Transcatheter Interventions in Adult Congenital Heart Disease.

Congenital heart disease (CHD) is the most common congenital birth defect with an incidence of 1 in 100. Current survival to adulthood is expected in 9 out of 10 children with severe CHD as the diagnostic, interventional, and surgical success improves. The adult CHD (ACHD) population is increasingly diverse, reflecting the broad spectrum of CHD and evolution of surgical techniques to improve survival. Similarly, transcatheter interventions have seen exponential growth and creativity to reduce the need for repeat sternotomies. This article focuses on newer data and evolving techniques for transcatheter interventions specific to certain ACHD populations.

Intra-aortic balloon pump treatment in an adult patient with a Fontan circulation and acute heart failure: a case report.

Background: There is limited evidence for the use of an intra-aortic balloon pump (IABP) in adult patients with a total cavopulmonary, or Fontan circulation. Case summary: A patient in his twenties with a Fontan circulation presented with sepsis, pneumonia, and pulmonary oedema. He was born with a hypoplastic left ventricle, atrioventricular septal defect, and hypoplastic aortic arch, and a total cavopulmonary circulation had been established within his first years of life. Standard of care treatment with antibiotics, non-invasive ventilatory support, loop diuretics, and vasopressors was initiated. Due to persistent pulmonary congestion and increasing general fatigue, an IABP was placed via a femoral artery to offload the failing systemic ventricle. Secondary to IABP treatment, mean arterial pressure rose, and vasodilatory nitroprusside could be introduced. Over 4 days of IABP treatment, the patient's general condition and ventricular systolic function improved significantly. Discussion: This case suggests that IABP treatment was important in the recovery of our patient with a Fontan circulation, pneumonia, and heart failure. We propose that during IABP treatment, an increase in stroke volume and a reduction in ventricular filling pressure is achieved, thereby increasing the transpulmonary pressure gradient that is central to pulmonary blood flow in Fontan patients. More definitive evidence is necessary to confirm our hypotheses.

Outcomes of extracardiac Fontan operation: A single institution experience with 398 patients.

OBJECTIVE: To evaluate the outcomes of the extracardiac (EC) Fontan operation at a single institution. METHODS: We conducted a retrospective study of 398 patients from a single institution who underwent their initial EC Fontan operation between 1997 and 2020. We determined the incidence of, and risk factors for, failure of the Fontan circulation (which includes death, Fontan takedown, heart transplantation, protein losing enteropathy, plastic bronchitis and functional status at the last follow up). RESULTS: The median follow-up time was 10.3 (IQR 6.4-14.6) years. The overall survival rate was 96% and 86% at 10 and 20 years after EC Fontan operation. There were 6 early (6/398, 1.5%) and 15 late deaths (15/398, 3.8%). Forty-nine patients (12.5%) developed failure of the Fontan circulation. Freedom from the failure of Fontan circulation at 10 years was 88% and 76% at 20 years. Risk factors for failure of the Fontan circulation were right ventricular (RV) dominance (hazard ratio [HR], 4.7; P < 0.001; 95% confidence interval [CI], 2.1-10.5), aortic atresia (HR 5.5; P < 0.001; 95% CI, 2.3-12.8) and elevated mean pulmonary artery (PA) pressure (HR, 2.3; P = 0.002; 95% CI, 1.2-6.7). CONCLUSIONS: Rates of failure of the Fontan circulation are low following the contemporary EC Fontan operation. Risk factors for failure of the EC Fontan circulation include RV dominance, aortic atresia and elevated PA pressures.

Contemporary Management of the Failing Fontan.

Adult patients with congenital heart disease have now surpassed the pediatric population due to advances in surgery and improved survival. One such complex congenital heart disease seen in adult patients is the Fontan circulation. These patients have complex physiology and are at risk for several complications, including thrombosis of the Fontan pathway, pulmonary vascular disease, heart failure, atrial arrhythmias, atrioventricular valve regurgitation, and protein-losing enteropathy. This review discusses the commonly encountered phenotypes of Fontan circulatory failure and their contemporary management.

