Fontan Groups Research Articles

Comparison of definitive approaches for conotruncal defects following bidirectional Glenn procedure

BackgroundStaged repair is common for complex conotruncal defects, often involving bidirectional Glenn (BDG) procedure. Following the cavopulmonary shunt, both Fontan completion and biventricular conversion (BiVC) serve as definitive approaches. The...

Validity Study Comparing Polar Ignite’s® Estimated VO2max to Traditional Cardiopulmonary Exercise Testing in Normal Cardiac Anatomy & Fontan Pediatric Patients

Cardiorespiratory fitness as represented by maximum oxygen uptake, VO2max, is considered the best indicator for overall cardiovascular health. Fitness technology such as wrist worn devices, now allows for an easy method to monitor an individual’s VO2max. This study sought to compare the estimated VO2max measurements from the Polar Ignite (Polar Electro Oy, Kempele, Finland) fitness watch (Polar Ignite) against the gold standard, cardiopulmonary exercise testing (CPET) in normal cardiac anatomy and Fontan pediatric patients. This single-center, prospective study enrolled patients with normal cardiac anatomy and single ventricle patients with Fontan palliation (Fontan) between 13-21 years. The Polar Ignite was fastened on the patient’s right or left wrist while supine and estimated VO2max was generated based on a non-exercise test (Polar Fitness Test). A maximal voluntary CPET using the standard Bruce Treadmill Protocol was then completed. Measurements from the two tests were compared using the intraclass correlation coefficient (ICC), Pearson correlation coefficient and Bland-Altman method. Forty-seven patients were enrolled, including n=36 (77%) normal cardiac patients and n=11 (23%) Fontan patients. The majority of participants were white (n=41, 87%) and female (n=36, 66%). Patients were 15.3±1.9 years old, weighed 65.7±16.6 kg, and were 168.0±10.4 cm tall on average. The mean estimated Polar Ignite VO2max and peak CPET VO2 was 43.9±6.1 ml/kg/min vs 37.7±8.2 ml/kg/min, respectively in the normal cardiac group, and 42.6±3.9 ml/kg/min vs 22.6±5.6 ml/kg/min, respectively in the Fontan group. We found poor validity (ICC=0.21) and a weak correlation (r=0.31, p=0.07) between VO2max measured by the Polar Ignite and CPET in the normal cardiac group and poor validity (ICC=0.08) and strong correlation (r=0.84, p=0.001) in the Fontan group. In Bland-Altman analyses, the mean bias between VO2max as measured by the Polar Ignite and CPET was 6.85 ml/kg/min among the normal cardiac group and 20.05 ml/kg/min among the Fontan group. The Polar Ignite overestimated VO2max compared to CPET in both the normal cardiac and Fontan groups and cannot replace formal testing.

Overgrowth of the Amygdala in Children with Single Ventricle Congenital Heart Disease.

Aim: Early life stress is associated with overgrowth of the amygdala, which plays a key role in the processing and memory of emotional responses. Herein, we aimed to explore the amygdala volume in children with single-ventricle congenital heart disease who experience repeated admissions during the neonatal period and infancy. Methods: We compared the amygdala volume measured using brain magnetic resonance imaging (MRI) between 40 patients after completion of the Fontan procedure and 40 age- and sex-matched control subjects Results: Age at the MRI study were 9.2 (8.5-11.1) and 10.2 (9.2-10.3) years in the Fontan and control groups, respectively. The maximum amygdala volume in the Fontan group was significantly larger than in the control group (1232 [983-1392] mm3/m2 vs. 980 [728-1166] mm3/m2, P < 0.001). The amygdala volume did not correlate to cardiac index (r = 0.260) and central venous pressure (r = -0.107) in the Fontan group. Conclusions: Children with single-ventricle congenital heart disease exhibited amygdala overgrowth.

Neuropsychological Screening in Pediatric Multidisciplinary Clinics: Group Characteristics and Predictive Utility.

