The trouble with kidneys derived from the non heart-beating donor: a single center 10-year experience

BACKGROUND: The demand for renal transplantation has increasingly outstripped the supply of donor organs especially over the past 10 years. Although related and unrelated live donation is being promoted as one option for increasing the donor pool, it is unlikely that this will in itself be able to bridge the gap. Non-heart beating donors (NHBD) can provide an alternative supply of organs, which should substantially increase the donor pool. METHODS: In Newcastle, NHBD kidneys have been used for transplantation for a period of 10 years. In the early period (1988-1993) excellent results were obtained (90.5% success); however, these donors were controlled NHBD, Maastricht category III. In the second phase (1994-1998) increasing numbers of donors were obtained from the Accident and Emergency Department unit. These were failed resuscitation for cardiac arrest (category II). The rates of success in this period were poor (45.5% success) and the program was halted. The third phase of the program used machine perfusion of the kidneys and glutathione S transferase enzyme analysis to assess viability. RESULTS: Using such approaches renal transplants from largely category II donors produced a success rate of 92.3% which was significantly better than the phase II period of the program (P=0.023, Fisher two-tail test). CONCLUSION: Machine perfusion and viability assessment of NHB kidneys in phase III of the program has increased our donor pool as well as improved the graft survival. This is particularly relevant for the use of the category II NHB donor where the incidence of primary nonfunction was high, illustrated by phase II where machine perfusion/viability assessment was not used.     

Outcome of transplantation using kidneys from controlled (Maastricht category 3) non-heart-beating donors

BACKGROUND: Many renal transplant centres are reluctant to use kidneys from non-heart-beating (NHB) donors because of the high incidence of primary non-function and delayed graft function reported in the literature. Here, we report our favourable experience of using kidneys from Maastricht category 3 donors (controlled NHB donors). MATERIALS AND METHODS: From January 1996 to June 2002, 42 renal transplants using kidneys from 25 controlled NHB donors were undertaken at our centre. The rates of primary non-function, delayed graft function (DGF), rejection and long-term graft and patient survival were compared with those of 84 recipients of grafts from heart-beating (HB donors) transplanted contemporaneously. RESULTS: Primary non-function did not occur in recipients of grafts from NHB donors but was seen in two grafts from HB donors. DGF occurred in 21 of 42 (50%) kidneys from NHB donors and 14 of 84 (17%) kidneys from HBD donars (p < 0.001). The acute rejection rates in the two groups were similar (33% for grafts from NHB donors vs. 40% from HB donors). By 1 month after transplantation, there was no significant difference in serum creatinine concentration between the two groups. Over a median follow-up period of 32 months (range 2-75 months), the actuarial graft survival rates at 1, 3 and 5 yr after transplantation were 84, 80 and 74% for recipients of kidneys from NHB donors, compared with 89, 85 and 80% for kidneys from HB donors. CONCLUSION: Controlled NHB donors are a valuable and under-used source of kidneys for renal transplantation. The outcome for recipients of kidney allografts from category 3 NHB donors is similar to that seen in recipients of grafts from conventional HB cadaveric donors.     

Effect of machine perfusion preservation on delayed graft function in non-heart-beating donor kidneys – early results

The functioning of non-heart-beating (NHB) donor kidneys upon transplantation is often delayed. To evaluate the effect of preservation by machine perfusion (MP) on early post-transplant function, 37 NHB donor kidneys were compared to 74 matched heart-beating (HB) donor kidneys preserved by cold storage (CS). The NHB donor kidneys were subject to 49 ± 34 min of warm ischemia. Delayed function (DF) and primary nonfunction (PNF) rates were significantly higher for NHB than for HB donor kidneys (49 % and 19 % vs 34 % and 7 %, respectively). Consequently, renal function was impaired but recovered within 6 months. MP could not eliminate the differences in DF rate between NHB and HB donor kidneys. However, NHB donor kidneys preserved by MP showed less DF than that reported in kidneys preserved by CS. This suggests that MP has a beneficial effect on ischemically damaged kidneys. The similar results observed with category 2 and category 3 NHB donors also suggest this effect. The high PNF rate emphasizes the need for viability tests that prevent the transplantation of nonviable organs. We conclude that MP alone is not sufficient to reduce DF and PNF rates in NHB donor kidneys. Received: 16 January 1997 Received after revision: 7 April 1997 Accepted: 11 April 1997     

