Changes in heart transplant waitlist and posttransplant outcomes in patients with restrictive and hypertrophic cardiomyopathy with the new heart transplant allocation system

Impact of the New Heart Allocation System on the Medium-Term Outcomes in Patients With Hypertrophic Cardiomyopathy

The introduction of the new heart allocation system in the United States in 2018 resulted in an increase in the number of heart transplants (HT) performed among patients with hypertrophic cardiomyopathy (HCM). However, whether that affected medium-term post-HT outcomes in this group of patients remains unknown. We conducted an analysis of the United Network for Organ Sharing Transplant Database, including adults with HCM who underwent heart transplantation between 2015 and 2021. Patients were divided into two equal-duration eras: Era 1 (October 17, 2015, to October 17, 2018) and Era 2 (October 18, 2018, to October 18, 2021). In the studied period, 444 patients with HCM underwent HT: 204 in Era 1 and 240 in Era 2. In Era 2, the waitlist time was shorter, transplant rates were higher, patients were less frequently supported with inotropes but more often with an IABP, ischemic time was longer, and donor-to-recipient distance larger. Pre- and post-transplant functional status was comparable across the two eras, while the pre-HT employment rate was higher in the new system. The 3 year survival was unchanged across eras. In the new allocation system, despite more frequent mechanical circulatory support (MCS) use and increased ischemic time, the medium-term outcomes of patients with HCM remained favorable.

Prognosis after heart transplant in patients with hypertrophic and restrictive cardiomyopathy. A nationwide registry analysis

INTRODUCTION AND OBJECTIVES

Posttransplant outcomes among recipients with a diagnosis of hypertrophic cardiomyopathy (HCM) or restrictive cardiomyopathy (RCM) remain controversial.

METHODS

Retrospective analysis of a nationwide registry of first-time recipients undergoing isolated heart transplant between 1984 and 2021. One-year and 5-year mortality in recipients with HCM and RCM were compared with those with dilated cardiomyopathy (DCM).

RESULTS

We included 3703 patients (3112 DCM; 331 HCM; 260 RCM) with a median follow-up of 5.0 [3.1-5.0] years. Compared with DCM, the adjusted 1-year mortality risk was: HCM: HR, 1.38; 95%CI, 1.07-1.78; P=.01, RCM: HR, 1.48; 95%CI, 1.14-1.93; P=.003. The adjusted 5-year mortality risk was: HCM: HR, 1.17; 95%CI, 0.93-1.47; P=.18; RCM: HR, 1.52; 95%CI, 1.22-1.89; P<.001. Over the last 20 years, the RCM group showed significant improvement in 1-year survival (adjusted R2=0.95) and 5-year survival (R2=0.88); the HCM group showed enhanced the 5-year survival (R2=0.59), but the 1-year survival remained stable (R2=0.16).

CONCLUSIONS

Both RCM and HCM were linked to a less favorable early posttransplant prognosis compared with DCM. However, at the 5-year mark, this unfavorable difference was evident only for RCM. Notably, a substantial temporal enhancement in both early and late mortality was observed for RCM, while for HCM, this improvement was mainly evident in late mortality.

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.

Decreased frequency of transplantation and lower post-transplant survival free of re-transplantation in LVAD patients with the new heart transplant allocation system

PURPOSE

To evaluate the effect of the new heart transplant (HT) allocation system in left ventricular assist device (LVAD) supported patients listed as bridge to transplantation (BTT).

METHODS

Adult patients who were listed for HT between October 18, 2016 and October 17, 2019, and were supported with an LVAD, enrolled in the UNOS database were included in this study. Patients were classified in the old or new system if they were listed or transplanted before or after October 18, 2018, respectively.

RESULTS

A total of 3261 LVAD patients were listed for transplant. Of these, 2257 were classified in the old and 1004 in the new system. The cumulative incidence of death or removal from the transplant list due to worsening clinical status at 360-days after listing was lower in the new system (4% vs. 7%, P = .011). LVAD Patients listed in the new system had a lower frequency of transplantation within 360-days of listing (52% vs. 61%, P < .001). A total of 1843 LVAD patients were transplanted, 1004 patients in the old system and 839 patients in the new system. The post-transplant survival at 360 days was similar between old and new systems (92.3% vs. 90%, P = .08). However, LVAD patients transplanted in the new system had lower frequency of the combined endpoint, freedom of death or re-transplantation at 360 days (92.2% vs. 89.6%, P = .046).

