Performance of risk prediction models for post-liver transplant patient and graft survival over time.

Given liver transplantation organ scarcity, selection of recipients and donors to maximize post-transplant benefit is paramount. Several scores predict post-transplant outcomes by isolating elements of donor and recipient risk, including the donor risk index, Balance of Risk, pre-allocation score to predict survival outcomes following liver transplantation/survival outcomes following liver transplantation (SOFT), improved donor-to-recipient allocation score for deceased donors only/improved donor-to-recipient allocation score for both deceased and living donors (ID2EAL-D/-DR), and survival benefit (SB) models. No studies have examined the performance of these models over time, which is critical in an ever-evolving transplant landscape. This was a retrospective cohort study of liver transplantation events in the UNOS database from 2002 to 2021. We used Cox regression to evaluate model discrimination (Harrell's C) and calibration (testing of calibration curves) for post-transplant patient and graft survival at specified post-transplant timepoints. Sub-analyses were performed in the modern transplant era (post-2014) and for key donor-recipient characteristics. A total of 112,357 transplants were included. The SB and SOFT scores had the highest discrimination for short-term patient and graft survival, including in the modern transplant era, where only the SB model had good discrimination (C ≥ 0.60) for all patient and graft outcome timepoints. However, these models had evidence of poor calibration at 3- and 5-year patient survival timepoints. The ID2EAL-DR score had lower discrimination but adequate calibration at all patient survival timepoints. In stratified analyses, SB and SOFT scores performed better in younger (< 40 y) and higher Model for End-Stage Liver Disease (≥ 25) patients. All prediction scores had declining discrimination over time, and scores relying on donor factors alone had poor performance. Although the SB and SOFT scores had the best overall performance, all models demonstrated declining performance over time. This underscores the importance of periodically updating and/or developing new prediction models to reflect the evolving transplant field. Scores relying on donor factors alone do not meaningfully inform post-transplant risk.

Causes of pre and post-donation deferrals among blood donors, at Kwale Satellite Blood Transfusion Center, Kwale County, Kenya, 2018-2022.

BACKGROUND: Both pre-donation and post-donation deferrals pose challenges to blood safety and availability. This study delved into the deferral rates before donations and their underlying reasons, as, transfusion transmissible infections (TTIs) leading to post-donation deferrals among potential blood donors at the Kwale Satellite Blood Transfusion Centre (KSBTC) in Kenya. METHODS: We performed a retrospective electronic record review of pre- and post-donation deferrals among blood donors at KSBTC, 2018-2022. The pre-donations deferral rate and reasons for deferral were analyzed. Accepted donations were analyzed to determine the prevalence of HIV, hepatitis B (HBV), hepatitis C (HCV), and syphilis. Descriptive statistics were calculated and both crude odds ratio (COR) and adjusted odds ratio (AOR), and their 95% confidence intervals (CI) were calculated. Variables with p < 0.05 were considered statistically significant. RESULTS: A review was conducted on 12,633 blood donation records. Among these, individuals 2,729/12,633 (21.60%) were deferred from donating with the primary reason being low hemoglobin levels, constituting 51.86% of deferrals. Around 773/9,904 (7.80%) of blood units, were discarded due to at least one TTI. Among these, HBV accounted for 4.73%, HIV for 2.01%, HCV for 1.21%, and Syphilis for 0.59% of cases. The adjusted odds ratio for male donors were, (aOR = 1.3, 95% CI 1.01-1.57), donors with none or primary education level (aOR = 1.4 95% CI 1.11-1.68), first-timer donors (aOR = 1.2, 95% CI 1.01-1.44), and static strategy for blood collection (aOR = 1.4, 95%CI 1.12-1.63) were independently potentially associated with testing positive for at least one TTI. CONCLUSION: The study indicates that TTIs continue to pose a risk to the safety of Kenya's bloodstock, with a notable prevalence of HBV infections. Male donors, individuals with limited education, first-time donors, and utilizing a fixed strategy for blood collection were identified as potential risk factors independently associated with TTIs.