Redox-Active Iron Released During Machine Perfusion Predicts Viability of Ischemically Injured Deceased Donor Kidneys

Redox-active iron, catalyzing the generation of reactive oxygen species, has been implicated in experimental renal ischemia-reperfusion injury. However, in clinical transplantation, it is unknown whether redox-active iron is involved in the pathophysiology of ischemic injury of non-heart-beating (NHB) donor kidneys. We measured redox-active iron concentrations in perfusate samples of 231 deceased donor kidneys that were preserved by machine pulsatile perfusion at our institution between May 1998 and November 2002 using the bleomycin detectable iron assay. During machine pulsatile perfusion, redox-active iron was released into the preservation solution. Ischemically injured NHB donor kidneys had significantly higher perfusate redox-active iron concentrations than heart-beating (HB) donor kidneys that were not subjected to warm ischemia (3.9 +/- 1.1 vs. 2.8 +/- 1.0 micromol/L, p = 0.001). Moreover, redox-active iron concentration was an independent predictor of post-transplant graft viability (odds ratio 1.68, p = 0.01) and added predictive value to currently available donor and graft characteristics. This was particularly evident in uncontrolled NHB donor kidneys for which there is the greatest uncertainty about transplant outcomes. Therefore, perfusate redox-active iron concentration shows promise as a novel viability marker of NHB donor kidneys.     

Factors predicting duration of delayed graft function in non-heart-beating donor kidney transplantation

Non-heart-beating donors (NHBDs) are an important potential source of donor organs, but kidneys from such donors are prone to delayed graft function (DGF) and primary nonfunction, which are multifactorial in origin but believed to be mainly due to warm ischemic injury. This retrospective study examined a series of 88 transplants from Maastricht category II and III NHBDs to examine the role of factors to predict the duration of DGF. The main factors affecting duration of DGF were total warm ischemic time, cold ischemic time, product of perfusate GST concentration and donor age, quality of postoperative graft perfusion, incidence of acute rejection, recipient cardiovascular risk score, maximum pressure on machine perfusion, and weight gain during machine perfusion. Primary nonfunction was not accurately predicted from these factors for kidneys that had passed the viability assessment.     

Non-heartbeating donation of kidneys for transplantation

There is a persistent shortage of kidneys available for transplantation. In the early 1980s, therefore, we published the concept of non-heartbeating (NHB) donation; that is, procurement of kidneys from donors whose death has been accompanied by irreversible circulatory arrest. NHB donors are generally categorized using four definitions; category III (awaiting cardiac arrest) and category IV (cardiac arrest while braindead)--or 'controlled'--donors are the most suitable for initiating NHB donation programs. Delayed graft function is associated with use of kidneys from such donors, but has no effect on graft survival in the short or long term. Use of kidneys from category I (dead upon arrival at hospital) and category II (unsuccessfully resuscitated), or 'uncontrolled', donors is likewise associated with delayed graft function, but also with an increased risk of primary nonfunction. Viability testing of donated organs from these sources is a prerequisite for transplantation. Machine preservation parameters and enzyme release measurements help to distinguish viable from nonviable kidneys. The proportion of NHB donor kidneys in the total pool of postmortem kidneys differs considerably between countries. In The Netherlands, the proportion is nearly 50%. This figure is markedly higher than that in the US and Canada, where national programs have now been initiated to increase rates of NHB donation. In the future, warm preservation techniques might facilitate better viability testing, thereby increasing NHB donation from category I and II donors and further reducing the shortage of kidneys available for transplantation.     

Early results of a non-heartbeating donor (NHBD) programme with machine perfusion

Freeman Hospital, Newcastle upon Tyne restarted their non-heartbeating donor (NHBD) programme in September 1998 using machine perfusion, due to early poor results with conventional cold storage (45 % graft survival, phase II). Since then, 15 NHBD kidneys have been transplanted. The retrieval protocol consisted of in situ perfusion with a double balloon triple lumen cannula in Maastricht category II male donors age range 13–59 years. Mean primary warm ischaemic time was 24.8 min (range 10–44). All kidneys were machine perfused through a locally developed perfusion system. The viability was assessed by serial measurements of total GST (maximum acceptable limit of 200 units/l) and intrarenal vascular resistance (IRVR) was recorded. Fifteen of the 22 kidneys (68.62 %) were transplanted. Delayed graft function (DGF) was seen in ten recipients (66.6 %), two kidneys had immediate function (IF), one organ was exported, two recipients died of unrelated causes and a further seven kidneys were discarded (two had high tGST, two were infected and three had poor flow characteristics). In phase III, a success rate of 91.7 % was thus achieved, which was better than the phase II period (P = 0.027, Fisher 2-tail test). Machine perfusion has been successfully introduced in phase III to the Newcastle NHBD programme and facilitates viability assessment of NHBD kidneys.     

