Prediction Model to Discard A Priori Liver Allografts

Machine Learning Prediction of Liver Allograft Utilization From Deceased Organ Donors Using the National Donor Management Goals Registry

Early prediction of whether a liver allograft will be utilized for transplantation may allow better resource deployment during donor management and improve organ allocation. The national donor management goals (DMG) registry contains critical care data collected during donor management. We developed a machine learning model to predict transplantation of a liver graft based on data from the DMG registry.

Methods

Several machine learning classifiers were trained to predict transplantation of a liver graft. We utilized 127 variables available in the DMG dataset. We included data from potential deceased organ donors between April 2012 and January 2019. The outcome was defined as liver recovery for transplantation in the operating room. The prediction was made based on data available 12-18 h after the time of authorization for transplantation. The data were randomly separated into training (60%), validation (20%), and test sets (20%). We compared the performance of our models to the Liver Discard Risk Index.

Results

Of 13 629 donors in the dataset, 9255 (68%) livers were recovered and transplanted, 1519 recovered but used for research or discarded, 2855 were not recovered. The optimized gradient boosting machine classifier achieved an area under the curve of the receiver operator characteristic of 0.84 on the test set, outperforming all other classifiers.

Conclusions

This model predicts successful liver recovery for transplantation in the operating room, using data available early during donor management. It performs favorably when compared to existing models. It may provide real-time decision support during organ donor management and transplant logistics.

Doppler ultrasonography and contrast-enhanced ultrasonography to evaluate liver allograft discard: A pilot prospective study

BACKGROUND

Broad hemodynamic changes, is believed to have a profoundly damaging effect on donor livers after brain death (DBD) or cardiac death (DCD). It remains unclear whether Doppler ultrasonography (DUS) and contrast-enhanced ultrasonography (CEUS), the imaging modalities to evaluate perfusion, could provide more information of liver discarded.

OBJECTIVE

To evaluate the ability of DUS and CEUS to predict the risk of DBD or DCD liver discarded.

METHODS

The consecutive DBD or DCD donors with DUS/CEUS examinations before surgical procurement from February 2016 to June 2018 at our institution were included. The US and CEUS images of each donor liver were analyzed and the parameters were recorded.

RESULTS

Among the 67 eligible donor livers, 15 (22.4%) were discarded and 52 (77.6%) were used. The discarded livers showed prolonged SAT of hepatic artery (0.08s vs 0.06s, OR = 2.169, P = 0.008) on DUS, less cases with homogeneous enhancement (40.0% vs 73.1%, OR = 0.243, P = 0.028) on CEUS, more cases with decreased enhancement (53.3% vs 19.2%, OR = 4.800, P = 0.009), and less difference of the peak time between portal vein and liver parenchymal (0.5s vs 6.7s, OR = 0.917, P = 0.034). The multivariable analysis showed that donor liver with prolonged SAT of hepatic artery (OR = 7.304, 95% CI: 1.195-44.655, P = 0.031) and decreased enhancement (OR = 2.588, 95% CI: 1.234-5.426, P = 0.012) were independent factors of liver discarded.

CONCLUSIONS

DUS/CEUS could be applied as a promising predictive tool to screen high-risk liver donors. The prolonged SAT of hepatic artery on DUS and the decrease of liver donor in enhancement on CEUS, indicating hemodynamic changes in DBD and DCD donor livers, were risk factors of liver discarded.

Prevalence and Profile of Discarded Liver Donors in a Tertiary Health Service in Brazil From 2015 to 2018

BACKGROUND

Little has changed in donor management and liver utilization rates in Brazil over the last decade. With a growing demand for liver donations, organ waste is an important obstacle toward better patient care. The study of discarded donors helps to shed light on the possibilities of increasing organ usage, including by using extended criteria donors.

METHODS

We retrospectively analyzed all discarded liver donors in a high-volume Brazilian transplant center from January 2015 to December 2018. Pertinent clinical and laboratorial data were collected from the donors' electronic health records.

