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

Survival transplantation of preserved non-heart-beating donor rat livers: preservation by hypothermic machine perfusion

BACKGROUND

Non-heart-beating donor (NHBD) livers are an untapped source with the potential to provide relief to the current donor shortage problem. Hypothermic machine perfusion (MP) has the potential to reclaim and preserve these marginal donor organs.

METHODS

This study compared 5-day survival in a rat NHBD liver transplantation model with simple cold storage (SCS) and MP-preserved tissues that had experienced 30 min of warm ischemia followed by a 5-hr preservation period with the University of Wisconsin solution. Total release of lactate dehydrogenase (LDH) and alanine aminotransferase (ALT) were determined at major time points. Bilirubin levels and histology were examined after 5-day survival.

RESULTS

Six of seven control livers and five of six MP livers survived, whereas SCS tissues had survival in zero of seven. The results showed that MP livers had reduced release of LDH and ALT after 5 hr of storage, 5.07+/-1.42 and 2.02+/-0.69 U (mean+/-SE), respectively, compared with SCS, 15.54+/-0.81 and 3.41.3+/-0.73 U, respectively. Bilirubin values after 5-day survival of MP livers (1.17+/-0.49 mg/dL) were comparable to controls (0.91+/-0.36 mg/dL). Histology confirms that SCS displayed increased necrosis and MP tissue showed regions of near normal hepatic structure.

CONCLUSIONS

These results suggest that MP for 5 hr improves survival and reduces cellular damage of liver tissue that has experienced 30 min of warm ischemia when compared with SCS tissues. Further studies need to be conducted, but this study suggests that MP preservation has the potential to reclaim and preserve NHBD liver tissues.

Kidney transplantation from non heart-beating donors

The use of non heart-beating donor (NHBD) kidneys to expand transplant programmes offers an answer to the problem of donor shortage. This source of kidneys is utilised by very few renal transplant units despite longstanding and growing evidence of equivalent graft function and survival, compared with cadaveric donor organs. This article reviews the selection criteria, technical approaches and logistical organisation involved in NHBD kidney retrieval and transplantation and outlines the evidence for graft function and survival, and patient outcome. The ethical and legal implications of running a NHBD programme are discussed, and some areas of current and likely future research are covered.

Experiences learned in the successful establishment of a nonheart beating donor program for renal transplantation

PURPOSE

With the continuing shortage of suitable donors increasing interest is being shown in nonheart beating donation. Such a resource is a new and, therefore, an underused source of donor organs. However because of the nature of such donors, the kidneys so derived have been damaged by primary warm ischemia, and so potentially they may never function. We introduced viability testing to identify such organs and, thus, avoid transplantation. We reviewed sentinel cases in our developing program from which we have learned.

MATERIALS AND METHODS

Machine perfusion was developed locally and used to test the kidneys derived from such donors. Flow characteristics and enzyme analysis were used to define usable kidneys. The definitions of acceptable criteria evolved through the study during a 3-year period.

RESULTS

As previously defined, acceptable criteria were initially adhered with decreasing resistance and a glutathione S-transferase of less than 200 IU/l/100 gm. After the series described acceptable limits were changed in favor of a high perfusion flow index, low temperature, low weight increase and low glutathione S-transferase.

CONCLUSIONS

If such criteria are adhered to, graft survival becomes reliable from such donors.

Liver transplantation from Maastricht category 2 non-heart-beating donors

BACKGROUND

The demand for liver transplantation has increasingly exceeded the supply of cadaver donor organs. Non-heart-beating donors (NHBDs) may be an alternative to increase the cadaver donor pool.

METHODS

The outcome of 20 liver transplants from Maastricht category 2 NHBDs is compared with 40 liver transplants from heart-beating donors (HBDs). After unsuccessful cardiopulmonary resuscitation (CPR), cardiopulmonary support (CPS) with simultaneous application of chest and abdominal compression (n=6), and cardiopulmonary bypass (CPB; n=14), which was hypothermic (n=7) or normothermic (n=7), were used to preserve the organs from NHBDs. Factors that may influence the outcome of livers from Maastricht category 2 NHBDs were also investigated.

RESULTS

With a minimum follow-up of 2 years, actuarial patient and graft survivals with livers from Maastricht category 2 NHBDs were 80% and 55%, respectively. Transplantation of organs from these donors was associated with a significantly higher incidence of primary nonfunction, biliary complications, and more severe initial liver dysfunction compared with livers from HBDs. Graft survival was 83% in livers from NHBDs preserved with CPS and 42% in those maintained with CPB. No graft failed if the duration of warm ischemia did not exceed 130 min with CPR or CPS, and if the period of CPB did not surpass 150 min when this method was used after CPR, regardless if it was hypothermic or normothermic.

