Orthotopic heart transplantation in patients with univentricular physiology

Heart Transplantation Following Fontan Failure: Long-Term Survival Analysis

Objectives: Fontan circulation presents significant challenges for patients with congenital heart disease, often necessitating heart transplantation (HTX) due to deteriorating functionality across multiple organ systems. However, the impact of prior Fontan palliation on HTX outcomes remains poorly understood, with early mortality rates suggesting a heightened risk. The aim of our study is to evaluate the long-term results after heart transplantation in patients with univentricular congenital heart disease previously palliated with Fontan circulation. Methods: A retrospective analysis was conducted on patients who underwent HTX for congenital heart disease. Patients were categorized into two groups based on the pre-HTX circulation pathway: the Failing Fontan Group (FFG) and the Biventricular Congenital Group (BCG). Data were collected from patients between 1987 and 2018. Early and late outcomes, including survival rates, were assessed and critically analyzed. Results: Of the 66 patients, 29 (43%) had a failing Fontan palliation (FFG), and 37 had biventricular congenital diseases (BCG) before heart transplantation. Early mortality (30-day) was not statistically different between the two group. The overall survival rate was 82.6 ± 13.9% at 1 year, 79.0 ± 14.9% at 5 years, 67.2 ± 17.6% at 10 years and 63.2 ± 18.2 ± at 15 years for the FFG, and 86.1 ±11.4% at 1 year, 79.5 ± 13.7% at 5 years, 75.7 ± 14.9% at 10 years, 75.7 ± 14.9% at 15 years for the BCG, with no statistically significant difference (Mantel Cox p value: 0.69, 0.89, 0.52 and 0.39, respectively). Regarding Cox-regression analysis, the long-term survival rate was not affected either by previous Fontan surgery or by the era of heart transplantation (before vs. after the year 2000). Conclusions: Although heart transplantation after Fontan palliation showed a higher risk in the early post-operative period, the medium- and long-term survival rates are comparable with biventricular circulation patients. Despite the failing Fontan patients being a challenging set of candidates for transplantation, it is a reasonable option in their treatment.

A Single-Institutional Experience with 36 Children Smaller Than 5 Kilograms Supported with the Berlin Heart Ventricular Assist Device (VAD) over 12 Years: Comparison of Patients with Biventricular versus Functionally Univentricular Circulation

OBJECTIVES

We reviewed outcomes in all 36 consecutive children <5 kg supported with the Berlin Heart pulsatile ventricular assist device (VAD) at the University of Florida, comparing those with univentricular circulation (n  =  23) to those with biventricular circulation (n  =  13).

METHODS

The primary outcome was mortality. Kaplan-Meier methods and log-rank tests were used to assess group differences in long-term survival after VAD insertion. T-tests using estimated survival proportions and standard errors were used to compare groups at specific time points.

RESULTS

Of all 82 patients ever supported with Berlin Heart at our institution, 49 (49/82  =  59.76%) weighed <10 kg and 36 (36/82  =  43.90%) weighed <5 kg. Of these 36 patients who weighed <5 kg, 26 (26/36  =  72.22%) were successfully bridged to transplantation. Of these 36 patients who weighed <5 kg, 13 (13/36  =  36.1%) had biventricular circulation and were supported with 12 biventricular assist devices (BiVADs) and 1 left ventricular assist device (LVAD) (Age [days]: median  =  67, range  =  17-212; Weight [kilograms]: median  =  4.1, range  =  3.1-4.9), while 23 (23/36  =  63.9%) had univentricular circulation and were supported with 23 single ventricle-ventricular assist devices (sVADs) (Age [days]: median  =  25, range  =  4-215; Weight [kilograms]: median  =  3.4, range  =  2.4-4.9). Of 13 biventricular patients who weighed <5 kg, 12 (12/23  =  92.3%) were successfully bridged to cardiac transplantation. Of 23 functionally univentricular patients who weighed <5 kg, 14 (14/23  =  60.87%) were successfully bridged to cardiac transplantation. For all 36 patients who weighed <5 kg: 1-year survival estimate after VAD insertion  =  62.7% (95% confidence interval [CI]  =  48.5%-81.2%) and 5-year survival estimate after VAD insertion  =  58.5% (95% CI  =  43.8%-78.3%). One-year survival after VAD insertion: 84.6% (95% CI  =  67.1%-99.9%) in biventricular patients and 49.7% (95% CI  =  32.3%-76.4%) in univentricular patients, P  =  0.018. Three-year survival after VAD insertion: 84.6% (95% CI  =  67.1%-99.9%) in biventricular patients and 41.4% (95% CI  =  23.6%-72.5%) in univentricular patients, P  =  0.005.

