Donor liver dysfunction: application of a new scoring system to identify the marginal donor

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.

Donor Hepatic Steatosis and Outcome After Liver Transplantation: a Systematic Review

BACKGROUND

There is increasing need to expand availability of donor liver grafts, including steatotic livers. Steatotic liver is associated with poor outcome post-transplantation but with conflicting results in the literature. The aim of this systematic review was to evaluate the impact of steatotic livers on liver transplantation outcomes.

METHODS

An electronic search of OVID Medline and Embase databases was performed to identify clinical studies that reported outcomes of steatotic livers in liver transplantation. Data were extracted, and basic descriptive statistics were used to summarise data pooled from individual clinical studies.

RESULTS

Ninety-two articles were identified, of which 34 met the inclusion criteria, and stratified analysis were performed. There was a lack of standardised definition of primary non-function or impaired primary function amongst the studies and description of type of steatosis. Severely (>60%) steatotic grafts are associated with increased risk of poor graft function, whilst moderate-severe (>30%) steatotic grafts are associated with decreased graft survival.

CONCLUSIONS

Available evidence showed increased risk of poor graft outcome in moderate-severe steatotic livers. A large prospective multi-centred trial will be required to identify the true risks of steatotic livers. Consistent definition of primary non-function/impaired primary function and description of type of steatosis is also required.

Impact of deceased organ donor demographics and critical care end points on liver transplantation and graft survival rates

BACKGROUND

The criteria for organ acceptance remain inconsistent, which limits the ability to standardize critical care practices. We sought to examine predictors of liver graft use and survival to better guide the selection and management of potential organ donors.

STUDY DESIGN

A prospective observational study of all donors managed by the 8 organ procurement organizations in United Network for Organ Sharing Region 5 was conducted from July 2008 to March 2011. Critical care end points that reflect the normal hemodynamic, acid-base, respiratory, endocrine, and renal status of the donor were collected at 3 time points. Critical care and demographic data associated with liver transplantation and graft survival rates were first determined using univariate analyses, and then logistic regression was used to identify independent predictors of these two outcomes.

RESULTS

From 961 donors, 730 (76%) livers were transplanted and 694 (95%) were functioning after 74 ± 73 days of follow-up. After regression analysis, donor BMI (odds ratio [OR] = 0.94), male sex (OR = 1.89), glucose <150 mg/dL (OR = 1.97), lower dopamine dose (OR = 0.95), vasopressin use (OR = 1.95), and ejection fraction >50% (OR = 1.77) remained as independent predictors of liver use. Graft survival was associated with lower donor BMI (OR = 0.91) and sodium levels (OR = 0.95).

CONCLUSIONS

After controlling for donor age, sex, and BMI, both hemodynamic and endocrine critical care end points were associated with increased liver graft use. Both donor BMI and lower sodium levels during the course of donor management were independently predictive of improved graft survival. These results may help guide the management and selection of potential organ donors after neurologic determination of death.

The biopsied donor liver: incorporating macrosteatosis into high-risk donor assessment

To expand the donor liver pool, ways are sought to better define the limits of marginally transplantable organs. The Donor Risk Index (DRI) lists 7 donor characteristics, together with cold ischemia time and location of the donor, as risk factors for graft failure. We hypothesized that donor hepatic steatosis is an additional independent risk factor. We analyzed the Scientific Registry of Transplant Recipients for all adult liver transplants performed from October 1, 2003, through February 6, 2008, with grafts from deceased donors to identify donor characteristics and procurement logistics parameters predictive of decreased graft survival. A proportional hazard model of donor variables, including percent steatosis from higher-risk donors, was created with graft survival as the primary outcome. Of 21,777 transplants, 5051 donors had percent macrovesicular steatosis recorded on donor liver biopsy. Compared to the 16,726 donors with no recorded liver biopsy, the donors with biopsied livers had a higher DRI, were older and more obese, and a higher percentage died from anoxia or stroke than from head trauma. The donors whose livers were biopsied became our study group. Factors most strongly associated with graft failure at 1 year after transplantation with livers from this high-risk donor group were donor age, donor liver macrovesicular steatosis, cold ischemia time, and donation after cardiac death status. In conclusion, in a high-risk donor group, macrovesicular steatosis is an independent risk factor for graft survival, along with other factors of the DRI including donor age, donor race, donation after cardiac death status, and cold ischemia time.

