Fontan Operation: A Comparison of Lateral Tunnel with Extracardiac Conduit

Does the External Pericardial Lateral Tunnel Fontan Pathway Enlarge to Accommodate Somatic Growth? A Preliminary Analysis

Objectives: An ideal Fontan pathway should be capable of adapting to changes in circulatory demands. The external pericardial lateral tunnel Fontan (EPLTF) is constructed of viable, autologous tissue and may be capable of changing in size. We investigated the ability of the EPLTF to enlarge with increasing physiologic demands of somatic growth. Methods: Retrospective review of echocardiographic images for patients with a minimum of five years follow-up after EPLTF. Serial echocardiographic measurements of the EPLTF pathway were obtained at three distinct locations: the inferior vena cava junction with the EPLTF, midsection of the EPLTF, and cross-sectional area of the EPLTF visualized in a four-chamber view. Body surface area (BSA) was calculated at the time of each echocardiographic measurement. Changes in echocardiographic measurements over time were analyzed and compared with changes in BSA. Results: A total of 332 echocardiographic studies from 38 patients were reviewed. Significant enlargement of the EPLTF pathway is observed at the inferior vena caval junction (P < .001), midsection (P < .01), and cross-sectional area (P < .001). Repeated measures correlation between pathway measurements and BSA is highly significant (P < .001). Conclusions: The EPLTF pathway enlarges over time in correlation with increasing BSA. Further research is needed to define ideal pathway size, differentiate normal physiologic growth from pathologic enlargement, and correlate changes with clinical outcomes.

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 (TA), pulmonary atresia (PA), hypoplastic left heart syndrome (HLHS), and double inlet left ventricle (DILV), all of which involve a functional single-ventricle physiology. The complexity of the patients' original anatomy combined with the anatomical and physiological consequences of the Fontan circulation creates challenges. Teens and adults living with Fontan palliation will need perioperative support for non-cardiac surgery, peripartum management for labor and delivery, interventions related to their structural heart disease, electrophysiology procedures, pacemakers, cardioversions, cardiac surgery, transplant, and advanced mechanical support. This review focuses on the anesthetic and ICU management of these patients during their perioperative journey, with an emphasis on the continuity of pre-intervention planning, referral pathways, and post-intervention intensive care unit (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 physiological 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 atrio- pulmonary (AP) Fontan at home waiting for a heart transplant. Each case will require an anesthetic and critical care plan tailored to their 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.

Perioperative outcomes of Fontan operation: Impact of heterotaxy syndrome

BACKGROUND/PURPOSE

Fontan operation is the standard surgical procedure for achieving long-term survival in single-ventricular complex congenital heart diseases (SV-CHD). We aim to identify the perioperative outcomes and impact of heterotaxy syndrome (HS) after Fontan operation in a tertiary pediatric cardiology center.

METHODS

Medical records were reviewed for all patients who received Fontan operation and who were born between 1997 and 2017 in our institution. Preoperative, operative, and postoperative risk factors for perioperative mortality and morbidity were analyzed.

RESULTS

Totally, 154 patients were enrolled (103 SV-CHD and 51 HS), and the male to female ratio was 92:62. The mean age of Fontan operation was 5.1 years, and extracardiac conduit comprised the majority (90.9%) of Fontan operation. Overall perioperative event-free survival to discharge was 91.6% (84.3% in HS and 95.1% in other SV-CHD, P = 0.032). For secondary outcomes, length of intensive care stay and duration of pleural effusion drainage were not significantly different between patients with HS and other SV-CHD, but postoperative arrhythmia was more common in HS group (31.4% vs. 12.6%, P = 0.005). In multivariable regression analysis, preoperative risk factors including operation year before 2007 and high PAP and postoperative factors of elevated postoperative CVP were associated with worse outcomes. HS was not a predictor of worse outcome after adjusting for preoperative PAP and operation era.

CONCLUSION

Surgical outcome has improved much in current era. Perioperative outcome is poorer in patients with HS than other SV-CHD, but HS is not a predictor of perioperative mortality after adjusting for hemodynamic factors.

The intra-extracardiac Fontan: preliminary results

OBJECTIVE

Since the intra-extracardiac Fontan (IECF) was popularized by Jonas in 2008, its claimed advantages over the traditional extracardiac or lateral tunnel Fontan are simplicity, suitability for nearly all subsets, flow characteristics, low risk of sinus node artery injury, and possibly, a lower incidence of arrhythmias. In this paper, we present our early experience with this modification of the Fontan operation.

METHODS

Between 2009 and 2018, 10 patients underwent IECF on cardiopulmonary bypass (CPB) and cardioplegic arrest at our institute. Analysis of preoperative, intraoperative, and early follow-up results was performed. A polytetrafluoroethylene (PTFE) graft was sutured proximally to the orifice of the inferior vena cava (IVC) and distally to the ipsilateral bidirectional superior cavopulmonary (BSCP) junction.

RESULTS

Nine patients had undergone a previous BSCP connection, and one patient had a primary IECF. Diagnoses were double outlet right ventricle (n = 2), unbalanced atrioventricular septal defect with associated atrioventricular valve regurgitation (n = 3), single ventricle with anomalies of cardiac situs (n = 2), and tricuspid atresia with borderline pulmonary arteries (n = 1) or tricuspid atresia with borderline pulmonary artery pressures (n = 2). Median aortic cross-clamp and CPB times were 42 min and 82 min respectively. There were no early or late deaths. Median intensive care stay was 3 days (1 to 23 days). There were no arrhythmias. Mean duration of pleural effusions was 9.5 (median 5.5) days. There were no arrhythmias at a median follow-up of 5 years (range 1 month to 9.3 years).

CONCLUSION

The IECF is simple, particularly at reoperations, in borderline patients and those needing concomitant intracardiac procedures. Early results are promising. These patients need constant surveillance.

