A2/A2B to B deceased donor kidney transplantation in the Kidney Allocation System era.

Kidney transplantation from blood type A2/A2B donors to type B recipients (A2→B) has increased dramatically under the current Kidney Allocation System (KAS). Among living donor transplant recipients, A2-incompatible transplants are associated with an increased risk of all-cause and death-censored graft failure. In light of this, we used data from the Scientific Registry of Transplant Recipients from December 2014 until June 2022 to evaluate the association between A2→B listing and time to deceased donor kidney transplantation (DDKT) and post-DDKT outcomes for A2→B recipients. Among 53 409 type B waitlist registrants, only 12.6% were listed as eligible to accept A2→B offers ("A2-eligible"). The rates of DDKT at 1-, 3-, and 5-years were 32.1%, 61.4%, and 72.1% among A2-eligible candidates and 14.1%, 29.9%, and 44.1% among A2-ineligible candidates, with the former experiencing a 133% higher rate of DDKT (Cox weighted hazard ratio (wHR) = 2.192.332.47; P < .001). The 7-year adjusted mortality was comparable between A2→B and B-ABOc (type B/O donors to B recipients) recipients (wHR 0.780.941.13, P = .5). Moreover, there was no difference between A2→B vs B-ABOc DDKT recipients with regards to death-censored graft failure (wHR 0.771.001.29, P > .9) or all-cause graft loss (wHR 0.820.961.12, P = .6). Following its broader adoption since the implementation of the kidney allocation system, A2→B DDKT appears to be a safe and effective transplant modality for eligible candidates. As such, A2→B listing for eligible type B candidates should be expanded.

Single center utilization and post-transplant outcomes of thoracoabdominal normothermic regional perfusion deceased cardiac donor organs.

INTRODUCTION: Thoracoabdominal normothermic regional perfusion (TA-NRP) following cardiac death is an emerging multivisceral organ procurement technique. Recent national studies on outcomes of presumptive TA-NRP-procured organs are limited by potential misclassification since TA-NRP is not differentiated from donation after cardiac death (DCD) in registry data. METHODS: We studied 22 donors whose designees consented to TA-NRP and organ procurement performed at our institution between January 20, 2020 and July 3, 2022. We identified these donors in SRTR to describe organ utilization and recipient outcomes and compared them to recipients of traditional DCD (tDCD) and donation after brain death (DBD) organs during the same timeframe. RESULTS: All 22 donors progressed to cardiac arrest and underwent TA-NRP followed by heart, lung, kidney, and/or liver procurement. Median donor age was 41 years, 55% had anoxic brain injury, 45% were hypertensive, 0% were diabetic, and median kidney donor profile index was 40%. TA-NRP utilization was high across all organ types (88%-100%), with a higher percentage of kidneys procured via TA-NRP compared to tDCD (88% vs. 72%, p = .02). Recipient and graft survival ranged from 89% to 100% and were comparable to tDCD and DBD recipients (p ≥ .2). Delayed graft function was lower for kidneys procured from TA-NRP compared to tDCD donors (27% vs. 44%, p = .045). CONCLUSION: Procurement from TA-NRP donors yielded high organ utilization, with outcomes comparable to tDCD and DBD recipients across organ types. Further large-scale study of TA-NRP donors, facilitated by its capture in the national registry, will be critical to fully understand its impact as an organ procurement technique.

Trends in the survival benefit of repeat kidney transplantation over the past 3 decades.