Heart Transplantation after Univentricular Palliation: Improved Outcomes and Increased Complexity.

AIM: Heart transplantation (HT) in patients with failing univentricular circulation is often challenging. This is compounded by the ever-increasing number of patients with prior Norwood-type reconstruction of the aorta, large aortic root, and often dense adhesions from multiple prior operations. We aimed to elucidate differences in outcomes of HT in patients with prior univentricular palliations, with and without prior Norwood-type aortic arch reconstruction (ArchRec). METHODS: All patients who underwent HT for failed univentricular palliation during the 1990-2022 period were included in the study. RESULTS: Of 45 patients, 18 had undergone ArchRec. Hospital mortality improved in the recent era (17.4% before 2006 vs 0% after 2006; p=0.11), despite a higher proportion of patients with ArchRec (17.4% before 2006 vs 60.8% after 2006, p=0.002). Patients with ArchRec had a higher number of prior cardiac surgeries (4.1±1.5 vs 3.2±1.3, p=0.04), longer cardiopulmonary bypass time (320±23 vs 242±21 min, p=0.02), more concomitant arch reconstruction (33.3% vs 0%, p=0.02), greater need for post-HT extracorporeal membrane oxygenation (33.3% vs 3.7%; p=0.01) and longer hospital stay (37.1±30.5 days vs 23.6±11.8 days, p=0.04). Freedom from death or retransplantation for all patients was 91%, 73%, 67%, and 53% at 1, 5, 10, and 15-years, respectively. Prior ArchRec, Fontan procedure, and earlier eras were not risk factors for death. CONCLUSIONS: The outcomes of HT after univentricular palliation have improved in recent times and low operative mortality can be achieved. Despite increased complexity, good similar outcomes can be achieved in patients with and without prior arch reconstruction regardless of the palliation stage.

Patient-specific closed-loop model of the fontan circulation: Calibration and validation.

The Fontan circulation, designed for managing patients with a single functional ventricle, presents challenges in long-term outcomes. Computational methods offer potential solutions, yet their application in cardiology practice remains largely unexplored. Our aim was to assess the ability of a patient-specific, closed-loop, reduced-order blood flow model to simulate pulsatile blood flow in the Fontan circulation. Using one-dimensional models, we simulated the aorta, superior and inferior venae cavae, and right and left pulmonary arteries, while lumping heart chambers and remaining vessels into zero-dimensional models. The model was calibrated with patient-specific haemodynamic data from combined cardiac catheterisation and magnetic resonance exams, using a novel physics-based stepwise methodology involving simpler open-loop models. Testing on a 10-year-old, anesthetised patient, demonstrated the model's capability to replicate pulsatile pressure and flow in the larger vessels and ventricular pressure. Average relative errors in mean pressure and flow were 2.9 % and 3.6 %, with average relative point-to-point errors (RPPE) in pressure and flow at 5.2 % and 16.0 %. Comparing simulation results to measurements, mean aortic pressure and flow values were 50.7 vs. 50.4 mmHg and 41.6 vs. 41.9 ml/s, respectively, while ventricular pressure values were 28.7 vs. 27.4 mmHg. The model accurately described time-varying ventricular volume with a RPPE of 2.9 %, with mean, minimum, and maximum ventricular volume values for simulation results vs. measurements at 59.2 vs. 58.2 ml, 38.0 vs. 37.6 ml, and 76.0 vs. 74.4 ml, respectively. It provided physiologically realistic predictions of haemodynamic changes from pulmonary vasodilation and atrial fenestration opening. The new model and calibration methodology are freely available, offering a platform to virtually investigate the Fontan circulation's response to clinical interventions and explore potential mechanisms of Fontan failure. Future efforts will concentrate on broadening the model's applicability to a wider range of patient populations and clinical scenarios, as well as testing its effectiveness.

Exercise capacity and muscle strength in patients who have undergone the Fontan procedure: a retrospective follow-up study.

