Heart transplantation from donation after circulatory death: Impact on waitlist time and transplant rate

Providing red blood cells to facilitate organ transplant via normothermic perfusion techniques: A single-center experience

BACKGROUND

Normothermic regional perfusion (NRP) and normothermic machine perfusion (NMP) are organ procurement and transport techniques that can improve organ quality, facilitate longer transport, and reduce postoperative complications, increasing organ availability and improving outcomes. NRP and NMP often require allogeneic red blood cells (RBCs). Our academic transfusion service began providing RBCs to support NRP and NMP for adult heart transplant (HT), orthotopic liver transplant (OLT), and multiorgan transplant (MOT) in August 2020.

METHODS

This single-center, retrospective study describes the implementation process and analyzes the characteristics of RBC support during the first 3 years of the perfusion programs. Timing and quantity of units issued and used, organ recipient demographics, and transplant outcomes were obtained from transfusion service and electronic medical records.

RESULTS

From 2020 to 2023, the transfusion service received 233 requests to support NRP and NMP perfusion cases. Of these, 105 cases resulted in RBC use, and units were returned or discarded in 112 cases. A total of 131 patients received perfusion-facilitated transplants (92 HT, 27 OLT, and 12 MOT). The majority of perfusion-facilitated HTs utilized NRP (81/92, 88%), whereas most perfusion-facilitated OLTs utilized NMP (21/27, 78%). Across all 233 requests, a total of 381 RBC units were used to facilitate 131 transplants, averaging 2.91 units/transplant.

DISCUSSION

Provision of RBCs for NRP and NMP techniques represents a novel method for transfusion services to support and facilitate life-saving organ transplants with only modest product use, about three RBC units per organ transplant in this single-center study.

Innovations in transplant techniques for complex anomalies

PURPOSE OF REVIEW

With advances in the field of congenital cardiac surgery and in the management of congenital heart defects in early life, the population of adult congenital heart disease (ACHD) patients is increasing. End-stage heart failure is currently the main cause of cardiovascular mortality and is expected to increase in the coming years. This review summarizes recent innovations in transplant techniques, with special attention to what is known in the population of ACHD recipients.

RECENT FINDINGS

The use of machine perfusion for heart preservation enables longer preservation times. Normothermic (organ care system - OCS) and hypothermic (hypothermic oxygenated perfusion - HOPE) machine perfusion will alleviate the time pressure associated with heart transplantation in the ACHD population, may allow for expansion of the geographical range in which donors can be matched and may improve graft quality. Donation after circulatory death (DCD) heart transplantation, either through direct procurement-machine perfusion (DP-MP) or thoraco-abdominal normothermic regional perfusion (TA-NRP) is a viable strategy to further expand the donor pool.

SUMMARY

The use of machine perfusion and DCD donors in ACHD is feasible and shows promise. Time pressure and shortage of donors is even more critical in ACHD than in other patient populations, making these innovations particularly relevant. Further clinical experience and research is needed to elucidate their impact.

Heart Transplantation After Donation After Circulatory Death: Early United States Experience

BACKGROUND

Given the renewed interest in heart transplantation after donation after circulatory death (DCD), a contemporary analysis of trends and longer-term survival is warranted.

METHODS

Adult heart transplant recipients (December 2019-September 2023) were identified in the Organ Procurement and Transplantation Network. Recipients were stratified as donation after brain death (DBD) or DCD. DCD procurements were further classified as direct procurement and perfusion (DCD-DPP) or normothermic regional perfusion (DCD-NRP), based on the declaration of death to cross-clamp interval (≥40 minutes DCD-NRP). The main outcome was posttransplant survival at 1 and 3 years.

RESULTS

Of 11,625 transplantations, 792 (7%) involved DCD allografts (249 DCD-NRP, 543 DCD-DPP). The proportion of transplants involving DCD allografts significantly increased from 2% (December 2019) to 11% (January-September 2023, P < .001). Upon adjusted analysis, 1-year posttransplant survival was similar for DBD vs DCD-DPP (hazard ratio [HR], 1.00; 95% CI, 0.66-1.66) or DCD-NRP (HR, 0.92; 95% CI, 0.49-1.72). This remained true at 3 years for DCD-DPP (HR, 1.07; 95% CI, 0.77-1.48) and DCD-NRP (HR, 1.04; 95% CI, 0.62-1.73). Incidence of postoperative stroke, dialysis, acute graft rejection, and primary graft dysfunction were similar across groups. Across various strata of recipient risk and center volume, survival was equivalent between the DBD and DCD cohorts.

CONCLUSIONS

Rates of DCD heart transplantation continue to rise. Across various recipient risk and center volume categories, DCD and DBD recipients show comparable posttransplant survival up to 3 years. These findings encourage broader use of such donors in attempts to expand the organ pool.