Repeat kidney transplantation (re-KT) is the preferred treatment for patients with graft failure. Changing allocation policies, widening the risk profile of recipients, and improving dialysis care may have altered the survival benefit of a re-KT. We characterized trends in re-KT survival benefit over 3 decades and tested whether it differed by age, race/ethnicity, sex, and panel reactive assay (PRA). By using the Scientific Registry of Transplant Recipient data, we identified 25 419 patients who underwent a re-KT from 1990 to 2019 and 25 419 waitlisted counterfactuals from the same year with the same waitlisted time following graft failure. In the adjusted analysis, a re-KT was associated with a lower risk of death (adjusted hazard ratio [aHR] = 0.63; 95% confidence interval [CI], 0.61-0.65). By using the 1990-1994 era as a reference (aHR = 0.77; 95% CI, 0.69-0.85), incremental improvements in the survival benefit were noted (1995-1999: aHR = 0.72; 95% CI, 0.67-0.78: 2000-2004: aHR = 0.59; 95% CI, 0.55-0.63: 2005-2009: aHR = 0.59; 95% CI, 0.56-0.63: 2010-2014: aHR = 0.57; 95% CI, 0.53-0.62: 2015-2019: aHR = 0.64; 95% CI, 0.57-0.73). The survival benefit of a re-KT was noted in both younger (age = 18-64 years: aHR = 0.63; 95% CI, 0.61-0.65) and older patients (age ≥65 years: aHR = 0.66; 95% CI, 0.58-0.74; Pinteraction = .45). Patients of all races/ethnicities demonstrated similar benefits with a re-KT. However, it varied by the sex of the recipient (female patients: aHR = 0.60; 95% CI, 0.56-0.63: male patients: aHR = 0.66; 95% CI, 0.63-0.68; Pinteraction = .004) and PRA (0-20: aHR = 0.69; 95% CI, 0.65-0.74: 21-80: aHR = 0.61; 95% CI, 0.57-0.66; Pinteraction = .02; >80: aHR = 0.57; 95% CI, 0.53-0.61; Pinteraction< .001). Our findings support the continued practice of a re-KT and efforts to overcome the medical, immunologic, and surgical challenges of a re-KT.

Neutralizing activity and 3-month durability of tixagevimab and cilgavimab prophylaxis against Omicron sublineages in transplant recipients.

Neutralizing antibody (nAb) responses are attenuated in solid organ transplant recipients (SOTRs) despite severe acute respiratory syndrome-coronavirus-2 vaccination. Preexposure prophylaxis (PrEP) with the antibody combination tixagevimab and cilgavimab (T+C) might augment immunoprotection, yet in vitro activity and durability against Omicron sublineages BA.4/5 in fully vaccinated SOTRs have not been delineated. Vaccinated SOTRs, who received 300 + 300 mg T+C (ie, full dose), within a prospective observational cohort submitted pre and postinjection samples between January 31, 2022, and July 6, 2022. The peak live virus nAb was measured against Omicron sublineages (BA.1, BA.2, BA.2.12.1, and BA.4), and surrogate neutralization (percent inhibition of angiotensin-converting enzyme 2 receptor binding to full length spike, validated vs live virus) was measured out to 3 months against sublineages, including BA.4/5. With live virus testing, the proportion of SOTRs with any nAb increased against BA.2 (47%-100%; P < .01), BA.2.12.1 (27%-80%; P < .01), and BA.4 (27%-93%; P < .01), but not against BA.1 (40%-33%; P = .6). The proportion of SOTRs with surrogate neutralizing inhibition against BA.5, however, fell to 15% by 3 months. Two participants developed mild severe acute respiratory syndrome-coronavirus-2 infection during follow-up. The majority of fully vaccinated SOTRs receiving T+C PrEP achieved BA.4/5 neutralization, yet nAb activity commonly waned by 3 months postinjection. It is critical to assess the optimal dose and interval of T+C PrEP to maximize protection in a changing variant climate.

Persistent SARS-CoV-2-specific immune defects in kidney transplant recipients following third mRNA vaccine dose.

Kidney transplant recipients (KTRs) show poorer response to SARS-CoV-2 mRNA vaccination, yet response patterns and mechanistic drivers following third doses are ill-defined. We administered third monovalent mRNA vaccines to n = 81 KTRs with negative or low-titer anti-receptor binding domain (RBD) antibody (n = 39 anti-RBDNEG; n = 42 anti-RBDLO), compared with healthy controls (HCs, n = 19), measuring anti-RBD, Omicron neutralization, spike-specific CD8+%, and SARS-CoV-2-reactive T cell receptor (TCR) repertoires. By day 30, 44% anti-RBDNEG remained seronegative; 5% KTRs developed BA.5 neutralization (vs 68% HCs, P < .001). Day 30 spike-specific CD8+% was negative in 91% KTRs (vs 20% HCs; P = .07), without correlation to anti-RBD (rs = 0.17). Day 30 SARS-CoV-2-reactive TCR repertoires were detected in 52% KTRs vs 74% HCs (P = .11). Spike-specific CD4+ TCR expansion was similar between KTRs and HCs, yet KTR CD8+ TCR depth was 7.6-fold lower (P = .001). Global negative response was seen in 7% KTRs, associated with high-dose MMF (P = .037); 44% showed global positive response. Of the KTRs, 16% experienced breakthrough infections, with 2 hospitalizations; prebreakthrough variant neutralization was poor. Absent neutralizing and CD8+ responses in KTRs indicate vulnerability to COVID-19 despite 3-dose mRNA vaccination. Lack of neutralization despite CD4+ expansion suggests B cell dysfunction and/or ineffective T cell help. Development of more effective KTR vaccine strategies is critical. (NCT04969263).

