Model for end-stage liver disease-based organ allocation: managing the exceptions to the rules

Assessing the outcome of organ allocation: choosing metrics

PURPOSE OF REVIEW

Organ allocation is a highly complex process with significant impact on outcomes of donor organs and end-stage organ disease patients. Policies governing allocation must incorporate numerous factors to meet stated objective. There have been significant alterations and ongoing discussion about changes in allocation policy for all solid organs in the United States. As with any policy change, rigorous evaluation of the impact of changes is important.

RECENT FINDINGS

This manuscript discusses metrics to consider to evaluate the impact of organ allocation policy that may be monitored on an ongoing basis including examples of research evaluating current policies. Potential metrics to evaluate allocation policy include the effectiveness, efficiency, equity, costs, donor rates, and transparency associated with the system.

SUMMARY

Ultimately, policies will often need to adapt to secular changes in donor and patient characteristics, clinical and technological advances, and overarching healthcare polices. Providing objective empirical evaluation of the impact of policies is a critical component for assessing quality of the allocation system and informing the effect of changes. The foundation of organ transplantation is built upon public trust and the dependence on the gift of donor organs, as such the importance of the most appropriate organ allocation policies cannot be overstated.

Treatment Barriers in Portopulmonary Hypertension

Portopulmonary hypertension (PoPH) is a form of pulmonary arterial hypertension (PAH) that can develop as a complication of portal hypertension. Treatment of PoPH includes PAH-specific therapies, and in certain cases, such therapies are necessary to facilitate a successful liver transplantation. A significant number of barriers may limit the adequate treatment of patients with PoPH and explain the poorer survival of these patients when compared to patients with other types of PAH. Until recently, only one randomized controlled trial has included PoPH patients, and the majority of treatment data have been derived from relatively small observational studies. In the present article, we review some of the barriers in the treatment of patients with PoPH and implications for liver transplantation.

Liver Transplantation for Cholestatic Liver Diseases in Adults

Liver transplantation (LT) is an established lifesaving therapy for patients with cholestatic liver diseases, including primary cholestatic diseases, namely primary sclerosing cholangitis and primary biliary cirrhosis, as well as secondary forms of cholestatic liver disease, including those with cholestatic complications of LT needing a retransplant. Patients with cholestatic liver diseases can be transplanted for complications of end-stage liver disease or for disease-specific symptoms before the onset of end-stage liver disease. These patients should be regularly assessed. Patient survival after LT for cholestatic liver diseases is generally better than for other indications.

Variable Use of Model for End-Stage Liver Disease Exception Points in Patients With Neuroendocrine Tumors Metastatic to the Liver and Its Impact on Patient Outcomes

BACKGROUND

The role of liver transplantation in management of patients with metastatic neuroendocrine tumors (NETs) is controversial. Because many such patients have low waitlist priority, centers may apply for model for end-stage liver disease (MELD) exception points to increase likelihood of receiving a liver transplant. No formal criteria exist for application or receipt of exception points for this indication. Few studies have assessed waitlist and posttransplantation outcomes in patients with metastatic NETs, and none examined the impact of exception points.

METHODS

We analyzed all adult patients waitlisted for liver transplantation for metastatic NETs between February 27, 2002, and June 4, 2014, and fit a multivariable model to evaluate the association between exception point status and posttransplantation outcomes.

RESULTS

There was variable use of MELD exception points across the United Network for Organ Sharing regions. Patients with an approved MELD exception were nearly twice as likely to be transplanted as those without exceptions (70.8% vs 39.1%, P < 0.001), and half as likely to be removed for death or clinical deterioration (9.2% vs 18.2%, P = 0.046). In multivariable models, posttransplantation survival was not associated with receipt of exception points, whereas risk of posttransplant mortality increased significantly with elevated serum total bilirubin level at transplantation. The 3-year posttransplant patient survival was 78% in transplant recipients with metastatic NETs whose total bilirubin level at transplantation was 1.3 mg/dL or less, compared to 36% in those with total bilirubin greater than 1.3 mg/dL.

CONCLUSIONS

Serum total bilirubin may serve as a predictor of poor posttransplant survival in patients with metastatic NETs and could help risk-stratify patients applying for MELD exception points.

TNF-α suppression by glutathione preconditioning attenuates hepatic ischemia reperfusion injury in young and aged rats

BACKGROUND AND AIM

Hepatic ischemia reperfusion (I/R) stimulates Kupffer cells and initiates injury through tumor necrosis factor-α (TNF-α) upregulation. Aim of this study was to compare the variable effects of reduced glutathione (GSH) pre-treatment on I/R liver injury in young and aged rats.

METHODS

Wistar male rats were sorted into young (groups I-III) and aged (groups IV-VI). All groups except sham (groups I and IV) were subjected to 90-min ischemia and 2-h reperfusion. The treatment groups received 200 mg/kg bwt (groups III and VI) of GSH, 30 min prior to I/R. Variable effects of GSH were studied by transaminase activities, thiobarbituric acid-reactive substances (TBARS), GSH level, GSH/oxidized GSH (GSSG) ratio, TNF-α level, apoptotic markers and confirmed by histopathological observations.

RESULTS

Our findings revealed that I/R inflicted more liver damage in aged rats than young rats. The GSH treatment prior to surgery significantly lowered the serum transaminase activities, hepatic TBARS level and effectively restored the GSH/GSSG ratio in both young and aged rats more remarkably in the mitochondria. Western analysis depicted that the GSH treatment effectively suppressed TNF-α expression and apoptotic markers in both young and aged rats. These findings were further confirmed by terminal deoxynucleotide transferase dUTP nick end labeling assay and histopathological observations of liver sections of young and aged rats.

CONCLUSION

Restoration of GSH/GSSG ratio through GSH pre-conditioning inhibits TNF-α and apoptosis in hepatic I/R injury. Hence, GSH pre-conditioning may be utilized in both young and aged individuals during liver transplantation/surgery for better post-operative outcomes.