Hypothermic pulsatile preservation of kidneys from uncontrolled deceased donors after cardiac arrest – a retrospective study

Kidneys from uncontrolled donors after cardiac arrest (uDCD) suffer from a period of warm ischemia between cardiac arrest and cold flushing. Aim of the study was to evaluate renal outcomes of uDCD kidneys selected on the basis of renal Resistance Index (RI) and its influence on graft function and survival. The study included 44 kidneys procured from 26 uDCD starting 1.1.2006 until 12.31.2013. The donors (Maastricht category II) underwent cardiopulmonary resuscitation by assisted ventilation and chest compression; the organs were preserved with in situ cold perfusion or a normothermic regional perfusion. All kidneys were perfused on hypothermic (1–4 °C) pulsatile perfusion machine (RM3; Waters Medical System) and discarded when RI ≥0.5 mmHg/ml/min after 6 h of perfusion. There was one (2.2%) primary non function, while 37 recipients (84.1%) experienced delayed graft function. Graft survival was 97.6% at 1 and 3 post‐transplantation years. Linear regression models showed that lower values of RI at the end of perfusion were associated with higher values of Modification of Diet in Renal Disease at 3 (P = 0.049) and 6 months after transplantation (P = 0.010) and with higher values of inulin clearance at 1 year (P = 0.030). RI showed to be a useful tool to select uDCD kidneys allowing to achieve good clinical results.     

Non-heart-beating donor kidneys in the Netherlands: allocation and outcome of transplantation

BACKGROUND: Since February 1, 2001, kidneys from both heart-beating (HB) and non-heart-beating (NHB) donors in The Netherlands have been indiscriminately allocated through the standard renal-allocation system. METHODS: Renal function and allograft-survival rate for kidneys from NHB and HB donors were compared at 3 and 12 months. RESULTS: The outcomes of 276 renal transplants, 176 from HB donors and 100 from NHB III donors, allocated through the standard renal allocation system, Eurotransplant Kidney Allocation System, and performed between February 1, 2001 and March 1, 2002 were compared. Three months after transplantation, graft survival was 93.7% for HB kidneys and 85.0% for NHB kidneys (P<0.05). At 12 months, graft survival was 92.0% and 83.0%, respectively (P<0.03). Serum creatinine levels in the two groups were comparable at both 3 and 12 months. Multivariate analysis identified previous kidney transplantation (relative risk [RR] 3.33; P<0.005), donor creatinine (RR 1.01; P<0.005), and NHB (RR 2.38; P<0.05) as independent risk factors for transplant failure within 12 months. In multivariate analysis of NHB data, a warm ischemia time (WIT) of 30 minutes or longer (P<0.005; RR 6.16, 95% confidence interval 2.11-18.00) was associated with early graft failure. No difference in 12-month graft survival was seen between HB and NHB kidneys after excluding the kidneys that failed in the first 3 months. CONCLUSION: Early graft failure was significantly more likely in recipients of kidneys from NHB donors. A prolonged WIT was strongly associated with this failure. Standard allocation procedures do not have a negative effect on outcome, and there is no reason to allocate NHB kidneys differently from HB kidneys.     

Nonheartbeating cadaveric organ donation.

OBJECTIVE: The authors evaluated the potential use of nonheartbeating (NHB) cadaver donors as an additional source to the current supply of brain-dead cadaver donors. SUMMARY BACKGROUND DATA: The numbers of cadaveric donors has not increased significantly during the last 5 years, despite a rising need for transplantable organs. Any improvement in cadaveric organ procurement will depend on the use of previously unrecognized potential donors. METHODS: During a 2-year period, 24 kidneys were retrieved from 12 NHB donors. Nineteen kidneys were transplanted. RESULTS: These kidneys sustained a mean warm ischemia time of 26 minutes (range 20-35 min). A mean lowest creatinine level of 2.0 mg/dL, (range 1.1-3.0 mg/dL), the rate of postoperative dialysis (22%), and a 1-year graft survival rate of 76% for kidneys from NHB-donated kidneys compare favorably to expected results achieved nationally from brain-dead cadaveric donors. CONCLUSIONS: Nonheartbeating donor kidneys can yield acceptable graft function and be of no disadvantage to recipients of cadaver transplants.     