Characterizing the risk of human leukocyte antigen-incompatible living donor kidney transplantation in older recipients.

Older compatible living donor kidney transplant (CLDKT) recipients have higher mortality and death-censored graft failure (DCGF) compared to younger recipients. These risks may be amplified in older incompatible living donor kidney transplant (ILDKT) recipients who undergo desensitization and intense immunosuppression. In a 25-center cohort of ILDKT recipients transplanted between September 24, 1997, and December 15, 2016, we compared mortality, DCGF, delayed graft function (DGF), acute rejection (AR), and length of stay (LOS) between 234 older (age ≥60 years) and 1172 younger (age 18-59 years) recipients. To investigate whether the impact of age was different for ILDKT recipients compared to 17 542 CLDKT recipients, we used an interaction term to determine whether the relationship between posttransplant outcomes and transplant type (ILDKT vs CLDKT) was modified by age. Overall, older recipients had higher mortality (hazard ratio: 1.632.072.65, P < .001), lower DCGF (hazard ratio: 0.360.530.77, P = .001), and AR (odds ratio: 0.390.540.74, P < .001), and similar DGF (odds ratio: 0.461.032.33, P = .9) and LOS (incidence rate ratio: 0.880.981.10, P = 0.8) compared to younger recipients. The impact of age on mortality (interaction P = .052), DCGF (interaction P = .7), AR interaction P = .2), DGF (interaction P = .9), and LOS (interaction P = .5) were similar in ILDKT and CLDKT recipients. Age alone should not preclude eligibility for ILDKT.

Outcomes after liver transplantation using deceased after circulatory death donors: A comparison of outcomes in the UK and the US.

BACKGROUND AND AIMS: Identifying international differences in utilization and outcomes of liver transplantation (LT) after donation after circulatory death (DCD) donation provides a unique opportunity for benchmarking and population-level insight. METHODS: Adult (≥18 years) LT data between 2008 and 2018 from the UK and US were used to assess mortality and graft failure after DCD LT. We used time-dependent Cox-regression methods to estimate hazard ratios (HR) for risk-adjusted short-term (0-90 days) and longer-term (90 days-5 years) outcomes. RESULTS: One-thousand five-hundred-and-sixty LT receipts from the UK and 3426 from the US were included. Over the study period, the use of DCD livers increased from 15.7% to 23.9% in the UK compared to 5.1% to 7.6% in the US. In the UK, DCD donors were older (UK:51 vs. US:33 years) with longer cold ischaemia time (UK: 437 vs. US: 333 min). Recipients in the US had higher Model for End-stage Liver Disease (MELD) scores, higher body mass index, higher proportions of ascites, encephalopathy, diabetes and previous abdominal surgeries. No difference in the risk-adjusted short-term mortality or graft failure was observed between the countries. In the longer-term (90 days-5 years), the UK had lower mortality and graft failure (adj.mortality HR:UK: 0.63 (95% CI: 0.49-0.80); graft failure HR: UK: 0.72, 95% CI: 0.58-0.91). The cumulative incidence of retransplantation was higher in the UK (5 years: UK: 11.9% vs. 4.6%; p < .001). CONCLUSIONS: For those receiving a DCD LT, longer-term post-transplant outcomes in the UK are superior to the US, however, significant differences in recipient illness, graft quality and access to retransplantation were seen between the two countries.

Patient-reported outcomes after Tixagevimab and Cilgavimab pre-exposure prophylaxis among solid organ transplant recipients: Safety, effectiveness, and perceptions of risk.

