Increased frequency of heart transplantation, shortened waitlist time and preserved post-transplant survival in adults with congenital heart disease, on the new heart transplant allocation system

Heart transplantation in adults with congenital heart diseases: A comprehensive meta-analysis on waiting times, operative, and survival outcomes

The rising prevalence of congenital heart disease (CHD) among adults has led to increased heart transplantation (HT) procedures in this population. However, CHD patients face significant challenges including longer waiting times, higher early mortality rates, and increased risks of complications such as renal dysfunction. This systematic review and meta-analysis examined 50 studies to assess waiting times, postoperative outcomes, and survival rates in CHD patients undergoing HT compared to non-CHD patients. Results revealed that CHD patients experience longer HT waiting times (mean difference [MD]: 53.86 days, 95 % CI: [22.00, 85.72], P = 0.0009) and increased ischemic times (MD: 20.01 min, 95 % CI: [10.51, 29.51], P < 0.0001), which may increase waitlist and early postoperative mortality. Regarding complications, renal dysfunction is more prevalent in CHD patients than in non-CHD patients (RR: 2.05, 95 % CI: [1.61, 2.61], P < 0.00001). Despite these challenges, long-term survival rates for CHD patients are comparable to those of non-CHD recipients, with significant improvements noted in recent allocation systems. Our findings emphasize the need for ongoing refinements in HT allocation systems to improve outcomes for CHD patients, particularly in reducing waiting times and managing post-transplant complications.

Differences in outcomes of combined heart-liver transplantation by primary cardiac diagnosis

Background

Combined heart-liver transplantation (CHLT) is a complex procedure with rising demand and is subject to ongoing assessment. Here, we provide an update on indications, patient outcomes, and risk factors.

Methods

This retrospective study utilized CHLT data from the United Network for Organ Sharing registry between 1990 and 2023. Recipient and donor characteristics, and risk factors for mortality were analyzed using Cox regression hazard models. Recipient and graft survival at 30 days, 1 year, and 5 years were analyzed using the Kaplan-Meier method.

Results

This cohort included 532 patients with median survival of 16.9 years (SD: 1.09). The most common indications for CHLT were congenital heart disease (36%) and dilated cardiomyopathy (31%). Patient survival at 30 days, 1 year, and 5 years were 94%, 85%, and 77%, respectively. Combined heart-liver graft survival was 93%, 85%, and 77%, respectively. Diabetes (hazard ratio [HR]: 1.74; p = 0.04) was associated with multigraft failure and mortality in multivariate analysis. Compared to congenital heart disease, dilated (HR: 0.55; p = 0.03) and restrictive myopathies (HR: 0.5; p = 0.03) were associated with improved graft and overall survival. Higher donor left ventricular ejection fraction (EF) was also associated with improved graft and overall survival (HR: 0.96; p = 0.008).

Conclusions

CHLTs are being performed at increasingly higher rates with comparable survival to single-organ transplants. Diabetes was associated with increased mortality. Recipient dilated or restrictive myopathies and higher donor EF were correlated with improved survival compared to congenital heart disease. Further studies are needed to better understand these observations.

Trends in Survival for Adult Organ Transplantation

Objective

Intent-to-treat analysis follows patients from listing to death, regardless of their transplant status, and aims to provide a more holistic scope of the progress made in adult solid-organ transplantation.

Background

Many studies have shown progress in waitlist and post-transplant survival for adult kidney, liver, heart, and lung transplants, but there is a need to provide a more comprehensive perspective of transplant outcomes for patients and their families.

Methods

Univariable and multivariable Cox regression analyses were used to analyze factors contributing to intent-to-treat survival in 813,862 adults listed for kidney, liver, heart, and lung transplants. The Kaplan-Meier method was used to examine changes in waitlist, post-transplant, and intent-to-treat survival. Transplantation rates were compared using χ2 tests.

Results

Intent-to-treat survival has steadily increased for liver, heart, and lung transplants. The percentage of patients transplanted within 1 year significantly increased for heart (57.4% from 52.9%) and lung (73.5% from 33.2%). However, the percentage of patients transplanted within 1 year significantly decreased from 35.8% to 21.2% for kidney transplant. Notably, intent-to-treat survival has decreased for kidneys despite increases in waitlist and post-transplant survival, likely because of the decreased transplant rate.