Outcomes following modified extracardiac Fontan procedure of direct total cavopulmonary connection with autologous vessels: a single-centre 10-year experience

OBJECTIVES

The modified extracardiac Fontan of direct total cavopulmonary connection (dTCPC) with entirely autologous vessels is a better solution in selected patients with functionally univentricular hearts because it combines the advantages of a tubular connection and of full growth potential. We investigated the mid-term to long-term outcomes of the physical condition of patients who had the dTCPC and assessed the growth potential of the autologous dTCPC pathway.

METHODS

From July 2005 to June 2014, 31 patients, aged 1.8-14.0 years, underwent a modified extracardiac Fontan with dTCPC at our institution. Twenty-two patients underwent a 1-stage dTCPC and 9 patients underwent a 2-stage dTCPC. The preoperative and postoperative data were reviewed retrospectively.

RESULTS

There were 17 (54.8%) boys and 14 (45.2%) girls, with a median age of 6.4 years (range 1.8-14.0 years) and a mean weight of 17.8 kg (range 9-41 kg). The mean follow-up period was 6.0 years (range 2.1-10.2 years). There was 1 early death and 2 late deaths. The event-free survival rate for the 31 patients was 88.9% at 10 years during the follow-up period. Late protein-losing enteropathy, thromboembolism, arrhythmia or heart failure were not observed. There was a significant difference between the preoperative and postoperative data for body mass index and the diameters of the autologous dTCPC pathway and pulmonary artery branches, confirming that the growth potential of the autologous dTCPC pathway was realized.

CONCLUSIONS

The dTCPC procedure could be performed with satisfactory midterm to long-term outcomes in selected patients. It has the potential of retaining the advantage of the extracardiac Fontan operation together with the potential for growth and the avoidance of prosthetic materials.

Autologous Right Auricular Versus PTFE Cavopulmonary Lateral Tunnel: Influence of Surgical Technique on Arrhythmias

BACKGROUND

To compare the incidence of arrhythmias and the overall survival at long-term follow-up of the right auricular baffle technique (RA) versus Gore-Tex^® (GT) baffle as intra-atrial cavopulmonary lateral tunnel, as well as the Nakata index and tunnel dimensions on cardiac magnetic resonance.

METHODS

Data were retrospectively collected. Serial 24-hour Holter recordings and cardiac magnetic resonance findings of the two groups were compared.

RESULTS

There was no significant difference in the estimated freedom from arrhythmias (87% at 10 years and 78% at 15 years vs 80% at 10 years and 70% at 15 years in RA and GT, respectively; P = .44) nor cumulative survival (86% at 10 years and 84% at 15 years vs 97% at 10 years and 81% at 15 years in RA and GT, respectively; P = .8). Also, no difference between the groups was observed in the Nakata index. The tunnel dimensions on cardiac magnetic resonance were significantly wider in the RA group. In reference to other potential risk indicators, using Cox proportional hazard regression analysis, only age (5 years or older at the time of total cavopulmonary connection) was associated with an increased risk for both arrhythmia and mortality.

CONCLUSIONS

This study demonstrated that there was no difference in freedom from arrhythmias, Nakata index, or survival between the two groups. This study confirmed the growth potential of the right auricular tunnel. However, the growth of the tunnel did not influence the incidence of arrhythmias.

Echocardiographic evaluation of univentricular physiology and cavopulmonary shunts

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

Surgical and Catheter-Based Reinterventions Are Common in Long-Term Survivors of the Fontan Operation

BACKGROUND

There are limited follow-up studies examining surgical and catheter-based reinterventions in long-term survivors of the Fontan operation.

METHODS AND RESULTS

All 773 patients who underwent Fontan at our institution between 1992 and 2009 were retrospectively reviewed. Current information regarding post-Fontan intervention was available for 70%. By 20 years after Fontan, 65% of patients had experienced either surgical or transcatheter intervention. The median time to first reintervention was 9.8 years. Freedom from reoperation was 69% at 15 years and 63% at 20 years. The most common operations were pacemaker placement and Fontan revision. Risk factors for pacemaker placement included systemic left ventricle (hazard ratio [HR], 2.2; P=0.006) and lateral tunnel Fontan (HR, 4.3; P=0.001). Freedom from interventional catheterization was 53% at 15 years and 50% at 20 years. The most common procedures performed were fenestration closure and pulmonary artery intervention. Catheter intervention for anatomic indications was associated with Fontan after 2002 (HR, 2.1; P=0.007), Norwood operation (HR, 2.3; P=0.001), and longer cardiopulmonary bypass time (HR, 1.1 per 10 minutes; P=0.001). Catheter intervention for physiological indications was associated with prolonged post-Fontan pleural drainage (HR, 4.0; P<0.001) and hypoplastic left heart syndrome (HR, 2.0; P=0.01).

CONCLUSIONS

In this study of Fontan survivors, two thirds of patients required surgical or catheter-based reintervention by 20 years. Families should be counseled that the Fontan is typically not the final stage of single-ventricle palliation.

Pathophysiology of thrombosis and anticoagulation post Fontan surgery

The Fontan procedure has transformed the lives of children born with single-ventricle physiology, previously deemed inoperable. Worldwide, there are an increasing number of children with Fontan circulation, with the potential for survival into adulthood. Due to the abnormal circulation, Fontan patients have an increased risk of thromboembolic (TE) events, with up to 25% of events leading to death. Despite the importance of preventing TE events in this patient population, there is currently no clinical consensus on the optimal monitoring, thromboprophylaxis therapies, and treatment of these events. This paper reviews the available literature regarding anticoagulation in the pediatric and adult Fontan population, including the mechanisms for thrombosis and current antithrombotic therapies.

Comparison of extracardiac conduit and lateral tunnel for functional single-ventricle patients: A meta-analysis

OBJECTIVE

This study aims to assess and compare the early and long-term effects of extracardiac conduit (EC) and lateral tunnel (LT) in patients with a functional single ventricle through meta-analysis.