BACKGROUND: Tixagevimab and Cilgavimab (T + C) is authorized for pre-exposure prophylaxis (PrEP) against Coronavirus Disease 2019 (COVID-19) in solid organ transplant recipients (SOTRs), yet patient-reported outcomes after injection are not well described. Furthermore, changes in risk tolerance after T + C PrEP have not been reported, of interest given uncertain activity against emerging Omicron sublineages. METHODS: Within a national prospective observational study, SOTRs who reported receiving T + C were surveyed for 3 months to ascertain: (1) local and systemic reactogenicity, (2) severe adverse events with focus on cardiovascular and alloimmune complications, and (3) breakthrough COVID-19, contextualized through (4) changes in attitudes regarding COVID-19 risk and behaviors. RESULTS: At 7 days postinjection, the most common reactions were mild fatigue (29%), headache (20%), and pain at injection sites (18%). Severe adverse events were uncommon; over 3 months of follow-up, 4/392 (1%) reported acute rejection and one (.3%) reported a myocardial infarction. Breakthrough COVID-19 occurred in 9%, 16-129 days after receiving full dose (300/300 mg) T + C, including two non-ICU hospitalizations. Most surveyed SOTRs (65%) felt T + C PrEP was likely to reduce their COVID-19 risk, and 70% reported increased willingness to engage in social activities such as visiting friends. However, few felt safe to return to in-person work (20%) or cease public mask-wearing (15%). CONCLUSIONS: In this prospective study of patient-reported outcomes, T + C was well tolerated with few serious events. Several COVID-19 breakthroughs were reported, notable as most SOTRs reported changes in risk tolerance after T + C. These results aid counseling of SOTRs regarding real-world safety and effectiveness of T + C.

External Validation of Toulouse-Rangueil eGFR12 Prediction Model After Living Donor Nephrectomy.

Decreased postdonation eGFR is associated with a higher risk of ESRD after living kidney donation, even when accounting for predonation characteristics. The Toulouse-Rangueil model (TRM) estimates 12 month postdonation eGFR (eGFR12) to inform counseling of candidates for living donation. The TRM was validated in several single-center European cohorts but has not been validated in US donors. We assessed the TRM in living kidney donors in the US using SRTR data 1/2000-6/2021. We compared the 2021 CKD-EPI equation eGFR12 observed estimates to the TRM eGFR12 predictions. Median (IQR) bias was -3.4 (-9.3, 3.4) mL/min/1.73 m2. Bias was higher for males vs. females (bias [IQR] -4.4 [-9.9, 1.8] vs. -2.9 [-8.8, 4.1]) and younger (31-40) vs. older donors (>50) (bias -4.9 [-10.6, 3.0] vs. -2.1 [-7.5, 4.0]). Bias was also larger for Black vs. White donors (bias (-6.7 [-12.1, -0.3], p < 0.001) vs. (-3.4 [-9.1, 3.1], p < 0.001)). Overall correlation was 0.71. In a sensitivity analysis using the 2009 CKD-EPI equation, results were generally consistent with exception to a higher overall bias (bias -4.2 [-9.8, 2.4]). The TRM overestimates postdonation renal function among US donors. Overestimation was greatest for those at higher risk for postdonation ESRD including male, Black, and younger donors. A new equation is needed to estimate postdonation renal function.

Coronavirus Disease 2019-Associated Pulmonary Aspergillosis in Mechanically Ventilated Patients.

BACKGROUND: Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) occurs in critically ill patients with COVID-19. Risks and outcomes remain poorly understood. METHODS: A retrospective cohort study of mechanically ventilated adult patients with COVID-19 admitted to 5 Johns Hopkins hospitals was conducted between March and August 2020. CAPA was defined using composite clinical criteria. Fine and Gray competing risks regression was used to analyze clinical outcomes and, multilevel mixed-effects ordinal logistic regression was used to compare longitudinal disease severity scores. RESULTS: In the cohort of 396 people, 39 met criteria for CAPA. Patients with CAPA were more likely than those without CAPA to have underlying pulmonary vascular disease (41% vs 21.6%, respectively; P = .01), liver disease (35.9% vs 18.2%; P = .02), coagulopathy (51.3% vs 33.1%; P = .03), solid tumors (25.6% vs 10.9%; P = .02), multiple myeloma (5.1% vs 0.3%; P = .03), and corticosteroid exposure during the index admission (66.7% vs 42.6%; P = .005), and had lower body mass indexes (median, 26.6 vs 29.9 [calculated as weight in kilograms divided by height in meters squared]; P = .04). Patients with CAPA had worse outcomes, as measured by ordinal severity of disease scores, requiring longer time to improvement (adjusted odds ratio, 1.081.091.1; P < .001), and advancing in severity almost twice as quickly (subhazard ratio, 1.31.82.5; P < .001). They were intubated twice as long as those without CAPA (subhazard ratio, 0.40.50.6; P < .001) and had longer hospital stays (median [interquartile range], 41.1 [20.5-72.4) vs 18.5 [10.7-31.8] days; P < .001). CONCLUSION: CAPA is associated with poor outcomes. Attention to preventive measures (screening and/or prophylaxis) is warranted in people with high risk of CAPA.

