At catheterization, all had a low cardiac index (1.9 ± 0.7 L•min-1•m-2), five had elevated pulmonary vascular resistance (>3 Wood units), and three had right pulmonary venous return obstruction by compression of an enlarged right atrium. Fenestrated lateral tunnel construction was undertaken 7.3 ± 3.6 years after atriopulmonary anastomosis, with one early death related to low cardiac output. After the lateral tunnel procedure, two patients had no clinical improvement (no change in clinical score) but five patients had either marked or partial improvement. The right pulmonary vein compression present in three patients was resolved after conversion. The mean clinical scores improved from 4.5 ± 1 to 3.0 ± 2 ( p < 0.04). In conclusion, conversion to a lateral tunnel procedure led to clinical improvement in five of eight patients at short-term follow-up and may be particularly indicated for patients with giant right atria or pulmonary vein compression who have symptoms. Pulmonary vein compression should be looked for in patients after modified Fontan procedures and can be relieved by conversion to the lateral tunnel procedure. (J THORAC CARDIOVASC SURG 1996;111:1169-76)
The purpose of this study was to estimate survival and quality of outcome and assess factors associated with outcome for patients out 5 to 15 years from their Fontan operation.
We studied 352 patients who had the Fontan operation prior to 1985. The overall 1-, 5-, and 10-year survival was 77%, 70%, and 60%, respectively. The following factors were significantly associated with lower survival: univentricular heart or complex congenital anomalies other than tricuspid atresia, early calendar year of operation, heterotaxia syndromes, early age at operation, increased pulmonary artery pressure, atrioventricular valve dysfunction, and higher (worse) New York Heart Association class. Reoperations were necessary for 103 of the 352 patients. At least 20% of the survivors have or have had cardiac arrhythmias requiring antiarrhythmic medication or mechanical pacemaker insertion. Between 7% and 10% of the patients have had or had protein-losing enteropathy/hypoproteinemia. At 5 years postoperatively, 122 patients (34.7%) were alive with a better New York Heart Association functional classification than preoperatively. Fifty-eight patients (16.5%) were alive and in the same functional classification, but 126 (35.8%) died within the first 5 years or were in a worse functional classification. Thirty-nine patients were doing excellently and 29 patients poorly 5 years after the operation. Of the surviving patients, 43% can do as much exercise as their peers, whereas 3% are incapable of exercise.
To assure good functional long-term outcome in addition to survival, clinicians must exclude from selection for Fontan operation patients known to be at high risk for death or poor outcome.
From November 1988 to May 1989, four patients underwent total right heart bypass by means of bidirectional cavopulmonary anastomosis and interposition of an extracardiac conduit from the inferior vena cava to the pulmonary artery. All of them had an uneventful postoperative course, and there have been no early or late deaths. We propose this technique as an alternative surgical option in candidates for a Fontan procedure with (1) hypoplasia or atresia of the left atrioventricular valve, (2) common atrioventricular valve, (3) anomalies of systemic and pulmonary venous return, or (4) auricular juxtaposition.
After a Fontan repair for congenital heart disease, 42 patients underwent graded supine bicycle exercise tests at levels relevant to normal daily activities. Results were compared with those of 28 age-matched normal control subjects. At rest, the cardiac index, stroke index and systolic blood pressure were comparable in both groups, but increases with exercise were smaller in the patients with a Fontan circulation. The heart rate at rest was higher in the Fontan group, but this difference disappeared as soon as exercise started. To determine whether there are limitations intrinsic to the Fontan circulation at these levels of exercise, the 10 best performers were compared with 10 age-matched control subjects; no differences were found in cardiac index, stroke index, heart rate or blood pressure at any exercise level. Analysis of the determinants of cardiac output showed that at the other end of the spectrum poor performance after a Fontan operation did not result from inadequate levels of heart rate, but from an inability to increase or maintain stroke volume. Multivariate analysis demonstrated that impairment of ventricular contractility, only when severe, predicted limited performance. There was no evidence of increased afterload, particularly in the poor performers. Therefore, ventricular filling, which is determined primarily by the pulmonary vascular bed, appears to be a major determinant of functional result after a Fontan repair.