Organ Donors: Heartbeating and Non-heartbeating

The limits of organ donation from heart-beating (HB) donors reached a plateau illustrated by the number of postmortem kidneys for transplantation. Programs such as the European Donor Hospital Education Program (EDHEP) and Donor Action have helped to stop a further decrease in the number instead of an expected increase. For kidneys, heart, liver, and lungs one must also explore the use of marginal donors as a possible additional source. Examples are donors with a horseshoe kidney, those at both ends of the age spectrum, and those with medical contraindication such as diabetes. We have enlarged our kidney donor pool considerably with non-heart-beating(NHB) donors. Because we preserve these kidneys in a preservation machine, we are able to perform viability testing. With glutathione S-transferase (GST) as a measure of tubular damage, we now decide whether to transplant based on GST values. For other organs, NHB donation does not seem to be an option other than for the liver when the warm ischemia time is short.     

The use of oxygenated perfluorocarbonic emulsion for initial in situ kidney perfusion

Protection of grafts from ischemia-reperfusion injury (IRI) remains an important problem, especially in uncontrolled donors. This study was performed to define the effect of oxygenated perfluorocarbonic emulsion for initial in situ conservation. One hundred and seventeen kidney grafts were procured from 2003 until 2006 from sixty one DCDs of Maastricht II and IV category. Control group donors (HTK group, n = 31) were operated using the traditional rapid laparotomy. The study group donors (Perftoran group, n = 30) had femoral access obtained in the ICU with initial perfusion by perfluorocarbonic PFG emulsion. The recipients were divided according to the type of the initial perfusion of the kidneys into a control group (n = 59) whose kidneys were initially perfused using HTK solution, and a study group (n = 58), who received kidneys preserved with initial perfusion in situ using oxygenated Perftoran. The rate of delayed graft function was significantly (up to 30%) higher among the control group. In the study group, the rate of immediate function was twice as high as that in the control group. By postoperative day 21, the level of serum creatinine in the study group decreased twice that of the control group. Initial perfusion with oxygenated perfluorocarbonic emulsion in situ may minimize a IRI of DCD kidneys.     

Renal graft function after prolonged agonal time in non-heart-beating donors

To deal with the increasing gap between organ demand and supply for kidney transplantation, many centers have started to use non-heart-beating (NHB) donors. When we initiated our program to utilize kidneys from such donors in 1998, we had no protocol for the maximal agonal period. This however was audited in retrospect. Our current wait time is now a maximum of 5 hours. Concern has been expressed in the past about possible deterioration in the quality of the organs with a protracted agonal time. We aimed in this study to examine the effect of prolonging agonal period on the quality of kidneys retrieved from Maastricht category III donors: A total of 40 kidneys were transplanted from 29 category III donors between 1998 and 2004. Eleven kidneys had donor agonal times of >5 hours; the remainder, agonal times <5 hours. Both groups were matched for donor and recipient factors. The mean glomerular filtration rates at 12 months for <5 hours versus >5 hours agonal time were 43.8 +/- 4.4 versus 49.8 +/- 5.8, respectively (P = .24) and at 24 months, 46.83 +/- 8.99 versus 37.67 +/- 3.85, respectively (P = .24). In conclusion, intermediate graft function is comparable to ones with shorter agonal time, although we await long-term results.     

Agonal period in potential non-heart-beating donors

The shortage of donor kidneys for renal transplantation is becoming more severe as the gap between the number of patients waiting for renal transplantation and the number of cadaveric organs available continues to widen. Therefore, many centres have started using non-heart-beating (NHB) donors. There was no clear plan for maximal duration of agonal period in Maastricht category NHB donors after withdrawal of treatment in Newcastle. This withdrawal has been audited in retrospect. Our current wait time is now a maximum of 5 hours; however, previously there have been some considerably longer periods. Concern has always been expressed about poor quality with protracted periods. Nonuse in this review of 58 kidneys can be expressed against time: 0 to 2 hours 13%, 2 to 5 hours 33%, and >5 hours 45%. Therefore, though the nonuse rate was significantly different between 0 to 2 hours and >5 hours (P < .05, chi-square), there were 16 transplants performed with kidneys >2 hours and 12 transplanted >5 hours. In conclusion, although good usable kidneys can still be used with protracted withdrawal, there are considerable logistical difficulties with our 5-hour cut-off, which means that one third of potential kidneys will not be utilized.     