To evaluate the feasibility of administering caregiver-report neuropsychological screening measures in pediatric multidisciplinary clinics (MDCs) and investigate predictive utility for cognitive and academic difficulties on follow-up testing. The Pediatric Perceived Cognitive Functioning (Peds PCF) and Colorado Learning Difficulties Questionnaire (CLDQ) were administered to caregivers of youth with history of brain tumor (BT), non-central nervous system (CNS) cancer, or Fontan circulation as part of routine neuropsychological consultation in MDCs from 2017 to 2019. We examined cross-sectional differences on screening measures, and relationships between screening and intellectual and academic test performance in a subset who presented for follow-up neuropsychological evaluation. Receiver operating characteristic (ROC) curve analysis was used to identify suggested cut scores on screening measures for predicting who would most benefit from further evaluation. Screening was completed with 192 families. Children with history of non-CNS cancer (n = 29) had fewer parent-reported cognitive and academic concerns compared with either BT (n = 88) or Fontan (n = 75) groups. Peds PCF and CLDQ scores were related to intellectual and academic test performance in the group presenting for neuropsychological evaluation (n = 68). ROC curve analysis identified cut scores across screening measures with maximal sensitivity and specificity for detecting neuropsychological difficulties. It is feasible to utilize parent rating measures during neuropsychological consultation in pediatric MDCs. The Peds PCF and CLDQ demonstrated sensitivity to intellectual and academic difficulties in children with significant medical histories. Screening may be a helpful tool for pediatric neuropsychologists and other professionals during MDC consultation to inform clinical management.

Systemic Venous Hypertension and Low Output Are Prevalent at Catheterization in Adults with Pulmonary Atresia and Intact Ventricular Septum Regardless of Repair Strategy

Patients with pulmonary atresia and intact ventricular septum (PA-IVS) require intervention early in life, and most survive to a definitive procedure of either Fontan circulation or right ventricle to pulmonary artery (RV-PA) repair. It remains unknown how surgical strategy impacts hemodynamics and comorbidities in adults. Retrospective analysis of adults (age ≥18 years) with PA-IVS undergoing hemodynamic catheterization at Mayo Clinic, MN between January 2000 through January 2020 was performed. 14 patients in the RV-PA group (71% biventricular, 29% 1.5 ventricle repair) and 19 post-Fontan patients [9 lateral tunnel (48%), 6 atriopulmonary (32%), and 4 extracardiac (21%)] were identified. Median age was 29 (21, 34) years. There were no differences in demographics and laboratory data (including MELD-XI) between groups. All patients assessed for liver disease had evidence of hepatic congestion or cirrhosis (14 in the Fontan group and 4 in the RV-PA group). Invasive hemodynamics were comparable between groups with the Fontan and RV-PA groups having similar systemic venous pressure (15.7±4.4 vs. 14.3±6.2, p = .44) and cardiac output (2.2±0.6 vs. 2.0±0.4 L/min/m2, p = .23). There was no difference in transplant-free survival (p = .92; 5-year transplant-free survival RV-PA 84%, Fontan 80%). Hemodynamic derangements, namely elevated systemic venous pressure and low cardiac output, are prevalent in patients with PA-IVS undergoing cardiac catheterization regardless of surgical strategy.

Abstract 15765: Clinical Significance of Submaximal Parameters of Exercise Stress Test in Characterizing Post-Fontan Patients

