Three decades of collaboration through the Pediatric Heart Transplant Society Registry: A journey through registry data with a highlight on children with single ventricle anatomy.

BACKGROUND: The Pediatric Heart Transplant Society (PHTS) Registry was founded 30 years ago as a collaborative effort among like-minded providers of this novel life-saving technique for children with end-stage heart failure. In the intervening decades, the data from the Registry have provided invaluable knowledge to the field of pediatric heart transplantation. This report of the PHTS Registry provides a comprehensive look at the data, highlighting both the longevity of the registry and one unique aspect of the PHTS registry, allowing for exploration into children with single ventricle anatomy. METHODS: The PHTS database was queried from January 1, 1993 to December 31, 2019 to include pediatric (age < 18 years) patients listed for HT. For our analysis, we primarily analyzed patients by era. The early era was defined as children listed for HT from January 1, 1993 to December 31, 2004; middle era January 1, 2005 to December 31, 2009; and recent era January 1, 2010 to December 31, 2019. Outcomes after listing and transplant, including mortality and morbidities, are presented as unadjusted for risk, but compared across eras. RESULTS: Since 1993, 11 995 children were listed for heart transplant and entered into the PHTS Registry with 9755 listed during the study period. The majority of listings occurred within the most recent era. Waitlist survival improved over the decades as did posttransplant survival. Other notable changes over time include fewer patients experiencing allograft rejection or infection after transplant. Waitlist and posttransplant survival have changed dramatically in patients with single ventricle physiology and significantly differ by stage of single ventricle palliation. SUMMARY: Key points from this PHTS Registry summary and focus on patients with single ventricle congenital heart disease in particular, include the changing landscape of candidates and recipients awaiting heart transplant. There is clear improvement in waitlist and transplant outcomes for children with both cardiomyopathy and congenital heart disease alike.

Effect of preoperative extracorporeal membrane oxygenation therapy on postventricular assist device outcomes: an analysis of the STS Pedimacs database.

OBJECTIVES: Extracorporeal membrane oxygenation (ECMO) support prior to ventricular assist device (VAD) therapy is frequently used for stabilizing INTERMACS 1 and 2 paediatric patients. Data regarding outcomes with this strategy is limited. METHODS: Patient characteristics and outcomes post-VAD therapy with and without preop ECMO support were compared. Survival and risk factor analysis was performed for all patients and INTERMACS profile 1 subgroup. RESULTS: Of 541 INTERMACS 1 and 2 patients enrolled in Paediatric Interagency Registry for Mechanical Circulatory Support registry, 391 received primary VAD implantation and ECMO prior to VAD therapy was utilized in 150 patients. Younger age (P < 0.0001) and shock (P < 0.0001) were more common in group 2, with lower survival at 1, 6 and 12 months compared to group 1 (P < 0.0001). Freedom from infection (P = 0.03) was higher in group 1. Freedom from stroke (P = 0.7) was similar. Paracorporeal continuous flow devices led to poor survival in both groups 1 and 2 (P = 0.4). Implantable continuous flow (P < 0.0001) and paracorporeal pulsatile devices (P = 0.007) had better survival in primary VAD group. INTERMACS profile 1, lower weight, hepatic dysfunction, renal failure, paracorporeal continuous and percutaneous devices were associated with higher mortality. Preop ECMO therapy was not associated with higher mortality (P = 0.12). Survival of INTERMACS profile 1 patient was similar at 1, 6 and 12 months in both groups (P = 0.1). CONCLUSIONS: INTERMACS profile 1, lower weight, hepatic dysfunction, renal failure and use of paracorporeal continuous flow or percutaneous assist devices are associated with a higher postoperative mortality. Preop ECMO therapy however is not independently associated with higher postop mortality.

The Effect of Infectious Complications During Ventricular Assist Device Use on Outcomes of Pediatric Heart Transplantation.