CONCLUSION

Pulsatile VAD facilitates bridge to transplantation in neonates and infants weighing <5 kg; however, survival after VAD insertion in these small patients is less in those with univentricular circulation in comparison to those with biventricular circulation.

Support with Single Ventricle-Ventricular Assist Device (sVAD) in Patients with Functionally Univentricular Circulation Prior to Fontan Operation

Some patients with functionally univentricular circulation develop cardiac failure refractory to maximal management and are supported with a ventricular assist device (VAD). The purpose of this manuscript is to summarize our previous publications related to single ventricle-ventricular assist device (sVAD) support in patients with functionally univentricular circulation and to describe our current institutional approach at University of Florida to sVAD support in neonates, infants, and children prior to Fontan. Our programmatic philosophy at University of Florida is to strive to identify the minority of neonates with functionally univentricular circulation who are extremely high-risk prior to initiating staged palliation and to stabilize these neonates with primary preemptive sVAD in preparation for cardiac transplantation; our rationale for this approach is related to the challenges associated with failed staged palliation and subsequent bail-out sVAD support and transplantation. A subset of extremely high-risk neonates and infants with functionally univentricular ductal-dependent circulation undergo primary preemptive sVAD insertion and subsequent cardiac transplantation. Support with VAD clearly facilitates survival on the waiting list during prolonged wait times and optimizes outcomes after Norwood (Stage 1) by providing an alternative pathway for extremely high-risk patients. Therefore, the selective utilization of sVAD in extremely high-risk neonates facilitates improved outcomes for all patients with functionally univentricular ductal-dependent circulation. At University of Florida, our programmatic approach to utilizing sVAD support as a bridge to transplantation in the minority of neonates with functionally univentricular circulation who are extremely high-risk for staged palliation is associated with Operative Mortality after Norwood (Stage 1) Operation of 2.9% (2/68) and a one-year survival of 91.1% (82/90) for all neonates presenting with hypoplastic left heart syndrome (HLHS) or HLHS-related malformation with functionally univentricular ductal-dependent systemic circulation. Meanwhile, at University of Florida, for all 82 consecutive neonates, infants, and children supported with pulsatile paracorporeal VAD: Kaplan-Meier survival estimated one year after VAD insertion = 73.3% (95% confidence interval [CI] = 64.1-83.8%), and Kaplan-Meier survival estimated five years after VAD insertion = 68.3% (95% CI = 58.4-79.8%). For all 48 consecutive neonates, infants, and children at University of Florida with biventricular circulation supported with pulsatile paracorporeal VAD: Kaplan-Meier survival estimated one year after VAD insertion = 82.7% (95% CI = 72.4-94.4%), and Kaplan-Meier survival estimated five years after VAD insertion = 79.7% (95% CI = 68.6-92.6%). For all 34 consecutive neonates, infants, and children at University of Florida with functionally univentricular circulation supported with pulsatile paracorporeal sVAD: Kaplan-Meier survival estimated one year after VAD insertion = 59.7% (95% CI = 44.9-79.5%), and Kaplan-Meier survival estimated five years after VAD insertion = 50.5% (95% CI = 35.0-73.0%). These Kaplan-Meier survival estimates for patients supported with pulsatile paracorporeal VAD are better in patients with biventricular circulation in comparison to patients with functionally univentricular circulation both one year after VAD insertion (P=0.026) and five years after VAD insertion (P=0.010). Although outcomes after VAD support in functionally univentricular patients are worse than in patients with biventricular circulation, sVAD provides a reasonable chance for survival. Ongoing research is necessary to improve the outcomes of these challenging patients, with the goal of developing strategies where outcomes after sVAD support in functionally univentricular patients are equivalent to the outcomes achieved after VAD support in patients with biventricular circulation.