Background: Fontan patients have diminished exercise capacity relative to healthy peers. Peak oxygen consumption (pVO2) is a useful marker for maximum exercise capacity, though it may not be achievable in certain patients. We studied clinical validity of submaximal parameters in exercise stress test (EST) in post-Fontan patients. Methods: We retrospectively analyzed EST of post-Fontan patients and age-matched controls by cycle ergometer. We obtained peak values of heart rate (pHR), VO2, oxygen pulse (pOP), respiratory quotient (pRQ), and work rate (pWR). Submaximal parameters included ventilatory anaerobic threshold (VAT), slopes of VO2/HR changes (ΔVO2/ΔHR) and HR/WR changes (ΔHR/ΔWR), and oxygen uptake efficiency slope (OUES). Data are shown as mean ± standard deviation. Results: Twenty four single right ventricle (SRV), 12 single left ventricle (SLV), and 24 controls were studied (Table 1).pHR, pVO2, pOP, and pWR were significantly lower in Fontan patients than in controls, but with no significant difference between SRV and SLV. ΔVO2/ΔHR and OUES were significantly lower in Fontan group than controls, whereas VAT and pRQ were comparable in all three groups. VAT was preserved in Fontan groups. Lower slope of ΔVO2/ΔHR and decreased OUES in the Fontan group suggests an intrinsic exercise limitation or limited stroke volume (SV) increase. This was compensated by a higher HR response up to AT, exhibited by the higher slope of ΔHR/ΔWR despite lower pHR in the Fontan group. Conclusions: Peak exercise parameters were significantly lower in Fontan patients although pRQ and VAT were comparable among the three groups. The lower ΔVO2/ΔHR and pOP in Fontan patients suggest limited SV reserve in response to exercise. A combination of lower ΔVO2/ΔHR and higher ΔHR/ΔWR characterizes Fontan patient. Inclusion of submaximal exercise parameters brings additional value in specifying the physiological responses to exercise.

Trisomy 21 Patients Undergoing Cavopulmonary Connections Need Improved Preoperative and Postoperative Care

Patients with trisomy 21 (T21) often have elevated pulmonary vascular resistance, which may result in a suboptimal cavopulmonary connection (CPC) after a Glenn or Fontan operation. The purpose of this study was to assess, in a nationwide, multiinstitution cohort of patients with CPC, the impact of T21 on patient morbidity, mortality, and resource use. A total of 23,271 pediatric patients with CPC (2004 to 2019) at 50 US hospitals were evaluated using the Pediatric Health Information System database. Univariable and multivariable regression analyses were used to assess risk-adjusted associations between Down syndrome and other risk factors and postoperative measures of morbidity, mortality, lengths of stay, and cost of hospitalization. The overall prevalence of T21 among patients who had undergone Glenn and Fontan procedures was 1.5% (199 of 13,268) and 0.8% (78 of 1003), respectively. Among both CPC cohorts, T21 status significantly increased unadjusted mortality, hospital lengths of stay, and total costs of hospitalization compared with the non-T21 CPC cohort (all P < .001). Patients with T21 also had a higher incidence of prolonged mechanical ventilation compared with patients without T21 in both Glenn and Fontan groups (P < .001). Multivariable regression analysis further estimated that patients with T21 are associated with a 5.5-fold increase in mortality (P < .001) compared with patients without T21. Finally, patients with T21 had increased long-term mortality compared with their peers. T21 significantly increases risk-adjusted morbidity, inpatient mortality, long-term mortality, and resource use after cavopulmonary connections. Further investigation is needed to clarify modifiable patient-level and center-specific risk factors to improve outcomes for patients with T21.

Three-dimensional imaging of pulmonary arterial vasa vasorum using optical coherence tomography in patients after bidirectional Glenn and Fontan procedures.

We evaluated pulmonary arterial (PA) vasa vasorum (VV) in Fontan candidate patients with a novel three-dimensional (3D) imaging technique using optical coherence tomography (OCT). This prospective study assessed the development of adventitial VV in the distal PA of 10 patients with bidirectional Glenn circulation (BDG group, 1.6 ± 0.3 years) and Fontan circulation (Fontan group, 3.3 ± 0.3 years), and in 20 children with normal PA haemodynamics and morphology (Control group, 1.5 ± 0.3 years). We assessed the PA VV with two-dimensional (2D) cross-sectional, multi-planar reconstruction (MPR), and volume rendering (VR) imaging. VV development was evaluated by the VV area/volume ratio, defined as the VV area/volume divided by the adventitial area/volume. Compared to the control group, the observed VV number and diameter on 3D images of MPR and VR were significantly higher, and curved and torturous-shaped VV were more frequently observed in the BDG and Fontan groups (P < 0.001, all). The median VV volume ratio was significantly greater in the BDG than in the control group (3.38% vs. 0.61%; P < 0.001). Although the VV volume ratio decreased significantly after the Fontan procedure (2.64%, P = 0.005 vs. BDG), the ratio remained higher than in the control group (P < 0.001 vs. control). 3D OCT imaging is a novel method that can be used to evaluate adventitial PA VV and may provide pathophysiological insight into the role of the PA VV in these patients.

