Faculty Bibliography

End-stage liver disease (ESLD) is associated with cognitive impairment ranging from subtle alterations in attention to overt hepatic encephalopathy that resolves after transplant. Natural language processing (NLP) may provide a useful method to assess cognitive status in this population. We identified 81 liver transplant recipients with ESLD (4/2013-2/2018) who sent at least one patient-to-provider electronic message pre-transplant and post-transplant, and matched them 1:1 to "healthy" controls-who had similar disease, but had not been evaluated for liver transplant-by age, gender, race/ethnicity, and liver disease. Messages written by patients pre-transplant and post-transplant and controls was compared across 19 NLP measures using paired Wilcoxon signed-rank tests. While there was no difference overall in word length, patients with Model for End-Stage Liver Disease Score (MELD) ≥ 30 (n = 31) had decreased word length in pre-transplant messages (3.95 [interquartile range (IQR) 3.79, 4.14]) compared to post-transplant (4.13 [3.96, 4.28], p = 0.01) and controls (4.2 [4.0, 4.4], p = 0.01); there was no difference between post-transplant and controls (p = 0.4). Patients with MELD ≥ 30 had fewer 6+ letter words in pre-transplant messages (19.5% [16.4, 25.9] compared to post-transplant (23.4% [20.0, 26.7] p = 0.02) and controls (25.0% [19.2, 29.4]; p = 0.01). Overall, patients had increased sentence length pre-transplant (12.0 [9.8, 13.7]) compared to post-transplant (11.0 [9.2, 13.3]; p = 0.046); the same was seen for MELD ≥ 30 (12.3 [9.8, 13.7] pre-transplant vs. 10.8 [9.6, 13.0] post-transplant; p = 0.050). Application of NLP to patient-generated messages identified language differences-longer sentences with shorter words-that resolved after transplant. NLP may provide opportunities to detect cognitive impairment in ESLD.

Delayed graft function (DGF) complicates 20%-40% of deceased-donor kidney transplants and is associated with increased length of stay and subsequent allograft failure. Accurate prediction of DGF risk for a particular allograft could influence organ allocation, patient counseling, and postoperative planning. Mitochondrial dysfunction, a reported surrogate of tissue health in ischemia-perfusion injury, might also be a surrogate for tissue health after organ transplantation. To understand the potential of mitochondrial membrane potential (MMP) in clinical decision-making, we analyzed whether lower MMP, a measure of mitochondrial dysfunction, was associated with DGF. In a prospective, single-center proof-of-concept study, we measured pretransplant MMP in 28 deceased donor kidneys and analyzed the association between MMP and DGF. We used hybrid registry-augmented regression to adjust for donor and recipient characteristics, minimizing overfitting by leveraging Scientific Registry of Transplant Recipients data. The range of MMP levels was 964-28 333 units. Low-MMP kidneys (MMP<4000) were more likely from female donors (75% vs 10%, P = .002) and donation after cardiac death donors (75% vs 12%, P = .004). For every 10% decrease in MMP levels, there were 38% higher odds of DGF (adjusted odds ratio = _1.08 1.38_1.78 , P = .01). In summary, MMP might be a promising pretransplant surrogate for tissue health in kidney transplantation and, after further validation, could improve clinical decision-making through its independent association with DGF.

OBJECTIVE:The aim of this study was to develop a novel chronic kidney disease (CKD) risk prediction tool for young potential living kidney donors. SUMMARY OF BACKGROUND DATA:Living kidney donor selection practices have evolved from examining individual risk factors to a risk calculator incorporating multiple characteristics. Owing to limited long-term data and lack of genetic information, current risk tools lack precision among young potential living kidney donors, particularly African Americans (AAs). METHODS:We identified a cohort of young adults (18-30 years) with no absolute contraindication to kidney donation from the longitudinal cohort study Coronary Artery Risk Development in Young Adults. Risk associations for CKD (estimated glomerular filtration rate <60 mL/min/1.73 m) were identified and assigned weighted points to calculate risk scores. RESULTS:A total of 3438 healthy adults were identified [mean age 24.8 years; 48.3% AA; median follow-up 24.9 years (interquartile range: 24.5-25.2)]. For 18-year olds, 25-year projected CKD risk varied by ethnicity and sex even without baseline clinical and genetic abnormalities; risk was 0.30% for European American (EA) women, 0.52% for EA men, 0.52% for AA women, 0.90% for AA men. Among 18-year-old AAs with apolipoprotein L1 gene (APOL1) renal-risk variants without baseline abnormalities, 25-year risk significantly increased: 1.46% for women and 2.53% for men; among those with 2 APOL1 renal-risk variants and baseline abnormalities, 25-year risk was higher: 2.53% to 6.23% for women and 4.35% to 10.58% for men. CONCLUSIONS:Young AAs were at highest risk for CKD, and APOL1 renal-risk variants drove some of this risk. Understanding the genetic profile of young AA potential living kidney donors in the context of baseline health characteristics may help to inform candidate selection and counseling.