To describe the impact of infectious adverse events (IAEs) during ventricular assist device (VAD) support on graft loss, infection, and rejection after pediatric heart transplant (HT). Pedimacs data were linked to Pediatric Heart Transplant Society (PHTS) data for patients receiving a VAD followed by HT between September 2012 and December 2016. Linked patients were categorized into IAE on VAD (group A) and no IAE on VAD (group B). Infectious adverse event locations included nondevice, device (external or internal), and sepsis. Post-HT outcomes for analysis were graft loss, infection, and rejection. Time-dependent analysis included Kaplan-Meier and multiphase parametric hazard function analysis. We linked 207 patients (age 9.4 ± 6.3 years). Post-HT follow-up was 19.4 patient-months (<8 days-4.1 years). Group A included 42 patients (20%) with 62 IAEs. Group B included 165 patients without an IAE. Group A patients were younger (7.4 ± 6.1 vs. 9.5 ± 6.3 years; p = 0.03), waited longer for HT (5.3 ± 4.1 vs. 2.9 ± 2.5 months; p = 0.0005), and were hospitalized longer post-HT (42 ± 59 vs. 23 ± 22 days; p = 0.05). VAD-related IAEs were rare (N = 11). Groups A and B had similar freedom from first post-HT infection, rejection, and graft loss (all p > 0.1). However, patients with VAD-related IAE were somewhat more likely to experience rejection (p = 0.03) and graft loss (p = 0.01). Children with an IAE on VAD who survive to HT are younger, wait longer for HT, and remain hospitalized longer than those without an IAE on VAD. Overall, IAE on VAD did not impact post-HT outcomes, but VAD-related IAE may be associated with graft loss and rejection.

Improved heart transplant survival for children with congenital heart disease and heterotaxy syndrome in the current era: An analysis from the pediatric heart transplant society.

BACKGROUND: Challenges exist with heterotaxy due to the complexity of heart disease, abnormal venous connections, and infection risks. This study aims to understand heart transplant outcomes for children with heterotaxy. METHODS: All children with congenital heart disease listed for transplant from 1993 to 2018 were included. Those with and without heterotaxy were compared. Waitlist outcomes and survival post-listing and transplant were analyzed. Post-transplant risk factors were identified using multiphase parametric hazard modeling. RESULTS: There were 4814 children listed, of whom 196 (4%) had heterotaxy. Heterotaxy candidates were older (5.8 ± 5.7 vs 4.2 ± 5.5 years, p < 0.01), listed at a lower urgency status (29.8% vs 18.4%, p < 0.01), more commonly single ventricle physiology (71.3% vs 59.2%, p < 0.01), and less often supported by mechanical ventilation (22% vs 29.1%, p < 0.05) or extracorporeal membrane oxygenation (3.6% vs 7.5%, p < 0.05). There were no differences in waitlist outcomes of transplant, death, or removal. Overall, post-transplant survival was worse for children with heterotaxy: one-year survival 77.2% vs 85.1%, with and without heterotaxy, respectively. Heterotaxy was an independent predictor for early mortality in the earliest era (1993-2004), HR 2.09, CI 1.16-3.75, p = 0.014. When stratified by era, survival improved with time. Heterotaxy patients had a lower freedom from infection and from severe rejection, but no difference in vasculopathy or malignancy. CONCLUSIONS: Mortality risk associated with heterotaxy is mitigated in the recent transplant era. Early referral may improve waitlist outcomes for heterotaxy patients who otherwise have a lower status at listing. Lower freedom from both infection and severe rejection after transplant in heterotaxy highlights the challenges of balancing immune suppression.

Clinical outcomes of children receiving ABO-incompatible versus ABO-compatible heart transplantation: a multicentre cohort study.