Quantifying excess deaths among solid organ transplant recipients in the COVID-19 era.

Estimating the total coronavirus disease 2019 (COVID-19) mortality burden of solid organ transplant recipients (SOTRs), both directly through COVID-19 infection and indirectly through other impacts on the healthcare system and society, is critical for understanding the disease's impact on the SOTR population. Using SRTR data, we modeled expected mortality risk per month pre-COVID (January 2015-February 2020) for kidney/liver/heart/lung SOTRs, and compared monthly COVID-era deaths (March 2020-March 2021) to expected rates, overall and among subgroups. Deaths above expected rates were designated "excess deaths." Between March 2020 and March 2021, there were 3739/827/265/252 excess deaths among kidney/liver/heart/lung SOTRs, respectively, representing a 41.2%/27.4%/18.5%/15.0% increase above expected deaths. 93.0% of excess deaths occurred in patients age≥50. The observed:expected ratio was highest among Hispanic SOTRs (1.82) and lowest among White SOTRs (1.20); 56.0% of excess deaths occurred among Black or Hispanic SOTRs. 64.7% of excess deaths occurred among patients who had survived ≥5 years post-transplant. Excess deaths peaked in January 2021; geographic distribution of excess deaths broadly mirrored COVID-19 incidence. COVID-19 likely caused over 5000 excess deaths among SOTRs in the US in a 13-month period, representing 1 in 75 SOTRs and a substantial proportion of all deaths among SOTRs during this time. SOTRs will remain at elevated mortality risk until the COVID-19 pandemic can be controlled.

Maximizing the use of potential donors through increased rates of family approach for authorization.

In the United States, a small proportion of potential deceased organ donor referrals lead to donation and recovery. Understanding variation in the processes involved between organ procurement organizations (OPOs) may help increase deceased donation and reduce the organ shortage. We studied 103 923 referrals from 10 OPOs from 2018 to 2019, of which 14.4% led to approach for authorization, 8.2% led to authorization, 5.1% led to organ recovery, and 4.8% led to transplantation. First-person authorization (FPA) was associated with threefold higher odds of donation (OR = 2.83 3.02 3.22 , p < .001). Female referrals had 11% lower odds of approach; when approached, Black and Hispanic referrals had 46% and 35% lower odds of authorization, respectively (all p < .001). There was substantial OPO-level variation in rates of approach, authorization, and organ recovery, which persisted after adjusting for age, sex, race, and FPA status. An OPO's relative rate of approach correlated strongly with its relative rate of donation among all referrals (ρ = 0.43). Correlation between an individual OPO's authorization rate among approached families, and overall rate of donation, was negative, suggesting that high authorization rates may be the result of selective approach practices. Therefore, approaching a higher proportion of families for authorization may lead to higher donation rates.

Heterologous Ad.26.COV2.S versus homologous BNT162b2/mRNA-1273 as a third dose in solid organ transplant recipients seronegative after two-dose mRNA vaccination.

Heterologous vaccination ("mixing platforms") for the third (D3) dose of SARS-CoV-2 vaccine is a potential strategy to improve antibody responses in solid organ transplant recipients (SOTRs), but data are mixed regarding potential differential immunogenicity. We assessed for differences in immunogenicity and tolerability of homologous (BNT162b2 or mRNA-1273; D3-mRNA) versus heterologous (Ad.26.COV2.S; D3-JJ) D3 among 377 SARS-CoV-2-infection naïve SOTRs who remained seronegative after two mRNA vaccines. We measured anti-spike titers and used weighted Poisson regression to evaluate seroconversion and development of high-titers, comparing D3-JJ to D3-mRNA, at 1-, 3-, and 6 month post-D3. 1-month post-D3, seroconversion (63% vs. 52%, p = .3) and development of high-titers (29% vs. 25%, p = .7) were comparable between D3-JJ and D3-mRNA recipients. 3 month post-D3, D3-JJ recipients were 1.4-fold more likely to seroconvert (80% vs. 57%, weighted incidence-rate-ratio: wIRR = 1.10 1.401.77 , p = .006) but not more likely to develop high-titers (27% vs. 22%, wIRR = 0.44 0.921.93 , p = .8). 6 month post-D3, D3-JJ recipients were 1.41-fold more likely to seroconvert (88% vs. 59%, wIRR = 1.04 1.411.93 , p = .029) and 2.63-fold more likely to develop high-titers (59% vs. 21%, wIRR = 1.38 2.635.00 , p = .003). There was no differential signal in alloimmune events or reactogenicity between platforms. SOTRs without antibody response after two mRNA vaccines may derive benefit from heterologous Ad.26.COV2.S D3.