CONCLUSION

The new HT allocation system has affected the LVAD-BTT population significantly. On the waitlist, LVAD patients have a decreased cumulative frequency of transplantation and a concomitant decrease in death or delisting due to worsening status. In the new system, LVAD patients have a decreased survival free of re-transplantation at 360 days post-transplant.

Disparities in heart and lung transplantation

PURPOSE OF REVIEW

Cardiothoracic transplantation is the definitive therapy for end-stage heart and lung disease. In service to this population, disparities in access and care must be simultaneously understood and addressed.

RECENT FINDINGS

There are sex, race, geographic, age, and underlying disease disparities in both heart and lung transplantation. Women have reduced waitlist survival but improved posttransplant survival when compared with men for both heart and lung transplantation. Black patients have worse outcome compared with other races postheart transplant. Geographic disparities impact the likelihood of receiving heart or lung transplant and the growing number of patients with advanced age seeking transplant complicates discussions on survival benefit. Finally, underlying disease has affected outcomes for both heart and lung transplant and now are incorporated into the allocation system.

SUMMARY

Though heart and lung transplantation have several existing disparities, it remains to be seen how advancements in medical technology, changes in donor organ allocation policies, and growing experience in patient selection will impact these concerns.

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.

The modified US heart allocation system improves transplant rates and decreases status upgrade utilization for patients with hypertrophic cardiomyopathy

BACKGROUND

On October 18, 2018, the US heart allocation policy was restructured to improve transplant waitlist outcomes. Previously, hypertrophic cardiomyopathy (HCM) patients experienced significant waitlist mortality and functional decline, often requiring status exemptions to be transplanted. This study aims to examine changes in waitlist mortality and transplant rates of HCM patients in the new system.

METHODS

Retrospective analysis was performed of the United Network for Organ Sharing Transplant Database for all isolated adult single-organ first-time heart transplant patients with HCM listed between October 17, 2013 and September 4, 2020. Patients were divided by listing date into eras based on allocation system. Era 1 spanned October 17, 2013 to October 17th, 2018 and Era 2 spanned October 18th, 2018 to September 4, 2020.

RESULTS

During the study period, 436 and 212 HCM patients were listed in Eras 1 and 2, respectively. Across eras, no differences in gender, ethnicity, BMI or functional status were noted (p>0.05). LVAD utilization remained low (Era 1: 3.7% vs Era 2: 3.3%, p = 0.297). Status upgrades decreased from 49.1% to 31.6% across eras (p = 0.001). There was no statistically significant difference in waitlist mortality across eras (p = 0.332). Transplant rates were improved in Era 2 (p = 0.005). Waitlist time among transplanted patients decreased in Era 2 from 97.1 to 63.9 days (p<0.001). There was no difference in one-year survival post-transplant (p = 0.602).

CONCLUSIONS

The new allocation system has significantly increased transplant rates, shortened waitlist times, and decreased status upgrade utilization for HCM patients. Moreover, waitlist mortality remained unchanged in the new system.

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

Historically, adult congenital patients have longer waitlist time and worse outcomes on the heart transplant waitlist as well as poorer early post-transplant survival. A new heart transplantation allocation system was implemented in the United States on October 18, 2018. The effect of the new allocation system on adult congenital patients is unknown. Adult congenital patients listed for transplantation between November 1, 2015 and September 30, 2019 registered in the United Network for Organ Sharing were included in the study. October 18, 2018 was used as the limit to distribute listed and transplanted patients into old and new groups. A total of 399 patients were listed for heart transplant only, 284 in the old system and 115 in the new system. Clinical characteristics were similar between both groups. The cumulative incidence of poor outcome on the transplant list was similar in both groups (P = .23), but the cumulative incidence of transplant was higher in the new system group (P < .009) and was associated with a shorter waitlist time. The one-year post-transplant outcome was similar between old and new groups (P = .37). The new allocation system has benefited adult congenital patients with increased cumulative frequency of transplantation without worsening short-term survival after transplantation.