Automated Segmentation of Kidney Cortex and Medulla in CT Images: A Multisite Evaluation Study.

BACKGROUND: In kidney transplantation, a contrast CT scan is obtained in the donor candidate to detect subclinical pathology in the kidney. Recent work from the Aging Kidney Anatomy study has characterized kidney, cortex, and medulla volumes using a manual image-processing tool. However, this technique is time consuming and impractical for clinical care, and thus, these measurements are not obtained during donor evaluations. This study proposes a fully automated segmentation approach for measuring kidney, cortex, and medulla volumes. METHODS: A total of 1930 contrast-enhanced CT exams with reference standard manual segmentations from one institution were used to develop the algorithm. A convolutional neural network model was trained (n=1238) and validated (n=306), and then evaluated in a hold-out test set of reference standard segmentations (n=386). After the initial evaluation, the algorithm was further tested on datasets originating from two external sites (n=1226). RESULTS: The automated model was found to perform on par with manual segmentation, with errors similar to interobserver variability with manual segmentation. Compared with the reference standard, the automated approach achieved a Dice similarity metric of 0.94 (right cortex), 0.90 (right medulla), 0.94 (left cortex), and 0.90 (left medulla) in the test set. Similar performance was observed when the algorithm was applied on the two external datasets. CONCLUSIONS: A fully automated approach for measuring cortex and medullary volumes in CT images of the kidneys has been established. This method may prove useful for a wide range of clinical applications.

Risk of transfusion-transmitted hepatitis E virus infection from pool-tested platelets and plasma.

BACKGROUND AND AIMS: Immunocompromised patients are at risk of chronic hepatitis E which can be acquired by blood transfusions. Currently, screening of blood donors (BDs) for HEV RNA with a limit of detection (LOD) of 2,000 IU/ml is required in Germany. However, this may result in up to 440,000 IU of HEV RNA in blood products depending on their plasma volume. We studied the residual risk of transfusion-transmitted (tt) HEV infection when an LOD of 2,000 IU/ml is applied. METHODS: Highly sensitive individual donor testing for HEV RNA on the Grifols Procleix Panther system (LOD 7.89 IU/ml) was performed. HEV loads were quantified by real-time PCR. RESULTS: Of 16,236 donors, 31 (0.19%) were HEV RNA positive. Three BDs had viral loads between 710 and 2,000 IU/ml, which pose a significant risk of tt hepatitis E with any type of blood product. Eight BDs had viral loads of >32 to 710 IU/ml, which pose a risk of tt hepatitis E with platelet or plasma transfusions because of their higher plasma volume compared to red blood cell concentrates. Eight of these 11 potentially infectious BDs were seronegative for HEV, indicating a recent infection. Only 8 of 31 donors had viral loads >2,000 IU/ml that would also have been detected by the required screening procedure and 12 had very low HEV loads (<32 IU/ml). CONCLUSIONS: Screening of BDs with an LOD of 2,000 IU/ml reduced the risk of tt HEV infection by about 73% for red blood cell concentrates but by just 42% for platelet and fresh frozen plasma transfusions. Single donor screening (LOD <32 IU/ml) should lead to an almost 100% risk reduction. LAY SUMMARY: Immunocompromised patients, such as solid organ or hematopoietic stem cell recipients, are at risk of chronic hepatitis E, which can be acquired via blood transfusions. The risk of transfusion-transmitted hepatitis E in these patients may not be sufficiently controlled by (mini-)pool hepatitis E virus RNA screening of blood donors. Single donor screening should be considered to improve the safety of blood products.

HIV incidence in US first-time blood donors and transfusion risk with a 12-month deferral for men who have sex with men.