Conclusion

Intent-to-treat survival steadily improved for liver, heart, and lung transplant over the 30-year study period. Continued advancements in allocation policy, immunosuppression, and improved care of patients on the waitlist may contribute to further progress in outcomes of all organs, but the increasing discrepancy in supply and demand of donor kidneys is alarming and has impeded the progress of kidney intent-to-treat survival.

Waitlist Outcomes in Candidates With Rare Causes of Heart Failure After Implementation of the 2018 French Heart Allocation Scheme

BACKGROUND

In 2018, an algorithm-based allocation system for heart transplantation (HT) was implemented in France. Its effect on access to HT of patients with rare causes of heart failure (HF) has not been assessed.

METHODS

In this national study, including adults listed for HT between 2018 and 2020, we analyzed waitlist and posttransplant outcomes of candidates with rare causes of HF (restrictive cardiomyopathy [RCM], hypertrophic cardiomyopathy, and congenital heart disease). The primary end point was death on the waitlist or delisting for clinical deterioration. Secondary end points included access to HT and posttransplant mortality. The cumulative incidence of waitlist mortality estimated with competing risk analysis and incidence of transplantation were compared between diagnosis groups. The association of HF cause with outcomes was determined by Fine-Gray or Cox models.

RESULTS

Overall, 1604 candidates were listed for HT. At 1 year postlisting, 175 patients met the primary end point and 1040 underwent HT. Candidates listed for rare causes of HF significantly differed in baseline characteristics and had more frequent score exceptions compared with other cardiomyopathies (31.3%, 32.0%, 36.4%, and 16.7% for patients with hypertrophic cardiomyopathy, RCM, congenital heart disease, and other cardiomyopathies). The cumulative incidence of death on the waitlist and probability of HT were similar between diagnosis groups (P=0.17 and 0.40, respectively). The adjusted risk of death or delisting for clinical deterioration did not significantly differ between candidates with rare and common causes of HF (subdistribution hazard ratio (HR): hypertrophic cardiomyopathy, 0.51 [95% CI, 0.19-1.38]; P=0.18; RCM, 1.04 [95% CI, 0.42-2.58]; P=0.94; congenital heart disease, 1.82 [95% CI, 0.78-4.26]; P=0.17). Similarly, the access to HT did not significantly differ between causes of HF (hypertrophic cardiomyopathy: HR, 1.18 [95% CI, 0.92-1.51]; P=0.19; RCM: HR, 1.19 [95% CI, 0.90-1.58]; P=0.23; congenital heart disease: HR, 0.76 [95% CI, 0.53-1.09]; P=0.14). RCM was an independent risk factor for 1-year posttransplant mortality (HR, 2.12 [95% CI, 1.06-4.24]; P=0.03).

CONCLUSIONS

Our study shows equitable waitlist outcomes among HT candidates whatever the indication for transplantation with the new French allocation scheme.

Heart Transplantation

Heart transplantation (HTx) remains the last therapeutic resort for patients with advanced heart failure. The present work is a clinically focused review discussing current issues in heart transplantation. Several factors have been associated with the outcome of HTx, such as ABO and HLA compatibility, graft size, ischemic time, age, infections, and the cause of death, as well as imaging and laboratory tests. In 2018, UNOS changed the organ allocation policy for HTx. The aim of this change was to prioritize patients with a more severe clinical condition resulting in a reduction in mortality of people on the waiting list. Advanced heart failure and resistant angina are among the main indications of HTx, whereas active infection, peripheral vascular disease, malignancies, and increased body mass index (BMI) are important contraindications. The main complications of HTx include graft rejection, graft angiopathy, primary graft failure, infection, neoplasms, and retransplantation. Recent advances in the field of HTx include the first two porcine-to-human xenotransplantations, the inclusion of hepatitis C donors, donation after circulatory death, novel monitoring for acute cellular rejection and antibody-mediated rejection, and advances in donor heart preservation and transportation. Lastly, novel immunosuppression therapies such as daratumumab, belatacept, IL 6 directed therapy, and IgG endopeptidase have shown promising results.

Are exceptions justified in the current heart allocation system?

Background

In the current 6-tiered heart allocation system, waitlisted candidates frequently receive an exception to any of the top 4 allocation statuses. Studies have shown varying results regarding the mortality risk of exceptions compared to standard criteria listings in the top 2 statuses. It remains unclear whether exception statuses in the current allocation system are justified.