BACKGROUND: Due to their relationship with clinical progression, follow-up of exercise capacity and muscle strength is important for optimal disease management in patients who have undergone the Fontan procedure. We aimed to retrospectively analyze exercise capacity and muscle strength trajectory over approximately 2 years. METHODS: Exercise capacity was assessed using an exercise stress test with the modified Bruce protocol on a treadmill, hand grip and knee extensor strength using a hand dynamometer, and body composition using a bioelectrical impedance device. Exercise capacity, muscle strength, and body composition follow-up data recorded between 2020 and 2022 were compared. RESULTS: Fifteen patients [median age from 17 (first assessment) to 18 years (last assessment), 5 females)] with a 20-month median follow-up time were analyzed retrospectively. There was an increase in weight, height, body mass index, and body fat weight (p<0.05). There was a tendency for increased handgrip strength (%) (p=0.069), but no significant difference was observed in the knee extensor strength of patients during the follow-up period (p>0.05). The changes in heart rate (HR) and oxygen saturation were higher in the last test than in the first test (p<0.05). Maximum HR (HRmax), % predicted HRmax and HR reserve recorded during the test and HR 1 minute after the test were similar between the first and last tests (p>0.05). CONCLUSIONS: After 20 months of follow-up, exercise capacity and muscle strength did not decline; instead, the body mass index and fat weight increased. Patients who have undergone the Fontan procedure may not be experiencing a decline in exercise capacity and muscle strength over relatively short time periods during childhood, adolescence, and early adulthood.

Anesthetic management in pregnant women with Fontan circulation: a case series.

BACKGROUND: Given the advances in medicine, women with Fontan circulation are now reaching childbearing age. However, data on the mode of delivery and anesthetic management of these patients are limited. We report the cases of five pregnant women with Fontan circulation. CASE PRESENTATION: The mean age at delivery was 28 ± 3 years, and the mean gestational period was 34 weeks and 3 days. Anticoagulation therapy was switched from warfarin and aspirin to continuous intravenous heparin. The modes of delivery were scheduled cesarean section (C/S) in one, emergency C/S in three, and vaginal delivery with epidural labor analgesia in one patient. Three patients underwent C/S under regional anesthesia; one received general anesthesia. The perinatal complications were heart failure, worsening valve regurgitation, and postoperative hematoma in three, four, and two patients, respectively. CONCLUSIONS: For C/S in women with Fontan circulation, regional anesthesia should be considered. Epidural labor analgesia can help prevent the decrease in pulmonary blood flow due to straining. We initiated labor analgesia or C/S with regional anesthesia at the appropriate time in four patients.

In a porcine model of implantable pacemakers for pediatric unilateral diaphragm paralysis, the phrenic nerve is the best target.

BACKGROUND: A frequent complication of Fontan operations is unilateral diaphragmatic paresis, which leads to hemodynamic deterioration of the Fontan circulation. A potential new therapeutic option is the unilateral diaphragmatic pacemaker. In this study, we investigated the most effective stimulation location for a potential fully implantable system in a porcine model. METHODS: Five pigs (20.8 ± 0.95 kg) underwent implantation of a customized cuff electrode placed around the right phrenic nerve. A bipolar myocardial pacing electrode was sutured adjacent to the motor point and peripherally at the costophrenic angle (peripheral diaphragmatic muscle). The electrodes were stimulated 30 times per minute with a pulse duration of 200 µs and a stimulation time of 300 ms. Current intensity was the only variable changed during the experiment. RESULTS: Effective stimulation occurred at 0.26 ± 0.024 mA at the phrenic nerve and 7 ± 1.22 mA at the motor point, a significant difference in amperage (p = 0.005). Even with a maximum stimulation of 10 mA at the peripheral diaphragm muscle, however, no effective stimulation was observed. CONCLUSION: The phrenic nerve seems to be the best location for direct stimulation by a unilateral thoracic diaphragm pacemaker in terms of the required amperage level in a porcine model.