Why did it take so long to start a non-heart-beating donor program in Belgium?

The first cadaver kidney transplant, performed in June 1963 in Belgium, was from a heart beating donor (HBD). It was the first ever in the world. Since that period, almost all cadaver organs were procured from brain death donors. When the Belgian law on organ donation and transplantation was published on February 1987, with its opting-out principle, no emphasis was placed on procuring organs after cardiac death. Based on the Maastricht experience, in the early nineties, the transplant community interpellated the National Belgian Council of Physicians to facilitate organ procurement in Non-Heart-Beating Donors (NHBD) following the law. But, the transplant community had to wait for the impulse of the first International Congress on NHBD in 1995,where the 4 categories of Maastricht NHBD were defined. It also published 12 Statements and Recommendations which were eventually approved by the European Council. Then all local Ethical Committees received queries for approving local NHBD programs. Almost all centres requested viability testing assessment of the NHBD organ prior to implantation, and proposed the introduction of machine perfusion technology. Finally, all centres joined their efforts and made a collaborative agreement with Organ Recovery Systems for a 24/7 machine perfusion service from a central laboratory. During a three year period (2003-2005), 46 NHBD kidneys were recovered. Among these kidneys, 32 were perfused in the Organ Recovery Systems central laboratory. The Delayed Graft Function (DGF) rate for these perfused kidneys was 25%. Only one graft was lost in this subgroup. Livers, pancreases (for islet preparation) and lungs (for experimental ex-vivo evaluation) were also recovered from these non-heart-beating donors.     

Prognostic significance of free radicals: mediated injury occurring in the kidney donor

BACKGROUND: Brain death is associated with hemodynamic disturbances in systemic circulation and metabolic storm, and, thus, free radical-mediated injury to donor tissues was hypothesized. An assessment of oxidative stress in the donor and its effect on posttransplant kidney graft function comprised the scope of the study. METHODS: A prospective study was performed in 27 donors and 50 kidney transplant recipients. Sera from 27 brain-dead organ donors and preservation media were tested for malondialdehyde (MDA) and for total antioxidant status (TAS). Kidneys were preserved in University of Wisconsin-gluconate solution with machine perfusion. Mean ischemia time was 36.7+/-8 hours. Organs were transplanted to recipients on the Polish National Waiting List and posttransplant kidney function was monitored periodically. Posttransplant delayed graft function (DF) was diagnosed when a patient required at least one dialysis within first week after transplantation. Acute rejection was diagnosed clinically and confirmed with fine-needle biopsy if necessary. RESULTS: Thirty-two recipients had immediate graft function (IF), and 18 suffered from DF. MDA level in preservation solution at the end of machine perfusion was significantly higher in the DF group (52.6+/-31 vs. 25.3+/-19 micromol/L) whereas donor TAS activity was lower (1.14+/-0.2 vs. 0.97+/-0.3 mmol/mL). Patients who suffered from acute rejection received kidneys from donors with significantly higher serum MDA (66+/-73 micromol/ml vs. 23+/-49 for patients without rejection). Serum creatinine 12 to 48 months after transplantation correlated to donor- and preservation-solution MDA (P<0.006). CONCLUSIONS: Free-radical mediated injury occurring in the donor and during preservation is strictly correlated with immediate and long-term kidney function. It may also cause grafts to be prone to acute rejection.     

Kidney Transplantation Using Elderly Non-Heart-Beating Donors: A Single-Center Experience

Although acceptable outcomes have been reported in both non-heart-beating (NHB) and elderly donors individually, the large pool of elderly NHB donors has not yet been fully utilized. In 1994, we expanded our transplant protocol to include NHB donors aged over 65 years and this study compares the clinical outcomes with regular NHB transplantations. Up to June 2005, 24 patients were transplanted at our center with kidneys from NHB donors aged 65 years or more, whereas 176 patients received grafts from conventional NHB donors during the same period. Grafts from older donors were associated with inferior glomerular filtration rates (29 vs. 44 mL/min after 1 year, p = 0.01) and graft survival (52% vs. 68% after 5 years, p = 0.19) compared to younger NHB donor grafts, although the difference in graft survival was not statistically significant. Exclusion of older NHB donor kidneys with severe vascular pathology resulted in similar graft survival of older and younger NHB donor kidneys. We conclude that the use of elderly NHB donors in order to expand the donor pool was associated with unacceptable clinical outcomes and cannot be justified without further refinement in their selection, for example, by histological assessment of pretransplant biopsies.     