CONCLUSION

Livers from Maastricht type 2 NHBDs may be used for transplantation if the period of warm ischemia during CPR or CPS does not exceed 130 min. Hypothermic or normothermic CPB after CPR preserves liver viability for an additional 150 min.

Pulsatile machine perfusion vs. cold storage of kidneys for transplantation: a rapid and systematic review

OBJECTIVE

To identify and prioritize key areas for further research in kidney preservation systems.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis of the effectiveness of machine perfusion and cold storage techniques in reducing delayed graft function (DGF) and improving graft survival in recipients of kidneys from beating and non-heart-beating donors. Literature quantifying the link between DGF and graft survival was used to evaluate the potential long-term impact of machine perfusion and cold storage systems. Cox proportional hazards modelling was used to predict graft survival and graft years gained over 10 yr. Monte Carlo sensitivity analysis was conducted to evaluate stochastic uncertainties within the model.

RESULTS

Machine perfusion leads to a relative risk of DGF of approximately 80% (67%, 96%) compared with cold storage, although the evidence base is limited in quality and study size. Direct evidence on graft survival at 1 yr demonstrates no statistically significant difference between machine perfusion and cold storage. Predictions based upon quantifying the link between DGF and graft survival suggest potential improvements of between 0 and 6% at 10 yr.

DISCUSSION

Studies of high methodological quality and sufficient size are required to determine whether machine preservation leads to reduce rates of DGF. Predicted impact on graft survival implies that direct evidence would require a large population followed up over a long period of time. Registry database analysis supported by validation of the link between DGF and graft survival may be preferable and more feasible than randomized controlled trials.

Nonheart-beating kidney donation: current practice and future developments

BACKGROUND

Nonheart-beating kidney donation (NHBD) is gaining acceptance as a method of donor pool expansion. However, a number of practitioners have concerns over rates of delayed graft function, acute rejection, and long-term graft survival. The ethical issues associated with NHBD are complex and may be a further disincentive. Tailored strategies for preservation, viability prediction, and immunosuppression for kidneys from this source have the potential to maximize the number of available organs. This review article presents the current practice of NHBD kidney transplantation, examines the results and draws comparisons with cadaveric kidneys, and explores some areas of potential development.

METHODS

A review of the current literature on NHBD kidney donation was performed.

RESULTS

The renewed interest in NHBD kidneys is driven by a continuing shortfall in available organs. Those centers involved in NHBD report an increase in kidney transplants of the order of 16% to 40% and there is no evidence that the financial costs are higher with NHBDs. The majority of experience comes from Maastricht category 2 NHBDs, where an estimation of warm time is possible. This is generally limited to 40 minutes. There are variations in the technique for kidney preservation prior to retrieval, but most centers use an aortic balloon catheter. Much work has looked at the ideal technique for kidney preservation prior to implantation. Evidence suggests that machine perfusion produces the best initial function rates, decreased use of adjuvant immunotherapy and fewer haemodialysis sessions than static cold storage.

CONCLUSION

Despite being associated with poorer initial graft function, the long-term allograft survival of NHBD kidneys does not differ from the results of transplantation from cadaveric kidneys. Further, serum creatinine levels are generally equivalent. Constant reassessment of the ethical issues is required for donation to be increased while respecting public concerns. Use of viability assessment and tailoring of immune suppression for NHBD kidneys may allow a further increase in donation from this source.

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.

Long-term results of renal transplantation using kidneys harvested from non-heartbeating donors: a 15-year experience

PURPOSE

To expand the pool of suitable organ donors we developed an organ procurement program of non-heartbeating donors during the last 15 years. We compare graft survival in patients receiving renal transplants procured from non-heartbeating with recipients of kidneys from heartbeating donors.

MATERIALS AND METHODS

From 1986 to 1999, 60 renal transplantations were performed with kidneys harvested from non-heartbeating donors (Mastrich category IV). Kidneys were procured using a double balloon triple lumen catheter inserted into the femoral artery. The 60 kidneys were selected from 70 non-heartbeating donors based on age younger than 50 years, warm ischemia less than 30 minutes, creatinine less than 200 micromol./l., and no hypertension or major histological lesions. Long-term results of graft survival and complications were compared with a series of 1,065 renal transplantations performed during the same period with kidneys procured from heartbeating donors.

RESULTS

Mean age of the recipients was statistically different as non-heartbeating donors were older. However, the 10-year graft survival rates were similar in both groups (50% versus 53%). Incidence of ureteral stenosis and fistula, arterial stenosis and thrombosis was not statistically different in both groups. On the other hand, delay graft function was more frequent in non-heartbeating donors (60% versus 40%, p = 0.01).

CONCLUSIONS

Despite a high rate of acute tubular necrosis, kidneys harvested from non-heartbeating donors had the same graft survival rates as those procured from heartbeating donors. Surgical complications were not different. Transplantation of selected kidneys procured from non-heartbeating donors should be promoted as a response to organ shortage.