BACKGROUND: ABO-incompatible heart transplantation increases donor availability in young children and is evolving into standard of care in children younger than 2 years. Previous smaller studies suggest similar outcomes to ABO-compatible heart transplantation, but persisting alterations of the immune system in ABO-incompatible recipients might increase the risk of some infections or benefit the graft owing to reduced HLA reactivity. We aimed to assess long-term outcomes in young children after they received ABO-incompatible or ABO-compatible heart transplantation. METHODS: In this multicentre, prospective cohort study, we analysed data from the Pediatric Heart Transplant Society registry to compare children who received ABO-incompatible or ABO-compatible heart transplantation before age 2 years between Jan 1, 1999, and June 30, 2018. Given significantly different clinical demographics between the two groups, we also matched each ABO-incompatible recipient to two ABO-compatible recipients using propensity score matching. We assessed patient and graft survival, coronary allograft vasculopathy, malignancy, acute rejection (any episode resulting in augmentation of immunosuppression), and infections (requiring intravenous antibiotic or antiviral therapy or life-threatening infections treated with oral therapy). FINDINGS: We included 2206 children who received a heart transplant before age 2 years, with 11 332·6 patient-years of cumulative observation time. Children who received an ABO-incompatible transplant (n=364) were younger and a larger proportion had congenital heart disease and ventilator and mechanical circulatory support than the ABO-compatible recipients (n=1842). After matching, only differences in blood group (more O in ABO-incompatible and more AB in ABO-compatible groups) and use of polyclonal induction therapy with anti-thymocyte globulins persisted. The two matched groups had similar post-transplantation graft survival (p=0·74), freedom from coronary allograft vasculopathy (p=0·75), and malignancy (p=0·51). ABO-incompatible recipients showed longer freedom from rejection (p=0·0021) in the overall cohort, but not after matching (p=0·48). Severe infections (p=0·0007), bacterial infections (p=0·0005), and infections with polysaccharide encapsulated bacteria (p=0·0005) that share immunological properties with blood group antigens occurred less frequently after ABO-incompatible heart transplantation. INTERPRETATION: ABO-incompatible heart transplantation for children younger than 2 years is a clinically safe approach, with similar survival and incidences of rejection, coronary allograft vasculopathy, and malignancy to ABO-compatible recipients, despite higher-risk pre-transplant profiles. ABO-incompatible transplantation was associated with less bacterial infection, particularly encapsulated bacteria, suggesting that the acquired immunological changes accompanying ABO tolerance might benefit rather than jeopardise transplanted children. FUNDING: Pediatric Heart Transplant Society.

Surveillance for cardiac allograft vasculopathy: Practice variations among 50 pediatric heart transplant centers.

BACKGROUND: Coronary allograft vasculopathy (CAV) is a leading cause of mortality after heart transplantation (HT) in children. Variation in CAV screening practices may impact detection rates and patient outcomes. METHODS: Among 50 Pediatric Heart Transplant Society (PHTS) sites from 2001 to 2016, coronary evaluations were classified as angiography or non-invasive testing, and angiograms were designated as routine or symptom based. CAV detection rates stratified by routine vs symptom-based angiograms were calculated. Freedom from CAV and mortality after CAV diagnosis, stratified by study indication, were calculated. RESULTS: A total of 3,442 children had 13,768 coronary evaluations; of these, 97% (n = 13,012) were for routine surveillance, and only 3% (n = 333) were for cause. Over the study period, CAV was detected in 472 patients (14%). Whereas 58% (n = 29) of PHTS sites evaluate by angiography alone, 42% reported supplementing with a non-invasive test, although only 423 non-invasive studies were reported. Angiographic detection of CAV was higher for symptom-based testing than for routine testing (29% vs 4%, p < 0.0001), although routine testing identified a majority of cases (88%; n = 414). The 10-year freedom from CAV was 77% overall. Once CAV is detected, 5-year graft survival was 58%, with lower survival for patients diagnosed after symptoms angiogram than after routine angiogram (30% vs 62%; p < 0.0001). CONCLUSIONS: Development of a robust model for CAV risk should allow low-risk patients to undergo less frequent invasive angiography without adverse impact on CAV detection rates or outcomes.

A current era analysis of ABO incompatible listing practice and impact on outcomes in young children requiring heart transplantation.

BACKGROUND: Heart transplantation from ABO incompatible (ABOi) donors has evolved into a progressively accepted therapy in young children. We assessed the recent practice of ABOi listing impact on waitlist and post-transplant outcomes. METHODS: Using the Pediatric Heart Transplant Society registry, we compared clinical presentation, waitlist parameters, and post-transplant survival of children < 2 years of age listed for ABOi vs ABO compatible (ABOc) heart transplant between January 2010 and June 2018 with sub-analysis of blood group O recipients. RESULTS: Among 2,039 patients, ABOi listing increased significantly with time from 49% (2010) to 72% (2017). ABOi-listed patients had lower age and body surface area, and higher proportion of congenital heart disease, mechanical ventilation, and high urgency status (all p < 0.01). Use of mechanical circulatory support was similar between groups. Of 1,288 patients reaching transplant, 239 (18.6%) received an ABOi organ (15%-40%/year). Death while waiting, removal from the waitlist, and waitlist survival were similar between groups. Time to transplant was significantly shorter for ABOi listing in blood group O patients (p < 0.02), approaching significance (p = 0.057) for all blood groups. Post-transplant survival was similar except for lower survival of patients listed ABOc but transplanted ABOi. These patients showed increasing need for mechanical circulatory support and high urgency listing while waiting. CONCLUSIONS: In the current era, primary listing for ABOi heart transplant has become routine for the majority of children < 2 years old, resulting in shorter waitlist time, especially in blood group O. Post-transplant survival is similar despite ABOi-listed children still showing a higher risk profile.