Current diagnostic and therapeutic strategies for the management of lymphatic insufficiency in patients with hypoplastic left heart syndrome

Children with hypoplastic left heart syndrome share unique hemodynamic features that alter lymphatic integrity at all stages of palliation. Lymphatic congestion is almost universal in this patient group to some extent. It may lead to reversal of lymphatic flow, the development of abnormal lymphatic channels and ultimately decompression and loss of protein rich lymphatic fluid into extra lymphatic compartments in prone individuals. Some of the most devastating complications that are associated with single ventricle physiology, notably plastic bronchitis and protein losing enteropathy, have now been proven to be lymphatic in origin. Based on the new pathophysiologic concept new diagnostic and therapeutic strategies have recently been developed. Dynamic contrast magnetic resonance lymphangiography is now mainstay in diagnosis of lymphatic insufficiency and allows a thorough assessment of anatomy and function of the main lymphatic compartments through intranodal, intrahepatic and intramesenteric lymphatic imaging. Contrast enhanced ultrasound can evaluate thoracic duct patency and conventional fluoroscopic lymphangiography has been refined for evaluation of patients where magnetic resonance imaging cannot be performed. Novel lymphatic interventional techniques, such as thoracic duct embolization, selective lymphatic duct embolization and liver lymphatic embolization allow to seal abnormal lymphatic networks minimally invasive and have shown to resolve symptoms. Innominate vein turn-down procedures, whether surgical or interventional, have been designed to reduce lymphatic afterload and increase systemic preload effectively in the failing Fontan circulation. Outflow obstruction can now be managed with new microsurgical techniques that create lympho-venous anastomosis. Short term results for all of these new approaches are overall promising but evidence is sparse and long-term outcome still has to be defined. This review article aims to summarize current concepts of lymphatic flow disorders in single ventricle patients, discuss new emerging diagnostic and therapeutic strategies and point out lacks in evidence and needs for further research on this rapidly growing topic.

Failures of the Fontan System in Univentricular Hearts and Mortality Risk in Heart Transplantation: A Systematic Review and Meta-Analysis

The Fontan procedure (FP) is the standard surgical treatment for Univentricular heart diseases. Over time, the Fontan system fails, leading to pathologies such as protein-losing enteropathy (PLE), plastic bronchitis (PB), and heart failure (HF). FP should be considered as a transitional step to the final treatment: heart transplantation (HT). This systematic review and meta-analysis aims to establish the risk of death following HT according to the presence of FP complications. There was a total of 691 transplanted patients in the 18 articles, immediate survival 88% (n = 448), survival from 1 to 5 years of 78% (n = 427) and survival from 5.1 to 10 years of 69% (n = 208), >10 years 61% (n = 109). The relative risk (RR) was 1.12 for PLE (95% confidence interval [CI] = 0.89-1.40, p = 0.34), 1.03 for HF (0.7-1.51, p = 0.88), 0.70 for Arrhythmias (0.39-1.24, p = 0.22), 0.46 for PB (0.08-2.72, p = 0.39), and 5.81 for CKD (1.70-19.88, p = 0.005). In patients with two or more failures, the RR was 1.94 (0.99-3.81, p = 0.05). After FP, the risk of death after HT is associated with CKD and with the presence of two or more failures.

Heart transplantation for patients with single ventricle physiology

Background

There is a growing population of palliated and unpalliated single ventricle physiology patients for whom heart transplantation is the only treatment option available. There is a paucity of reports of heart transplantation in this challenging and growing subset of patients from our part of the world. The purpose of the article is to briefly review our experience in the subgroup and compare it with the available literature.