In 2015, the US Food and Drug Administration published revised guidance that recommended a change in blood donor deferral of men who have sex with men (MSM) from an indefinite to a 12-month deferral since the donor last had sex with a man. We assessed whether HIV incidence in first-time blood donors or associated transfusion risk increased. Donations in 4 major blood collection organizations were monitored for 15 months before and 2 years after implementation of the 12-month MSM deferral policy. HIV-positive donations were classified as recently acquired or long-term using a recent infection testing algorithm and incidence in both periods estimated. Residual transfusion transmission risk was estimated by multiplying incidence by the length of the infectious window period. The latter was estimated using a model based on infectious dose and the sensitivity of nucleic acid testing. Factors associated with incident infection in each period were assessed using Poisson regression. Overall HIV incidence in first-time donors before implementation of the 12-month MSM deferral was estimated at 2.62 cases per 100 000 person-years (105 PY) (95% credible interval [CI], 1.53-3.93 cases/105 PY), and after implementation at 2.85 cases/105 PY (95% CI, 1.96-3.93 cases/105 PY), with no statistically significant change. In male first-time donors, the incidence difference was 0.93 cases/105 PY (95% CI, -1.74-3.58 cases/105 PY). The residual risk of HIV transfusion transmission through components sourced from first-time donors was estimated at 0.32 transmissions per million (106) packed red blood cell transfusions (95% CI, 0.29-0.65 transmissions/106 transfusions) before and 0.35 transmissions/106 transfusions (95% CI, 0.31-0.65 transmissions/106 transfusions) after implementation. The difference was not statistically significant. Factors associated with incident infection were the same in each period. We observed no increase in HIV incidence or HIV transfusion transmission risk after implementation of a 12-month MSM deferral policy.

A retrospective study assessing the characteristics of COVID-19 convalescent plasma donors and donations.

BACKGROUND: Although many trials are currently investigating the safety and efficacy of convalescent plasma (CP) in critically ill COVID-19 patients, there is a paucity of ongoing and published studies evaluating the CP donors' side. This retrospective study reports the first Italian experience on CP donors' selection and donations. METHODS: Patients aged 18-68 years who had recovered from COVID-19 at least 2 weeks previously were recruited between March 18 and June 30, 2020 in a study protocol at the Italian hospitals of Pavia and Mantova. RESULTS: During the study period, 494 of 512 donors recruited were judged eligible and underwent 504 plasmapheresis procedures. Eighty-five percent (437/512) of the CP donors were males. The average time between symptom recovery and CP donation was 36.6 (±20.0) days. Four hundred and eighty-eight plasmapheresis procedures (96.8%) were concluded and each unit was divided into two subunits (total 976) with an average volume of 316.2 (±22.7) mL. Ninety-three percent (460/494) of CP donors at the time of plasma donation had a neutralizing IgG titer ≥1:80. Plasmapheresis-related adverse reactions occurred in 2.6% (13/504) of cases; all the reactions were mild and none required therapeutic intervention. Donors' age and COVID-19 severity were positively associated with greater antibody responses. CONCLUSION: This study demonstrates the feasibility and safety of a pilot CP program conducted in Italy. The identification of factors (ie, age and severity of COVID-19) positively associated with higher neutralizing antibody titers at the time of donation may help to optimize the selection of CP donors.

Supplemental findings of the 2019 National Blood Collection and Utilization Survey.

INTRODUCTION: Supplemental data from the 2019 National Blood Collection and Utilization Survey (NBCUS) are presented and include findings on donor characteristics, autologous and directed donations and transfusions, platelets (PLTs), plasma and granulocyte transfusions, pediatric transfusions, transfusion-associated adverse events, cost of blood units, hospital policies and practices, and implementation of blood safety measures, including pathogen reduction technology (PRT). METHODS: National estimates were produced using weighting and imputation methods for a number of donors, donations, donor deferrals, autologous and directed donations and transfusions, PLT and plasma collections and transfusions, a number of crossmatch procedures, a number of units irradiated and leukoreduced, pediatric transfusions, and transfusion-associated adverse events. RESULTS: Between 2017 and 2019, there was a slight decrease in successful donations by 1.1%. Donations by persons aged 16-18 decreased by 10.1% while donations among donors >65 years increased by 10.5%. From 2017 to 2019, the median price paid for blood components by hospitals for leukoreduced red blood cell units, leukoreduced apheresis PLT units, and for fresh frozen plasma units continued to decrease. The rate of life-threatening transfusion-related adverse reactions continued to decrease. Most whole blood/red blood cell units (97%) and PLT units (97%) were leukoreduced. CONCLUSION: Blood donations decreased between 2017 and 2019. Donations from younger donors continued to decline while donations among older donors have steadily increased. Prices paid for blood products by hospitals decreased. Implementation of PRT among blood centers and hospitals is slowly expanding.