[Imaging of congenital heart defects with a focus on magnetic resonance imaging and computed tomography]. / Bildgebung angeborener Herzfehler mit Fokus auf Magnetresonanz- und Computertomographie.

CLINICAL ISSUE: Due to advances in diagnostics and therapy, the survival rate of patients with congenital heart defects is continuously increasing. The aim of this review is to compare various imaging modalities that are used in the diagnosis of congenital heart defects. METHODS: Transthoracic echocardiography is the imaging method of choice in the presence of a congenital heart defect because of its wide availability and non-invasiveness. It can be complemented by transesophageal echocardiography, cardiac catheterization, computed tomography (CT), and magnetic resonance imaging (MRI) of the heart and vessels close to the heart. METHODICAL INNOVATIONS: The radiation exposure of CT examinations of the heart is continuously decreasing because of improved technologies. MRI is also being continuously optimized, e.g., by the acquisition of MR angiographies without contrast medium application or a thin three-dimensional (3D) visualization of the entire heart with the possibility of reconstruction in all spatial planes (whole-heart technique) as well as 2D to 4D flow. PRACTICAL RECOMMENDATION: Due to the complexity of congenital heart defects and the variety of possible pathologies, the choice of imaging modality and its exact performance has to be coordinated in an interdisciplinary context and individually adapted.

Long-term incidence of arrhythmias in extracardiac conduit Fontan and comparison between systemic left and right ventricle.

AIMS: The extracardiac conduit-Fontan (ECC) has become the preferred technique for univentricular heart palliation, but there are currently no data on the incidence of long-term arrhythmias. This study investigated the incidence of arrhythmias and relation to single ventricle morphology in the long-term follow-up (FU) in ECC. METHODS AND RESULTS: All patients with ECC performed in our Centre between 1987 and 2017 were included (minimum FU 5 years). Of 353 consecutive patients, 303 [57.8% males, aging 8-50 (median 20) years at last FU] were considered and divided into two groups depending on left (194 in Group 1) or right (109 in Group 2) ventricular morphology. Eighty-five (28%) experienced ≥1 arrhythmic complications, with early and late arrhythmias in 17 (5.6%) and 73 (24.1%) patients, respectively. Notably, late bradyarrhythmias occurred after 6 years in 21 (11%) patients in Group 1, and in 15 (13.8%) in Group 2 [P = 0.48]. Late tachyarrhythmias occurred in 55 (18.2%) patients after 12 years: 33 (17%) in Group 1 and 22 (20.2%) patients in Group 2 [P  = 0.5]. Ventricular tachycardias (VT) were documented after 12.5 years in 14 (7.2%) patients of Group 1 and 15 (13.8%) of Group 2 [P = 0.06] with a higher incidence in Group 2 during the FU [P = 0.005]. CONCLUSION: Extracardiac conduit is related to a significant arrhythmic risk in the long-term FU, higher than previously reported. Bradyarrhythmias occur earlier but are less frequent than tachyarrhythmias. Interestingly, patients with systemic right ventricle have a significantly higher incidence of VT, especially in a very long FU.

High-Risk Congenital Heart Disease in Pregnancy.

High-risk congenital heart disease (CHD) in pregnancy presents a complex clinical challenge. With improved medical care and increased survival rates, a growing population of adults with complex CHD are surviving to adulthood, including women of reproductive age. This chapter focuses on risk stratification and management of pregnant women with high-risk CHD, emphasizing the importance of considering both anatomical and physiological complexity. Maternal physiological changes, such as blood volume increase, cardiac output changes, and alterations in vascular resistance, can significantly impact high-risk CHD patients. Management of high-risk CHD in pregnancy necessitates a multidisciplinary approach and individualized care.

Lung Function in Fontan Patients Over a Ten-Year Period: Is the Fontan Circulation Impairing Lung Development?