RESULTS

In our study period, there were 248 liver harvests, of which 67 (27.0%) were discarded. Most discarded donors were male (65.7%). More than three-quarters of donors were Caucasian (79.1%). Median donor body mass index was 26.27 kg/m², and most discarded donors presented no comorbidities. Donor liver injury tests were abnormal in 56 (83.5%) out of 67 discarded donors. Forty-three (64.1%) donors presented elevated transaminases. Alanine aminotransferase levels were elevated in 35 (52.2%) discarded donors, with a median value of 38 U/L. Half of all discarded livers were due to graft-related issues. Twenty-eight organs (41.79%) presented external pathologic alterations. Organ refusal due to donor clinical and laboratorial condition was reported in 24 cases.

CONCLUSION

It is clear there is a considerable issue of organ waste in Brazil, with the subjective judgment of graft quality and inadequate interpretation of donor's laboratorial exams leading to excessive denial of organs that could be fitted into extended criteria for donation.

Comparison of Two Questionnaires on Informed Consent in "Marginal" Donor Liver

The necessity of liver donors has contributed to overcoming the traditional criteria and to propose new ones for the acceptance of livers for transplantation. For this reason expanded or extended criteria donation (ECD) or even overextended criteria for marginal or high-risk organ donors have been developed. Ethical, Legal and Psychological Aspects of Organ Transplantation (ELPAT) and European Liver and Intestine Transplant Association (ELITA) - European Liver Transplantation Registry (ELTR) coordinated the distribution of a previously reported questionnaire that was sent to 53 European liver transplant centers. Criteria were divided based on the response rate. Donor criteria such as steatosis and serum sodium >165 mmol/L, as well as recipient criteria such as previous history of cancer, were not considered contraindications to transplantation in more than 60% of cases. Criteria such as ICU (intensive care unit) stay, body mass index >30, serum bilirubin >3 mg/dL, and HIV infection or critical illness were not considered adequate for transplantation in 30% to 59% of cases. On the other hand, there was no agreement on other extended liver donor and recipient criteria, such as age up to 80 years, serum glutamic oxaloacetic transaminase >90 U/L, serum glutamic pyruvic transaminase >105 U/L, high-risk sex practices, drug users, patients older than 65 years, and patients younger than 65 years, respectively. Criteria such as serum sodium could not be considered ECD criteria. In conclusion, development of more studies and inclusion of more liver transplantation centers are required to confirm these data.

Extended criteria donors in liver transplantation Part I: reviewing the impact of determining factors

The definition and factors of extended criteria donors have already been set; however, details of the various opinions still differ in many respects. In this review, we summarize the impact of these factors and their clinical relevance. Elderly livers must not be allocated for hepatitis C virus (HCV) positives, or patients with acute liver failure. In cases of markedly increased serum transaminases, donor hemodynamics is an essential consideration. A prolonged hypotension of the donor does not always lead to an increase in post-transplantation graft loss if post-OLT care is proper. Hypernatremia of less than 160 mEq/L is not an absolute contraindication to accept a liver graft per se. The presence of steatosis is an independent and determinant risk factor for the outcome. The gold standard of the diagnosis is the biopsy. This is recommended in all doubtful cases. The use of HCV+ grafts for HCV+ recipients is comparable in outcome. The leading risk factor for HCV recurrence is the actual RNA positivity of the donor. The presence of a proper anti-HBs level seems to protect from de novo HBV infection. A favourable outcome can be expected if a donation after cardiac death liver is transplanted in a favourable condition, meaning, a warm ischemia time < 30 minutes, cold ischemia time < 8-10 hours, and donor age 50-60 years. The pathway of organ quality assessment is to obtain the most relevant information (e.g. biopsy), consider the co-existing donor risk factors and the reserve capacity of the recipient, and avoid further technical issues.