Faculty Bibliography

Patient and graft survival are similar following whole versus split liver transplants (SLT) among pediatric and adult recipients, yet SLTs are rarely used. We sought to determine the survival benefit associated with accepting a splittable offer for SLT versus declining and waiting for a subsequent offer using 2010-2018 SRTR data on 928 pediatric and 1814 adult LT candidates who were ever offered a splittable graft. We compared eventual mortality, regardless of subsequent transplants, between those who accepted versus declined a splittable liver offer with adjustment for PELD/MELD, diagnosis, and weight among pediatric candidates, and matching for MELD, height, and offer among adult candidates. Among pediatric candidates ≤7kg, splittable offer acceptance versus decline was associated with a 63% reduction in mortality (aHR _0.17 0.37_0.80 , p=0.01; 93.1% versus 84.0% one-year survival post-decision). Within one year of decline for those ≤7kg, 6.4% died and 31.1% received a whole liver transplant. Among pediatric candidates >7kg, there was no significant difference associated with acceptance of a splittable offer (aHR _0.63 1.07_1.82 , p=0.81; 91.7% vs 94.4% one-year survival post-decision). Within one year of decline for those >7kg, 1.8% died and 45.8% received a whole liver. Among adult candidates, splittable offer acceptance was associated with a 43% reduction in mortality (aHR _0.39 0.57_0.83, p=0.005; 92.2% vs 84.4% one-year survival post-decision). Within one year of decline for adult candidates, 7.9% died and 39.3% received a whole liver. Conclusion: Accepting splittable offers for SLT could significantly improve survival for small children and adults on the waitlist.

BACKGROUND:Early steroid withdrawal (ESW) is a viable maintenance immunosuppression strategy in low-risk kidney transplant recipients. A low panel reactive antibody (PRA) may indicate low-risk condition amenable to ESW. We aimed to identify the threshold value of PRA above which ESW may pose additional risk, and to compare the association of ESW with transplant outcomes across PRA strata. METHODS:We studied 121,699 deceased-donor kidney-only recipients in 2002-2017 from SRTR. Using natural splines and ESW-PRA interaction terms, we explored how the associations of ESW with transplant outcomes change with increasing PRA values, and identified a threshold value for PRA. Then, we assessed whether PRA exceeding the threshold modified the associations of ESW with 1-year acute rejection, death-censored graft failure, and death. RESULTS:The association of ESW with acute rejection exacerbated rapidly when PRA exceeded 60. Among PRA≤60 recipients, ESW was associated with a minor increase in rejection (aOR=1.001.051.10) and with a tendency of decreased graft failure (aHR=0.910.971.03). However, among PRA>60 recipients, ESW was associated with a substantial increase in rejection (aOR=1.191.271.36; interaction p<0.001) and with a tendency of increased graft failure (aHR=0.981.081.20; interaction p=0.028). The association of ESW with death was similar between PRA strata (PRA≤60, aHR=0.910.961.01; and PRA>60, aHR=0.900.991.09; interaction p=0.5). CONCLUSIONS:Our findings show that the association of ESW with transplant outcomes is less favorable in recipients with higher PRA, especially those with PRA>60, suggesting a possible role of PRA in the risk assessment for ESW.

Nondirected kidney donors can initiate living donor chains that end to patients on the waitlist. We compared 749 National Kidney Registry (NKR) waitlist chain end transplants to other transplants from the NKR and the Scientific Registry of Transplant Recipients between February 2008 and September 2020. Compared to other NKR recipients, chain end recipients were more often older (53 vs. 52 years), black (32% vs. 15%), publicly insured (71% vs. 46%), and spent longer on dialysis (3.0 vs. 1.0 years). Similar differences were noted between chain end recipients and non-NKR living donor recipients. Black patients received chain end kidneys at a rate approaching that of deceased donor kidneys (32% vs. 34%). Chain end donors were older (52 vs. 44 years) with slightly lower glomerular filtration rates (93 vs. 98 ml/min/1.73 m² ) than other NKR donors. Chain end recipients had elevated risk of graft failure and mortality compared to control living donor recipients (both p < .01) but lower graft failure (p = .03) and mortality (p < .001) compared to deceased donor recipients. Sharing nondirected donors among a multicenter network may improve the diversity of waitlist patients who benefit from living donation.

BACKGROUND AND AIMS/OBJECTIVE:Frailty is a well-established risk factor for poor outcomes in patients with cirrhosis awaiting liver transplantation (LT), but whether it predicts outcomes among those who have undergone LT is unknown. APPROACH AND RESULTS/UNASSIGNED:Adult LT recipients from 8 US centers (2012-2019) were included. Pre-LT frailty was assessed in the ambulatory setting using the Liver Frailty Index (LFI). "Frail" was defined by an optimal cut point of LFI ≥ 4.5. We used the 75th percentile to define "prolonged" post-LT length of stay (LOS; ≥12 days), intensive care unit (ICU) days (≥4 days), and inpatient days within 90 post-LT days (≥17 days). Of 1166 LT recipients, 21% were frail pre-LT. Cumulative incidence of death at 1 and 5 years was 6% and 16% for frail and 4% and 10% for nonfrail patients (overall log-rank p = 0.02). Pre-LT frailty was associated with an unadjusted 62% increased risk of post-LT mortality (95% CI, 1.08-2.44); after adjustment for body mass index, HCC, donor age, and donation after cardiac death status, the HR was 2.13 (95% CI, 1.39-3.26). Patients who were frail versus nonfrail experienced a higher adjusted odds of prolonged LT LOS (OR, 2.00; 95% CI, 1.47-2.73), ICU stay (OR, 1.56; 95% CI, 1.12-2.14), inpatient days within 90 post-LT days (OR, 1.72; 95% CI, 1.25-2.37), and nonhome discharge (OR, 2.50; 95% CI, 1.58-3.97). CONCLUSIONS:Compared with nonfrail patients, frail LT recipients had a higher risk of post-LT death and greater post-LT health care utilization, although overall post-LT survival was acceptable. These data lay the foundation to investigate whether targeting pre-LT frailty will improve post-LT outcomes and reduce resource utilization.