DESIGN

A systematic search was performed in PubMed, Embase, Cochrane Library, CNKI, VIP, CBM, and WanFang databases for papers that were published until August 1, 2016. Cochrane systematic review method was used for paper screening and information retrieve, and RevMan 5.3 software was applied for the meta-analysis.

RESULTS

Data for 10 studies with a total of 3814 patients were retrieved. The advantages of EC comparing to LT include: lower 30 day postsurgery supraventricular arrhythmia incidence (Relative Risk [RR] = 0.31 [0.17, 0.55], P < .001), lower protein loss enteropathy incidence (RR = 0.33 [0.11, 0.96], P = .04), and requiring no cardiopulmonary bypass. However, the chest drainage time was longer (mean difference [MD] = 1.99 [1.83, 2.15], P < .001) in EC. There were no significant differences in early postoperative mortality, long-term mortality, long-term arrhythmia, Fontan takedown, ventilator-assisted ventilation, ICU stay, thrombosis, pleural effusion, and pericardial effusion between EC and LT.

CONCLUSIONS

EC had a lower incidence of supraventricular arrhythmia (30 days after operation) and the rate of protein losing enteropathy than LT, and requiring no cardiopulmonary bypass. These show that EC has an advantage over the LT in patients with a functional single ventricle.

Lateral Atrial Tunnel Fontan Operation Predisposes to the Junctional Rhythm

The goal of the study was to compare the early postoperative course after fenestrated lateral atrial tunnel (LT) and non-fenestrated extracardiac conduit (EC) Fontan operation (FO) in a single center where both techniques were parallelly used. Between 2004 and 2012, 56(32.7%) children underwent LT and 113(66.1%) EC FO. The mean age was 3.7 ± 2.9 years and mean weight was 14.6 ± 7.3 kg. The most common malformation was hypoplastic left heart syndrome (50.9%). The general approach was to perform LT in children after hemi-Fontan operation and EC in patients after Glenn anastomosis. Medical records were retrospectively reviewed. The hospital survival was 100%. In EC group, cardiopulmonary bypass time (CPB) was shorter (p = 0.004) and less patients needed aortic cross-clamping (p < 0.001). Children after EC stayed longer in the hospital (p = 0.016) and manifested more often prolonged effusions (p = 0.038). The incidence of all forms of junctional rhythm was higher in the LT group, early postoperatively (p < 0.001), during hospitalization (p = 0.004) and at discharge (p < 0.001). Children after LT required more often temporary pacemaker stimulation (p < 0.001). Patients without postoperative normofrequent sinus rhythm had longer CPB time (p = 0.008) and were more often operated on with aortic cross-clamping (p = 0.028). Lateral atrial tunnel Fontan operation with fenestration facilitates early adaptation to the total passive pulmonary flow, but predisposes the patients to the loss of sinus rhythm. The crucial role in the preservation of sinus rhythm plays the last step of the multistage surgery of the single ventricle malformations, probably not only the surgical technique but also factors associated with the cardiopulmonary bypass.

Arrhythmias After Fontan Operation with Intra-atrial Lateral Tunnel Versus Extra-cardiac Conduit: A Systematic Review and Meta-analysis

Current studies on the incidence of arrhythmias after the intra-atrial lateral tunnel (ILT) Fontan operation and the extra-cardiac conduit (ECC) Fontan operation are limited, with controversial results. This systematic review aimed to compare the prevalence of arrhythmias in patients who underwent ECC or ILT Fontan. Relevant studies comparing the incidence of arrhythmias and pacemaker implantation in ILT with ECC were identified through a literature search using MEDLINE, EMBASE, and the cochrane central register of controlled trials. The outcome measures included baseline characteristics, early (≤30 days) and late (>30 days) arrhythmias and pacemaker implantation. 16 publications involving 3499 patients were included. In the meta-analysis, although the overall risk of early arrhythmias was lower for the ILT group, statistically, no significant difference was observed (odds ratio [OR] 0.78; 95% confidence interval [CI] 0.61-1.01; p = 0.06). Similarly, there was no significant difference between the two cohorts in the incidence of postoperative permanent pacemaker therapy (OR 1.36; 95% CI 0.86-2.14; p = 0.19). However, we found significantly increased incidence of late arrhythmias in ILT group compared with ECC group (OR 1.96; 95% CI 1.64-2.35; p < 0.01). Although our systematic review and meta-analysis suggested that there was no significant difference in early arrhythmias and in pacemaker implantation between the ILT and ECC groups, ECC procedure could significantly lower the risk of late arrhythmias after Fontan surgery. Given that some limitations cannot be overcome, well-designed randomized controlled trials are needed to confirm our findings.

The Long-Term Management of Children and Adults with a Fontan Circulation: A Systematic Review and Survey of Current Practice in Australia and New Zealand

Although long-term survival is now the norm, Fontan patients face significant morbidity and premature mortality. Wide variation exists in long-term Fontan management. With an aim of improving their long-term management, we conducted a systematic review to identify best available evidence and gaps in knowledge for future research focus. We also surveyed cardiologists in Australia and New Zealand managing Fontan patients, to determine the alignment of current local practice with best available evidence. A systematic review was conducted using strict search criteria (PRISMA guidelines), pertaining to long-term Fontan management. All adult congenital and paediatric cardiologists registered with The Australia and New Zealand Fontan Registry were invited to respond to an online survey. Reasonable quality evidence exists for non-inferiority of aspirin over warfarin for thromboprophylaxis in standard-risk Fontan patients. No strong evidence is currently available for the routine use of ACE inhibitors, beta blockers or pulmonary vasodilators. Little evidence exists regarding optimal arrhythmia treatment, exercise restriction/prescription, routine fenestration closure, elective Fontan conversion and screening/management of liver abnormalities. Although pregnancy is generally well tolerated, there are high rates of miscarriage and premature delivery. Thirty-nine out of 78 (50 %) cardiologists responded to the survey. Heterogeneity in response was demonstrated with regard to long-term anti-coagulation, other medication use, fenestration closure and pregnancy and contraception counselling. Substantial gaps in our knowledge remain with regard to the long-term management of Fontan patients. This is reflected in the survey of cardiologists managing these patients. We have identified a number of key areas for future research.