The role of marginal donors in liver transplantation. The Hungarian experience

A májátültetések számát korlátozza a beültetésre alkalmas donorszervek mennyisége. A szervhiány megoldására az egyik lehetőség az úgynevezett marginális donorok (extended donor criteria) elfogadása a májátültetési programban. Célkitűzés: A magyar májátültetési program szervdonációs jellemzőinek vizsgálata, különös tekintettel a marginális donorokra. Módszer: Donor- és recipiensadatok retrospektív feldolgozása 2003. január és 2008. december között. A marginálisdonor-kritériumrendszert nemzetközi ajánlások alapján állítottuk fel. Eredmények: A vizsgált periódus alatt összesen 1078 donort jelentettek a klinikán. Nyolcszázharmincöt esetben (77,4%) alkalmatlannak ítélték a donormájat a transzplantációra, 243 esetben (22,6%) volt beültetésre alkalmas a donormáj. A beültetett májgraftok közül 40 (16%) származott marginális, 203 (84%) nem marginális donorból. Marginális májgraftok beültetése esetén nem volt különbség a beteg- és grafttúlélésben, a posztoperatív graftfunkciót jelző paraméterekben és az általános szövődmények gyakoriságában. A korai hepatitis C-rekurrencia gyakoribb volt marginális graft beültetése esetén. Következtetések: A májátültetésre váró betegek száma hazánkban is folyamatosan növekszik. Marginális májgraftok alkalmazása esetén a betegek morbiditása és mortalitása nem különbözik számottevően a standard donorokból származó májgraftok beültetése után tapasztalt eredményektől. Hepatitis C-vírus esetén nem javasolt marginális májgraft beültetése. A donorok felső életkori határának kiterjesztése megfontolandó.

Predictive value of frozen-section analysis in the histological assessment of steatosis before liver transplantation

Histological quality assessment of donated livers is a key factor for extending the cadaveric donor pool for liver transplantation. We retrospectively compared frozen-section analysis with routine histological permanent slides and the outcomes of grafts in liver biopsies from 294 candidate donors. The kappa concordance coefficient of agreement between frozen-section analysis and routine histological analysis was very good for macrosteatosis (kappa = 0.934), microsteatosis (kappa = 0.828), and total steatosis (kappa = 0.814). The correlation between the mean amounts of macrosteatosis, microsteatosis, and total steatosis in frozen and permanent sections was also significant (P < 0.001, Spearman's test). Macrosteatosis and microsteatosis were overestimated to >30% in 4 of 32 cases (12.5%) and in 23 of 62 cases (37.1%), respectively. The only 2 histological parameters of frozen sections able to predict graft dysfunction within 7 days of transplantation were macrosteatosis and total steatosis (P = 0.018 and P = 0.015, respectively, Mann-Whitney test). None of the other histopathological features evaluated in frozen sections, including portal inflammation, lobular necrosis, myointimal thickening, biliocyte regression, cholestasis, hepatocellular polymorphism, lipofuscin storage, and fibrous septa, were significantly correlated with the graft outcome. The frozen-section histological evaluation of biopsies from cadaveric liver donors is an accurate, time-effective, and predictive method for the assessment of graft suitability.

Quantitative estimation of the degree of hepatic macrovesicular steatosis in a disease-free population: a single-center experience in mainland China

The aim of this study was to derive a simple equation to enable the extent of hepatic macrovesicular steatosis (HMS) to be predicted quantitatively from data obtained noninvasively and hence avoid unnecessary liver biopsies. One hundred sixty-seven potential living liver donors and 45 subjects suspected of having nonalcoholic fatty liver disease (NAFLD) underwent percutaneous liver biopsy to evaluate HMS quantitatively. Their hepatic unenhanced computed tomography (CT) attenuation, body mass index (BMI), and indices of serum lipids were reviewed. Logistic regression analysis was undertaken to screen for independent predictors of HMS. Linear regression analysis was then used to plot the relationship between the severity of histologically confirmed HMS and identified independent predictors of HMS. For potential donors with HMS of severity > or = 5% by histological assessment, the following equation was derived: HMS = 47.7 + 1.48BMI - 1.14CT (R2 = 0.74)The calculated HMS for potential donors with histologically confirmed HMS of severity < 5% seemed to be unreliable (R(2) = = 0.230, P < 0.3). In addition, in subjects suspected of having NAFLD, there was a close agreement between values for histologically confirmed HMS and calculated values for HMS derived from the equation (intraclass correlation coefficient = 0.88). Hepatic CT imaging in conjunction with other noninvasive clinical data may enable the extent of HMS to be accurately predicted with the equation derived from potential donors with appreciable degrees of histologically confirmed HMS.

A role for complement in the enhanced susceptibility of steatotic livers to ischemia and reperfusion injury

Hepatic steatosis typically renders the donor organ unusable, as donor organs with >30% steatosis are more likely to develop graft failure. The mechanisms leading to failure are not well defined, but steatosis enhances hepatic susceptibility to ischemia reperfusion injury (IRI). We investigated the role of complement in hepatic IRI in lean and steatotic (diet-induced) mice. Steatotic mice were significantly more susceptible to total warm hepatic IRI than lean mice as determined by serum alanine aminotransferase, histopathologically assessed damage, and 24-h survival. C3 deficiency protected both lean and steatotic mice from IRI, as determined by all measured outcomes. Furthermore, treatment of wild-type mice with the complement inhibitor CR2-Crry provided protection equivalent to that seen in C3-deficient mice. Importantly, although steatotic livers were much more susceptible to IRI than lean livers, by most measures there was no statistical difference between the level of IRI to steatotic or lean livers when complement was inhibited. To investigate the clinical relevance of these findings in the context of transplantation, we treated recipients of lean or steatotic liver grafts with saline or CR2-Crry. There was a marked reduction in graft inflammation and injury and significantly improved 7-day survival in CR2-Crry-treated recipients of either lean or steatotic grafts. These data indicate that complement plays a key role in the enhanced susceptibility of steatotic livers to IRI and suggest that complement inhibition represents a potential strategy to reduce the donor shortage by allowing the more routine use of marginal steatotic donor livers.