A study was undertaken to determine the early and long-term outcomes dictated by the Fontan state per se (a state in which the force driving pulmonary blood flow is solely or largely a residue, in the systemic venous pressure, of the main ventricular chamber's contractile force) and the transition (by surgery) to it from the state of congenital heart disease under optimal conditions (after a "perfect" Fontan operation). The primary study design used a solution of a multivariate risk factor equation for death, by which survival rate under optimal conditions was predicted to be 92%, 89%, 88%, 86%, 81%, and 73% at 1 month, 6 months, and 1, 5, 10, and 15 years, respectively, after the Fontan operation. The hazard function (instantaneous risk of death at each moment in time after the operation) had an early rapidly declining phase of hazard that at about 6 months began to give way to a late hazard phase, which was rising by about 6 years after surgery. A secondary study design, using the theory of competing risks, yielded survival and hazard function information very similar to that of the primary study design. The functional capacity of the patients as expressed by New York Heart Association class was less, the longer the period of follow-up. No risk factors (other than older age at time of surgery) were found for the late decline in survival or the decline in functional status. The inference is that the premature decline in survival and functional status and the late rise in hazard function are from the Fontan state per se and that the Fontan operation is, therefore, palliative but not curative.
Two modifications of the Fontan operation are proposed for prevention of pulmonary venous obstruction in patients with left atrioventricular valve atresia or single atrioventricular valve. In the first technique, a bipedicled flap of right atrial wall is used to separate systemic and pulmonary venous drainages; an atriopulmonary connection is constructed by use of the right atrial appendage, and the defect in the right atrial wall is repaired with a pericardial patch. In the second technique, the superior vena cava is transected and the cardiac and cephalad ends are anastomosed separately to the pulmonary arterial confluence. A patch is positioned inside the right atrium to separate the systemic from the pulmonary venous drainage. Both techniques achieve unrestricted systemic and pulmonary venous channels. Severe atrial arrhythmias, present in the four patients operated on with the first procedure, were not seen in 12 patients who had repair with the second procedure.
The original Fontan procedure included a classic superior vena cava-to-right pulmonary artery (Glenn) shunt. Subsequent experience demonstrated that this anastomosis was not essential and was an unnecessary commitment of the larger right pulmonary circulation to the smaller blood volume of the superior vena caval return. With application of the Fontan principle to more complex cardiac malformations, there has been a reconsideration of possible benefits of a cavopulmonary shunt in selected patients. A modified shunt from the divided end of the superior vena cava to the side of the undivided right pulmonary artery utilized in 21 patients is described. This shunt is designed to allow bidirectional pulmonary arterial distribution of both superior vena caval inflow and right atrial outflow after completion of the Fontan procedure. Twelve patients had the bidirectional shunt performed prior to a Fontan operation; five of these had a subsequent atriopulmonary connection and seven await operation. Eight patients had construction of this shunt at the time of their Fontan procedure. One patient had a bidirectional shunt constructed following atriopulmonary anastomosis to help relieve right atrial outflow obstruction. Two patients with univentricular heart undergoing simultaneous Fontan procedure and a bidirectional shunt died while in the hospital. The remaining 19 patients have been followed up for 2 months to 9 years with one late sudden death at 9 years. There have been no bidirectional cavopulmonary shunt failures, stenoses, kinks, or recognized pulmonary arteriovenous malformations. Postoperatively, eight patients had assessment of pulmonary distribution of shunt blood flow by angiography. Seven of these patients were also evaluated by radionuclide angiography. Superior vena caval blood flow via the bidirectional cavopulmonary shunt tended to be greater to the right lung, but bilateral pulmonary flow was documented in all but one patient. After Fontan operation, six of seven patients tested also demonstrated bilateral distribution of atriopulmonary flow. We concluded from our experience that this modified shunt provides excellent relief of cyanosis, allows bidirectional pulmonary distribution of both superior vena caval return and also the right atrial blood flow after atriopulmonary connection, and may be done before, with, or after a Fontan procedure and is compatible with all currently recommended modifications. Perioperative hemodynamic adjustments to the Fontan procedure may be improved by reducing atrial volume, and this may also be of potential benefit in the long-term adaptation to Fontan physiology by minimizing atrial distention.