Low utilization of adult-to-adult LDLT in Western countries despite excellent outcomes: International multicenter analysis of the US, the UK, and Canada.

BACKGROUND & AIMS: Adult-to-adult living donor liver transplantation (LDLT) offers an opportunity to decrease the liver transplant waitlist and reduce waitlist mortality. We sought to compare donor and recipient characteristics and post-transplant outcomes after LDLT in the US, the UK, and Canada. METHODS: This is a retrospective multicenter cohort-study of adults (≥18-years) who underwent primary LDLT between Jan-2008 and Dec-2018 from three national liver transplantation registries: United Network for Organ Sharing (US), National Health Service Blood and Transplantation (UK), and the Canadian Organ Replacement Registry (Canada). Patients undergoing retransplantation or multi-organ transplantation were excluded. Post-transplant survival was evaluated using the Kaplan-Meier method, and multivariable adjustments were performed using Cox proportional-hazards models with mixed-effect modeling. RESULTS: A total of 2,954 living donor liver transplants were performed (US: n = 2,328; Canada: n = 529; UK: n = 97). Canada has maintained the highest proportion of LDLT utilization over time (proportion of LDLT in 2008 - US: 3.3%; Canada: 19.5%; UK: 1.7%; p <0.001 - in 2018 - US: 5.0%; Canada: 13.6%; UK: 0.4%; p <0.001). The 1-, 5-, and 10-year patient survival was 92.6%, 82.8%, and 70.0% in the US vs. 96.1%, 89.9%, and 82.2% in Canada vs. 91.4%, 85.4%, and 66.7% in the UK. After adjustment for characteristics of donors, recipients, transplant year, and treating transplant center as a random effect, all countries had a non-statistically significantly different mortality hazard post-LDLT (Ref US: Canada hazard ratio 0.53, 95% CI 0.28-1.01, p = 0.05; UK hazard ratio 1.09, 95% CI 0.59-2.02, p = 0.78). CONCLUSIONS: The use of LDLT has remained low in the US, the UK and Canada. Despite this, long-term survival is excellent. Continued efforts to increase LDLT utilization in these countries may be warranted due to the growing waitlist and differences in allocation that may disadvantage patients currently awaiting liver transplantation. LAY SUMMARY: This multicenter international comparative analysis of living donor liver transplantation in the United States, the United Kingdom, and Canada demonstrates that despite low use of the procedure, the long-term outcomes are excellent. In addition, the mortality risk is not statistically significantly different between the evaluated countries. However, the incidence and risk of retransplantation differs between the countries, being the highest in the United Kingdom and lowest in the United States.

Survival Benefit of Split-Liver Transplantation for Pediatric and Adult Candidates.

Patient and graft survival are similar following whole-liver transplantations (WLTs) versus split-liver transplantations (SLTs) among pediatric and adult recipients, yet SLTs are rarely used. We sought to determine the survival benefit associated with accepting a splittable graft offer for SLT versus declining and waiting for a subsequent offer using 2010 to 2018 Scientific Registry of Transplant Recipients (SRTR) data on 928 pediatric and 1814 adult liver transplantation candidates who were ever offered a splittable graft. We compared eventual mortality, regardless of subsequent transplants, between those patients who accepted versus declined a split liver offer with adjustments for Pediatric End-Stage Liver Disease/Model for End-Stage Liver Disease (MELD) scores, diagnosis, and weight among pediatric candidates and matching for MELD score, height, and offer among adult candidates. Among pediatric candidates ≤7 kg, split liver offer acceptance versus decline was associated with a 63% reduction in mortality (adjusted hazard ratio [aHR], 0.17 0.370.80 [P = 0.01]; 93.1% versus 84.0% 1-year survival after decision). Within 1 year of decline for those ≤7 kg, 6.4% died and 31.1% received a WLT. Among pediatric candidates >7 kg, there was no significant difference associated with acceptance of a split liver offer (aHR, 0.63 1.071.82 [P = 0.81]; 91.7% versus 94.4% 1-year survival after decision). Within 1 year of decline for those >7 kg, 1.8% died and 45.8% received a WLT. Among adult candidates, split liver offer acceptance was associated with a 43% reduction in mortality (aHR, 0.39 0.570.83 [P = 0.005]; 92.2% versus 84.4% 1-year survival after decision). Within 1 year of decline for adult candidates, 7.9% died and 39.3% received a WLT. Accepting split liver offers for SLT could significantly improve survival for small children and adults on the waiting list.