Y-graft modification to the Fontan procedure: Increasingly balanced flow over time

ObjectiveThe use of Y-grafts for Fontan completion is hypothesized to offer more balanced hepatic flow distribution (HFD) and decreased energy losses. The purpose of this study was to evaluate the hemodynamic performance of Y-grafts over time using serial cardiac magnetic resonance data and to compare their performance with extracardiac Fontan connections. MethodsTen Fontan patients with commercially available Y-graft connections and serial postoperative cardiac magnetic resonance data were included in this study. Patient-specific computational fluid dynamics simulations were used to estimate HFD and energy losses. Y-graft performance was compared with 3 extracardiac conduit Fontan groups (n = 10 for each) whose follow-up times straddle the Y-graft time points. ResultsY-graft HFD became significantly more balanced over time (deviation from 50% decreased from 18% ± 14% to 8% ± 8%; P = .015). Total cavopulmonary connection resistance did not significantly change. Y-grafts at 3-year follow-up showed more balanced HFD than the extracardiac conduit groups at both the earlier and later follow-up times. Total cavopulmonary connection resistance was not significantly different between any Y-graft or extracardiac conduit group. ConclusionsY-grafts showed significantly more balanced HFD over a 3-year follow-up without an increase in total cavopulmonary connection resistance, and therefore may be a valuable option for Fontan completion. Additional follow-up data at longer follow-up times are still needed to thoroughly characterize the potential advantages of Y-graft use.

Biventricular repair versus Fontan completion for patients with d- or l-transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction

ObjectivesD-transposition of the great arteries and l-transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction are complex biventricular congenital heart diseases for which decision-making regarding surgical strategy remains challenging. We investigated the intermediate-term outcomes of Fontan versus biventricular procedures in these patients. MethodsWe analyzed 129 patients with d-transposition of the great arteries/ventricular septal defect/left ventricular outflow tract obstruction (n = 85) or l-transposition of the great arteries/ventricular septal defect/left ventricular outflow tract obstruction (n = 44) and 2 functional ventricles from Australia who had primary surgical management (29 Fontan, 100 biventricular repair) undertaken between 1990 and 2015. ResultsMedian operative age of patients was 2.9 years (range, 0.2-26.8 years). During a median follow-up of 6.2 years (range, 2 days to 25.8 years), 9 patients died after biventricular repair (3 early and 6 late deaths). One patient received a transplant 1.2 years after Fontan completion. Overall transplant-free survivals at 1, 5, 10, and 15 years were 95%, 93%, 92%, and 90%, respectively. Overall reintervention-free survivals at 1, 5, 10, and 15 years were 79%, 64%, 45%, and 29% respectively. Biventricular repair tended to be associated with a higher rate of death, transplantation, or reintervention than the Fontan pathway (hazard ratio, 1.83; 95% confidence interval, 0.90-3.71; P = .10). Some 73% of transplant-free survivors had New York Heart Association class I. Functional status was similar between the Fontan and biventricular groups. ConclusionsIntermediate-term outcomes were comparable between patients with d-transposition of the great arteries/ventricular septal defect/left ventricular outflow tract obstruction and patients with l-transposition of the great arteries/ventricular septal defect/left ventricular outflow tract obstruction. Both Fontan and biventricular pathways are associated with excellent mortality and functional outcomes. Biventricular patients have a greater risk of reintervention. The Fontan procedure is a viable option when anatomic risk factors preclude biventricular repair.