Extracorporeal Membrane Oxygenation as a Bridge to Durable Mechanical Circulatory Support: An Analysis of the STS-INTERMACS Database.

BACKGROUND: Limited data are available regarding the outcomes of patients supported by extracorporeal membrane oxygenation (ECMO) who undergo durable mechanical circulatory support implantation (dMCS). We analyzed the clinical characteristics, outcomes, and risk factors for mortality in patients who were bridged with ECMO to dMCS. METHODS: Adult patients who received dMCS between January 2008 and December 2017 (n=19 824), registered in the Society of Thoracic Surgeons-Interagency Registry for Mechanical Assisted Circulatory Support (STS-INTERMACS) database were included. Baseline characteristics, outcomes, risk factors, and adverse events were compared between ECMO-supported patients (n=933) and INTERMACS profile 1 (IP-1) patients not supported by ECMO (n=2362). A propensity match analysis was performed. RESULTS: ECMO patients had inferior survival at 12 months (66.1%) than non-ECMO patients (75.4%; P<0.0001). The proportion of patients transplanted at 2 years after dMCS was similar between the ECMO (30.8%) and non-ECMO (31.8%) groups (P=0.49). A multiphase parametric hazard model identified 2 different periods based on risk of death. ECMO patients had a high hazard for death in the first 6 months after implantation (hazard ratio, 2.18 [1.79-2.66]; P<0.001). Multivariable analysis showed that ECMO was an independent risk factor associated with poor outcome during the early phase after dMCS (hazard ratio, 1.69 [1.37-2.09]; P<0.0001) but not during the constant phase. ECMO patients had similar outcomes to non-ECMO patients when a propensity matched cohort was analyzed. CONCLUSIONS: ECMO-supported patients before dMCS have lower survival compared with other IP-1 patients. A multivariable analysis showed that ECMO is an independent risk factor of poor outcome after dMCS. However, a propensity matched analysis suggested that when important clinical variables are controlled the outcome of both groups is similar. These data support the implantation of dMCS in carefully selected ECMO patients.

Renal injury and recovery in pediatric patients after ventricular assist device implantation and cardiac transplant.

BACKGROUND: The use of ventricular assist devices (VADs) in children with heart failure may be of particular benefit to those with accompanying renal failure, as improved renal function is seen in some, but not all recipients. We hypothesized that persistent renal dysfunction at 7 days and/or 1 month after VAD implantation would predict chronic kidney disease (CKD) 1 year after heart transplantation (HT). METHODS: Linkage analysis of all VAD patients enrolled in both the PEDIMACS and PHTS registries between 2012 and 2016. Persistent acute kidney injury (P-AKI), defined as a serum creatinine ≥1.5× baseline, was assessed at post-implant day 7. Estimated glomerular filtration rate (eGFR) was determined at implant, 30 days thereafter, and 12 months post-HT. Pre-implant eGFR, eGFR normalization (to ≥90 mL/min/1.73 m2 ), and P-AKI were used to predict post-HT CKD (eGFR <90 mL/min/1.73 m2 ). RESULTS: The mean implant eGFR was 85.4 ± 46.5 mL/min/1.73 m2 . P-AKI was present in 19/188 (10%). Mean eGFR at 1 month post-VAD implant was 131.1 ± 62.1 mL/min/1.73 m2 , significantly increased above baseline (P < 0.001). At 1 year post-HT (n = 133), 60 (45%) had CKD. Lower pre-implant eGFR was associated with post-HT CKD (OR 0.99, CI: 0.97-0.99, P = 0.005); P-AKI was not (OR 0.96, CI: 0.3-3.0, P = 0.9). Failure to normalize renal function 30 days after implant was highly associated with CKD at 1 year post-transplant (OR 12.5, CI 2.8-55, P = 0.003). CONCLUSIONS: Renal function improves after VAD implantation. Lower pre-implant eGFR and failure to normalize renal function during the support period are risk factors for CKD development after HT.

