The impact of machine perfusion of the heart on warm ischemia time and organ yield in donation after circulatory death

Asystolic donor warm ischemia time is associated with development of postreperfusion syndrome in donation after circulatory death liver transplant

BACKGROUND

Individual events during donation after circulatory death (DCD) procurement, such as hypotensive or hypoxic warm ischemia, or circulatory arrest are all a part of donor warm ischemia time (dWIT), and may have differing effects on the outcome of the liver graft. This study aimed to identify risk factors for postreperfusion syndrome (PRS), a state of severe hemodynamic derangement following graft reperfusion, and its impact on DCD liver transplantation (LT) outcomes.

METHODS

This was a retrospective analysis using 106 DCD LT. Detailed information for events during procurement (withdrawal of life support; systolic blood pressure < 80 mmHg; oxygen saturation < 80%; circulatory arrest; aortic cold perfusion) and their association with the development of PRS were examined using logistic regression.

RESULTS

The overall incidence of PRS was 26.4%, occurring in 28 patients. Independent risk factors for PRS were asystolic dWIT (odds ratio (OR) 3.65, 95% confidence interval (CI) 1.38-9.66) and MELD score (OR 1.06, 95% CI 1.01-1.10). Total bilirubin was significantly higher in the PRS group at postoperative day (POD) 1 (p = .02; 5.2 mg/dL vs. 3.4 mg/dL), POD 3 (p = .049; 4.5 mg/dL vs. 2.8 mg/dL), and POD 7 (p = .04; 3.1 mg/dL vs. 1.9 mg/dL). Renal replacement therapy after LT was more likely to be required in the PRS group (p = .01; 48.2% vs. 23.1%).

CONCLUSION

Asystolic dWIT is a risk factor for the development of PRS in DCD LT. Our results suggest that asystolic dWIT should be considered when selecting DCD liver donors.

The learning curve of liver procurement from donation after circulatory death donor

PURPOSE

This study aimed to evaluate the learning curve for donation after circulatory death (DCD) liver procurement.

METHODS

DCD liver procurements performed by a single surgeon (n = 36) were separated into two phases: the learning and established phases.

RESULTS

A cumulative sum analysis using the operative donor warm ischemia time (oWIT) and donor hepatectomy time (dHT) showed that ten and seven cases, respectively, were needed for stable surgical procedures. The established phase (n = 26, since Case 11) was likely to have a shorter oWIT (p = 0.06; 7.5 min vs. 9 min) and dHT (p = 0.09; 32 min vs. 37 min) than the learning phase. While the hospital stay was significantly shorter and donor age was older in the established phase (p = 0.04 and p < 0.01; 12 days vs. 41 days and 38 years vs. 24 years, respectively), the incidence rates of post-transplant complications such as early allograft dysfunction (p = 0.74) and vascular complications (p = 0.53) were similar.

CONCLUSIONS

The learning curve for DCD liver procurement demonstrated that 10 cases were required to establish these techniques. The oWIT and dHT for DCD liver procurement can represent markers of operative efficiency.

Donor utilization in heart transplant with donation after circulatory death in the United States

Heart transplantation using donation after circulatory death (DCD) was recently adopted in the United States. This study aimed to characterize organ yield from adult (≥18 years) DCD heart donors in the United States using the United Network for Organ Sharing registry. The registry does not identify potential donors who do not progress to circulatory death, and only those who progressed to death were included for analysis. Outcomes included organ recovery from the donor operating room and organ utilization for transplant. Multiple logistic regression was used to identify predictors of heart recovery and utilization. Among 558 DCD procurements, recovery occurred in 89.6%, and 92.5% of recovered hearts were utilized for transplant. Of 506 DCD procurements with available data, 65.0% were classified as direct procurement and perfusion and 35.0% were classified as normothermic regional perfusion (NRP). Logistic regression identified that NRP, shorter agonal time, younger donor age, and highest volume of organ procurement organizations were independently associated with increased odds for heart recovery. NRP independently predicted heart utilization after recovery. DCD heart utilization in the United States is satisfactory and consistent with international experience. NRP procurements have a higher yield for DCD heart transplantation compared with direct procurement and perfusion, which may reflect differences in donor assessment and acceptance criteria.

Preserved 2-y Liver Transplant Outcomes Following Simultaneous Thoracoabdominal DCD Organ Procurement Despite Effects on Liver Utilization Rate

Background

Current techniques for donation after circulatory determination of death (DCD) heart procurement, through either direct procurement and machine perfusion or thoracoabdominal normothermic regional perfusion (NRP), have demonstrated excellent heart transplant outcomes. However, the impact of thoracoabdominal DCD (TA-DCD) heart procurement on liver allograft outcomes and utilization is poorly understood.

Methods

One hundred sixty simultaneous heart and liver DCD donors were identified using the United Network for Organ Sharing/Organ Procurement and Transplantation Network database between December 2019 and July 2021. Liver outcomes from TA-DCD donors were stratified by heart procurement technique and evaluated for organ utilization, graft survival, and patient survival. Results were compared with abdominal-only DCD (A-DCD; n = 1332) and donation after brain death (DBD; n = 12 891) liver transplants during the study interval. Kaplan-Meier methods with log-rank testing were used to evaluate patient and graft survival.