Calcium-handling abnormalities underlying atrial arrhythmogenesis in a Fontan operation canine model.

Atrial tachyarrhythmia (AT) is a common complication in patients who have undergone a Fontan operation. In this study, we investigated whether abnormal Ca2+ handling contributes to the Fontan operation-related atrial arrhythmogenic substrate. Mongrel dogs were randomly assigned to sham and Fontan groups. The Fontan operation model was developed by performing an atriopulmonary anastomosis. After 14days, an electrophysiological study was performed to evaluate the AT vulnerability. Ca2+ handlingproperties were measured by loading atrial cardiomyocytes (CMs) with fura-2 AM. The L-type Ca2+ (ICa-L) and Na+-Ca2+exchanger (INCX) currentsof the CMs were recorded by the whole-cell patch-clamp technique. The key Ca2+ handling proteins expression was assessed by Western blotting. The AT inducibility was higher in the Fontan group than in the sham group (85.71 vs. 14.29%, P < 0.05). The Fontan operation resulted in decreased Ca2+ transient (CaT) amplitude and sarcoplasmic reticulum (SR) Ca2+ content, but in enhanced diastolic intracellular Ca2+ concentration and SR Ca2+ leak in the atrial CMs. The spontaneous CaT events, triggered ectopic activity and INCX density were increased, but ICa-L density was reduced in CMs from the Fontan atria (all P < 0.05). Additionally, the Fontan operation resulted in decreased SR Ca2+ ATPase expression and Cav1.2 expression, but in increased NCX1 and Ser2814-phosphorylated ryanodine receptor 2. The calmodulin-dependent protein kinase II expression and function were markedly enhanced in the Fontan atria. The Fontan operation caused atrial CM Ca2+ handling abnormalities that produced arrhythmogenic-triggered activity and increased vulnerability to AT in experimental Fontan dogs.

Differentiation of Impaired From Preserved Hemodynamics in Patients With Fontan Circulation Using Real-time Phase-velocity Cardiovascular Magnetic Resonance.

Progressive impairment of hemodynamics in patients with Fontan circulation is common, multifactorial, and associated with decreased quality of life and increased morbidity. We sought to assess hemodynamic differences between patients with preserved (preserved Fontans) and those with impaired circulation (impaired Fontans) after pulmonary vasodilation using oxygen and under forced breathing conditions. Real-time phase-contrast cardiovascular magnetic resonance was performed using non-ECG triggered echo-planar imaging (temporal resolution=24 to 28 ms) in the ascending aorta (AAo) and superior vena cava (SVC)/inferior vena cava (IVC) on room air, after 100% oxygen inhalation (4 L/min; 10 min) and on forced breathing in 29 Fontan patients (17.2±7.3 y) and in 32 controls on room air (13.4±3.7 y). The simultaneously recorded patients' respiratory cycle was divided into 4 segments (expiration, end-expiration, inspiration, and end-inspiration) to generate respiratory-dependent stroke volumes (SVs). The imaging data were matched with physiological data and analyzed with home-made software. The mean SVi (AAo) was 46.1±11.1 mL/m in preserved Fontans versus 30.4±6.2 mL/m in impaired Fontans (P=0.002) and 51.1±6.9 mL/m in controls (P=0.107). The cutoff value for differentiation of Fontan groups was SVi (AAo, end-expiratory) of 32.1 mL/m. After hyperoxygenation, the mean SVi (AAo) increased to 48.7±12.7 mL/m in preserved Fontans (P=0.045) but remained unchanged in impaired Fontans (31.1±5.8 mL/m, P=0.665). Simultaneously, heart rates decreased from 75.2±15.9 to 70.8±16.4 bpm (preserved; P=0.000) but remained unchanged in impaired circulation (baseline: 84.1±9.8 bpm, P=0.612). Compared with physiological respiration, forced breathing increased the maximum respiratory-related cardiac index difference (ΔCImax) in preserved Fontans (SVC: 2.5-fold, P=0.000; and IVC: 1.8-fold, P=0.000) and to a lower extent in impaired Fontans (both veins, 1.5-fold; P(SVC)=0.011, P(IVC)=0.013). There was no impact on mean blood flow. Oxygen affected the pulmonary vascular system by vasodilation and increased SVi in preserved Fontans but had no effect on impaired Fontans. Forced breathing increased ΔCImax but did not change the mean blood flow by sole activation of the ventilatory pump. End-expiratory aortic SVi represents a valuable measure for classifying the severity of Fontan hemodynamics impairment.