Methods

We performed a retrospective cohort study on all adults waitlisted for heart transplant between November 1, 2018, and December 31, 2022, contained in the United Network for Organ Sharing database. The waitlist mortality and transplantation rate of all exception status and standard criteria listings were compared and ranked, using status 6 as the reference status, in univariable and multivariable Cox models including status as a time-dependent variable.

Results

A total of 17,116 heart waitlist candidates were included in the study. The waitlist mortality rates of exceptions in status 1 and 2 were lower than, but close to, the mortality rates of their standard criteria counterparts: status 1 standard (hazard ratio) HR 43.47 (p < 0.001), status 1 exception HR 31.48 (p < 0.001), status 2 standard HR 10.21 (p < 0.001), status 2 exception HR 7.76 (p < 0.001). The mortality rate of exceptions in status 3 and 4 was higher than, but also close to, the mortality rate of their standard criteria counterparts: status 3 standard HR 2.61 (p < 0.001), status 3 exception HR 4.18 (p < 0.001), status 4 standard HR 1.31 (p = 0.104), and status 4 exception HR 2.13 (p < 0.001).

Conclusions

Based on waitlist mortality over a longer study period than previous analyses, high-priority exceptions are appropriately placed in the current heart allocation system. The current allocation system requires a large fraction of candidates to seek exceptions, suggesting that we should focus on objective data to risk stratify all heart waitlist candidates, and thereby reduce the need for exceptions.

Novel Therapeutic Strategies in Heart Failure in Adult Congenital Heart Disease: of Medicines and Devices

PURPOSE OF REVIEW

This paper reviews the latest literature on the growing field of heart failure in the adult congenital heart disease population.

RECENT FINDINGS

After highlighting the increasing prevalence and a few of the unique potential causes, including the concept of early senescence, this review begins with novel medical management strategies such as the angiotensin II receptor blocker and neprilysin inhibitors and sodium glucose cotransporter-2 inhibitors. Then, it addresses the latest applications of percutaneous techniques like implantable hemodynamic monitoring, transcatheter pulmonary and aortic valve replacement, and mitral clips. Cardiac resynchronization therapy and novel lymphatic system imaging and intervention are then described. Finally, the use of mechanical support devices, temporary and durable, is discussed as well as heart and combined heart and liver transplantation. There have been recent exciting advances in the strategies used to manage adult congenital heart disease patients with heart failure. As this population continues to grow, it is likely we will see further rapid evolution in this field.

Clinical Outcomes of Adult Fontan-Associated Liver Disease and Combined Heart-Liver Transplantation

BACKGROUND

The impact of Fontan-associated liver disease (FALD) on post-transplant mortality and indications for combined heart-liver transplant (CHLT) in adult Fontan patients remains unknown.

OBJECTIVES

The purpose of this study was to assess the impact of FALD on post-transplant outcomes and compare HT vs CHLT in adult Fontan patients.

METHODS

We performed a retrospective-cohort study of adult Fontan patients who underwent HT or CHLT across 15 centers. Inclusion criteria were as follows: 1) Fontan; 2) HT/CHLT referral; and 3) age ≥16 years at referral. Pretransplant FALD score was calculated using the following: 1) cirrhosis; 2) varices; 3) splenomegaly; or 4) ≥2 paracenteses.

RESULTS

A total of 131 patients (91 HT and 40 CHLT) were included. CHLT recipients were more likely to be older (P = 0.016), have a lower hemoglobin (P = 0.025), require ≥2 diuretic agents pretransplant (P = 0.051), or be transplanted in more recent decades (P = 0.001). Postmatching, CHLT demonstrated a trend toward improved survival at 1 year (93% vs 74%; P = 0.097) and improved survival at 5 years (86% vs 52%; P = 0.041) compared with HT alone. In patients with a FALD score ≥2, CHLT was associated with improved survival (1 year: 85% vs 62%; P = 0.044; 5 years: 77% vs 42%; P = 0.019). In a model with transplant decade and FALD score, CHLT was associated with improved survival (HR: 0.33; P = 0.044) and increasing FALD score was associated with worse survival (FALD score: 2 [HR: 14.6; P = 0.015], 3 [HR: 22.2; P = 0.007], and 4 [HR: 27.8; P = 0.011]).