Outcomes of total cavopulmonary connection for single ventricle palliation

BACKGROUND

The aim of this study was to review the early and mid-term outcomes of the total cavopulmonary connection (TCPC) procedure and evaluate risk factors for prolonged pleural effusions.

METHODS

The clinical records of 82 consecutive patients, who underwent a TCPC operation between January 2008 and December 2013, were reviewed for incidence of prolonged pleural effusions, duration of ventilation time and pleural drainage, length of intensive care unit (ICU) stay, and early and mid-term morbidity and mortality.

RESULTS

The median age at surgery was 3.0 years. The main single ventricle diagnoses included 18 cases of a double-inlet single ventricle, 17 cases of heterotaxy, 16 cases of tricuspid atresia, 4 cases of mitral atresia, 12 cases of unbalanced complete atrioventricular canal (CAVC), 5 cases of double-outlet right ventricle (DORV) combined with ventricular septal defect (VSD) and pulmonary stenosis (PS), 4 cases of transposition of the great arteries (TGA) combined with VSD and PS, 4 cases of corrected transposition of great arteries (cTGA) combined VSD and PS, and 2 cases of criss-cross heart. Preoperative mean pulmonary artery pressure (mPAP) was 13.66±2.21 mmHg with 23.2% (n=19) higher than 15 mmHg. A total of 61 (74.4%) patients underwent a fenestration. The perioperative mortality was 4.9%. The median duration of pleural effusion was 10 days (range, 3-80 days), and prolonged pleural effusions occurred in 16 (19.5%) patients. Multivariable analysis revealed that mPAP >15 mmHg was independently associated with prolonged pleural effusions (OR, 8.33; 95% CI, 2.33-29.74; P=0.001), and creation of a fenestration was associated with decreased odds of effusion (OR, 0.21; 95% CI, 0.06-0.74; P=0.015). Five-year estimated Kaplan-Meier survival of two-stage TCPC was significantly higher than that of one-stage group(96.7% vs. 79.7%, P=0.023). Patients with heterotaxy or obstructed totally anomalous pulmonary venous connection (TAPVC) had significantly worse mid-term survival.

CONCLUSIONS

Staged TCPC improved the early and mid-term survival of patients with a single ventricle. mPAP >15 mmHg was independently associated with prolonged pleural effusions and a fenestration significantly associated with a lower odds of effusion.

Modification of hemi-Fontan operation for patients with functional single ventricle and anomalous pulmonary venous connection to the superior vena cava: mid-term results

OBJECTIVES

Fontan candidates with mixed totally anomalous pulmonary venous connection often have postoperative pulmonary venous obstruction after cavopulmonary anastomosis. Because some pulmonary venous obstructions have no intimal hypertrophy at reoperation, we considered such pulmonary venous obstructions to be caused by 3D deformities arising from dissection or mobilization of the vessels, and hypothesized that keeping the pulmonary venous branches in a natural position could avoid such obstruction. Here, we evaluated a modified hemi-Fontan strategy consisting of minimal dissection with no division of vessels and patch separation between systemic and pulmonary venous flow.

METHODS

We retrospectively reviewed clinical records of infants with a functional single ventricle and supracardiac anomalous pulmonary venous connection who had undergone this procedure between 2002 and 2012.

RESULTS

Nine infants underwent this procedure (median age, 5.6 months; range 3.2-30), all with right atrial isomerism and several pulmonary venous branches directly and separately connecting to the superior vena cava. In 5 patients, all pulmonary veins drained into the superior vena cava; in 1, the right pulmonary veins drained into the superior vena cava and in 3, a pulmonary venous branch drained into the superior vena cava. The median follow-up was 6.9 years (0.8-13 years). Three patients underwent reoperation for postoperative pulmonary venous obstruction caused by intimal hypertrophy; however, we confirmed no pulmonary venous obstruction caused by 3D deformities on the pulmonary venous branches connecting separately to the superior vena cava. Although 2 patients were effectively relieved from pulmonary venous obstruction, 1 died due to recurrent pulmonary venous obstruction. There was no late death and no sinus-node dysfunction. Eight patients underwent successful Fontan operation and catheterization. The median interval from the Fontan operation to the latest catheterization was 3.7 years (0.9-3.7 years). The median arterial oxygen saturation was 94% (91-97%) and the central venous pressure was 12 mmHg (8-14 mmHg); no deficiency of pulmonary arteries and veins was noted.

CONCLUSIONS

For patients with functional single ventricle and anomalous pulmonary venous connections to the superior vena cava, our novel strategy of second-stage palliation could avoid postoperative pulmonary venous obstruction caused by 3D deformities, but may not eliminate pulmonary venous obstruction caused by intimal hypertrophy.

Management of the failing Fontan

With and increasing number of early survivors after the palliation of the single ventricle physiology there is a burgeoning Fontan population worldwide that will pose unique challenges because of the inevitable sequelae related to the absence of the alleged "needless" sub-pulmonic ventricle. The increasing number and older-age single-ventricle patients highlights the results of successful contemporary surgical palliation in children, leading to the development of an adult single-ventricle population with unpredictable socio-economic and health service impacts. The wide variability in clinical status of patients with Fontan circulation reflects not only the broadened spectrum of morphological substrates involved, but also the evolving surgical techniques during the last four decades. This has come in the wake of a gradual understanding of an incredibly tricky physiology. The magnitude of the disease, the physio-pathological mechanisms, and the therapeutic options to optimize the "failing Fontan" status and to delay the irreversible deterioration of "Fontan failure" condition are discussed in this review.