Outcomes of children supported with an intracorporeal continuous-flow left ventricular assist system.

BACKGROUND: Since 2012, there has been growing use of the HeartWare (Medtronic, Mounds View, MN) intracorporeal continuous flow (CF) ventricular assist device (VAD) in children, despite it not being labeled for use in pediatric patients. We sought to describe the use and outcomes of children with HeartWare VADs. METHODS: We identified all patients aged < 19 years and young adults aged 19 to 30 years supported with HeartWare who were entered into the pediatric portion (Pedimacs) of the Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) and the Intermacs registries, respectively, between September 2012 and June 2017. Adverse events and outcomes were analyzed and compared. RESULTS: We identified 192 children and 247 young adult HeartWare patients. Baseline characteristics of children differed from young adults, with lower median weight of 51.5 kg (range, 13.1-162) vs 75.8 kg (range, 29.8-191; p ≤ 0.0001) and body surface area of 1.5 m2 (range, 0.6-2.9 m2) vs 1.9 m2 (range, 1.1-3.2 m2; p ≤ 0.0001) . At the time of implant, 12 children weighed < 20 kg, and 58.3% of these children had congenital heart disease compared with 11.7% in children who weighed ≥ 20 kg and 6.1% in young adults (p ≤ 0.0001). Median duration of support was 2.8 months (IQR, 1.3-6.0 months) in children and 9.7 months (IQR 4.0-19.2 months) in young adults (p ≤ 0.0001). Serious adverse events in children and young adults included infection in 27% and 44% of patients, respectively (p=0.0002), major bleeding in 23% and 23%, respectively (p = 0.9), device malfunction/pump thrombosis in 11% and 19.0%, respectively (p = 0.04), and stroke in 10% and 12%, respectively (p = 0.5). Of the children who weighed < 20 kg at time of implant, 0% had major bleeding, 16.7% had infections, and 8.3% had stroke. Overall survival was not statistically different between children and young adults, and there was no increased mortality in children who weighed < 20 kg. Rate of discharge on HeartWare was 80% in young adults vs 48% in children who weighed ≥ 20 kg and only 33% in children who weighed < 20 kg. CONCLUSIONS: Survival in children supported with HeartWare is encouraging and comparable to young adults; however, adverse events are not uncommon in children. Ongoing evaluation of the HeartWare use in children is necessary to further decrease the rate of adverse events and understand obstacles to discharge.

Outcomes of children with congenital heart disease implanted with ventricular assist devices: An analysis of the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs).

BACKGROUND: The reported ventricular assist device (VAD) experience in the pediatric congenital heart disease (CHD) population is limited. We sought to describe contemporary use and outcomes of VADs in children with CHD and compare these outcomes to those of non-CHD children. METHODS: Patients enrolled in the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) between September 19, 2012 through June 30, 2017 were included. CHD was classified as biventricular vs single ventricle (Stages 1, 2, or 3). Outcomes were compared between groups and multivariable analysis was used to identify factors associated with mortality on the device. RESULTS: Among the 471 patients enrolled, 108 (24%) had CHD (45 biventricular and 63 single ventricle). CHD patients were younger (5.7 ± 5.7 years vs 9.8 ± 6.5 years; p < 0.0001) and smaller (0.8 ± 0.5 m2 vs 1.2 ± 0.7 m2; p < 0.0001) compared with non-CHD patients. CHD patients were more likely to receive a paracorporeal continuous-flow VAD (36.1% vs 12.9%; p < 0.0001) and less likely to receive an implantable continuous-flow VAD (27.8% vs 55.0%; p < 0.0001) compared with non-CHD patients. After 6 months on a VAD, CHD patients had higher mortality (36.4% vs 12.1%) and a lower transplantation rate (29.1% vs 59.9%) than non-CHD patients (p < 0.0001). In the multivariable analysis, CHD was the factor most strongly associated with mortality on VAD (hazard ratio [HR] = 2.9; p < 0.0001), whereas the factors implantable continuous-flow device and high-volume center were protective (HR = 0.3, p < 0.0001, and HR = 0.6, respectively; p = 0.02). CONCLUSIONS: VAD use in children with CHD is associated with increased mortality and decreased transplant rates compared to children without CHD. For the subgroup of children with CHD who received implantable continuous-flow VADs, survival rates were higher and comparable to those of children without CHD. Increased experience correlated with better survival in pediatric VADs.