Non-heart-beating Donors: Renewed Source of Organs for Renal Transplantation during the Twenty-first Century

Abstract The growing demand of organs for renal transplantation makes it necessary to explore alternative routes for kidney donation. Non-heart-beating donors (NHBDs) are a valuable source of cadaveric organs and have been the subject of renewed interest in recent years. In addition to difficulties with legal and ethical acceptability, there are concerns regarding medical safety. The current NHBD program at St. George’s Hospital in London was started in March 1995. A total of 41 kidneys from category I to III donors (according to the Maastricht classification) were retrieved from the Accident and Emergency Department and several intensive care units and were subsequently transplanted. Cold in situ perfusion was commenced via femoral access or rapid aortic cannulation in most donors. Of these transplanted kidneys, 35 started functioning within 4 weeks. The permanent nonfunction (PNF) rate was 14.6% (6/41) and the estimated 1-year graft survival 82.9% (34/41). The delayed graft function (DGF) rate (defined as recipients requiring posttransplant dialysis for 3 days or longer) was 80.0% (28/35). The median serum creatinine concentration in patients with a functioning graft at 1 year was 165 μmol/L. NHBD kidneys have contributed about 15% to the regional transplant activity over the last 6 years, even though not all potential NHBDs were used. It was possible to lower the PNF rate with strict donor selection criteria and more recently with pulsatile machine perfusion. NHBDs represent a valuable source for kidneys and can extend the donor pool. More experience is currently needed to continue to lower PNF rates reliably before promoting more widespread use of NHBDs for renal transplantation.     

Non-heart-beating kidney transplantation: 6-year outcomes

Non-heart-beating donor kidneys (NHBD) are being used to increase the donor pool due to the scarcity of cadaveric heart beating donors (HBD). We evaluated the long-term outcomes of renal transplantation using NHBD kidneys, comparing the first 100 NHBD kidneys transplanted at our facility to the next consecutive cadaveric HBD kidneys for graft survival, recipient survival, and quality of graft function. Recipient survival (P = .22) and graft survival (P = .19) at 6 years did not differ between recipients of NHBD (83%, 80%) and HBD (89%, 87%) kidneys. Quality of graft function using the mean glomular filtration rates were significantly lower in the NHBD group up to 3 months following discharge (41 +/- 2 vs 47 +/- 2, P = .007) but were then comparable up to 6 years following transplantation (43 +/- 5 vs 46 +/- 4, P = .55).     

Non-heart-beating organ donors: a potential source of islets for transplantation?

BACKGROUND: The shortage of organ donors relative to the number of patients on transplant waiting lists has led to a renewed interest in the use of non-heart-beating (NHB) organ donors in many centers. The lack of donors is also a problem for islet transplantation. The disparity between donor organs and potential recipients is further exacerbated by the requirement to transplant a large number of islets to increase the chance of success and the high level of variability in islet isolation yield. Non-heart-beating (NHB) donors have not previously been assessed as a source of islets for transplantation, and it is unknown what affects the additional factor of warm ischemic injury associated with NHB organs may have on the success of islet isolation. METHODS: This study assesses the yield and function of islets from NHB donors and compares the results with islets obtained from heart-beating brain-dead (HB) donors. RESULTS: There were no differences in the yield of islets per gram of pancreas, 1788 (0-4620) NHB vs. 1580 (26-2544) HB (median, range). The secretory function was also similar in both groups, with stimulation indices of 0.71-3.49 for NHB vs. 0.30-3.57 for HB (overall range). There was no correlation between islet yield and warm ischemia time in the NHB donor group. CONCLUSIONS: In conclusion, the study has demonstrated that it is possible to isolate large numbers of islets from NHB donor pancreata and that, where NHB donor programs exist, these could provide a significant addition to the number of potentially transplantable islets.