New blood donors in times of crisis: Increased donation willingness, particularly among people at high risk for attracting SARS-CoV-2.

BACKGROUND: Traditionally, during crises the number of new blood donors increases. However, the current coronavirus disease 2019 (COVID-19) pandemic created additional barriers to donate due to governmental prevention measures and increased personal health risks. In this report, we examined how the pandemic affected new donor registrations in the Netherlands, especially among groups with higher risk profiles for severe COVID-19. Additionally, we explored the role of media for blood donation and new donor registrations. STUDY DESIGN AND METHODS: We analyzed new donor registrations and attention for blood donation in newspapers and on social media from January until May 2020, in comparison to the same period in 2017 to 2019. RESULTS: After the introduction of nationwide prevention measures, several peaks in new donor registrations occurred, which coincided with peaks in media attention. Interestingly, people with a higher risk profile for COVID-19 (e.g., due to age or region of residence) were overrepresented among new registrants. DISCUSSION: In sum, the first peak of the current pandemic has led to increased new blood donor registrations, despite the associated increased health risks. Time and future studies will have to tell whether these new donors are one-off 'pandemic' donors or if they will become regular, loyal donors.

Deterrents in recruitment of COVID-19 convalescent plasma donors: Experience from a hospital-based blood centre in India.

INTRODUCTION: Recruitment of Covid-19 convalescent plasma (CCP) donors may present as a challenge due to inexperience and differences in donor profile as compared to whole blood donation. Present study highlights the deterrents to recruiting CCP donors at a hospital based blood centre. MATERIALS AND METHODS: Potential CCP donors were contacted individually by telephone and a group approach through camp organisers from May to July 2020. Recruitment challenges were noted and deferrals of these recruited donors during screening and medical examination was obtained and analysed. RESULTS: Total 1165 potential CCP donors were contacted. Around 47% donors were lost due to challenges related to information storage and retrieval. Fear of health, family pressure, and fear of a new procedure were major reason (27.2%) for unwillingness to donate. The main reasons for deferral among potential donors were multiparity (38%) and being overage/underage (31.6%). Finally, 468 donors were recruited including 408 by individual approach and 60 by a group approach. From these absence of detectable COVID-19 antibodies were found in 15.4%. Few donors (9.0%) were deferred as they had not completed 28 days post recovery. CONCLUSION: The process of CCP donor recruitment differs from that of whole blood donation and requires an individualised approach with involvement of clinicians in the initial phases of the pandemic. A group approach targeting specific organisations could be adopted for a successful CCP collection program. There is a need to relook into some aspects of donor selection such as consideration of multiparous female donors and overage/underage donors after reviewing scientific evidence.

A forecasting model to estimate the drop in blood supplies during the SARS-CoV-2 pandemic in Italy.

OBJECTIVES: To estimate the number of actually Severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) infected blood donors applying a statistical forecasting model. BACKGROUND: Following the outbreak of the SARS-CoV-2 epidemic, a drop in blood donation has been observed. It is crucial to determine the actual number of potential SARS-CoV-2-positive donors to define the measures and ensure adequate blood supply. METHODS: The cumulative incidence of SARS-CoV-2 positivity, calculated on the general population, was applied to the donor population by estimating the number of positive subjects. The calculation model was validated by the linear interpolation method. The number of blood units actually discarded based on post-donation information was also taken into account. RESULTS: Three months after the outbreak, 5322 donors were estimated to be positive for SARS-CoV-2 and were therefore potentially excluded from donation. A total of units of blood components were discarded following post donation information. The estimated number of donors deceased (180) and the number of clinically recovered individuals in the same period was also considered. CONCLUSION: This forecasting model can be used to obtain information on blood donors' involvement during future SARS-CoV-2 outbreaks, especially in case of changes concerning epidemiology, incidence by age bracket and geographical distribution and also for new outbreaks of emerging viruses.

