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

Abstract

Successful normothermic machine perfusion of heart allografts (MPH) has led to rapid growth in transplantation of donation after circulatory death (DCD) heart allografts but has introduced complexity in the procurement process. This study examines the impact of MPH use in DCD procurements on warm ischemia time (WIT) and organ yield. DCD procurements from 2019 to 2020 were identified using the OPTN database. Procurements with and without the use of MPH were compared using propensity score matching. Observed to expected (O:E) yield ratios were calculated, where the expected values were obtained using the models developed by the Scientific Registry of Transplant Recipients. In total, 1237 DCD procurements met inclusion criteria (MPH: 109 and control: 1128). After PSM, no difference was found between groups in median total WIT (24.0 min vs. 24.0 min, p = .89), but the MPH group demonstrated shorter median operative WIT (circulatory arrest to cross‐clamp; 8.7 min vs. 10.9 min, p = .003). The overall organ yield of DCD heart donors was observed to be 33% higher than expected (O:E 1.33; 95% CI: 1.22–1.45). Observed yield of non‐heart organs was not significantly different from expected for liver, kidney, lung, and pancreas grafts. MPH use in DCD procurements does not lead to delays in WIT and does not negatively affect organ yield of other concurrently procured organs.

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

“…Previously, Feizpour et al 29 . defined “total WIT” as duration between time of withdrawal of life support and aortic cross‐clamp time.…”

“…These results are different from the previously reported data. 29 Of note, additional donor WIT contributed by blood collection utilizing HM might not be accurately reflected as time from a skin incision to cold abdominal organ flush is not available in this database. 30 When using a timeline from pronouncement of death to abdominal organ flush, overall delay in operative WIT was noted for both LT and KT in the HM group.…”

“…When considering the true impact of "warm ischemia," functional donor WIT is likely more important and reliable than total WIT. 31 Compared to Feizpour et al, 29 our study had a few methodological differences: we investigated donor WIT in recipients who underwent only LT or KT, we defined WIT differently based on the definition of controlled DCD, 23 and we excluded DCD heart recovery with HM for research, where the heart team might not delay the flushing of abdominal organs. 30…”

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

“…In the article by Feizpour et al, 1 the authors use the United Network for Organ Sharing (UNOS) database to show that machine perfusion of heart allografts (MPH) in the setting of donation after circulatory death (DCD) recovery did not impact donor warm ischemia time (WIT) or organ yield rates. While we concur with the overall results, there are some concerns about overall interpretation of the results.…”

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

“…Other single-center trials, however, showed significant improvements in early and late outcomes [ 99 , 100 ]. Many more ECD and even DCD organs were used and transplanted successfully [ 101 - 104 ]. The first PROTECT trial in Europe reported a 30-day graft survival rate of 100% using SCD organs [ 105 ].…”