Comprehensive rhythm evaluation in a large contemporary Fontan population.

Rhythm disturbances are an important cause of morbidity in Fontan patients. Currently, the total cavopulmonary connection is performed by using the intra-atrial lateral tunnel (ILT) ('baffle ILT' or 'prosthetic ILT'), or the extracardiac conduit (ECC). The aim of the study was to evaluate rhythm abnormalities and compare the surgical techniques in a contemporary cohort. In a cross-sectional multicentre study, 115 patients (age 12.5 ± 3.1 years) underwent rhythm evaluation using ECG, exercise testing and Holter, including heart rate variability. Medical history was reviewed for episodes of arrhythmia. Sinus node dysfunction (SND) was found in 29%, 3 of whom required pacemaker therapy. No difference was found in the incidence of SND between ILT and ECC patients. Sinus pauses occurred only in the ILT group. Exercise testing showed no difference in peak heart rate between the groups. Heart rate reserve (P = 0.023) and heart rate recovery (HRrecovery) (P < 0.001) were lower in ILT patients. Atrial arrhythmias were more common in ILT patients (15 vs 1%, P = 0.004), but only in those with a baffle ILT. One patient had symptomatic ventricular tachycardia (VT). Holter recordings showed sub-clinical VT in 6% of patients, which was associated with larger end-diastolic (P = 0.035) and end-systolic volumes (P = 0.029). The overall incidence of arrhythmia was low, although SND was frequently present in both Fontan groups. ILT patients had slower HRrecovery, and ILT patients with the more extensive baffle technique had more atrial arrhythmias and more sinus pauses. The significance of asymptomatic ventricular arrhythmias in this young population remains to be determined.

Echocardiographic Assessment of Pulmonary Arteries Pulsatility Index in Fontan Circulation.

BackgroundLate complications after Fontan procedure may be due to the absence of pump and pulsatile pulmonary blood flow in this type of palliation. Our aim was to quantify the degree of pulsation by echocardiographic method in patients with extracardiac total cavopulmonary connection (ECTCPC) in comparison with biventricular circulation and few cases of pulsatile Fontan.MethodsIn a case series study, pulsatility index (PI) derived by echocardiographic method were compared between 20 patients with ECTCPC, 6 patients with pulsatile Fontan and 18 normal individual aged 4 to 20 years old. All patients were in New York Heart Association class of I and there was no report of complication.ResultsIn patients with ECTCPC pulmonary artery branches Doppler flow study showed lower peak and mean velocities compared to the pulsatile Fontan and normal groups. ECTCPC patients had PI of 0.59 ± 0.14 and 0.59 ± 0.09 for right and left pulmonary arteries (RPA and LPA) respectively. PI was higher in patients with preserved antegrade flow (RPA PI = 0.94 ± 0.26, LPA PI = 0.98 ± 0.27) and in normal individuals (RPA PI = 1.59 ± 0.12, LPA PI = 1.64 ± 0.17) for both branches (p = 0.000).ConclusionUsing a Doppler derived index for pulsatility, patients with ECTCPC had the least pulsation. The pulmonary artery flow pattern in patients with preserved antegrade flow showed higher pulsatility indices in both branches. Normal individuals had the greatest pulsatility index.