Methods

This was a single-institution retrospective observational study of 16 patients with single ventricle physiology who were transplanted between 2016 and 2019 and their outcomes. The study groups were divided into those with ventricular dysfunction (group 1), who fare substantially better than those with normal ventricular function (group 2) whose short-term outcomes were poorer. Worsening cyanosis, poor candidature for completion Fontan procedure due to severe atrioventricular valve regurgitation or pulmonary artery anatomy, protein-losing enteropathy, plastic bronchitis, and worsening systemic venous congestion are indications in those with normal ventricular function.

Results

Patients with ventricular dysfunction as the main indication had excellent early survival with no early mortality compared to 40% mortality in patients with normal ventricular function. Patients who survived to leave the hospital had however similar long-term outcomes. Two patients with protein-losing enteropathy resolved completely by one month. Normal ventricular function, pulmonary artery stenting, early Fontan failure (6 months), ascites, and need for desensitization were risk factors for early mortality. After the early acute phase of increased risk, the mortality risk plateaued off.

Conclusion

Transplantation in patients with single ventricle and ventricular dysfunction can be offered with a good early and late outcome. There is a need to have multi-institutional and multi-disciplinary collaboration along with work in basic sciences to better understand the effects of failed Fontan physiology with normal ventricular function.

Combined Hybrid Procedure and VAD insertion in 9 High-Risk Neonates and Infants with HLHS

BACKGROUND

We report nine high-risk neonates and infants with HLHS stabilized with a Hybrid Approach + VAD insertion (Hybrid+VAD) in preparation for transplantation.

METHODS

Nine patients with HLHS (7 neonates, 2 infants) presented with anatomical and/or physiological features associated with increased risk for conventional univentricular palliation with the Norwood Operation (large coronary sinusoids/fistulas, severe tricuspid regurgitation, cardiogenic shock, restrictive atrial septum). These patients underwent combined VAD insertion (Berlin EXCOR) and stage 1 hybrid palliation (application of bilateral pulmonary bands, stent placement in the PDA, and atrial septectomy if needed). During this same era, at our institution, 41 neonates underwent Norwood Operation, three neonates underwent Hybrid Approach "Stage 1" without VAD, and three HLHS patients were supported with prostaglandin while awaiting transplantation.

RESULTS

At Hybrid+VAD insertion, median age = 20 days (range = 13-143) and median weight = 3.25 kilograms (range = 2.43-4.2). Six patients survive (67%) and three patients died (33%). Five survivors are at home doing well after successful transplantation and one survivor is doing well in the ICU on VAD support awaiting transplantation. Only one of six survivors (16.7%) required intubation more than 10 days after Hybrid+VAD insertion. In eight patients no longer on VAD, median length of VAD support was 119.5 days (range = 56-196 days).

CONCLUSIONS

High-risk patients with HLHS who are suboptimal candidates for Norwood palliation can be successfully stabilized with pulsatile VAD insertion along with hybrid palliation while awaiting cardiac transplantation; these patients may be extubated and optimized for transplantation while on VAD.

Technical modifications for transplant in the failing Fontan

INTRODUCTION

Heart transplant after Fontan completion poses a unique surgical challenge. Twenty patients are presented, stressing the technical hints performed in the five anastomoses to match the graft in the recipient.

METHODS

Data are collected from 20 Fontan patients between 2013 and 2019. Age (13 years), weight (37 kg.), and time interval between Fontan and transplant (7 years) are presented as median. Extracardiac conduit (size 18/20) was implanted in 15 patients, whereas atrio-pulmonary connection was performed in 4 and lateral tunnel in 1. Six patients developed protein-losing enteropathy. Seventeen stents had been previously deployed.