Functional recovery of preserved livers following warm ischemia: improvement by machine perfusion preservation

BACKGROUND

Hypothermic machine perfusion preservation has the potential to relieve the current donor shortage problem by reclaiming and preserving marginal donor organs including those from viable non-heart-beating donors. A number of problems exist with the current machine perfusion technology for preserving livers, and much research is needed to determine the clinical impact of this technology in preserving non-heart-beating donor livers.

METHODS

This study was conducted to compare the poststorage function and microcirculation of simple cold stored and machine perfusion preserved livers that had experienced 30 min of warm ischemia followed by a 10 hr preservation period. In an isolated rat liver perfusion model, lactate dehydrogenase activity, indocyanine green secretion, and portal pressure values were determined at major time points. An intravital microscopy was conducted to assess microcirculation.

RESULTS

The results showed an increase in flow homogeneity of machine perfused livers, which correlated with the reduction in portal pressure when compared with simple cold storage (5.4+/-0.4 vs. 8.7+/-0.6 mm Hg). A reduction in lactate dehydrogenase levels in the perfusate (333+/-22 vs.103+/-8 U/L) and an increase in bile production of the machine perfused livers (4.9+/-0.5 vs. 33.2+/-1.7 microg/min/g liver) and indocyanine green secretion (11.7+/-1.7 vs. 21.2+/-2.1 Abs/g bile) were observed at all time points (mean+/-SE of final point given). Intravital microscopic examination indicated that large regions of non flow, as indicated by the absence of fluorescein isothiocyanate-labeled albumin, were observed in the simple cold stored tissue, whereas machine perfused liver showed increase flow homogeneity. Values of bile production, indocyanine secretion, and cellular damages were comparable with controls. Histologic examination confirmed that simple cold stored tissue displayed increased vacuolization, and machine perfused tissue showed regions of normal hepatic structure.

CONCLUSION

These results suggest that machine perfusion for 10 hr improves both poststorage function and microcirculation while reducing cellular damage of liver tissue that has experienced 30 min of warm ischemia, when compared with simple cold storage. Further studies need to be conducted, but this study suggests that machine perfusion preservation has the potential to reclaim and preserve liver tissues after warm ischemic insult.

Long-term renal function in kidneys from non-heart-beating donors: A single-center experience

BACKGROUND

Cadaveric kidneys from brain-stem-dead donors continue to be limited because the number of donors has reached a plateau. Wide recruitment of non-heart-beating donors (NHBD) could significantly increase the donor pool. NHBD renal transplants are underused because of the concern of poor quality graft function from such donors. In response to this perception, we reviewed 46 NHBD renal transplants performed in our center since 1998.

METHODS

All NHBD kidneys were machine-perfused using the Newcastle continuous-hypothermic pulsatile preservation system before transplantation. A control heart-beating-donor (HBD) group was taken as the next consecutive HBD renal transplant to the NHBD transplant. The outcome and quality of function of the groups of renal transplants were analyzed for short-term and long-term performance.

RESULTS

The renal transplant patients were matched for donor and recipient factors. Survival rates for allografts and patients were similar for 1 to 3 years. There was an increased incidence of delayed graft function in the NHBD renal transplants in the perioperative period. The creatinine clearance was 22.8+/-2.3 mL/minute for NHBD patients and 44.4+/-2.9 mL/minute for HBD patients at the time of discharge from hospital. This difference equalized after 3 months and the creatinine clearance for NHBD was 44.2+/-2.4 mL/minute and for HBD 49.2+/-3.4 mL/minute.

CONCLUSIONS

Our results for NHBD renal transplants confirm that such grafts suffer primary warm ischemic injury, shown by the increased incidence of acute tubular necrosis and consequent delayed graft function. This produced poor renal function at the time of hospital discharge. After 3 months, the renal function of NHBD cases improved to the level seen in HBD patients.

Kidney transplantation from donors without a heartbeat

BACKGROUND

The dramatic shortage of kidney donors has triggered interest in other sources of organs, such as donors without a heartbeat. Accumulating evidence suggests that the short-term survival of cadaveric kidneys from such donors is similar to that of cadaveric kidneys from donors with a heartbeat. However, no data from large, matched studies with long-term follow-up are available. We conducted a matched, single-center study of kidney transplants obtained from donors without a heartbeat and those from donors with a heartbeat, with a 15-year follow-up period.

METHODS

Between 1985 and 2000, 122 kidney transplantations involving donors without a heartbeat were performed at the University of Zurich, in Switzerland. Outcomes of these procedures were compared with those of 122 transplantations of kidneys from donors with a heartbeat. The recipients were matched according to age, sex, number of transplantations, and calendar period of transplantation.

