Surgical and logistical concerns for ex vivo–based perfusion strategies for “donation after circulatory death” multiorgan recovery

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.

Donation After Circulatory Death Heart Transplant: Current State and Future Directions

Orthotopic heart transplant is the gold standard therapeutic intervention for patients with end-stage heart failure. Conventionally, heart transplant has relied on donation after brain death for organ recovery. Donation after circulatory death (DCD) is the donation of the heart after confirming that circulatory function has irreversibly ceased. DCD-orthotopic heart transplant differs from donation after brain death-orthotopic heart transplant in ways that carry implications for widespread adoption, including differences in organ recovery, storage and ethical considerations surrounding normothermic regional perfusion with DCD. Despite these differences, DCD has shown promising early outcomes, augmenting the donor pool and allowing more individuals to benefit from orthotopic heart transplant. This review aims to present the current state and future trajectory of DCD-heart transplant, examine key differences between DCD and donation after brain death, including clinical experiences and innovations in methodologies, and address the ongoing ethical challenges surrounding the new frontier in heart transplant with DCD donors.

Comparative Analysis of Ischemia-Reperfusion Injury in Heart Transplantation: A Single-Center Study Evaluating Conventional Ice-Cold Storage versus the Paragonix SherpaPak Cardiac Transport System

BACKGROUND

Since the 2018 allocation system change in heart transplantation (HT), ischemic times have increased, which may be associated with peri-operative and post-operative complications. This study aimed to compare ischemia reperfusion injury (IRI) in hearts preserved using ice-cold storage (ICS) and the Paragonix SherpaPak TM Cardiac Transport System (CTS).

METHODS

From January 2021 to June 2022, consecutive endomyocardial biopsies from 90 HT recipients were analyzed by a cardiac pathologist in a single-blinded manner: 33 ICS and 57 CTS. Endomyocardial biopsies were performed at three-time intervals post-HT, and the severity of IRI manifesting histologically as coagulative myocyte necrosis (CMN) was evaluated, along with graft rejection and graft function.

RESULTS

The incidence of IRI at weeks 1, 4, and 8 post-HT were similar between the ICS and CTS groups. There was a 59.3% statistically significant reduction in CMN from week 1 to 4 with CTS, but not with ICS. By week 8, there were significant reductions in CMN in both groups. Only 1 out of 33 (3%) patients in the ICS group had an ischemic time >240 mins, compared to 10 out of 52 (19%) patients in the CTS group. During the follow-up period of 8 weeks to 12 months, there were no significant differences in rejection rates, formation of de novo donor-specific antibodies and overall survival between the groups.

CONCLUSION

The CTS preservation system had similar rates of IRI and clinical outcomes compared to ICS despite longer overall ischemic times. There is significantly more recovery of IRI in the early post operative period with CTS. This study supports CTS as a viable option for preservation from remote locations, expanding the donor pool.

Donation after circulatory death heart procurement strategy impacts utilization and outcomes of concurrently procured abdominal organs

INTRODUCTION

The impact of donation after circulatory death (DCD) heart procurement techniques on the utilization and outcomes of concurrently procured DCD livers and kidneys remains unclear.

METHODS

Using the United Network for Organ Sharing database, we identified 246 DCD donors whose heart was procured using direct procurement and ex-situ machine perfusion and 128 DCD donors whose heart was procured using in-situ thoracoabdominal normothermic regional perfusion (12/2019-03/2022). We evaluated the transplantation rate of concurrently procured DCD livers and kidneys (defined as the number of organs transplanted/total number of organs available for procurement) and their post-transplant outcomes.

RESULTS

The transplantation rate of concurrently procured DCD livers was higher with in-situ perfusion compared to direct procurement (67.1% vs 56.5%, p = 0.045). After excluding pediatric, multiorgan, and repeat transplant recipients, there was no difference in 6-month liver graft failure rate (direct procurement 0.9% vs in-situ perfusion 0%, p > 0.99). Recipients of kidneys procured with in-situ perfusion had less delayed graft function (11.3% vs 41.5%, p < 0.0001) shorter length of stay, and lower serum creatinine at discharge (both p < 0.05). Six-month recipient survival in the direct procurement and in-situ perfusion group were similar after DCD liver and kidney transplantation (p = 0.24 and 0.79 respectively).

CONCLUSIONS

Compared to direct procurement, DCD heart procurement with in-situ thoracoabdominal normothermic regional perfusion was associated with increased utilization of DCD livers and a lower incidence of delayed graft function in concurrently procured DCD kidneys. Broader implementation of DCD heart transplantation must maximize the transplant potential of concurrently procured abdominal organs and ensure their successful outcomes.

Hemodynamic and Clinical Performance of Hearts Donated After Circulatory Death

BACKGROUND

Donor organ demand continues to outpace supply in heart transplantation. Utilization of donation after circulatory death (DCD) hearts could significantly increase heart donor availability for patients with advanced heart failure.

OBJECTIVES

The purpose of this study was to describe hemodynamic and clinical profiles of DCD hearts in comparison to standard of care (SOC) hearts donated after brain death (DBD).

METHODS

This single-center retrospective cohort study of consecutive heart transplant recipients analyzed right heart catheterization measurements, inotrope scores, echocardiograms, and clinical outcomes between DCD and DBD heart recipients.

RESULTS

Between April 2016 and February 2022, 47 DCD and 166 SOC hearts were transplanted. Median time from DCD consent to transplant was significantly shorter compared with SOC waiting list time (17 days [6-28 days] vs 70 days [23-240 days]; P < 0.001). Right heart function was significantly impaired in DCD recipients compared with SOC recipients 1 week post-transplant (higher median right atrial pressure (10 mm Hg [8-13 mm Hg] vs 7 mm Hg [5-11 mm Hg]; P < 0.001), higher right atrial pressure to pulmonary capillary wedge pressure ratio (0.64 [0.54-0.82] vs 0.57 [0.43-0.73]; P = 0.016), and lower pulmonary arterial pulsatility index (1.66 [1.27-2.50] vs 2.52 [1.63-3.82]; P < 0.001), but was similar between groups by 3 weeks post-transplant. DCD and SOC recipient mortality was similar at 30 days (DCD 0 vs SOC 2%; P = 0.29) and 1 year post-transplant (DCD 3% vs SOC 8%; P = 0.16).

CONCLUSIONS

DCD heart utilization is associated with transient post-transplant right heart dysfunction and short-term clinical outcomes otherwise similar to transplantation using DBD hearts.