RESULTS

The five anastomoses underwent some changes. Left atrium once, aorta 9 times, superior vena cava 7 times, pulmonary branches 15 times, and inferior vena cava 12 times. Follow-up was complete for a median of 42 months (range 6-84). Two patients died. ECMO was needed in six cases for pulmonary hypertension. Four patients had collateral vessels occluded in the cath lab, and stents were placed in superior vena cava (1) and aorta (1) post-transplant. Protein-losing enteropathy was resolved in five patients. Interestingly, one patient was on a systemic assist device before transplant (Levitronix) and right assistance (ECMO) afterwards.

CONCLUSIONS

Transplant in Fontan patients is actually challenging. Hints in every of the five proposed anastomoses must be anticipated, including stents removal. Extra tissue from the donor (innominate vein, aortic arch, and pericardium) is strongly advisable. ECMO for right ventricular dysfunction was needed in nearly one-third of the cases. Overall results can match other transplant cohorts.

Superior Cavopulmonary Connection: Its Physiology, Limitations, and Anesthetic Implications

The superior cavopulmonary connection (SCPC) or "bidirectional Glenn" is an integral, intermediate stage in palliation of single ventricle patients to the Fontan procedure. The procedure, normally performed at 3 to 6 months of life, increases effective pulmonary blood flow and reduces the ventricular volume load in patients with single ventricle (parallel circulation) physiology. While the SCPC, with or without additional sources of pulmonary blood flow, cannot be considered a long-term palliation strategy, there are a subset of patients who require SCPC palliation for a longer interval than the typical patient. In this article, we will review the physiology of SCPC, the consequences of prolonged SCPC palliation, and modes of failure. We will also discuss strategies to augment pulmonary blood flow in the presence of an SCPC. The anesthetic considerations in SCPC patients will also be discussed, as these patients may present for noncardiac surgery from infancy to adulthood.

An overview of mechanical circulatory support in single-ventricle patients

The population of people with a single-ventricle is continually increasing due to improvements across the spectrum of medical care. Unfortunately, a proportion of these patients will develop heart failure. Often, for these patients, mechanical circulatory support (MCS) represents the only available treatment option. While single-ventricle patients currently represent a small proportion of the total number of patients who receive MCS, as the single-ventricle patient population increases, this number will increase as well. Outcomes for these complex single-ventricle patients who require MCS has begun to be evaluated. When considering the entire population, survival to hospital discharge is 30-50%, though this must be considered with the significant heterogeneity of the single-ventricle patient population. Patients with a single-ventricle have unique anatomy, mechanisms of failure, indications for MCS and the type of support utilized. This has made the interpretation and the generalizability of the limited available data difficult. It is likely that some subsets will have a significantly worse prognosis and others a better one. Unfortunately, with these limited data, indications of a favorable or poor outcome have not yet been elucidated. Though currently, a database has been constructed to address this issue. While the outcomes for these complex patients is unclear, at least in some situations, they are poor. However, significant advances may provide improvements going forward, including new devices, computer simulations and 3D printed models. The most important factor, however, will be the increased experience gained by the heart failure team to improve patient selection, timing, device and configuration selection and operative approach.

Transplantation in the single ventricle population

The single ventricle patient population comprises the most complex cohort presenting to the cardiac transplant team, in terms of demographics, anatomic substrate, and unique physiology. It is also the most rapidly growing diagnostic group presenting for heart transplantation. In this manuscript, we aim to describe the changing landscape of transplantation in single ventricle conditions through reflection on our own institution's practice and experience, alongside contemporary literature review. Single ventricle patients are heterogeneous in terms of age, anatomic diagnosis and physiology according to surgical stage of repair. Progress in surgical palliative strategies has impacted upon the present composition of the population, with growing numbers of hypoplastic left heart syndrome patients and those with late physiology failure following Fontan completion. Multiple prior surgeries, immunological sensitivity and multi-organ involvement impart high peri-operative risk but can be mitigated in part by careful pre-operative planning by a dedicated multi-disciplinary team addressing issues such as planning of concurrent reconstructive surgery, minimizing the post-operative effect of collaterals, timely harvesting, oversizing of donor organs to minimize graft failure, and strategies to address anticipated post-operative elevation in pulmonary vascular resistance. Determining optimal timing for transplant in these patients remains unclear, but understanding the risk of alternative surgical options can help guide decision making with regards to listing.