Clinical Profiles of Adult Patients With Single Ventricular Physiology

This study was performed to clarify the present global clinical status, including medication(s) and social abilities, of adult patients with single ventricular physiology (SVP). Clinical charts were retrospectively reviewed to evaluate the global clinical status, including functional capacity, medication(s), complications, and social activities of 68 adult patients with SVP aged 20-53 years (41 males); 50 had undergone the Fontan operation and they were divided into the young adult (25 patients) and adult Fontan groups. The others were cyanotic patients without the Fontan operation (non-Fontan group). Although the Fontan groups showed better functional capacity, higher arterial oxygen saturation and brain natriuretic peptide levels, and a better renal function, there was no difference in the cardiovascular events during follow-up between the 3 groups. The most frequent complication was arrhythmia without a significant group difference, although the non-Fontan group showed a high percentage of heart failure. Only 41 patients (60%) had a job and 8 (12%) were married. Although the Fontan groups had favorable pathophysiological conditions, the high rate of cardiovascular events, as well as unsatisfactory social situations, indicate the importance of meticulous life-long management of patients with SVP, regardless of the type of surgical intervention.

Somatic Growth after Fontan and Mustard Palliation

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

514: Donor (+)/recipient (-) EBV mismatch leads to a high incidence of post-transplant lymphoproliferative disorder in pediatric lung transplant recipients

22.9 5.9, 19.8 3.7 and 18.5 3.0 in TX, Fontan and healthy groups, p 0.01) and baseline HR (107 11, 88 14 and 90 17 beats/min, p 0.001) compared to control groups. Both TX and Fontan patients had similar degree of chronotropic impairment (peak HR 158 19 (76 9%predicted), 164 17 (79 8%predicted) and 196 10 beats/min (95 5% predicted) in TX, Fontan and healthy groups). However, exercise duration was significantly lower in TX patients (9.1 2.0, 10.7 2.5 and 14.4 2.3 min, p 0.01). HR recovery was markedly slower in TX patients compared to control groups at both 1 minute (5 7 beats (3 4%), 23 10 beats (15 7%) and 39 15 beats (20 7%), p 0.001) and 3 minutes (20 13 beats (13 8%), 50 15 beats (30 9%) and 80 15 beats (41 7%), p 0.001) following peak exercise. In multivariable linear regression models, patient group and BMI were predictors of HR recovery at 1 and 3 minutes; exercise duration was not. Conclusions: Heart rate recovery following maximal exercise is markedly slower in children one-year following heart transplant compared to age-matched controls. Whether chronotropic response and HR recovery improve with time due to autonomic re-innervation is unknown and requires serial studies in these patients.

Post-exercise heart rate, blood pressure and oxygen uptake dynamics in pediatric patients with Fontan circulation: Comparison with patients after right ventricular outflow tract reconstruction

Background Post-exercise heart rate (HR) and oxygen uptake (V˙O 2) recover more slowly in patients with the Fontan circulation, but little is known about the determinants of the delayed recovery. Purpose To evaluate the post-exercise cardiovascular dynamics and clinical profiles in these patients. Methods and results We studied 51 Fontan patients (14±4 years) (atriopulmonary connection, APC=18 and total cavopulmonary connection, TCPC=33) and compared the results with 34 patients after right ventricular outflow tract reconstruction (RVOTR) with identical exercise capacity and arterial baroreflex sensitivity (BRS) (15±4 years) and with 26 controls (14±4 years). There were no differences in post-exercise HR or V˙O 2 declines between the Fontan and RVOTR groups. Although the systolic blood pressure (SBP) decline was delayed in the RVOTR group ( p<0.01), its early decline in the Fontan group was rapid and equivalent to that in controls. In Fontan patients, BRS had a great impact on early HR decline ( p<0.05) and early V˙O 2 decline was determined by peak V˙O 2, age and cardiac index ( p<0.05–0.001). TCPC and lower BRS were the main determinants of the slower SBP decline ( p<0.05). In another study of repeated paired exercise tests before and after Fontan operation, post-exercise SBP decline became greater after the operation ( p<0.07). Conclusions In the Fontan group, post-exercise HR and V˙O 2 declines are markedly delayed and are determined by cardiac vagal nervous activity, exercise capacity and age, respectively. Despite identical impaired hemodynamics and exercise capacity, post-exercise SBP decline is greater in the Fontan group, especially after APC, than in the RVOTR patients.