Screening for SARS-CoV-2 antibodies in convalescent plasma in Brazil: Preliminary lessons from a voluntary convalescent donor program.

BACKGROUND: Coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) collection began in two Brazilian hospitals for treatment of severe/critical patients. METHODS AND MATERIALS: Mild/moderate COVID-19 convalescents were selected as CCP donors after reverse transcription polymerase chain reaction (RT-PCR) confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and absence of symptoms for ≥14 days plus (a) age (18-60 years), body weight greater than 55 kg; (b) immunohematological studies; (c) no infectious markers of hepatitis B virus, hepatitis C virus, human immunodeficiency virus, human T-lymphotropic virus-1/2, Chagas and syphilis infection; (d) no HLA antibodies (multiparous); (e) second RT-PCR (nasopharyngeal swab and/or blood) negativity; (f) virus neutralization test (cytopathic effect-based virus neutralization test neutralizing antibody) and anti-nucleocapsid protein SARS-CoV-2 IgM, IgG, and IgA enzyme-linked immunosorbent assays. RESULTS: Among 271 donors (41 females, 230 males), 250 presented with neutralizing antibodies. Final RT-PCR was negative on swab (77.0%) or blood (88.4%; P = .46). Final definition of RT-PCR was only defined at more than 28 days after full recovery in 59 of 174 (33.9%) RT-PCR -ve, and 25/69 RT-PCR +ve (36.2%; 13 between 35 and 48 days). Neutralizing antibody titers of 160 or greater were found in 63.6%. Correlation between IgG signal/cutoff of 5.0 or greater and neutralizing antibody of 160 or greater was 82.4%. Combination of final RT-PCR -ve with neutralizing antibody ≥160 was 41.3% (112/271). Serial plasma collection showed decline in neutralizing antibody titers and IgA levels (P < .05), probably denoting a "golden period" for CCP collection (≤28 days after joining the program); IgA might have an important role as neutralizing antibody. Donor's weight, days between disease onset and serial plasma collection, and IgG and IgM levels are important predictors for neutralizing antibody titer. CONCLUSIONS: RT-PCR +ve cases are still detected in 36.2% within 28 to 48 days after recovery. High anti-nucleocapsid protein IgG levels may be used as a surrogate marker to neutralizing antibody.

Attitudes and willingness to donate blood among gay and bisexual men in Australia.

BACKGROUND: Men who have sex with men in Australia are currently ineligible to donate blood (are "deferred") for 12 months since last oral or anal sexual contact with another man. In Australia and overseas, there has been limited research on attitudes and perceptions related to blood donation in this population. STUDY DESIGN AND METHODS: Questions on blood donation histories and attitudes toward the deferral policy were included in the questionnaire of an online prospective cohort of gay and bisexual men (GBM) living in Australia. RESULTS: In 2018, 1595 GBM responded to the survey. In this sample, 28.7% reported previously donating blood. Among the remaining men who had never donated blood, 64.5% expressed an interest in doing so. Nearly all men indicated they were not willing to abstain from sex with another man for 12 months in order to donate, and the vast majority believed the rule was unfair, too strict, and homophobic. Three-quarters (77.7%) said that if the policy changed, they would likely donate blood. Age and openness about one's sexuality were independently associated with one's willingness to donate blood in the absence of the deferral. CONCLUSION: There was a high level of willingness and desire to donate blood among GBM. However, rather than abstaining from sex in order to donate, many men comply with the deferral policy and do not donate. A less conservative deferral policy may increase donations from GBM.

Living or deceased-donor kidney transplant: the role of psycho-socioeconomic factors and outcomes associated with each type of transplant.

