Graft function after kidney transplantation from non-heartbeating donors according to maastricht category

PURPOSE

Donor shortages have led to some groups using alternative sources such as non-heartbeating donors (NHBDs). Kidneys from NHBDs suffer from warm ischemia at cardiac arrest which is reflected by acute tubular necrosis of the allograft, resulting in a period of delayed graft function. NHBDs are categorized by the circumstances surrounding the agonal events of death which reflect differences in the likelihood of ischemic injury to the kidney. In this study we determined the impact of ischemic injury on the renal function of kidneys procured from different categories of NHBDs.

MATERIALS AND METHODS

From 1998 to 2003, 144 kidneys were procured from 72 NHBDs resulting in 93 transplants characterized into Maastricht categories II, III and IV NHBD renal transplants. Renal function after transplant was evaluated from the last dialysis until discharge from hospital, and then at 3 monthly intervals thereafter.

RESULTS

Primary warm ischemic time is more prolonged in the uncontrolled donor (category II) than controlled donor (category III greater than IV). Delayed graft function occurs more frequently (Maastricht category II 83.8%, III 67.4% and IV 0%, ANOVA p <0.05) and the return to normal function is more prolonged in uncontrolled donors. This is illustrated by the greater incidence of acute tubular necrosis (Maastricht category II 81.1%, III 65.2% and IV 50.0%, ANOVA p = nonsignificant) in the kidney allograft. There was no difference in year 1 allograft survival (Maastricht category II 83.9%, III 92.5% and IV 100%, ANOVA p = nonsignificant).

CONCLUSIONS

Early graft function is poorest in kidneys derived from Maastricht category II donors and best in category IV with III in-between. However, after 3 months the function of kidneys from all donors is the same.

Anti-vimentin Antibody Detection in Recipients of Heart-Beating and Non–Heart Beating Donor Kidneys

Alternative donor sources include non-heart-beating donors (NHBDs). There donors have been exposed to significant ischemia, so that it is common to utilize machine perfusion to either improve the organs or at least assess their viability. Both prolonged warm ischemia and machine perfusion can potentially damage the vascular endothelium, thereby exposing vimentin to antigenic recognition. The aim of this study was to determine whether anti-vimentin antibodies could be detected in the blood of renal transplant recipients at specific time points after transplant and whether they could be related to the donor source. Fifty-one recipients of NHBD kidneys were compared to 52 recipients of heart-beating donor (HBD) kidneys. All recipients had similar anti-vimentin levels pretransplant. However, at 1 month those kidneys from Maastricht category II NHB donors showed significantly higher levels. At 6 months both Maastricht category II and category III NHB donor recipients displayed significantly higher levels than recipients of HBD kidneys.

The effect of inadequate in situ perfusion in the non heart-beating donor

In situ aortic perfusion in the nonheart-beating donors (NHBD) is an important procedure to reduce primary warm ischaemic injury prior to formal donor organ retrieval. It allows an interim period to obtain donor family consent and theatre preparation. This study describes our experience of inadequate aortic perfusions resulting from difficult aortic cannulations and associated adverse outcome despite reasonable viability tests. Since 1998, all NHBD in our institution are perfused in situ using a double balloon triple lumen (DBTL) catheter inserted through a femoral artery cut-down procedure. The DBTL catheter is positioned with distal occlusive balloon at the aortic bifurcation using the "pull-back" technique, the proximal occlusive balloon lies above the renal arteries. This provides selective aortic perfusion in particular the kidneys. Venous decompression using a femoral vein catheter enables a "two-way infusion system". Pre-transplant viability status of retrieved kidneys is determined by measuring pressure/resistance characteristics to the flow and biochemical markers for ischaemic injury. There were 90 NHBD renal transplants performed from 72 donors. Three renal transplants were carried out from three donors of ineffective in situ perfusion secondary to cannulation difficulties. Femoral cannulation was difficult as a result of extensive atherosclerosis of donor vessels. The comparison of allograft outcome from effective and ineffective in situ perfusion of donors showed high rate of primary nonfunction (PNF) from ineffective perfusion (chi-squared, P < 0.0001). The cases demonstrated poor outcome from ineffective perfusion related to the cannulation difficulties. Therefore a strict policy should be taken in cases where aortic cannulation and perfusion is inadequate, despite pretransplant assessment. In these circumstances, the primary warm ischaemia time should be extended to include this period of ineffective perfusion.

Do tissue damage biomarkers used to assess machine-perfused NHBD kidneys predict long-term renal function post-transplant?

BACKGROUND

Renal transplantation in many units is limited by the availability of donor organs. Kidneys obtained from non-heart-beating donors (NHBD) represent an important resource, with the potential to substantially increase the available donor organ pool. Such kidneys are associated with increased warm ischaemic tissue injury which may be assessed by hypothermic machine perfusion. Within our transplant centre, a key component of such damage assessment and viability screening involves the quantification of the tissue damage biomarkers glutathione S-transferase in kidney perfusates.

METHODS

Since 1998, 126 NHBD kidneys were machine-perfused prior to implantation, resulting in 74 transplants. Kidney perfusate samples were assayed for glutathione S-transferase in "real time", and alanine aminopeptidase and fatty acid binding protein in "retrospect".

RESULTS

The pre-transplant concentration of these tissue injury biomarkers determined pre-transplant did not correlate with subsequent longer-term renal function, as assessed by measurement of serum creatinine (tGST: Spearman correlation r=-0.02; Ala-AP: r=0.02; H-FABP: r=-0.05) and creatinine clearance (tGST: r=0.08; Ala-AP: r=-0.02; H-FABP: r=0.14) for those kidneys that had passed their viability tests.

CONCLUSIONS

Thus whilst these biomarkers may represent reliable pre-transplant indicators of immediate kidney viability and short-term kidney function, they do not predict the efficacy of renal function in the longer term.

Improving the quality of kidneys from non-heart-beating donors, using streptokinase: an animal model

BACKGROUND

Non-heart-beating donors (NHBD) offer a promising potential to increase the cadaveric organ donor pool, especially for kidneys. However, almost half of NHBD kidneys are discarded after viability assessment. This wastage is costly in both human and monetary terms. Intravascular thrombosis at the time of donor death is an event leading to failure in the viability assessment. We have developed an animal model to investigate the effects of the addition of streptokinase to the in situ flush medium before transplant in an attempt to redress the situation.

METHODS

Two groups of eight healthy young Landrace Yorkshire white pigs were entered into the study. Both groups were subjected to approximately 70 min warm ischemia. Both groups received an intravascular flush with 4 L of Marshall's solution with heparin (1000 IU/L); one group of pigs also had streptokinase (1.5 MIU/L) added. After donor nephrectomy, all kidneys were machine perfused for 4 hr. Data on perfusion characteristics were taken and samples of kidney effluent were assayed for tissue damage biomarkers, glutathione S-transferase (GST) and alanine aminopeptidase (Ala-AP). Wedge sections of porcine kidneys were taken at the end of perfusion, for histological analysis.

RESULTS

Data on machine perfusion parameters (temperature, mean pressure index, resistance) indicate better cooling, lower resistance, and lower mean pressure index in the streptokinase-treated group of pigs. GST and Ala-AP levels were increased in the nonstreptokinase group perfusates. Histopathological analysis of porcine kidneys indicated more ischemic injury and tissue damage in the nonstreptokinase group.

CONCLUSION

The use of streptokinase in this porcine NHBD model conferred benefits to donor kidneys when assessed by machine perfusion. Markers of biochemical injury indicated that less renal tissue damage occurred with the incorporation of streptokinase in the in situ flush medium.