Surgical results of patients with a functional single ventricle.

Overall mortality of the patients with a functional single ventricle is still high, though excellent mid- and long-term results of the modified Fontan procedure have been reported. This study assessed the factors that affect the surgical outcomes mainly in the pre-Fontan stage and performed long-term survival analysis. Between January 1988 and December 2000, 405 patients with a functional single ventricle underwent surgical interventions and were followed up until June 2001. The mean follow-up period was 74.5+/-69.4 months and 95% of the patients were followed up completely. Their median age was 2.5 months at the time of shunt or pulmonary artery banding (PAB), 8.6 months at BCPS, and 28.6 months at the Fontan operation. The variables of the anatomical lesions with single ventricle physiology, combined abnormalities, surgical pathways leading to the Fontan stage, age at operation, study periods, and type of the Fontan procedure were analyzed. The role of BCPS in the long-term results was evaluated. Overall survival after birth was 60.1+/-2.8% at 10 years. In multivariate analysis, complete atrioventricular septal defect-typed lesion, pulmonary venous obstruction, total anomalous pulmonary venous connection, and interruption of aortic arch were risk factors for long-term survival, while pulmonary stenosis was demonstrated as a favorable prognostic factor. In this study, there was no significant survival difference between the early and late study period. Actuarial mortality in the pre-Fontan stage was 41.3% in the non-BCPS group and 16.3% in the BCPS group (P<0.001). The 10-year survival rates of the populations in staged and primary Fontan groups were not significantly different (P=0.24). The long-term survival rate of the atriopulmonary Fontan group was significantly lower than that of lateral tunnel Fontan (60.3+/-6.3% vs. 86.8+/-3.1% at 10 years, P=0.0001). This study revealed that the overall survival was disappointing and there were still problems that need to be solved in the pre-Fontan stage to improve the overall survival. The role of BCPS was not to contribute to the longer survival after Fontan operation, but to lower mortality in the pre-Fontan stage, which can offer a higher probability to proceed to the Fontan procedure successfully.

Epicardial pacemaker implantation and follow-up in patients with a single ventricle after the Fontan operation

Objectives: There is an increasing incidence of sinus node dysfunction after the Fontan procedure. Inability to maintain atrioventricular synchrony after the Fontan operation has been associated with an adverse late outcome. Although pacing may be helpful as a primary or adjunct modality after the Fontan procedure, the effects of performing a late thoracotomy or sternotomy for epicardial pacemaker implantation are unknown. In addition, little is known about the long-term effectiveness of epicardial leads in patients with single ventricles. The purpose of this study was to compare the hospital course and follow-up of epicardial pacing lead implantation in patients with Fontan physiology and patients with 2-ventricle physiology. Methods: We retrospectively reviewed all isolated epicardial pacemaker implantations and outpatient evaluations performed between January 1983 and June 2000. Results: There was no difference in the perioperative course for the 31 Fontan patients (27 atrial and 41 ventricular leads [68 total]) compared with the 56 non-Fontan subjects (9 atrial and 61 ventricular leads [70 total]). The median length of stay in Fontan and non-Fontan patients was 3 and 4 days, respectively. There was no early mortality in either group. Pleural drainage for 5 days or longer was reported in 4% of the Fontan cohort and 3% of the non-Fontan group. Late pleural effusions were identified in only 2 patients in the Fontan group and 2 patients in the non-Fontan group. There was no significant difference in epicardial lead survival between the Fontan group and the non-Fontan group (1 year, 96%; 2 years, 90%; 5 years, 70%). The overall incidence of lead failure was 17% (24/138). Conclusions: Epicardial leads can be safely placed in Fontan patients at no additional risk compared to patients with biventricular physiology. Sensing and pacing qualities were relatively constant in both the Fontan and non-Fontan groups over the first 2 years after implantation. (J Thorac Cardiovasc Surg 2001;121:804-11)