BACKGROUND:Recent changes in deceased donor organ allocation for livers (Share-35) and kidneys (kidney allocation system) have resulted in broader sharing of organs and increased cold ischemia time (CIT). Broader organ sharing however is not the only cause of increased CIT. METHODS:This was a retrospective registry study of CIT in same-hospital liver transplants (SHLT, n = 4347) and same-hospital kidney transplants (SHKT, n = 9707) between 2004 and 2014. RESULTS:In SHLT, median (interquartile range) CIT was 5.0 (3.5-6.5) hours versus 6.6 (5.1-8.4) hours in other-hospital LT. donation after circulatory death donors, donor biopsy, male recipient, recipient obesity, and previous transplant were associated with increased CIT. Model for End-Stage Liver Disease at transplant of 29+ or status 1a was associated with decreased CIT. SHLT CIT varied by Organ Procurement Organization and transplant-center (P < 0.01), with center median CIT ranging from 2.0 to 7.8 hours across 118 centers. In SHKT, CIT was 13.0 (8.5-19.0) hours versus 16.5 (11.3-22.6) hours in other-hospital KT. Overweight donors, donation after cardiac death donors, right-kidney, donor biopsy, recipient obesity, use of mechanical perfusion, additional KT procedures on the same day, and transplant center annual volume were associated with increased CIT. Older donor age, extended criteria donors, and underweight recipients were associated with decreased CIT. SHKT CIT varied by Organ Procurement Organization and transplant-center (P < 0.001), with center median CIT ranging from 3.3 to 29 hours across 206 centers. Transplant centers with longer SHKT also had longer SHLT (P = 0.01). CONCLUSIONS:Same-hospital transplants already have a significant amount of CIT, even without transporting the organ to another hospital.

OBJECTIVE:African Americans and other minorities are known to face barriers to health care influencing their access to organ transplantation but it is not known whether these barriers exist among pediatric liver transplant waitlist candidates. We sought to determine whether outcomes on the waitlist (ie, mortality, deceased donor liver transplantation [DDLT], and living-donor liver transplantation [LDLT]) varied by race/ethnicity. METHODS:National registry data were studied to estimate the race/ethnicity-specific risk of waitlist mortality, DDLT and LDLT in children (<18 years) waitlisted between March 2002 and March 2015. RESULTS:There was no evidence of racial/ethnic disparities in waitlist mortality. Compared to Caucasians, LDLT varied by race/ethnicity, with only 6.7% African Americans and 10.3% Hispanic children receiving LDLT compared with 12.4% Caucasian, 13.3% Asian, and 9.4% mix/other children. In an adjusted Cox proportional hazards model, African Americans were half as likely as Caucasians to use LDLT (hazard ratio [HR]: 0.410.550.73) but had similar use of DDLT (HR: 0.981.061.16). In a model that considered mortality, DDLT, and LDLT as competing risks, African Americans had significantly reduced incidence of LDLT (subhazard ratio [sHR]: 0.410.560.75) compared to Caucasians, but increased use of DDLT (sHR: 1.061.161.26). CONCLUSIONS:Compared to Caucasian children, African-American children are less likely to use LDLT but have higher rates of DDLT and similar survival on the waitlist. Additional research is necessary to understand the clinical and socioeconomic factors contributing to lower utilization of LDLT among African-American children awaiting transplantation.