BACKGROUND: Kidney transplant improves patients' survival and quality of life. Worldwide, concern about the equality of access to the renal transplant wait-list is increasing. In Iran, patients have the choice to be placed on either the living or deceased-donor transplant wait-list. METHODS: This was a prospective study performed on 416 kidney transplant recipients (n = 217 (52.2%) from living donors and n = 199 (47.8%) from deceased donors). Subjects were recruited from four referral kidney transplant centers across Tehran, Iran, during 2016-2017. The primary outcome was to identify the psycho-socioeconomic factors influencing the selection of type of donor (living versus deceased). Secondary objective was to compare the outcomes associated with each type of transplant. The impact of psycho-socioeconomic variables on selecting type of donor was evaluated by using multiple logistic regression and the effect of surgical and non-surgical variables on the early post-transplant creatinine trend was assessed by univariate repeated measure ANOVA. RESULTS: Based on standardized coefficients, the main predictors for selecting living donor were academic educational level (adjusted OR = 3.25, 95% CI: 1.176-9.005, p = 0.023), psychological status based on general health questionnaire (GHQ) (adjusted OR = 2.46, 95% CI: 1.105-5.489, p = 0.028), and lower monthly income (adjusted OR = 2.20, 95% CI: 1.242-3.916, p = 0.007). The waiting time was substantially shorter in patients who received kidneys from living donors (p < 0.001). The early post-transplant creatinine trend was more desirable in recipients of living donors (ß = 0.80, 95% CI: 0.16-1.44, p-value = 0.014), patients with an ICU stay of fewer than five days (ß = - 0.583, 95% CI: - 0.643- -0.522, p-value = < 0.001), and those with less dialysis duration time (ß = 0.016, 95% CI: 0.004-0.028, p-value = 0.012). Post-operative surgical outcomes were not different across the two groups of recipients (p = 0.08), however, medical complications occurred considerably less in the living-donor group (p = 0.04). CONCLUSION: Kidney transplant from living donors was associated with shorter transplant wait-list period and better early outcome, however, inequality of access to living donors was observed. Patients with higher socioeconomic status and higher level of education and those suffering from anxiety and sleep disorders were significantly more likely to select living donors.

Review of the discard and/or refusal rate of offered donor hearts to pediatric waitlisted candidates.

We aimed to review current literature on the discard rate of donor hearts offered to pediatric recipients and assess geographical differences. Consequences and ways to reduce the discard rate are discussed. A systemic review on published literature on pediatric transplantation published in English since 2010 was undertaken. Additionally, a survey was sent to international OPOs with the goal of incorporating responses from around the world providing a more global picture. Based on the literature review and survey, there is a remarkably wide range of discard and/or refusal for pediatric hearts offered for transplant, ranging between 18% and 57% with great geographic variation. The data suggest that that the overall refusal rate may have decreased over the last decade. Reasons for organ discard were difficult to identify from the available data. Although the refusal rate of pediatric donor hearts seems to be lower compared to that reported in adults, it is still as high as 57% with geographic variation.

Eplet mismatch analysis and allograft outcome across racially diverse groups in a pediatric transplant cohort: a single-center analysis.

HLA eplet mismatch load has been suggested as an improvement to HLA antigen mismatch determination for organ selection. Given that eplet mismatches are determined based on amino acid sequence difference among HLA alleles, and that the frequency of HLA alleles varies between racial groups, we investigated the correlation between eplet mismatch load and allograft outcomes in 110 pediatric kidney transplant recipients who received their first organ from a donor of the same race (SRT) versus a donor of a different race (DRT). Adjusted modified Poisson regression was used to assess the interaction between eplet mismatch load and race mismatch and its effect on outcome. Caucasians and living donor recipients had lower eplet mismatched loads against their donors compared with non-Caucasian and deceased donor recipients. Overall, for the entire population, the risk of de novo HLA-DSA development was significantly increased with higher eplet loads (p < 0.001). Compared with the SRT group, the DRT group had higher eplet loads when compared with their donor, for HLA class I but not HLA class II molecules; however, there was no significant difference in the incidence of de novo HLA-DSA between the 2 groups. The risk of rejection increased significantly for DRT compared with SRT, only when class I eplet load was ≥ 70 (p = 0.04). Together this data show that eplet mismatch load analysis is an effective tool for alloimmune risk assessment. If considered for donor selection, acceptable eplet mismatch loads determined from studies in homogenous populations may restrict transplantation across racially diverse donor and patient groups with no evidence of poor outcome. Therefore, an acceptable eplet mismatch load threshold must consider the heterogeneity of the transplant population.

