Peritoneal cooling may provide improved protection for uncontrolled donors after cardiac death: an exploratory porcine study

Machine perfusion versus cold storage of livers: a meta-analysis

Different organ preservation methods are key factors influencing the results of liver transplantation. In this study, the outcomes of experimental models receiving donation after cardiac death (DCD) livers preserved through machine perfusion (MP) or static cold storage (CS) were compared by conducting a meta-analysis. Standardized mean difference (SMD) and 95% confidence interval (CI) were calculated to compare pooled data from two animal species. Twenty-four studies involving MP preservation were included in the meta-analysis. Compared with CS preservation, MP can reduce the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and hyaluronic acid (HA) and the changes in liver weight. By contrast, MP can enhance bile production and portal vein flow (PVF). Alkaline phosphatase (ALP) levels and histological changes significantly differed between the two preservation methods. In conclusion, MP of DCD livers is superior to CS in experimental animals.

Recommendations for donation after circulatory death kidney transplantation in Europe

Donation after circulatory death (DCD) donors provides an invaluable source for kidneys for transplantation. Over the last decade, we have observed a substantial increase in the number of DCD kidneys, particularly within Europe. We provide an overview of risk factors associated with DCD kidney function and survival and formulate recommendations from the sixth international conference on organ donation in Paris, for best-practice guidelines. A systematic review of the literature was performed using Ovid Medline, Embase and Cochrane databases. Topics are discussed, including donor selection, organ procurement, organ preservation, recipient selection and transplant management.

Beyond poiseuille: preservation fluid flow in an experimental model

Poiseuille's equation describes the relationship between fluid viscosity, pressure, tubing diameter, and flow, yet it is not known if cold organ perfusion systems follow this equation. We investigated these relationships in an ex vivo model and aimed to offer some rationale for equipment selection. Increasing the cannula size from 14 to 20 Fr increased flow rate by a mean (SD) of 13 (12)%. Marshall's hyperosmolar citrate was three times less viscous than UW solution, but flows were only 45% faster. Doubling the bag pressure led to a mean (SD) flow rate increase of only 19 (13)%, not twice the rate. When external pressure devices were used, 100 mmHg of continuous pressure increased flow by a mean (SD) of 43 (17)% when compared to the same pressure applied initially only. Poiseuille's equation was not followed; this is most likely due to “slipping” of preservation fluid within the plastic tubing. Cannula size made little difference over the ranges examined; flows are primarily determined by bag pressure and fluid viscosity. External infusor devices require continuous pressurisation to deliver high flow. Future studies examining the impact of perfusion variables on graft outcomes should include detailed equipment descriptions.

The super-rapid technique in Maastricht category III donors: has it developed enough for marginal liver grafts from donors after cardiac death?

PURPOSE OF REVIEW

Follow-up data from donors following cardiac death (DCD) liver transplants suggest an increased risk of graft failure and morbid complications, and the risk increased with grafts from marginal donors. Donor warm ischaemia (dWIT) stands out as the common aetiological factor. Aim of this review is to examine if super-rapid technique had developed sufficiently enough to improve the effects of dWIT that had been started since treatment withdrawal in category III DCD marginal donors.

RECENT FINDINGS

The recent findings suggest limited evolvement, but these have not been contributed to reduce dWIT significantly. Evidence suggests hypoperfusion and circulatory stop occurring well before electrophysical inactivity; hence, dWIT is probably underestimated. Time spent since cardiac death to aortic cross clamp is directly linked to ischaemic complications; limited modifications to surgical technique alone have failed to make an impact on these complications. Marginal grafts generally perform worse, increasing the overall financial cost of patient management.

SUMMARY

Irrespective of the speed at which aortic perfusion is instituted, the technical developments have not been able to improve outcomes/utility of marginal DCD grafts. The future of the DCD programmes should explore the means of reviving organ damage incurred during dWIT that are incorporated to the super-rapid technique of organ harvest.

Extracorporeal membrane oxygenation for resuscitation of deceased cardiac donor livers for hepatocyte isolation

BACKGROUND

Deceased cardiac donors (DCDs) have become a useful source of organs for liver transplantation; nevertheless, there are concerns about the longevity of these grafts. The aim of this study was to evaluate the use of extracorporeal membrane oxygenation (ECMO) to resuscitate DCD porcine livers as a preclinical model using hepatocyte isolation and viability as a marker to assess whole-graft preservation.