RESULTS

The characteristics of the recipients did not differ significantly between the two groups. We observed a significantly higher incidence of delayed graft function among the patients who received kidneys from donors without a heartbeat (48.4 percent) than among the patients who received kidneys from donors with a heartbeat (23.8 percent) (P<0.001). However, the long-term rate of graft survival was similar in the two groups (P=0.98): at 10 years, the rate of graft survival was 78.7 percent for kidneys from donors without a heartbeat and 76.7 percent for kidneys from donors with a heartbeat.

CONCLUSIONS

Although the incidence of delayed graft function is significantly higher with kidneys from donors without a heartbeat than with kidneys from donors with a heartbeat, there is no difference in long-term outcome between the two types of graft.

Machine perfusion for kidneys: how to do it at minimal cost

Due to a shortage of organs for transplantation, many centres use marginal grafts to increase their donor pool. As kidneys from non-heart-beating donors (NHBD) have sustained initial ischaemic damage, their viability is difficult to predict. Hypothermic pulsatile perfusion has not only been used to improve the condition of such grafts, but also allows viability assessment. Suitable systems are becoming more readily available, but they are expensive. We have used existing dialysis equipment with modified sterilised inserts to create a pulsatile hypothermic perfusion system. With this system, 41 NHBD kidneys were perfused for up to 8 h; their intravascular renal resistance (IRVR), flow characteristics as well as glutathione S transferase (GST) measurements were performed to assess viability. This hypothermic pulsatile perfusion system is now an integral component of our NHBD programme.

Role of hepatocytes and bile duct cells in preservation-reperfusion injury of liver grafts

In liver transplantation, it is currently hypothesized that nonparenchymal cell damage and/or activation is the major cause of preservation-related graft injury. Because parenchymal cells (hepatocytes) appear morphologically well preserved even after extended cold preservation, their injury after warm reperfusion is ascribed to the consequences of nonparenchymal cell damage and/or activation. However, accumulating evidence over the past decade indicated that the current hypothesis cannot fully explain preservation-related liver graft injury. We review data obtained in animal and human liver transplantation and isolated perfused animal livers, as well as isolated cell models to highlight growing evidence of the importance of hepatocyte disturbances in the pathogenesis of normal and fatty graft injury. Particular attention is given to preservation time-dependent decreases in high-energy adenine nucleotide levels in liver cells, a circumstance that (1) sensitizes hepatocytes to various stimuli and insults, (2) correlates well with graft function after liver transplantation, and (3) may also underlie the preservation time-dependent increase in endothelial cell damage. We also review damage to bile duct cells, which is increasingly being recognized as important in the long-lasting phase of reperfusion injury. The role of hydrophobic bile salts in that context is particularly assessed. Finally, a number of avenues aimed at preserving hepatocyte and bile duct cell integrity are discussed in the context of liver transplantation therapy as a complement to reducing nonparenchymal cell damage and/or activation.

Comparison of proteolytic enzymes and glutathione S-transferase levels in non-heart-beating donors' (NHBD) kidney perfusates

In order to identify biochemical markers of kidney damage prior to transplantation, we determined the levels of activity of a range of proteolytic enzymes in kidney perfusate samples from non-heart-beating donor (NHBD) cases. Urinary protease activities have been described as indices of kidney damage in renal disease; their potential as markers of tissue damage in kidneys before transplantation has not been assessed. In an attempt to identify additional/improved biochemical markers, the present study compared the levels of total glutathione S-transferase (GST) with corresponding levels of several proteolytic enzymes in perfusate fluid from machine perfused NHBD kidneys. Proteases were selected to represent factors that may influence enzyme efflux, such as intracellular localization or molecular size.

METHODS

Perfusate samples were obtained over an 8-hour period from machine-preserved NHBD kidneys. Protease activities in these samples were determined by fluorometric assays and comparison made with total GST activity. Individual proteases were analysed in the transplanted and non-transplanted kidney groups (discarded on the basis of other viability parameters).

RESULTS

A correlation between protease activity and total GST was obtained for only leucyl- and pyroglutamyl aminopeptidase. Furthermore, in the transplanted group, it was possible to set nominal upper limits of activity for alanyl-arginyl- and dipeptidyl IV-aminopeptidase (AP). In the non-transplanted kidney group protease levels were increased above "normal" upper limits for the same enzyme types. By the use of alanyl AP it was possible to discriminate 75% of unsuitable kidneys discarded by the use of other criteria.

CONCLUSION

The lack of correlation between total GST and protease activity for most of the enzymes investigated and alanyl AP levels in perfusate samples could be related to differences in cellular localisation, suggesting that assays of alanyl AP may give complimentary biochemical information relating to kidney tissue damage. Quantification of alanyl AP in machine perfusate samples may be a valuable additional independent biomarker of tissue damage.