Surgical repair of tricuspid atresia has been carried out in three patients; two of these operations have been successful. A new surgical procedure has been used which transmits the whole vena caval blood to the lungs, while only oxygenated blood returns to the left heart. The right atrium is, in this way, `ventriclized', to direct the inferior vena caval blood to the left lung, the right pulmonary artery receiving the superior vena caval blood through a cava-pulmonary anastomosis. This technique depends on the size of the pulmonary arteries, which must be large enough and at sufficiently low pressure to allow a cava-pulmonary anastomosis. The indications for this procedure apply only to children sufficiently well developed. Younger children or those whose pulmonary arteries are too small should be treated by palliative surgical procedures.
Twenty-seven patients (3 to 22 years) underwent the Fontan operation. Seventeen had tricuspid atresia and 10 had other complex lesions. Sixteen patients had a Glenn shunt (12 prior to, three simultaneous with, and one following the Fontan operation). One early death (3.7%) occurred in a 4 1/2-year-old child with tricuspid atresia II-C, previous pulmonary artery banding, and a closing ventricular septal defect (80 mm Hg gradient). There were two late deaths (7.4%) from Candida sepsis, after 4 and 6 months, respectively. The 24 patients who survived the Fontan operation had postoperative hospital stays of 6 to 90 days (average 18). Patients with tricuspid atresia and an established Glenn shunt (nine patients, Group I) had postoperative hospital stays of 7 to 19 days (average 9.5), and none had significant pleural or pericardial effusions. Patients with tricuspid atresia without a Glenn shunt (seven patients, Group II) had postoperative hospital stays of 6 to 60 days (average 17.5), with three having significant effusions. Of the patients with other complex lesions, all without an established Glenn shunt, five had significant effusions. Four additional major complications (two tricuspid patch disruptions with ineffective pulmonary blood flow and two complete occlusions of a valved conduit) were encountered in which the Glenn shunt proved lifesaving. We believe that an established Glenn shunt played a major role in attaining minimal postoperative hemodynamic instability, effusions, renal failure, and mortality in our patients. The Glenn shunt should be considered in patients who are less than ideal candidates for the Fontan operation.
Acute removal of a ventricular volume overload, in the face of relatively unchanging ventricular mass, results in geometric alterations that can impair diastolic ventricular performance after Fontan operation. We investigated whether geometric alterations were (1) more severe after Fontan operation than after hemi-Fontan operation, (2) more severe in infants than in children, and (3) more severe in the morphologic right ventricle than in the morphologic left ventricle. We studied 22 patients, 11 with hypoplastic left heart syndrome and 11 with a functionally single morphologic left ventricle. After Fontan operation, right ventricular end-diastolic volume declined by 52% from 36.6 +/- 12.2 to 17.5 +/- 9.3 mL. Right ventricular wall thickness increased from 6.8 +/- 1.3 to 7.5 +/- 1.8 mm. Left ventricular end-diastolic volume diminished by 40% from 57.6 +/- 23.3 to 34.8 +/- 17.6 mL. Left ventricular wall thickness increased from 7.0 +/- 2.1 to 8.7 +/- 1.9 mm. The alterations in right ventricular geometry are more marked early after Fontan operation than early after the hemi-Fontan procedure. Geometric alterations in the left ventricle appear to be more severe in infants than in children. Finally, alterations in the morphologic right ventricle appear to be of similar magnitude to those in the morphologic left ventricle.
This study sought to evaluate the effect of offsetting cavopulmonary connections at varying pulmonary flow ratios to determine the optimal geometry of the connection.