Outcomes following concomitant multiorgan heart transplantation from circulatory death donors: The United States experience

BACKGROUND

Donation after circulatory death (DCD) has reemerged as a method of expanding the donor heart pool. Given the high waitlist mortality of multiorgan heart candidates, we evaluated waitlist outcomes associated with willingness to consider DCD offers and post-transplant outcomes following DCD transplant for these candidates.

METHODS

We identified adult multiorgan heart candidates and recipients between January 1, 2020 and March 31, 2023 nationally. Among candidates that met inclusion criteria, we compared the cumulative incidence of transplant, with waitlist death/deterioration as a competing risk, by willingness to consider DCD offers. Among recipients of DCD versus brain death (DBD) transplants, we compared perioperative outcomes and post-transplant survival.

RESULTS

Of 1,802 heart-kidney, 266 heart-liver, and 440 heart-lung candidates, 15.8%, 12.4%, and 31.1%, respectively, were willing to consider DCD offers. On adjusted analysis, willingness to consider DCD offers was associated with higher likelihood of transplant for all multiorgan heart candidates and decreased likelihood of waitlist deterioration for heart-lung candidates. Of 1,100 heart-kidney, 173 heart-liver, and 159 heart-lung recipients, 5.4%, 2.3%, and 2.5%, respectively, received DCD organs. Recipients of DCD and DBD heart-kidney transplants had a similar likelihood of perioperative outcomes and 1-year survival. All other DCD multiorgan heart recipients have survived to the last follow-up.

CONCLUSIONS

Multiorgan heart candidates who were willing to consider DCD offers had favorable waitlist outcomes, and heart-kidney recipients of DCD transplants had similar post-transplant outcomes to recipients of DBD transplants. We recommend the use of DCD organs to increase the donor pool for these high-risk candidates.

Revolutionizing Donor Heart Procurement: Innovations and Future Directions for Enhanced Transplantation Outcomes

Heart failure persists as a critical public health challenge, with heart transplantation esteemed as the optimal treatment for patients with end-stage heart failure. However, the limited availability of donor hearts presents a major obstacle to meeting patient needs. In recent years, the most groundbreaking progress in heart transplantation has been in donor heart procurement, significantly expanding the donor pool and enhancing clinical outcomes. This review comprehensively examines these advancements, including the resurgence of heart donation after circulatory death and innovative recovery and evaluation technologies such as normothermic machine perfusion and thoraco-abdominal normothermic regional perfusion. Additionally, novel preservation methods, including controlled hypothermic preservation and hypothermic oxygenated perfusion, are evaluated. The review also explores the use of extended-criteria donors, post-cardiopulmonary resuscitation donors, and high-risk donors, all contributing to increased donor availability without compromising outcomes. Future directions, such as xenotransplantation, biomarkers, and artificial intelligence in donor heart evaluation and procurement, are discussed. These innovations promise to address current limitations and optimize donor heart utilization, ultimately enhancing transplantation success. By identifying recent advancements and proposing future research directions, this review aims to provide insights into advancing heart transplantation and improving patient outcomes.

Impact of dual thoracic recovery from circulatory death donors on heart and lung transplant outcomes

OBJECTIVES

Concomitant heart and lung recovery can result in increased operative complexity, ischemic time, and competition for resources and anatomic territory. Dual thoracic recovery from circulatory death donors may have additional risks that are not fully understood. We investigated the effects of dual heart and lung recovery from circulatory death donors on thoracic transplant outcomes.

METHODS

Using the United Network for Organ Sharing database, we categorized all adult thoracic circulatory death donor transplants from 2019 to 2023 by whether the donor heart, lung, or both (dual donors) were recovered. Heart and lung transplant outcomes were compared between dual recovery donors and heart-only or lung-only donors, respectively, using multivariable analyses.

RESULTS

Of the 2513 donors included, 42.9% were heart-only, 45.0% were lung-only, and 12.0% were dual donors. Recipients of dual versus heart-only donors had similar likelihood of post-transplant dialysis (18.9% vs 18.3%, P = .84), likelihood of stroke (2.9% vs 4.7%, P = .34), and 2-year risk of mortality (adjusted hazard ratio, 1.15 [95% CI, 0.90-1.47], P = .26), but lower likelihood of acute rejection (10.2% vs 16.1%, P = .04). Recipients of dual and lung-only donors had similar likelihood of predischarge acute rejection (7.6% vs 8.5%, P = .70), intubation at 72 hours (38.9% vs 45.1%, P = .13), and extracorporeal membrane oxygenation at 72 hours (13.1% vs 18.1%, P = .11), as well as 2-year risk of mortality (adjusted hazard ratio, 1.16 [95% CI, 0.74-1.82], P = .52).

CONCLUSIONS

Recovering both the heart and lungs from a circulatory death donor does not negatively impact transplant outcomes. Outcomes in this population should continue to be investigated as more data and longer-term follow-up become available.