Arrhythmia diagnosis and management throughout life in congenital heart disease

Arrhythmias, covering bradycardia and tachycardia, occur in association with congenital heart disease (CHD) and as a consequence of surgical repair. Symptomatic bradycardia can occur due to sinus node dysfunction or atrioventricular block secondary to either unrepaired CHD or surgical repair in the area of the conduction system. Tachyarrhythmias are common in repaired CHD due to scar formation, chamber distension or increased chamber pressure, all potentially leading to abnormal automaticity and heterogeneous conduction properties as a substrate for re-entry. Atrial arrhythmias occur more frequently, but ventricular tachyarrhythmias may be associated with an increased risk of sudden cardiac death, notably in patients with repaired tetralogy of Fallot or aortic stenosis. Defibrillator implantation provides life-saving electrical therapy for hemodynamically unstable arrhythmias. Ablation procedures with 3D electroanatomic mapping technology offer a viable alternative to pharmacologic or device therapy. Advances in electrophysiology have allowed for successful management of arrhythmias in patients with congenital heart disease.

Successful radiofrequency catheter ablation of sinoatrial nodal reentrant tachycardia after a total cavo-pulmonary connection procedure with an extra-cardiac conduit

We report a tachyarrhythmia case of a 32-year-old female with a single ventricle and heterotaxy syndrome. She had surgery involving a total cavo-pulmonary connection procedure using an extra-cardiac conduit (EC) at the age of 17 years. A tachycardia was repetitively induced with single atrial extrastimuli. An activation map was created revealing a centrifugal propagation pattern from the high atrial wall adjacent to the EC. At that site, a structure resembling the crista terminalis was recognized with intracardiac echocardiography. Therefore, high output energy was required to eliminate the tachycardia. It was thought to be a sinoatrial nodal reentrant tachycardia. <Learning objective: Radiofrequency catheter ablation (RFCA) of supraventricular tachycardia (SVT) after a total cavo-pulmonary connection with an extra-cardiac conduit is challenging and the diagnosis of the SVT is difficult. However the electrophysiological features observed during the electrophysiological study using a three-dimensional mapping system, anatomical features observed with intracardiac echocardiography, and pharmacological features seen during a rapid intravenous injection of adenosine triphosphate can lead to an accurate diagnosis, and moreover lead to a successful RFCA.>.

Prevalence of arrhythmias late after the Fontan operation

The extracardiac conduit (ECC) modification of the Fontan procedure has been theorized to reduce the risk of sinus node dysfunction and atrial arrhythmia compared with the intra-atrial lateral tunnel (ILT) Fontan. This study aimed to compare the prevalence of early and late arrhythmias in patients who underwent ECC and ILT Fontan from a similar era with long-term follow-up at a single institution. A retrospective cohort study was conducted of all patients who underwent ECC or ILT Fontan from 1995 to 2005 at The Children's Hospital of Philadelphia. Bradyarrhythmias (including sinus node dysfunction), tachyarrhythmias, and pacemaker burden prevalence was determined throughout early (<30 days) and late (>30 days) postoperative periods. Of 434 patients undergoing the Fontan procedure during the study period, a total of 87 and 106 patients who underwent ECC and ILT Fontan, respectively, met the inclusion criteria. There were no significant differences in risk of sinus node dysfunction or tachyarrhythmia in both early and late postoperative periods. Although the overall risk of late postoperative pacemaker therapy was lower for the ECC cohort (4.9% vs 15.7%, p=0.03), when adjusting for follow-up time, no significant difference was observed (odds ratio 3.1, 95% confidence interval 0.6 to 15.2, p=0.16). In conclusion, the overall prevalence of late postoperative arrhythmias observed after contemporary Fontan modifications is low. Intra-atrial reentrant tachycardia, a potentially fatal complication of the atriopulmonary Fontan operation was infrequently encountered in both ECC and ILT Fontan cohorts. Pacemaker use was higher in the ILT group, although this difference may be explained by differences in follow-up time. Despite the low prevalence of arrhythmias after contemporary Fontan modifications, ongoing surveillance is warranted as the onset of arrhythmias may emerge after longer follow-up time.

The extracardiac conduit Fontan procedure in Australia and New Zealand: hypoplastic left heart syndrome predicts worse early and late outcomes

OBJECTIVES

To identify factors associated with hospital and long-term outcomes in a binational cohort of extracardiac conduit (ECC) Fontan recipients.

METHODS

All patients who underwent an ECC Fontan procedure from 1997 to 2010 in Australia and New Zealand were identified, and perioperative, follow-up, echocardiographic and reintervention data collected. Risk factors for early and late mortality, failure and adverse outcomes were analysed.

RESULTS

A total of 570 patients were identified, and late follow-up was available in 529 patients. The mean follow-up was 6.7 years (standard deviation: 3.5) and completeness of the follow-up was 98%. There were seven hospital mortalities (1%) and 21 patients (4%) experienced early failure (death, Fontan takedown/revision or mechanical circulatory support). Prolonged length of stay occurred in 10% (57 patients), and prolonged effusions in 9% (51 patients). Overall survival at 14 years was 96% (95% confidence interval [CI]: 93-98%), and late survival for patients discharged with intact Fontan was 98% (95% CI: 94-99%). The rates of late failure (late death, transplantation, takedown, New York Heart Association class III/IV or protein-losing enteropathy) and adverse events (late failure, reoperation, percutaneous intervention, pacemaker, thromboembolic event or supraventricular tachycardia) per 100 patient-years were 0.8 and 3.8, and their 14-year freedoms were 83% (95% CI: 70-91%) and 53% (95% CI: 41-64%), respectively. After adjustment for confounders, hypoplastic left heart syndrome (HLHS) was strongly associated with prolonged effusions (OR: 2.9, 95% CI: 1.4-5.9), late failure (hazard ratio [HR]: 2.8, 95% CI: 1.1-7.5) and adverse events (HR: 3.6, 95% CI: 1.3-7.5).