Machine learning methods in organ transplantation.

PURPOSE OF REVIEW: Machine learning techniques play an important role in organ transplantation. Analysing the main tasks for which they are being applied, together with the advantages and disadvantages of their use, can be of crucial interest for clinical practitioners. RECENT FINDINGS: In the last 10 years, there has been an explosion of interest in the application of machine-learning techniques to organ transplantation. Several approaches have been proposed in the literature aiming to find universal models by considering multicenter cohorts or from different countries. Moreover, recently, deep learning has also been applied demonstrating a notable ability when dealing with a vast amount of information. SUMMARY: Organ transplantation can benefit from machine learning in such a way to improve the current procedures for donor--recipient matching or to improve standard scores. However, a correct preprocessing is needed to provide consistent and high quality databases for machine-learning algorithms, aiming to robust and fair approaches to support expert decision-making systems.

Machine-learning algorithms for predicting results in liver transplantation: the problem of donor-recipient matching.

PURPOSE OF REVIEW: Classifiers based on artificial intelligence can be useful to solve decision problems related to the inclusion or removal of possible liver transplant candidates, and assisting in the heterogeneous field of donor-recipient (D-R) matching. RECENT FINDINGS: Artificial intelligence models can show a great advantage by being able to handle a multitude of variables, be objective and help in cases of similar probabilities. In the field of liver transplantation, the most commonly used classifiers have been artificial neural networks (ANNs) and random forest classifiers. ANNs are excellent tools for finding patterns which are far too complex for a clinician and are capable of generating near-perfect predictions on the data on which they are fit, yielding excellent prediction capabilities reaching 95% for 3 months graft survival. On the other hand, RF can overcome ANNs in some of their limitations, mainly because of the lack of information on the variables they provide. Random forest algorithms may allow for improved confidence with the use of marginal organs and better outcome after transplantation. SUMMARY: ANNs and random forest can handle a multitude of structured and unstructured parameters, and establish non explicit relationships among risk factors of clinical relevance.

Mitigating Racial and Sex Disparities in Access to Living Donor Kidney Transplantation: Impact of the Nation's Longest Single-center Kidney Chain.

OBJECTIVE: In this study, we sought to assess likelihood of living donor kidney transplantation (LDKT) within a single-center kidney transplant waitlist, by race and sex, after implementation of an incompatible program. SUMMARY BACKGROUND DATA: Disparities in access to LDKT exist among minority women and may be partially explained by antigen sensitization secondary to prior pregnancies, transplants, or blood transfusions, creating difficulty finding compatible matches. To address these and other obstacles, an incompatible LDKT program, incorporating desensitization and kidney paired donation, was created at our institution. METHODS: A retrospective cohort study was performed among our kidney transplant waitlist candidates (n = 8895). Multivariable Cox regression was utilized, comparing likelihood of LDKT before (era 1: 01/2007-01/2013) and after (era 2: 01/2013-11/2018) implementation of the incompatible program. Candidates were stratified by race [white vs minority (nonwhite)], sex, and breadth of sensitization. RESULTS: Program implementation resulted in the nation's longest single-center kidney chain, and likelihood of LDKT increased by 70% for whites [adjusted hazard ratio (aHR) 1.70; 95% confidence interval (CI), 1.46-1.99] and more than 100% for minorities (aHR 2.05; 95% CI, 1.60-2.62). Improvement in access to LDKT was greatest among sensitized minority women [calculated panel reactive antibody (cPRA) 11%-49%: aHR 4.79; 95% CI, 2.27-10.11; cPRA 50%-100%: aHR 4.09; 95% CI, 1.89-8.82]. CONCLUSIONS: Implementation of an incompatible program, and the resulting nation's longest single-center kidney chain, mitigated disparities in access to LDKT among minorities, specifically sensitized women. Extrapolation of this success on a national level may further serve these vulnerable populations.