Few studies have investigated how the Fontan circulation affects lung function, and no studies have investigated the development of lung function over longer time in these patients. We aimed to describe the development of lung function in Fontan patients over a 10-year period. Pulmonary function tests (PFT), including spirometry and diffusion capacity for Carbon Monoxide (DLCO) and Nitric Oxide (DLNO), were conducted in a Danish Fontan cohort in 2011 (PFT-I). In 2021, re-investigations were performed (PFT-II). We investigated changes in percent predicted (%pred) lung function from PFT-I to PFT-II. Patients were categorized into a pediatric group (age under 18 at PFT-I) and an adult group (age 18 or older at PFT-I). Out of the 81 patients completing PFT-I, 48 completed PFT-II. In the pediatric group (32 patients), there were significant declines in %pred forced expiratory volume in 1s (99.7 (92.4, 104.4)-89.3 (84.9, 97.2), p < 0,001), forced vital capacity (98.3 (87.8, 106.1)-96.7 (86.7, 100.6), p = 0.008), and alveolar volume (95.5 (89.5, 101.6)-89.5 (79.7, 93.2), p < 0.001). The corresponding measurements remained stable in the adult group. However, the median %pred DLNO significantly declined in the adult group (58.4 (53.3, 63.5)-53.7 (44.1, 57.3), p = 0.005). Over a 10-year period, several lung function parameters declined significantly in the younger Fontan patients, suggesting possible impairments in lung development during growth. The decline in %pred DLNO in the adult patient group indicates deterioration of the membrane component of diffusion capacity, implying that the Fontan circulation might negatively affect the alveolar membrane over time.

Cerebral embolic protection during transcatheter stent expansion of restrictive extra-cardiac Fontan conduit.

We report a 20-year-old female patient (76 Kg/164 cm) with an extra-cardiac Fontan circulation who was referred to our institution for exertional dyspnoea and desaturation. The patient was diagnosed with a large calcified thrombus at the level of the Fontan fenestration, protruding inside the lumen of the conduit and reducing the diameter by half with a 3 mmHg pressure gradient. Transcatheter stent expansion of the obstructed extra-cardiac conduit was done with a 48 mm long XXL PTFE-covered Optimus-CVS® under temporary cerebral embolic protection with a TriGUARD-3™ deflection filter device (Keystone Heart). There was no procedural complication and the 3 months clinical outcomes are good.

Leg-focused high-weight resistance training improves ventricular stroke volume, exercise capacity and strength in young patients with a Fontan circulation.

AIMS: Effective therapy to improve exercise capacity in Fontan patients is lacking. Leg-focused high-weight resistance training might augment the peripheral muscle pump and thereby improve exercise capacity. METHODS AND RESULTS: This randomized semi-cross-over controlled trial investigated the effects of a 12-week leg-focused high-weight resistance training plus high-protein diet, on (sub)maximal exercise capacity, cardiac function (assessed with cardiovascular magnetic resonance), muscle strength, and quality of life in paediatric Fontan patients. Twenty-eight paediatric Fontan patients were included, 27 patients, (median age 12.9 [10.5-15.7]), and successfully completed the programme. Peak oxygen uptake (PeakVO2) at baseline was reduced [33.3 mL/kg/min (27.1-37.4), 73% (62-79) of predicted]. After training PeakVO2/kg and Peak workload improved significantly with +6.2 mL/kg/min (95%CI: 3.4-9.0) (+18%) P < 0.001 and +22 Watts (95%CI: 12-32) (+18%) P < 0.001, respectively, compared to the control period. Indexed single ventricle stroke volume increased significantly [43 mL/beat/m2 (40-49) vs. 46 (41-53), P = 0.014], as did inferior vena cava flow [21 mL/beat/m2 (18-24) vs. 23 (20-28), P = 0.015], while superior vena cava flow remained unchanged. The strength of all measured leg-muscles increased significantly compared to the control period. Self-reported quality of life improved on the physical functioning and change in health domains of the child health questionnaire, parent-reported quality of life improved the bodily pain, general health perception, and change in health domains compared to the control period. CONCLUSION: In a relatively large group of 27 older Fontan children, 12-weeks of leg-focused high-weight resistance training improved exercise capacity, stroke volume, (sub)maximal exercise capacity, muscle strength, and domains of quality of life. REGISTRATION: International Clinical Trials: Trial NL8181.