Utilization and outcomes of expanded criteria donors in adults with congenital heart disease

BACKGROUND

Use of donation after circulatory death (DCD) and hepatitis C virus (HCV) positive donors in heart transplantation have increased the donor pool. Given poor waitlist outcomes in the adult congenital heart disease (ACHD) population, we investigated waitlist outcomes associated with willingness to consider DCD and HCV+ offers and post-transplant outcomes following HCV+ and DCD transplantation for these candidates.

METHODS

Using the United Network for Organ Sharing database, we identified adult ACHD candidates and recipients listed or transplanted, respectively, between 01/01/2016 and 09/30/2023 for the HCV analysis and between 12/01/2019 and 09/30/2023 for the DCD analysis. Among candidates, we compared the cumulative incidence of transplant, with waitlist death/deterioration as a competing risk, by willingness to consider HCV+ and DCD offers. Among recipients of HCV+ (vs HCV-) and DCD (vs brain death [DBD]) transplants, we compared perioperative outcomes and post-transplant survival.

RESULTS

Of 1,436 ACHD candidates from 01/01/2016 to 09/30/2023, 37.0% were willing to consider HCV+ heart offers. Of 886 ACHD candidates from 12/01/2019 to 09/30/2023, 15.5% were willing to consider DCD offers. On adjusted analysis, willingness to consider HCV+ offers was associated with 84% increased likelihood of transplant, and willingness to consider DCD offers was associated with 56% increased likelihood of transplant. Of 904 transplants between 01/01/2016 and 09/30/2023, 6.4% utilized HCV+ donors, and of 540 transplants between 12/01/2019 and 09/30/2023, 6.9% utilized DCD donors. Recipients of HCV+ (vs HCV-) and DCD (vs DBD) heart transplants had similar likelihood of perioperative outcomes and 1-year survival.

CONCLUSIONS

ACHD candidates who were willing to consider HCV+ and DCD offers were more likely to be transplanted and had similar post-transplant outcomes compared to recipients of HCV- and DBD organs.

Pediatric heart transplantation: Looking forward after five decades of learning

Heart transplantation has become the standard of care for pediatric patients with end-stage heart disease throughout the world. Since the first transplant was performed in 1967, the number of transplants has grown dramatically with 13 449 pediatric heart transplants being reported to The International Society of Heart and Lung Transplant (ISHLT) between January 1992 and June 30, 2018. Outcomes have consistently improved over the last few decades, specifically short-term outcomes. Most recent survival data demonstrate that recipients who survive to 1-year post-transplant have excellent long-term survival with more than 60% of those who were transplanted as infants being alive 25 years later. Nonetheless, the rates of graft loss beyond the first year have remained relatively constant over time; driven primarily by our poor understanding and lack of treatments for chronic allograft vasculopathy (CAV). Acute rejection, CAV, graft failure, and infection continue to be the major causes of death within the first 5 years post-transplant. In addition, renal dysfunction, malignancy, and the need for re-transplantation remain as significant issues that require close follow-up. Looking forward, key challenges include improving donor utilization rates (including donation after cardiac death (DCD) and the use of ex vivo perfusion devices), the development of non-invasive biomarkers for rejection, efforts to mitigate the long-term effects of immunosuppression, and prevention of CAV. It is not possible to cover the entire evolution of pediatric heart transplantation over the last five decades, but in this review, we hope to touch on key observations, lessons learned, and practice changes that have advanced the field, as well as glance ahead to the next decade.

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.

Outcomes of Heart Transplant Donation After Circulatory Death

BACKGROUND

Heart transplantation using donation after circulatory death (DCD) allografts is increasingly common, expanding the donor pool and reducing transplant wait times. However, data remain limited on clinical outcomes.

OBJECTIVES

We sought to compare 6-month and 1-year clinical outcomes between recipients of DCD hearts, most of them recovered with the use of normothermic regional perfusion (NRP), and recipients of donation after brain death (DBD) hearts.

METHODS

We conducted a single-center retrospective observational study of all adult heart-only transplants from January 2020 to January 2023. Recipient and donor data were abstracted from medical records and the United Network for Organ Sharing registry, respectively. Survival analysis and Cox regression were used to compare the groups.

RESULTS

During the study period, 385 adults (median age 57.4 years [IQR: 48.0-63.7 years]) underwent heart-only transplantation, including 122 (32%) from DCD donors, 83% of which were recovered with the use of NRP. DCD donors were younger and had fewer comorbidities than DBD donors. DCD recipients were less often hospitalized before transplantation and less likely to require pretransplantation temporary mechanical circulatory support compared with DBD recipients. There were no significant differences between groups in 1-year survival, incidence of severe primary graft dysfunction, treated rejection during the first year, or likelihood of cardiac allograft vasculopathy at 1 year after transplantation.

CONCLUSIONS

In the largest single-center comparison of DCD and DBD heart transplantations to date, outcomes among DCD recipients are noninferior to those of DBD recipients. This study adds to the published data supporting DCD donors as a safe means to expand the heart donor pool.