CONCLUSIONS

Higher FALD scores were associated with post-transplant mortality. Although prospective confirmation of our findings is necessary, compared with HT alone, CHLT recipients were older with higher FALD scores, but had similar survival overall and superior survival in patients with a FALD score ≥2.

Morbidity and Mortality in Adult Fontan Patients After Heart or Combined Heart-Liver Transplantation

BACKGROUND

An increasing number of adult Fontan patients require heart transplantation (HT) or combined heart-liver transplant (CHLT); however, data regarding outcomes and optimal referral time remain limited.

OBJECTIVES

The purpose of this study was to define survivorship post-HT/CHLT and predictors of post-transplant mortality, including timing of referral, in the adult Fontan population.

METHODS

A retrospective cohort study of adult Fontan patients who underwent HT or CHLT across 15 centers in the United States and Canada was performed. Inclusion criteria included the following: 1) Fontan; 2) HT/CHLT referral; and 3) age ≥16 years at the time of referral. Date of "failing" Fontan was defined as the earliest of the following: worsening fluid retention, new ascites, refractory arrhythmia, "failing Fontan" diagnosis by treating cardiologist, or admission for heart failure.

RESULTS

A total of 131 patients underwent transplant, including 40 CHLT, from 1995 to 2021 with a median post-transplant follow-up time of 1.6 years (Q1 0.35 years, Q3 4.3 years). Survival was 79% at 1 year and 66% at 5 years. Survival differed by decade of transplantation and was 87% at 1 year and 76% at 5 years after 2010. Time from Fontan failure to evaluation (HR/year: 1.23 [95% CI: 1.11-1.36]; P < 0.001) and markers of failure, including NYHA functional class IV (HR: 2.29 [95% CI: 1.10-5.28]; P = 0.050), lower extremity varicosities (HR: 3.92 [95% CI: 1.68-9.14]; P = 0.002), and venovenous collaterals (HR: 2.70 [95% CI: 1.17-6.20]; P = 0.019), were associated with decreased post-transplant survival at 1 year in a bivariate model that included transplant decade.

CONCLUSIONS

In our multicenter cohort, post-transplant survival improved over time. Late referral after Fontan failure and markers of failing Fontan physiology, including worse functional status, lower extremity varicosities, and venovenous collaterals, were associated with post-transplant mortality.

Impact of the 2018 UNOS Heart Transplant Policy Changes on Patient Outcomes

In 2018, the United Network for Organ Sharing implemented a 6-tier allocation policy to replace the prior 3-tier system. Given increasing listings of critically ill candidates for heart transplantation and lengthening waitlist times, the new policy aimed to better stratify candidates by waitlist mortality, shorten waiting times for high priority candidates, add objective criteria for common cardiac conditions, and further broaden sharing of donor hearts. There have been significant shifts in cardiac transplantation practices and patient outcomes following the implementation of the new policy, including changes in listing practices, waitlist time and mortality, transplant donor characteristics, post-transplantation outcomes, and mechanical circulatory support use. This review aims to highlight emerging trends in United States heart transplantation practice and outcomes following the implementation of the 2018 United Network for Organ Sharing heart allocation policy and to address areas for future modification.

Changes in waitlist and posttransplant outcomes in patients with adult congenital heart disease after the new heart transplant allocation system

OBJECTIVE

In 2018, the United Network for Organ Sharing (UNOS) introduced new criteria for heart allocation. This study sought to assess the impact of this change on waitlist and posttransplant outcomes in adult congenital heart disease (ACHD) recipients.

METHODS

Between January 2010 and March 2020, we extracted first heart transplant ACHD patients listed from the UNOS database. We compared waitlist and post-transplant outcomes before and after the policy change.

RESULTS

A total of 1206 patients were listed, 951 under the old policy and 255 under the new policy. Prior to transplant, recipients under the new policy era were more likely to be treated with extracorporeal membrane oxygenation (P = .018), and have intra-aortic balloon pumps (P < .001), and less likely to have left ventricular assist devices (P = .027).Compared to patients waitlisted in the pre-policy change era, those waitlisted in the post policy change era were more likely to receive transplants (P = .001) with no significant difference in waiting list mortality (P = .267) or delisting (P = .915). There was no difference in 1-year survival post-transplant between the groups (P = .791).

CONCLUSION

The new policy altered the heart transplant cohort in the ACHD group, allowing them to receive transplants earlier with no changes in early outcomes after heart transplantation.