Preservation solutions alter Mrp2-dependent bile flow in cold ischemic rat livers

BACKGROUND

Previously, decreased organic anion transport through multidrug resistance protein 2 (Mrp2) was observed without any notable cell lysis, even when the livers were stored for 8 hours in University of Wisconsin solution (UW). The aim of this study was to examine the bile flow and its constituents, markers of graft dysfunction without necrosis in cold ischemic livers, using the following preservation media: UW, ET-Kyoto solution (ET-K) and histidine-tryptophan-ketoglutarate solution (HTK).

MATERIALS AND METHODS

Rat livers were stored at 4 degrees C for 8 hours in the preservation media, and reperfused to collect the bile and determine their constituents. Glycyrrhizin (GL) and/or glutathione (GSH) were added to the media as necessary. The transport efficiency of Mrp2 was assessed by the biliary excretion of 5-carboxyfluorescein (CF), a fluoroprobe excreted from Mrp2. The Intracellular distribution of Mrp2 was determined by immunostaining.

RESULTS

Livers stored for 8 hours exhibited significantly decreased bile production and biliary glutathione (GSH) levels without notable cell lysis. CF excretion was significantly delayed in all solutions. However, these markers were remarkably improved by the redistribution of Mrp2 from the cytoplasm to the canalicular membrane, when the livers were exposed to UW in the presence of GL. Moreover, livers exposed to the Kyoto and HTK solutions increased their bile production and organic anion transport in the presence of GL and GSH.

CONCLUSION

These results suggest that the addition of GL and GSH to preservation solutions improves bile production and biliary organic anion transport by increasing Mrp2 localization to the bile canaliculi in post-cold ischemic livers. (248 words).

Fingerprinting of human bile during liver transplantation by capillary electrophoresis

Increasing rates of success in liver transplantation have increased the number of cases considered. However, liver post-transplant graft dysfunction of liver transplants (TXs) is not fully understood and by applying holistic approaches we can investigate metabolic change deriving from confounding factors such as liver fat content, ischaemia time, donor age, recipient's health, etc. Twenty-six hepatic bile samples taken from liver donors and recipients were retrieved from a total of six TXs, from these one recipient underwent post-graft dysfunction. CE was employed to fingerprint bile collected at 10 min increments in the donors and in the recipients. The electropherograms of these samples were aligned and normalised using correlation optimised warping algorithms and modelled with multivariate techniques. The resulting metabolic signatures were compared; in general donors and recipients showed distinct fingerprints and clustered separately. When a partial least square discriminant analysis (PLS-DA) model was constructed between donor and recipient's samples, a recipient of a 32 year old liver with normal steatosis, and shortest cold ischaemia time showed as the observation nearest to its donor observation, denoting minimal metabolic change. This study proposes CE fingerprinting of human bile as a promising technique to help unravel the complex metabolic pathways involved during transplantation.

O doador marginal: experiência de um centro de transplante de fígado

RACIONAL: Desde que o uso de enxertos marginais é solução aceita para escassez de órgãos para transplante, ele tornou-se muito comum em todo mundo e a literatura vem mostrando efetividade desses enxertos no transplante de fígado. OBJETIVO: Apresentar a experiência do Serviço de Transplante Hepático do Hospital Universitário Oswaldo Cruz, em transplante de fígado com o uso de doadores marginais. MÉTODOS: Estudo retrospectivo em 137 transplantes ortotópicos de fígado, usando enxertos marginais entre 1999 e 2006, com acompanhamento mínimo de 180 dias. Os receptores foram classificados de acordo com a função inicial do enxerto no pós-operatório como normal (FN) e disfunção primária (DP). RESULTADOS: Não foi observada diferença estatisticamente significante entre os grupos FN e DP com os seguintes parâmetros dos doadores: idade, sódio sérico, tempo de protrombina, esteatose hepática, transaminases sérica, pressão sanguínea, drogas vasoativas, índice de massa corpórea, parada cardíaca antes da doação de órgão, doador em assistolia e tempo de isquemia quente. Análise da curva de sobrevida (Kaplan-Meier) de pacientes e de enxertos de fígado de pacientes que receberam fígado de doadores ideais versus doadores marginais não mostrou diferença com significância estatística. CONCLUSÃO: Pode ser recomendado o uso de enxertos marginais para transplantes hepáticos, inclusive os provenientes de doadores com o coração parado.