BACKGROUND:The association between exposure to air pollution and papillary thyroid carcinoma is unknown. We sought to estimate the relationship between long-term exposure to the fine (diameter ≤ 2.5 μm) particulate matter component of air pollution and the risk of papillary thyroid cancer. METHODS:Adult (age ≥18) patients with newly diagnosed papillary thyroid carcinoma between January 1, 2013 and December 31, 2016 across a single health system were identified using electronic medical records. Data from 1,990 patients with papillary thyroid carcinoma were compared with 3,980 age- and sex-matched control subjects without any evidence of thyroid disease. Cumulative fine (diameter <2.5 μm) particulate matter exposure was estimated by incorporating patients' residential zip codes into a deep learning neural networks model, which uses both meteorological and satellite-based measurements. Conditional logistic regression was performed to assess for association between papillary thyroid carcinoma and increasing fine (diameter ≤2.5 μm) particulate matter concentrations over 1, 2, and 3 years of cumulative exposure preceding papillary thyroid carcinoma diagnosis. RESULTS:n = 0.04). Among current smokers (n = 623), the risk of developing papillary thyroid carcinoma was highest (adjusted odds ratio = 1.35, 95% confidence interval: 1.12-1.63). CONCLUSION/CONCLUSIONS:Increasing concentration of fine (diameter ≤2.5 μm) particulate matter in air pollution is significantly associated with the incidence of papillary thyroid carcinoma with 2 and 3 years of exposure. Our novel findings provide additional insight into the potential associations between risk factors and papillary thyroid carcinoma and warrant further investigation, specifically in areas with high levels of air pollution both nationally and internationally.

BACKGROUND:Air pollution is associated with cardiopulmonary disease and death in the general population. Fine particulate matter (PM2.5) is particularly harmful due to its ability to penetrate into areas of gas exchange within the lungs. Persons with advanced lung disease are believed to be particularly susceptible to PM2.5 exposure but few studies have examined the effect of exposure on this population. Here we investigate the association between PM2.5 exposure and adverse waitlist events among lung transplant (LT) candidates. METHODS:US registry data were used to identify LT candidates listed between 1/1/2010-12/31/2016. Annual PM2.5 concentration at year of listing was estimated for each candidate's ZIP Code using NASA's SEDAC Global Annual PM2.5 Grids. We estimated crude and adjusted hazard ratios for adverse waitlist events, defined as death or removal, using Cox proportional hazards regression. RESULTS:Of the 15,075 included candidates, median age at listing was 60, 43.8% were female and 81.7% were non-Hispanic white. Median ZIP Code PM2.5 concentration was 9.06µg/m3. When compared to those living in ZIP Codes with lower PM2.5 exposure (PM2.5 <10.53µg/m3), candidates in ZIP Codes in the highest quartile of PM2.5 exposure (≥10.53µg/m3) had 1.14-fold (95%CI 1.04-1.25) risk of adverse waitlist events. The result remained significant after adjusting for demographics, education, insurance, smoking, lung allocation score, BMI, and blood type (HR=1.17; 95%CI 1.07-1.29). CONCLUSIONS:Elevated ambient PM2.5 concentration was associated with adverse waitlist events among LT candidates. These findings highlight the impact of air pollution on clinical outcomes in this critically ill population.

BACKGROUND:In older adults (≥65) access to and outcomes following kidney transplantation (KT) have improved over the past three decades. It is unknown if there were parallel trends in re-KT. We characterized the trends, changing landscape, and outcomes of re-KT in older adults. METHODS:Among the 44,149 older kidney-only recipients (1995-2016) in the Scientific Registry of Transplant Recipients, we identified 1,743 who underwent re-KT. We analyzed trends and outcomes (mortality, death-censored graft failure [DCGF]) by eras (1995-2002, 2003-2014 and 2015-2016) that were defined by changes to the ECD and KDPI policies. RESULTS:Among all older kidney-only recipients during 1995-2002, 2003-2014, 2015-2016 the proportion that were re-KTs increased from 2.7%-4.2%-5.7% p<0.001, respectively. Median age at re-KT (67-68-68, p=0.04), years on dialysis after graft failure (1.4-1.5-2.2, p=0.003), donor age (40.0-43.0-43.5, p=0.04), proportion with PRA 80-100 (22.0%-32.7%-48.7%, p<0.001) and donations after circulatory death (1.1%-13.4%-19.5%, p<0.001) have increased. Despite this, the 3-year cumulative incidence for mortality (22.3%-19.1%-11.5%, p=0.002) and DCGF (13.3%-10.0%-5.1%, p=0.01) decreased over time. Compared with deceased donor re-transplant recipients during 1995-2002, those during 2003-2014 and 2015-2016 had lower mortality hazard (aHR=0.78, 95%CI:0.63-0.86 and aHR=0.55, 95%CI:0.35-0.86, respectively). These declines were noted but not significant for DCGF and in living donor re-KTs. CONCLUSIONS:In older re-transplant recipients, outcomes have improved significantly over time despite higher risk profiles; yet they represent a fraction of the KTs performed. Our results support increasing access to re-KT in older adults; however, approaches to guide the selection and management in those with graft failure need to be explored.