Is leg-focused high-weight resistance training an effective therapy to improve reduced exercise capacity in patients with a Fontan circulation? Key Finding: Twelve weeks of leg-focused high-weight resistance training in children with a Fontan circulation improved exercise capacity, single ventricular stroke volume, (sub)maximal exercise capacity, muscle strength, and physical domains of quality of life. Take-home Message: Leg-focused high-weight resistance training results in improved exercise capacity, cardiac function, and quality of life patients with a Fontan circulation. Patients with a Fontan circulation should be motivated to perform lower limb strengthening exercises.

Quality of Life in the Danish Fontan Population is Unchanged Over the Past Decade-A Nationwide Longitudinal Study.

Knowledge about health-related quality of life (HRQoL) over time in Fontan patients is sparse. We aimed to describe HRQoL over a ten-year period in a population-based Fontan cohort. Further, we compared HRQoL in Fontan patients with the general population. In 2011, Danish Fontan patients were invited to participate in a nationwide study assessing HRQoL. Depending on age, 152 participants filled out either the Pediatric Quality of Life Inventory or the 36-Item Short Form Health Survey. After a decade, patients from the initial study were invited to participate in a follow-up study. All were given the same questionnaire as in the first study, plus the 12-Item Short Form Health Survey (SF-12) as part of the Danish National Health Survey. HRQoL over time was described, and SF-12 scores were compared with the general population. A total of 109 Fontan patients completed the questionnaires in both studies. The mean patient age was 14.9 ± 6.6 years and 25.6 ± 6.5 years respectively. Despite an increase in complications, HRQoL did not decrease during the study period. Physical HRQoL scores were lower than mental HRQoL scores at both time points. The SF-12 physical component score was significantly lower in Fontan patients than in the general population (median score 52 vs. 56, p < 0.001), while the SF-12 mental component score was comparable (median score 51 vs. 50, p = 0.019). HRQoL remained stable over a ten-year period in a contemporary Danish Fontan cohort. Still, the physical HRQoL remained significantly lower than that of the general population.

Intraoperative transit-time flow measurement of caval veins before and after bidirectional cavopulmonary anastomosis.

BACKGROUND: Haemodynamic changes in caval venous flow distribution occurring during bidirectional cavopulmonary anastomosis operation are still largely unknown. METHODS: Transit time flow measurements were performed in 15 cavopulmonary anastomosis operations. Superior and inferior caval vein flows were measured before and after the cavopulmonary anastomosis. Ratio of superior caval vein to overall caval veins flow was calculated. RESULTS: Mean superior caval vein flow ratio before cavopulmonary anastomosis was higher than previously reported for healthy children. Superior caval vein flow ratio decreased in 14/15 patients after cavopulmonary anastomosis: mean 0.63 ± 0.12 before versus 0.43 ± 0.14 after. No linear correlation between intraoperative superior caval vein pressure and superior caval vein flow after cavopulmonary anastomosis was found. Neither Nakata index nor pulmonary vascular resistance measured at preoperative cardiac catheterisation correlated with intraoperative flows. None of patients died or required a take down. CONCLUSIONS: The higher mean superior caval vein flow ratio before cavopulmonary anastomosis compared to healthy children suggests flow redistribution in univentricular physiology to protect brain and neurodevelopment. The decrease of superior caval vein flow ratio after cavopulmonary anastomosis may reflect the flow redistribution related to trans-pulmonary gradient. The lack of correlation between superior caval vein pressure and superior caval vein flow could be explained by limited sample size and multifactorial determinants of caval veins flow, although pressure remain essential. Larger sample of measurements are needed to find flow range potentially predictive for clinical failure. To authors' knowledge, this is the first intraoperative flow measurement of both caval veins during cavopulmonary operations.