Interagency registry for mechanically assisted circulatory support report on the total artificial heart.

BACKGROUND: We sought to better understand the patient population who receive a temporary total artificial heart (TAH) as bridge to transplant or as bridge to decision by evaluating data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database. METHODS: We examined data related to survival, adverse events, and competing outcomes from patients who received TAHs between June 2006 and April 2017 and used hazard function analysis to explore risk factors for mortality. RESULTS: Data from 450 patients (87% men; mean age, 50 years) were available in the INTERMACS database. The 2 most common diagnoses were dilated cardiomyopathy (50%) and ischemic cardiomyopathy (20%). Risk factors for right heart failure were present in 82% of patients. Most patients were INTERMACS Profile 1 (43%) or 2 (37%) at implantation. There were 266 patients who eventually underwent transplantation, and 162 died. Overall 3-, 6-, and 12-month actuarial survival rates were 73%, 62%, and 53%, respectively. Risk factors for death included older age (p = 0.001), need for pre-implantation dialysis (p = 0.006), higher creatinine (p = 0.008) and lower albumin (p < 0.001) levels, and implantation at a low-volume center (≤10 TAHs; p < 0.001). Competing-outcomes analysis showed 71% of patients in high-volume centers were alive on the device or had undergone transplantation at 12 months after TAH implantation vs 57% in low-volume centers (p = 0.003). CONCLUSIONS: Patients receiving TAHs have rapidly declining cardiac function and require prompt intervention. Experienced centers have better outcomes, likely related to patient selection, timing of implantation, patient care, and device management. Organized transfer of knowledge to low-volume centers could improve outcomes.

Outcomes following implantation of mechanical circulatory support in adults with congenital heart disease: An analysis of the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS).

BACKGROUND: Adults with congenital heart disease represent an expanding and unique population of patients with heart failure (HF) in whom the use of mechanical circulatory support (MCS) has not been characterized. We sought to describe overall use, patient characteristics, and outcomes of MCS in adult congenital heart disease (ACHD). METHODS: All patients entered into the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) between June 23, 2006, and December 31, 2015, were included. Patients with ACHD were identified using pre-operative data and stratified by ventricular morphology. Mortality was compared between ACHD and non-ACHD patients, and multivariate analysis was performed to identify predictors of death after device implantation. RESULTS: Of 16,182 patients, 126 with ACHD stratified as follows: systemic morphologic left ventricle (n = 63), systemic morphologic right ventricle (n = 45), and single ventricle (n = 17). ACHD patients were younger (42 years ± 14 vs 56 years ± 13; p < 0.0001) and were more likely to undergo device implantation as bridge to transplant (45% vs 29%; p < 0.0001). A higher proportion of ACHD patients had biventricular assist device (BiVAD)/total artificial heart (TAH) support compared with non-ACHD patients (21% vs 7%; p < 0.0001). More ACHD patients on BiVAD/TAH support were INTERMACS profile 1 compared with patients on systemic left ventricular assist device (LVAD) support (35% vs 15%; p = 0.002). ACHD and non-ACHD patients with LVADs had similar survival; survival was worse for patients on BIVAD/TAH support. BiVAD/TAH support was the only variable independently associated with mortality (early phase hazard ratio 4.4; 95% confidence interval, 1.8-11.1; p = 0.001). For ACHD patients receiving MCS, ventricular morphology was not associated with mortality. CONCLUSIONS: ACHD patients with LVADs have survival similar to non-ACHD patients. Mortality is higher for patients requiring BiVAD/TAH support, potentially owing to higher INTERMACS profile. These outcomes suggest a promising role for LVAD support in ACHD patients as part of the armamentarium of therapies for advanced HF.