Offer Acceptance Patterns for Liver Donors Aged 70 and Older.

Despite a documented survival benefit, older liver donor (OLD, age ≥70) graft offers are frequently declined, with utilization worsening over the last decade. To understand how offer acceptance varies by center, we studied 1113 eventually transplanted OLD grafts from 2009 to 2017 using Scientific Registry of Transplant Recipients (SRTR) data and random-intercept multilevel logistic regression. To understand how center-level acceptance of OLD graft offers might be associated with waitlist and posttransplant outcomes, we studied all adult, actively listed, liver-only candidates and recipients during the study period using Poisson regression (transplant rate), competing risks regression (waitlist mortality), and Cox regression (posttransplant mortality). Among 117 centers, OLD offer acceptance ranged from 0 (23 centers) to 95 acceptances, with a median odds ratio of 2.88. Thus, a candidate may be three times as likely to receive an OLD graft simply by listing at a different center. Centers in the highest quartile (Q4) of OLD acceptance (accepted 39% of OLD offers) accepted more nationally shared organs (Q4 versus Q1: 14.1% versus 0.0%, P < 0.001) and had higher annual liver transplant volume (Q4 versus Q1: 80 versus 21, P < 0.001). After adjustment, nationally shared OLD offers (adjusted odds ratio [aOR]: 0.16, 95% confidence interval [CI]: 0.13-0.20) and offers to centers with higher median Model for End-Stage Liver Disease (MELD) at transplant (aOR: 0.74, 95% CI: 0.62-0.87) were less likely to be accepted. OLD offers to centers with higher annual transplant volume were more likely to be accepted (aOR: 1.21, 95% CI: 1.14-1.30). Additionally, candidates listed at centers within the highest quartile of OLD graft offer acceptance had higher deceased donor liver transplantation (DDLT) rates (adjusted incidence rate ratio: 1.45, 95% CI: 1.41-1.50), lower waitlist mortality (adjusted subhazard ratio: 0.76, 95% CI: 0.72-0.76), and similar posttransplant survival (adjusted hazard ratio: 0.93, 95% CI: 0.86-1.01) when compared with those listed at centers in the lowest quartile of OLD graft offer acceptance. The wide variation in OLD offer acceptance supports the need for optimizing the organ offer process and efficiently directing OLD offers to centers more likely to use them.

Characterizing the landscape and impact of infections following kidney transplantation.

Infections remain a major threat to successful kidney transplantation (KT). To characterize the landscape and impact of post-KT infections in the modern era, we used United States Renal Data System (USRDS) data linked to the Scientific Registry of Transplant Recipients (SRTR) to study 141 661 Medicare-primary kidney transplant recipients from January 1, 1999 to December 31, 2014. Infection diagnoses were ascertained by International Classification of Diseases, Ninth Revision (ICD-9) codes. The cumulative incidence of a post-KT infection was 36.9% at 3 months, 53.7% at 1 year, and 78.0% at 5 years. The most common infections were urinary tract infection (UTI; 46.8%) and pneumonia (28.2%). Five-year mortality for kidney transplant recipients who developed an infection was 24.9% vs 7.9% for those who did not, and 5-year death-censored graft failure (DCGF) was 20.6% vs 10.1% (P < .001). This translated to a 2.22-fold higher mortality risk (adjusted hazard ratio [aHR]: 2.15 2.222.29 , P < .001) and 1.92-fold higher DCGF risk (aHR: 1.84 1.911.98 , P < .001) for kidney transplant recipients who developed an infection, although the magnitude of this higher risk varied across infection types (for example, 3.11-fold higher mortality risk for sepsis vs 1.62-fold for a UTI). Post-KT infections are common and substantially impact mortality and DCGF, even in the modern era. Kidney transplant recipients at high risk for infections might benefit from enhanced surveillance or follow-up to mitigate these risks.