MATERIALS AND METHODS

We randomized Landrace pigs into three groups after cardiac death and 30 min of warm ischemia: group 1, peritoneal cooling with intravascular cooling for 2 h; group 2, ECMO for 2 h; and group 3, control (conventional intravascular cooling and retrieval). We then reperfused group 1 and 2 livers for 2 h on an ex vivo reperfusion circuit and isolated hepatocytes.

RESULTS

After reperfusion, hepatocyte viability was significantly improved in the ECMO group compared to the cooling groups, as measured by trypan blue, methylthiazolyldiphenyl-tetrazolium bromide, and seeding efficiency. Glycogen and reduced glutathione content were significantly used in the ECMO group both before and after reperfusion compared with group 2. The adenosine diphosphate:adenosine triphosphate ratio showed an improved trend (lower) in the ECMO group compared with the cooling group but did not reach statistical significance either before or after reperfusion.

CONCLUSIONS

This preclinical study suggests that ECMO is a viable technique for liver preservation that gives an improved yield of hepatocytes when isolated from a DCD liver, suggesting improved liver preservation.

Trends in liver transplantation 2011

This review will highlight some of the important recent trends in liver transplantation. When possible, we will compare and contrast these trends across various regions of the world, in an effort to improve global consensus and better recognition of emerging data.

Impact of normothermic preservation with extracellular type solution containing trehalose on rat kidney grafting from a cardiac death donor

Background

The aim of this study was to investigate factors that may improve the condition of a marginal kidney preserved with a normothermic solution following cardiac death (CD) in a model of rat kidney transplantation (RTx).

Methods

Post-euthanasia, Lewis (LEW) donor rats were left for 1 h in a 23°C room. These critical kidney grafts were preserved in University of Wisconsin (UW), lactate Ringer's (LR), or extracellular-trehalose-Kyoto (ETK) solution, followed by intracellular-trehalose-Kyoto (ITK) solution at 4, 23, or 37°C for another 1 h, and finally transplanted into bilaterally nephrectomized LEW recipient rats (n = 4–6). Grafts of rats surviving to day 14 after RTx were evaluated by histopathological examination. The energy activity of these marginal rat kidneys was measured by high-performance liquid chromatography (HPLC; n = 4 per group) and fluorescence intensity assay (n = 6 per group) after preservation with UW or ETK solutions at each temperature. Finally, the transplanted kidney was assessed by an in vivo luciferase imaging system (n = 2).

Results

Using the 1-h normothermic preservation of post-CD kidneys, five out of six recipients in the ETK group survived until 14 days, in contrast to zero out of six in the UW group (p<0.01). Preservation with ITK rather than ETK at 23°C tended to have an inferior effect on recipient survival (p = 0.12). Energy activities of the fresh donor kidneys decreased in a temperature-dependent manner, while those of post-CD kidneys remained at the lower level. ETK was superior to UW in protecting against edema of the post-CD kidneys at the higher temperature. Luminescence intensity of successful grafts recovered within 1 h, while the intensity of grafts of deceased recipients did not change at 1 h post-reperfusion.

Conclusions

Normothermic storage with extracellular-type solution containing trehalose might prevent reperfusion injury due to temperature-dependent tissue edema.

Preservation techniques for donors after cardiac death kidneys

PURPOSE OF REVIEW

The purpose of the present review is to describe the techniques currently used to preserve kidneys from donors after cardiac death.

RECENT FINDINGS

Automated chest compression devices may be used to improve organ perfusion between cardiac death and preservation measures. Normothermic extracorporeal membrane oxygenation reduces warm ischemic injury and has the ability to improve organ viability in donors after cardiac death.

SUMMARY

Kidneys from donors after cardiac death expand the donor pool but are inevitably subjected to a period of warm ischemia. Reduction of warm ischemic injury to the organs improves transplant outcome. To reduce this injury in organs from donors after cardiac death, different preservation techniques are used. Automated chest compression devices improve organ perfusion between cardiac death and the start of organ preservation. In-situ preservation with double-balloon triple-lumen catheter is an easy technique to preserve organs in uncontrolled donors and is used in many centers to cool and flush the organs. In controlled donors, organs can also be flushed after laparotomy and direct cannulation of the aorta. Extracorporeal membrane oxygenation reduces warm ischemic injury and the use of normothermic perfusion seems promising. Optimal preservation is essential to improve the viability of kidneys from donors after cardiac death, to fully utilize this large donor pool.