Results

One hundred thirty-three of 160 livers procured from TA-DCD donors proceeded to transplant. TA-DCD donors were younger (mean 28.26 y; P < 0.0001) with lower body mass index (mean 26.61; P < 0.0001) than A-DCD and DBD donors. TA-DCD livers had equivalent patient survival ( P = 0.893) and superior graft survival (P = 0.009) compared with A-DCD. TA-DCD livers had higher rates of organ discard for long warm ischemia time (37.0%) than A-DCD (20.5%) and DBD (0.5%; P < 0.0001), with direct procurement and machine perfusion procurements leading to a higher discard rate (18.5%) than NRP procurements (7.4%).

Conclusions

Liver transplants after TA-DCD donation demonstrated equivalent patient outcomes and excellent graft outcomes. NRP procurements resulted in the lowest rate of organ discard after DCD donation and may represent an optimal strategy to maximize organ utilization.

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.

The Year in Cardiothoracic Transplant Anesthesia: Selected Highlights From 2021 Part II: Cardiac Transplantation

This article spotlights the research highlights of this year that specifically pertain to the specialty of anesthesia for heart transplantation. This includes the research on recent developments in the selection and optimization of donors and recipients, including the use of donation after cardiorespiratory death and extended criteria donors, the use of mechanical circulatory support and nonmechanical circulatory support as bridges to transplantation, the effect of COVID-19 on heart transplantation candidates and recipients, and new advances in the perioperative management of these patients, including the use of echocardiography and postoperative outcomes, focusing on renal and cerebral outcomes.

Normothermic Regional Perfusion Can Improve Both Utilization and Outcomes in DCD Liver, Kidney, and Pancreas Transplantation

Normothermic regional perfusion (NRP) has gained widespread adoption in multiple European countries. The aim of this study was to examine the influence of thoracoabdominal-NRP (TA-NRP) on the utilization and outcomes of liver, kidney, and pancreas transplantation in the United States.

Methods

Using the US national registry data between 2020 and 2021, donation after circulatory death (DCD) donors were separated into 2 groups: DCD with TA-NRP and without TA-NRP. There were 5234 DCD donors; among them 34 donors were with TA-NRP. After 1:4 propensity score matching, the utilization rates were compared between DCD with and without TA-NRP.

Results

Although the utilization rates of kidney and pancreas were comparable (P = 0.71 and P = 0.06, 94.1% versus 95.6% and 8.8% versus 2.2%, respectively), that of liver in DCD with TA-NRP was significantly higher (P < 0.001; 70.6% versus 39.0%). Among 24 liver transplantations, 62 kidney transplantations, and 3 pancreas transplantations from DCD with TA-NRP, there were 2 liver grafts and 1 kidney graft that failed within 1 y after transplantation.

Conclusions

TA-NRP in the United States significantly increased the utilization rate of abdominal organs from DCD donors with comparable outcomes after transplantation. Increasing use of NRP may expand the donor pool without compromising transplant outcomes.

Does utilization of heart machine perfusion for donation after cardiac death transplantation affect outcomes of other abdominal transplanted organs?

INTRODUCTION

Machine perfusion of heart for donation after circulatory death (DCD) is being increasingly utilized. Current protocols for utilizing heart DCD's machine perfusion might prolong donor warm ischemic time for nonheart organs. The aim of this study was to analyze the effects of utilizing heart machine perfusion on liver and kidney transplants from the same donor.

METHODS

We analyzed data of DCD donors from the United Network for Organ Sharing (UNOS) from January-2020 to September-2021 among two groups: donors with heart machine perfusion (HM) and without heart machine perfusion (NHM). Propensity score (PS) matching was performed to compare the short-term outcomes of liver and kidney transplants between two groups.

RESULTS

Total of 102 liver and 319 kidney transplants were performed using organs from donors with HM. After PS matching, no statistically significant difference was seen in 1-year graft survival (GS) for both liver and kidney transplants between two groups (liver HM 90.6% vs. NHM 90.2%, p = .47; kidney HM 95.2% vs. NHM 92.9%, p = .40). There was no difference in the delayed graft function (DGF) rates in kidney transplantation (KT) (HM 42% vs. NHM 35%, p = .062).

CONCLUSION

Utilization of heart machine perfusion in DCD donors had no significant impact on 1-year outcomes of liver and kidney transplantation.

Cold but not too cold: advances in hypothermic and normothermic organ perfusion

Transplantation is the method of choice and, in many cases, the only method of treatment for patients with end-stage organ disease. Excellent results have been achieved, and the main focus today is to extend the number of available donors. The use of extended-criteria donors or donors after circulatory death is standard, but is accompanied by an increased risk of ischemia reperfusion injury. This review presents newly developed machine perfusion techniques using hypothermic, subnormothermic, or normothermic conditions, with or without oxygenation. Possibilities for treatment and quality assessment in decision-making about organ acceptability are also discussed.