Living Donation Versus Donation After Circulatory Death Liver Transplantation for Low Model for End-Stage Liver Disease Recipients.

In this era of organ scarcity, living donor liver transplantation (LDLT) is an alternative to using deceased donors, and in Western countries, it is more often used for recipients with low Model for End-Stage Liver Disease (MELD) scores. We sought to compare the patient survival and graft survival between recipients of liver transplantation from living donors and donation after circulatory death (DCD) donors in patients with low MELD scores. This is a retrospective cohort analysis of adult liver transplant recipients with a laboratory MELD of ≤20 who underwent transplantation between January 1, 2003 and March 31, 2016. Recipients were categorized by donor graft type (DCD or LDLT), and recipient and donor characteristics were compared. Ten-year patient and graft survival curves were calculated using Kaplan-Meier analyses, and a mixed-effects model was performed to determine the contributions of recipient, donor, and center variables on patient and graft survival. There were 36,705 liver transplants performed: 32,255 (87.9%) from DBD donors, 2166 (5.9%) from DCD donors, and 2284 (6.2%) from living donors. In the mixed-effects model, DCD status was associated with a higher risk of graft failure (relative risk [RR], 1.27; 95% confidence interval [CI], 1.16-1.38) but not worse patient survival (RR, 1.27; 95% CI, 0.96-1.67). Lower DCD center experience was associated with a 1.21 higher risk of patient death (95% CI, 1.17-1.25) and a 1.13 higher risk of graft failure (95% CI, 1.12-1.15). LDLT center experience was also predictive of patient survival (RR, 1.03; 95% CI, 1.02-1.03) and graft failure (RR, 1.05; 95% CI, 1.05-1.06). In conclusion, for liver transplant recipients with low laboratory MELD, LDLT offers better graft survival and a tendency to better patient survival than DCD donors.

Older Donor Age Is a Risk Factor for Negative Outcomes After Adult Living Donor Liver Transplantation Using Small-for-Size Grafts.

Adult-to-adult living donor liver transplantation (ALDLT) using small-for-size grafts (SFSGs), ie, a graft with a graft-to-recipient weight ratio (GRWR) <0.8%, has been a challenge that should be carefully dealt with, and risk factors in this category are unclear. Therefore, we aimed to examine the risk factors and outcomes of ALDLT using SFSGs over a 13-year period in 121 patients who had undergone their first ALDLT using SFSGs. Small-for-size syndrome (SFSS), early graft loss, and 1-year mortality were encountered in 21.6%, 14.9%, and 18.4% of patients, respectively. By multivariate analysis, older donor age (≥45 years) was an independent risk factor for SFSS (odds ratio [OR], 4.46; P = 0.004), early graft loss (OR, 4.11; P = 0.02), and 1-year mortality (OR, 3.76; P = 0.02). Child-Pugh C class recipients were associated with a higher risk of SFSS development (P = 0.013; OR, 7.44). Despite no significant difference between GRWR categories in the multivariate outcome analysis of the whole population, in the survival analysis of the 2 donor age groups, GRWR <0.6% was associated with significantly lower 1-year survival than the other GRWR categories in the younger donor group. Moreover, in the high final portal venous pressure (PVP) group (>15 mm Hg), younger ABO-compatible donors showed 100% 1-year survival with a significant difference from the group of other donors. Older donor age was an independent risk factor for SFSS, early graft loss, and 1-year mortality after ALDLT using SFSGs. GRWR should not be <0.6%, and PVP modulation is indicated when grafts from older or ABO-incompatible donors are used.