CONCLUSIONS

The extracardiac Fontan procedure provides excellent survival into the second decade of life, but half of patients will suffer a late adverse event by 14 years. Patients with HLHS are at higher risk of late adverse events than other morphological groups, but their survival is still excellent.

Thrombosis and Thromboembolic Complications in Fontan Patients

Hemodynamic fluctuations and thromboembolic complications are significant areas of concern during the postoperative management of patients with univentricular hearts. The objective of this study is to review the incidence and risk factors associated with thrombosis and thromboembolic complications following total cavopulmonary anastomosis, the third stage of the palliative surgical procedure. A literature search of published evidence was conducted on OvidSP MEDLINE(R) and Embase followed by paired title, abstract, and full-text screening based on specific inclusion criteria. High risks of thromboembolic outcomes were identified across studies, with variable incidences between 3% and 20%, high mortality rates up to 38%, and an inverse relationship with prophylaxis treatment administration. Several risk factors for thrombotic complications, including chronic systemic venous hypertension, protein-losing enteropathy, passive blood flow, atrial arrhythmias, conduit stenosis, prosthetic material use, coagulation factor abnormalities, and several patient characteristics were identified. Based on these findings, a prophylactic anticoagulation algorithm has been proposed.

Fontan hemodynamics from 100 patient-specific cardiac magnetic resonance studies: a computational fluid dynamics analysis

OBJECTIVES

This study sought to quantify average hemodynamic metrics of the Fontan connection as reference for future investigations, compare connection types (intra-atrial vs extracardiac), and identify functional correlates using computational fluid dynamics in a large patient-specific cohort. Fontan hemodynamics, particularly power losses, are hypothesized to vary considerably among patients with a single ventricle and adversely affect systemic hemodynamics and ventricular function if suboptimal.

METHODS

Fontan connection models were created from cardiac magnetic resonance scans for 100 patients. Phase velocity cardiac magnetic resonance in the aorta, vena cavae, and pulmonary arteries was used to prescribe patient-specific time-averaged flow boundary conditions for computational fluid dynamics with a customized, validated solver. Comparison with 4-dimensional cardiac magnetic resonance velocity data from selected patients was used to provide additional verification of simulations. Indexed Fontan power loss, connection resistance, and hepatic flow distribution were quantified and correlated with systemic patient characteristics.

RESULTS

Indexed power loss varied by 2 orders of magnitude, whereas, on average, Fontan resistance was 15% to 20% of published values of pulmonary vascular resistance in single ventricles. A significant inverse relationship was observed between indexed power loss and both systemic venous flow and cardiac index. Comparison by connection type showed no differences between intra-atrial and extracardiac connections. Instead, the least efficient connections revealed adverse consequences from localized Fontan pathway stenosis.

CONCLUSIONS

Fontan power loss varies from patient to patient, and elevated levels are correlated with lower systemic flow and cardiac index. Fontan connection type does not influence hemodynamic efficiency, but an undersized or stenosed Fontan pathway or pulmonary arteries can be highly dissipative.

Reflections on five decades of the fontan kreutzer procedure

The first successful total right heart bypass via atriopulmonary anastomosis (APA) were reported in 1971 for patients with tricuspid atresia. At the Children's Hospital of Buenos Aires, the cohort of such procedures started in July, when the first fenestrated right heart by pass was performed, with the interposition of a homograft between the right atrial appendage and the main pulmonary artery. In the second patient, instead of placing a homograft, the APA was achieved with the patient's own pulmonary root harvested from the outflow tract of the right ventricle. These techniques were soon replaced in 1978 with the development of the direct valveless posterior APA. Since the very beginning the principle was that the right atrium only functions as a pathway rather than a pump (reason why no inferior vena cava valves were ever used), and the diastolic properties of the systemic ventricle regulate the only real "pump" of this system. The late hemodynamic problems inherent of the APA diminished with modern surgical techniques like the lateral tunnel (LT) or the extracardiac conduit (EC). In spite of the improvement in prognosis and quality of life that the modern techniques have brought for univentricular hearts (UH), with the passing of time, deterioration of this system is frequently seen, due to chronic low cardiac output, elevated central venous pressure making heart transplantation the final stage of treatment. Progressive increase in pulmonary vascular resistances and ventricular dysfunction result in a decline in quality of life and survival. However, the timing of this occurrence is variable, and many survivors enjoy today a satisfactory clinical status. The challenge is to develop a better solution for UH, but in the mean time the Fontan Kreutzer palliation represents the best and only surgical option. It is undoubtedly one of the triumphs of cardiac surgery in congenital heart disease.

Fontan conversion templates: patient-specific hemodynamic performance of the lateral tunnel versus the intraatrial conduit with fenestration

Intraatrial-conduit Fontan is considered a modification of both extracardiac and lateral-tunnel Fontan. In this study, the patient-specific hemodynamic performance of intraatrial-conduit and lateral-tunnel Fontan with fenestration, considered as conversion templates, was investigated based on the authors' patient cohort. Pulsatile computational fluid dynamics simulations were performed using patient-specific models of intraatrial-conduit and lateral-tunnel Fontan patients. Real-time "simultaneous" inferior and superior vena cava, pulmonary artery, and fenestration flow waveforms were acquired from ultrasound. Multiple hemodynamic performance indices were investigated, with particular focus on evaluation of the pulsatile flow performance. Power loss inside the lateral-tunnel Fontan appeared to be significantly higher than with the intraatrial-conduit Fontan for patient-specific cardiac output and normalized connection size. Inclusion of the 4-mm fenestration at a 0.24 L/min mean flow resulted in a lower cavopulmonary pressure gradient and less time-averaged power loss for both Fontan connections. Flow structures within the intraatrial conduit were notability more uniform than within the lateral tunnel. Hepatic flow majorly favored the left lung in both surgical connections: conversion from lateral-tunnel to intraatrial-conduit Fontan resulted in better hemodynamics with less power loss, a lower pressure gradient, and fewer stagnant flow zones along the conduit. This patient-specific computational case study demonstrated superior hemodynamics of intraatrial-conduit Fontan over those of lateral-tunnel Fontan with or without fenestration and improved performance after conversion of the lateral tunnel to the intraatrial conduit. The geometry-specific effect of the nonuniform hepatic flow distribution may motivate new rationales for the surgical design.