Mortality Risk Stratification in Fontan Patients Who Underwent Heart Transplantation

The number of patients who require orthotopic heart transplantation (OHT) for failing Fontan physiology continues to grow; however, the methods and tools to evaluate risk of OHT are limited. This study aimed to identify a set of preoperative variables and characteristics that were associated with a greater risk of postoperative mortality in patients who received OHT for failing Fontan physiology. Thirty-six Fontan patients were identified as having undergone OHT at University of California-Los Angeles Medical Center from 1991 to 2014. Data were collected retrospectively and analyzed. The primary end point was designated as postoperative mortality. After an average follow-up time of 3.5 years, 17 (44%) patients suffered postoperative mortality. Patient characteristics including (1) age <18 years at the time of OHT, (2) Fontan-OHT interval of <10 years, (3) systemic ventricular ejection fraction <20%, (4) moderate-to-severe atrioventricular valve insufficiency, (5) an elevated Model of End-stage Liver Disease, eXcluding INR score, or (6) need for advanced mechanical support before surgery were associated with an increased incidence of postoperative mortality. Using these risk factors, we present a theoretical framework to stratify risk of postoperative death in failing Fontan patients after OHT. In conclusion, a method such as this may aid in the transplantation evaluation and listing process of patients with failing Fontan physiology.

Twin-to-Twin Heart Transplantation: A Unique Event With a 25-Year Follow-Up

Solid organ transplantation in pediatric patients has been a reality since 1954, when the first kidney transplantation was successfully performed between identical twins. We report the long-term outcomes, with more than 25 years of follow-up, in a patient born with hypoplastic left heart syndrome (HLHS) who received a heart transplant from a dizygotic twin. While we would not wish for this situation to reoccur, we hope that in reporting it, we can add to the discussion surrounding pediatric heart transplantation and the management of HLHS.

The evolving role of the total artificial heart in the management of end-stage congenital heart disease and adolescents

Advances in medical therapies have yielded improvement in morbidity and a decrease in mortality for patients with congenital heart disease, both surgically palliated and uncorrected. An unintended consequence is a cohort of adolescent and adult patients with heart failure who require alternative therapies. One intriguing option is placement of a total artificial heart (TAH) either as a bridge to transplant or as a destination therapy. Of the 1091 Jarvik-7 type TAH (Symbion, CardioWest and SynCardia) placed between 1985 and 2012, only 24 have been performed in patients with congenital heart disease, and a total of 51 were placed in patients younger than 21. At our institution, the SynCardia TAH was implanted in a 19-year-old patient with cardiac allograft failure because of chronic rejection and related multisystem organ failure including need for hemodialysis. Over the next year, she was nutritionally and physically rehabilitated, as were her end organs, allowing her to come off dialysis, achieve normal renal function and eventually be successfully transplanted. Given the continued growth of adolescent and adult congenital heart disease populations with end-stage heart failure, the TAH may offer therapeutic options where previously there were few. In addition, smaller devices such as the SynCardia 50/50 will open the door for applications in smaller children. The Freedom Driver offers the chance for patients to leave the hospital with a TAH, as does the AbioCor, which is a fully implantable TAH option. In this report, we review the history of the TAH and potential applications in adolescent patients and congenital heart disease.

The adult with a fontan: a panacea without a cure? Review of long-term complications

The univentricular heart includes a spectrum of complex cardiac defects that are managed by staged palliative surgical procedures, ultimately resulting in a Fontan procedure. Since 1971, when it was first developed, the procedure has undergone several variations. These patients require lifelong management, including a thorough knowledge of their anatomic substrate, hemodynamic status, management of rhythm and ventricular function, together with multi-organ evaluation. As these patients enter middle age, there is increasing awareness of long-term complications and mortality. This review highlights the concept behind the staged surgical palliations, the unique single ventricle physiology and the long-term complications in this complex cohort of patients.