MELD is MELD is MELD? Transplant center-level variation in waitlist mortality for candidates with the same biological MELD.

Recently, model for end-stage liver disease (MELD)-based liver allocation in the United States has been questioned based on concerns that waitlist mortality for a given biologic MELD (bMELD), calculated using laboratory values alone, might be higher at certain centers in certain locations across the country. Therefore, we aimed to quantify the center-level variation in bMELD-predicted mortality risk. Using Scientific Registry of Transplant Recipients (SRTR) data from January 2015 to December 2019, we modeled mortality risk in 33 260 adult, first-time waitlisted candidates from 120 centers using multilevel Poisson regression, adjusting for sex, and time-varying age and bMELD. We calculated a "MELD correction factor" using each center's random intercept and bMELD coefficient. A MELD correction factor of +1 means that center's candidates have a higher-than-average bMELD-predicted mortality risk equivalent to 1 bMELD point. We found that the "MELD correction factor" median (IQR) was 0.03 (-0.47, 0.52), indicating almost no center-level variation. The number of centers with "MELD correction factors" within ±0.5 points, and between ±0.5-± 1, ±1.0-±1.5, and ±1.5-±2.0 points was 62, 41, 13, and 4, respectively. No centers had waitlisted candidates with a higher-than-average bMELD-predicted mortality risk beyond ±2 bMELD points. Given that bMELD similarly predicts waitlist mortality at centers across the country, our results support continued MELD-based prioritization of waitlisted candidates irrespective of center.

Survival benefit of accepting kidneys from older donation after cardiac death donors.

Kidneys from older (age ≥50 years) donation after cardiac death (DCD50) donors are less likely to be transplanted due to inferior posttransplant outcomes. However, candidates who decline a DCD50 offer must wait for an uncertain future offer. To characterize the survival benefit of accepting DCD50 kidneys, we used 2010-2018 Scientific Registry for Transplant Recipients (SRTR) data to identify 92 081 adult kidney transplantation candidates who were offered a DCD50 kidney that was eventually accepted for transplantation. DCD50 kidneys offered to candidates increased from 590 in 2010 to 1441 in 2018. However, 34.6% of DCD50 kidneys were discarded. Candidates who accepted DCD50 offers had 49% decreased mortality risk (adjusted hazard ratio [aHR] 0.46 0.510.55 , cumulative mortality at 6-year 23.3% vs 34.0%, P < .001) compared with those who declined the same offer (decliners). Six years after their initial DCD50 offer decline, 43.0% of decliners received a deceased donor kidney transplant (DDKT), 6.3% received living donor kidney transplant (LDKT), 22.6% died, 22.0% were removed for other reasons, and 6.0% were still on the waitlist. Comparable survival benefit was observed even with DCD donors age ≥60 (aHR: 0.42 0.520.65 , P < .001). Accepting DCD50 kidneys was associated with a substantial survival benefit; providers and patients should consider these benefits when evaluating offers.

Liver transplantation in the United States during the COVID-19 pandemic: National and center-level responses.

COVID-19 has profoundly affected the American health care system; its effect on the liver transplant (LT) waitlist based on COVID-19 incidence has not been characterized. Using SRTR data, we compared observed LT waitlist registrations, waitlist mortality, deceased donor LTs (DDLT), and living donor LTs (LDLT) 3/15/2020-8/31/2020 to expected values based on historical trends 1/2016-1/2020, stratified by statewide COVID-19 incidence. Overall, from 3/15 to 4/30, new listings were 11% fewer than expected (IRR = 0.84 0.890.93 ), LDLTs were 49% fewer (IRR = 0.37 0.510.72 ), and DDLTs were 9% fewer (IRR = 0.85 0.910.97 ). In May, new listings were 21% fewer (IRR = 0.74 0.790.84 ), LDLTs were 42% fewer (IRR = 0.39 0.580.85 ) and DDLTs were 13% more (IRR = 1.07 1.151.23 ). Centers in states with the highest incidence 3/15-4/30 had 59% more waitlist deaths (IRR = 1.09 1.592.32 ) and 34% fewer DDLTs (IRR = 0.50 0.660.86 ). By August, waitlist outcomes were occurring at expected rates, except for DDLT (13% more across all incidences). While the early COVID-affected states endured major transplant practice changes, later in the pandemic the newly COVID-affected areas were not impacted to the same extent. These results speak to the adaptability of the transplant community in addressing the pandemic and applying new knowledge to patient care.