Presurgical evaluation of Fontan connection options for patients with apicocaval juxtaposition using computational fluid dynamics

Apicocaval juxtaposition (ACJ) is a rare congenital heart defect associated with single ventricle physiology where optimal positioning of the Fontan conduit for completion of total cavopulmonary connection (TCPC) is still controversial. In ACJ, the cardiac apex is ipsilateral with the inferior vena cava (IVC), risking kinking and collapse of the Fontan conduit at the apex of the heart. The purpose of this study is to evaluate two viable routes for Fontan conduit connection in patients with ACJ, using computational fluid dynamics. Internal energy loss evaluations were used to determine contribution of conduit curvature to the energy efficiency of each cavopulmonary anastomosis configuration. This percentage of energy loss contribution was found to be greater in the case of a curved extracardiac conduit connection (44%, 4.1 mW) traveling behind the ventricular apex, connecting the IVC to the left pulmonary artery, than the straighter lateral tunnel conduit (6%, 1.4 mW) installed through the ventricular apex. In contrast, net energy loss across the anastomosis was significantly lower with extracardiac TCPC (9.3 mW) in comparison with lateral tunnel TCPC (23.2 mW), highlighting that a curved Fontan conduit is favorable provided that it is traded off for a superior cavopulmonary connection efficiency. Therefore, a relatively longer and curved Fontan conduit has been demonstrated to be a suitable connection option independent of anatomical situations.

Extracardiac conduit Fontan procedure versus intra-atrial lateral tunnel Fontan procedure

The Fontan procedure has provided excellent surgical palliation for patients with various types of univentricular hearts, and it has evolved over time. Among many modifications, the lateral tunnel Fontan connection (LTF) and the extracardiac Fontan connection (ECF) are currently the most popular techniques for completing the total cavopulmonary connection. The advantages and disadvantages of both techniques are reviewed here. The advantages of the ECF includes adaptability to all types of univentricular hearts, ease of construction without aortic cross clamping and fewer atrial suture lines. The advantages of the LTF include the ability to complete Fontan circulation in young, very small patients with potential for growth. This review also compares post-operative arrhythmias and fluid dynamics associated with both techniques.

Challenges in the management of patients with functionally univentricular heart in Turkey

Management of patients with functionally univentricular heart encompasses a wide array of developments over the years in every country. This article describes our working group experiences and 30-year story of single ventricle surgery in Turkey. Diagnosis, surgical treatment, and medical treatment of this complex group of patients necessitate courageous and continuous team effort with multi-institutional collaboration.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

Heart failure treatment in the intensive care unit in children

Although pediatric heart failure is generally a chronic, progressive disorder, recovery of ventricular function may occur with some forms of cardiomyopathy. Guidelines for the management of chronic heart failure in adults and children have recently been published by the International Society for Heart and Lung Transplantation the American College of Cardiology, and the American Heart Association. The primary aim of heart failure therapy is to reduce symptoms, preserve long-term ventricular performance, and prolong survival primarily through antagonism of the neurohormonal compensatory mechanisms. Because some medications may be detrimental during an acute decompensation, physicians who manage these patients as inpatients must be knowledgeable about the medications and therapeutic goals of chronic heart failure treatment. Understanding the mechanisms of chronic heart failure may foster improved understanding of the treatment of decompensated heart failure.

Antiplatelet versus anticoagulation therapy after extracardiac conduit Fontan: a systematic review and meta-analysis

The benefits of prophylactic anticoagulation or antiplatelet therapy for patients undergoing extracardiac conduit (ECC) Fontan procedure still are a matter of debate. Through a systematic review and meta-analysis, this study aimed to determine the incidence of thromboembolism among patients undergoing ECC Fontan who received anticoagulation or antiplatelet therapy. Until February 2010, MEDLINE studies describing the incidence of thromboembolic events after ECC Fontan were reviewed. Information on type of drugs and clinical outcome was extracted. The 20 studies analyzed involved 1,075 patients: 220 (20.4%) in the antiplatelet group and 855 (79.5%) in the anticoagulation group. The mean follow-up period ranged from 2 to 144 months. The overall thromboembolism rate was 5.2% (95% confidence interval [CI], 3.8-7%; I(2) = 0%; p(het) = 0.32). The effect of different therapeutic strategies on the occurrence of thromboembolic and bleeding events was analyzed. Interestingly, the anticoagulation therapy compared with the antiplatelet therapy was not associated with a significant reduction in the incidence of overall thromboembolic complications (5% vs 4.5%, respectively; I(2) = 0%; p(het) = 0.80). Only two cases of bleeding were observed among patients receiving anticoagulant therapy at the time of the event. For patients undergoing ECC Fontan, the rate of thromboembolic and bleeding events associated with antiplatelet therapy is similar to that associated with anticoagulation therapy.

The intra/extracardiac conduit fenestrated fontan

The intra/extracardiac conduit technique for the Fontan procedure has important advantages relative to the extracardiac conduit. Fenestration is easily achieved and there is less risk of injury to the crista terminalis, so that the risk of late atrial arrhythmias may be reduced.

