Missed opportunities for DCD kidney donors: Evaluation of warm ischemic time and associated functional warm ischemic time.

Many transplant centers utilize a hard cutoff of 2 hours of warm ischemic time (WIT), defined as the time from withdrawal of life-sustaining measures to cold organ flush, to exclude donation after circulatory determination of death (DCD) kidney donation. As a result, almost a quarter of withdrawals to retrieve DCD organs fail to produce kidney transplants in Ontario. In order to assess our ability to increase organ yield, we wanted to characterize WIT and functional WIT (fWIT, time from systolic blood pressure <50 mm Hg to cold organ flush), as well as determine the time at which potential donors eventually die in those that did not become organ donors. A retrospective review of all DCD kidney donors in Ontario was performed utilizing the Trillium Gift of Life Database from April 2013 to February 2018. Of 350 DCD kidney donors analyzed, 46.9% had < 0.5 hours, 51.7% between 0.5 and 2 hours, and 1.4% >2 hours of WIT. In each of these categories (WIT <0.5 hours, 0.5-2 hours and >2 hours), the percentage of patients with fWIT <30 minutes was 100%, 94.4%, and 100%, respectively (P = NS). There were 106 potential donors who did not end up donating due to WIT >2 hours. Of these, 20.8% died between 2 and 4 hours, 10.4% between 4 and 6 hours, and 68.8% beyond 6 hours. The percentage of donors with fWIT >30 minutes did not increase with increasing WIT in DCD donors that went on to donate organs. These data support assessment of waiting up to 4 hours for DCD kidney donation as long as fWIT remains low.

Law J ，Hornby K ，Payne C ，Sener A ，Luke PP ... -  《-》

Impact of Warm Ischemia Time on Donation After Circulatory Death Kidney Transplant Outcomes.

Efforts to address the shortage of donor organs include increasing the use of renal allografts from donors after circulatory death (DCD). While warm ischemia time (WIT) is thought to be an important factor in DCD kidney evaluation, few studies have compared the relationship between WIT and DCD kidney outcomes, and WIT acceptance practices remain variable. We conducted a single-center retrospective review of all adult patients who underwent deceased donor kidney transplantation from 2000 to 2021. We evaluated the impact of varied functional warm ischemia time (fWIT) in controlled DCD donors by comparing donor and recipient characteristics and posttransplant outcomes between high fWIT (>60 min), low fWIT (≤60 min), and kidneys transplanted from donors after brain death (DBD). Two thousand eight hundred eleven patients were identified, 638 received low fWIT DCD, 93 received high fWIT DCD, and 2080 received DBD kidneys. There was no significant difference in 5-year graft survival between the DCD low fWIT, high fWIT, and DBD groups, with 84%, 83%, and 83% of grafts functioning, respectively. Five-year patient survival was 91% in the low fWIT group, 92% in the high fWIT group, and 90% in the DBD group. An increase in kidney donor risk index (KDRI) (HR 3.37, 95% CI = 2.1-5.7) and high CIT compared to low CIT (HR 2.12, 95% CI = 1.4-3.1) have higher hazard ratios for 1-year graft failure. Increased acceptance of kidneys from selected DCD donors with prolonged fWIT may present an opportunity to increase kidney utilization while preserving outcomes. Our group specifically prioritizes the use of kidneys from younger donors, with lower KDPI, and without acute kidney injury, or risk factors for underlying chronic kidney disease.

Alghannam K ，Fine J ，Howard B ，Loza J ，Goussous NM ，Sageshima J ，Mineyev NM ，Wang AX ，Perez RV ，Than PA ... -  《-》

Influence of lung donor agonal and warm ischemic times on early mortality: Analyses from the ISHLT DCD Lung Transplant Registry.

In this study we aimed to assess the impact of agonal time and warm ischemic time on early survival in Category III donation-after-circulatory-death (DCD) donor lung transplants (LTxs) using data reported to the International Society for Heart and Lung Transplantation (ISHLT) DCD Lung Transplant Registry. In this retrospective study, data were analyzed for 507 DCD LTxs done between January 2005 and June 2015. DCD lung donor agonal time (defined as withdrawal of life support to cessation of cardiac output) and warm ischemic time (WIT; defined as donor systolic blood pressure <50 mm Hg to cold pulmonary artery flush) were divided into 3 clinical timing categories (<30 minutes, 30 to 60 minutes, >60 minutes) and 3 tertiles. Univariate analysis was undertaken for all categorizations, and Day 30/Day 365 Kaplan‒Meier survival rates were calculated and compared. Multivariable analysis included Cox proportional hazards regression models to estimate hazard of 365-day mortality. Four hundred sixty-five and 301 DCD LTxs had data to analyze in the agonal and warm ischemic time groups, respectively. Day 30 and Day 365 post-transplant survival overall were 96% and 90%, respectively, and not statistically different according to agonal or WIT category or tertile. Current experience with DCD Category III LTx does not show a relationship between the duration of donor agonal phase or warm ischemic time up to 60 minutes and early survival. These results suggest the true limits of clinical DCD allograft warm ischemic times may not yet be reached. Global variations in clinical DCD practice are apparent. Continued accurate recording and analyses of DCD processes is warranted.

Levvey B ，Keshavjee S ，Cypel M ，Robinson A ，Erasmus M ，Glanville A ，Hopkins P ，Musk M ，Hertz M ，McCurry K ，Van Raemdonck D ，Snell G ... -  《-》

Organ donation after circulatory death as compared with organ donation after brain death in Switzerland - an observational study.

Elmer A ，Rohrer ML ，Benden C ，Krügel N ，Beyeler F ，Immer FF ... -  《-》

Functional evaluation of human donation after cardiac death donor hearts using a continuous isolated myocardial perfusion technique: Potential for expansion of the cardiac donor population.

To investigate the resuscitation potential and contractile function in adult human donation after cardiac death (DCD) hearts by ex vivo perfusion. With institutional review board approval and under the DCD protocol at the University of Wisconsin (UW) Organ Procurement Organization, 5 brain dead (BD) and 5 DCD donor hearts were evaluated. All BD hearts were declined for clinical transplantation because of coronary artery disease, advanced age, or social history. All hearts were preserved by flushing and cold storage with UW solution. By using our ex vivo perfusion system, the left ventricular end systolic pressure-volume relationship (LV-ESPVR) was assessed for 2 hours of oxygenated blood reperfusion. All BD (n = 5) and 4 DCD hearts were successfully resuscitated. One DCD heart was unable to be resuscitated due to prolonged warm ischemic time (WIT; 174 minutes). Mean WIT for resuscitated DCD hearts (from extubation to flushing with cold UW solution) was 34 ± 3 minutes (range, 26 to 40 minutes); mean cold ischemic time for BD donors was 211 ± 31 minutes compared with 177 ± 64 minutes for DCD donors. The calculated LV-ESPVRs for BD hearts after 1 and 2 hours of reperfusion were 6.9 ± 0.7 and 5.7 ± 1.0 mm Hg/mL, respectively; LV-ESPVRs for DCD hearts after 1 and 2 hours of reperfusion were 5.6 ± 1.5 (P = .45) and 3.0 ± 0.7 mm Hg/mL (P = .07), respectively. We successfully resuscitated and measured ex vivo cardiac function in human DCD and BD donor hearts. Resuscitation potential in DCD hearts was achieved when the WIT was less than 40 minutes. Contractile performance in DCD hearts tended to be lower compared with BD hearts. Further investigation with longer reperfusion periods seems warranted.

Osaki S ，Locher MR ，Lushaj EB ，Akhter SA ，Kohmoto T ... -  《-》