Previous investigators have demonstrated energy conservation within the streamlined contours of the total cavopulmonary connection compared with that of the atriopulmonary connection. However, their surgical design of connecting the two cavae directly opposite each other may result in high energy losses. Others have introduced a unidirectional connection with some advantages but with concerns about the formation of arteriovenous malformation in the lung excluded from hepatic venous return. Thus, an optimal surgical design has not been determined.
In the present models, the caval connections were offset through a range of 0.0 to 2.0 diameters by 0.5 superior cava diameter increments. Flow ratios were fixed for superior and inferior cavae and varied for right and left pulmonary arteries as 70:30, 60:40, 50:50, 40:60 and 30:70 to stimulate varying lung resistance. Pressure measurements and flow visualization were done at steady flows of 2, 4 and 6 liters/min to stimulate rest and exercise.
Our data show that the energy losses at the 0.0-diameter offset were double the losses of the 1.0 and 1.5 diameters, which had minimal energy losses. This result was attributable to chaotic patterns seen on flow visualization in the 0.0-diameters offset. Energy savings were more evident at the 50:50 right/left pulmonary artery ratio. Energy losses increased with increased total flow rates.
The results strongly suggest the incorporation of caval offsets in future total cavopulmonary connections.
The purpose of this study was to review a large, evolving, single-center experience with the Fontan operation and to determine risk factors influencing early and late outcome.
The first 500 patients undergoing modifications of the Fontan operation at our institution were identified. Perioperative variables were recorded and a cross-sectional review of survivors was undertaken.
The incidence of early failure decreased from 27.1% in the first quartile of the experience to 7.5% in the last quartile. In a multivariate model, the following variables were associated with an increased probability of early failure: a mean preoperative pulmonary artery pressure of 19 mm Hg or more (p < 0.001), younger age at operation (p = 0.001), heterotaxy syndrome (p = 0.03), a right-sided tricuspid valve as the only systemic atrioventricular valve (p = 0.001), pulmonary artery distortion (p = 0.04), an atriopulmonary connection originating at the right atrial body or appendage (p = 0.001), the absence of a baffle fenestration (p = 0.002), and longer cardiopulmonary bypass time (p = 0.001). An increased probability of late failure was associated with the presence of a pacemaker before the Fontan operation (p < 0.001). A morphologically left ventricle with normally related great arteries or a single right ventricle (excluding heterotaxy syndrome and hypoplastic left heart syndrome) were associated with a decreased probability of late failure (p = 0.003).
These analyses indicate that early failure has declined over the study period and that this decline is related in part to procedural modifications. A continuing late hazard phase is associated with few patient-related variables and does not appear related to procedural variables.
This article has no abstract; the first 100 words appear below.
IN the first publication of this series of papers attention was called to the need of a method for the direct delivery of venous blood into the pulmonary arterial circulation.¹ The congenital anomalies of the heart that might be remedied from this operation are characterized by malfunction of the right atrium or right ventricle or both. More specifically, the cardiac conditions that would benefit from circulatory bypass of the right side of the heart include stenosis or atresia of the tricuspid and pulmonary outflow tracts, Ebstein's anomaly, single ventricle, bilocular heart and transposition of the great vessels with an associated . . .
*From the Department of Surgery, Yale University School of Medicine.
Supported in part by grants from the Victoria Foundation for Cardiovascular Research at Yale and United States Public Health Service (H851-C-7).
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NEW HAVEN, CONNECTICUT
† Associate professor of surgery, Yale University School of Medicine.
Previous observations that major destruction of the right ventricular walls causes but slight changes in venous and arterial pressures were confirmed. Furthermore, additional observations indicated that the compensatory reaction of the damaged ventricle to stress is diminished surprisingly little. The results are considered evidence that the cauterization procedure and others of a similar nature do not produce right heart failure and, therefore, would not be expected to cause venous congestion. The subsidiary muscular mechanism which maintains the right ventricular pump remains enigmatic; but evidence is submitted that the damaged right ventricle is regulated independently of the left.