The Fontan/Kreutzer procedure at 40: an operation for the correction of tricuspid atresia

The first atriopulmonary anastomosis (APA) with neither a valve in the inferior vena cava (IVC) nor an Glenn shunt was performed in 1971. A fenestration was intentionally left in the atrial septum. In a second patient, the APA incorporated the patient's own pulmonary valve, which had been removed from the outflow tract of the right ventricle. Since the early days, our rationale was that the right atrium would only function as a pathway, and the end diastolic pressure and the systole of the main ventricle would be the principal "pump" of this system. The late hemodynamic problems of the APA have decreased with newer and better surgical techniques, such as the lateral tunnel (LT) or the extracardiac conduit (EC). Although these procedures have improved the prognosis and quality of life of patients with a univentricular heart (UH), in the long run, deterioration frequently occurs because of chronic low cardiac output and high central venous pressure. Progressive increase in pulmonary vascular resistances and ventricular dysfunction are frequently the underlying reasons for this deterioration. However, such deterioration is not inevitable in every case, as shown in the longest survivor of the world after 34 years of follow-up. The Fontan Kreutzer (FK) palliation represents the best surgical option despite its uncertain late outcome. Certainly, it is one of the triumphs of cardiac surgery in congenital heart disease.

Rational approach to surgical management of complex forms of double outlet right ventricle with modified Fontan operation

OBJECTIVE

Surgical alternatives to biventricular repair of complex forms of double outlet right ventricle (DORV) remain controversial. The available knowledge of the Fontan operation (FO) for children with this anomaly is limited. The aim of this report is to analyze the results and risk factors of the FO performed as an alternative to the biventricular repair of complex DORV.

METHODS

Between 1980 and 2007, 47 patients with complex forms of DORV underwent a modified FO. Concomitant defects included noncommitted, subpulmonary or multiple ventricular septal defects, anomalies of atrioventricular valves and/or caval veins, and ventricular hypoplasia. Thirty-five of 45 patients (77%) have undergone a hemi-Fontan and 35 patients (77%; 10 children without previous hemi-Fontan) have had a completion FO without mortality or Fontan takedown. Risk factors for adverse outcomes were determined by multivariate analyses.

RESULTS

There were no early but six late deaths. The follow-up period ranged from 1 year to 25 years (mean 10.0 +/- 6.5). The actuarial survival was 93% at 1 year, 87% at 10, 15, and 25 years. Multivariate analysis identified preoperative left or common atrioventricular valve insufficiency (P = .001) and decreased left ventricular ejection fraction (<50%) (P = .02) as risk factors for late death and/or morbidity. The only risk factor for a late adverse outcome and poor functional status was increased preoperative pulmonary vascular resistance (>4.0 Woods units/m(2)) (P = .005).

CONCLUSION

FO provides good early- and mid-term results in the treatment of complex forms of DORV. The increased preoperative pulmonary vascular resistance was a significant negative risk factor for adverse outcome in this patient population.

Hemodynamic performance of stage-2 univentricular reconstruction: Glenn vs. hemi-Fontan templates

Flow structures, hemodynamics and the hydrodynamic surgical pathway resistances of the final stage functional single ventricle reconstruction, namely the total cavopulmonary connection (TCPC) anatomy, have been investigated extensively. However, the second stage surgical anatomy (i.e., bi-directional Glenn or hemi-Fontan template) has received little attention. We thus initiated a multi-faceted study, involving magnetic resonance imaging (MRI), phase contrast MRI, computational and experimental fluid dynamics methodologies, focused on the second stage of the procedure. Twenty three-dimensional computer and rapid prototype models of 2nd stage TCPC anatomies were created, including idealized parametric geometries (n = 6), patient-specific anatomies (n = 7), and their virtual surgery variant (n = 7). Results in patient-specific and idealized models showed that the Glenn connection template is hemodynamically more efficient with (83% p = 0.08 in patient-specific models and 66% in idealized models) lower power losses compared to hemi-Fontan template, respectively, due to its direct end-to-side anastomosis. Among the several secondary surgical geometrical features, stenosis at the SVC anastomosis or in pulmonary branches was found to be the most critical parameter in increasing the power loss. The pouch size and flare shape were found to be less significant. Compared to the third stage surgery the hydrodynamic resistance of the 2nd stage is considerably lower (both in idealized models and in anatomical models at MRI resting conditions) for both hemi- and Glenn templates. These results can impact the surgical design and planning of the staged TCPC reconstruction.

Caval blood flow during supine exercise in normal and Fontan patients

BACKGROUND

Extracardiac total cavo-pulmonary connection (TCPC) bypasses the right atrium and has in theory better hemodynamics than intraatrial TCPC repair. Both are thought to have inferior hemodynamics compared with a normal circulation. Direct comparison of flow rates at rest and during exercise with magnetic resonance imaging technique have not been performed.

METHODS

The study comprised 20 children. Six children (median age, 9.3 years; interquartile range, 2.2) had undergone extracardiac TCPC. Eight children (median age, 8.9 years; interquartile range, 5.0) had an intraatrial TCPC, and 6 children (median age, 10.3 years; interquartile range, 2.6) were healthy control subjects. Blood flows in the aorta, inferior vena cava, and superior vena cava were measured at rest and during two levels of submaximal supine bicycle exercise (0.5 W/kg and 1.0 W/kg) using a magnetic resonance imaging scanner mounted with a bicycle.

RESULTS

Heart rate, respiratory rate, inspiratory fraction, and blood flow rates in the aorta and inferior vena cava increased equally in all three groups. If patients were grouped together, flow rates were significantly lower, and the inspiratory flow fraction in the inferior vena cava was significantly higher, than in control subjects. Retrograde flows were observed in all three groups at rest but tapered off with exercise.

CONCLUSIONS

At submaximal levels of lower limb exercise, patients with extracardiac as well as intraatrial TCPC showed a similar increase in respiration, heart rate, and aortic and caval flow rates as healthy control subjects. This is in accordance with the observation that many patients with TCPC perform well during daily life activities.