Faculty Bibliography

The SRTR maintains the liver-simulated allocation model (LSAM), a tool for estimating the impact of changes to liver allocation policy. Integral to LSAM is a model that predicts the decision to accept or decline a liver for transplant. LSAM implicitly assumes these decisions are made identically for adult and pediatric liver transplant (LT) candidates, which has not been previously validated. We applied LSAM's decision-making models to SRTR offer data from 2013 to 2016 to determine its efficacy for adult (≥18) and pediatric (<18) LT candidates, and pediatric subpopulations-teenagers (≥12 to <18), children (≥2 to <12), and infants (<2)-using the area under the receiver operating characteristic (ROC) curve (AUC). For nonstatus 1A candidates, all pediatric subgroups had higher rates of offer acceptance than adults. For non-1A candidates, LSAM's model performed substantially worse for pediatric candidates than adults (AUC 0.815 vs. 0.922); model performance decreased with age (AUC 0.898, 0.806, 0.783 for teenagers, children, and infants, respectively). For status 1A candidates, LSAM also performed worse for pediatric than adult candidates (AUC 0.711 vs. 0.779), especially for infants (AUC 0.618). To ensure pediatric candidates are not unpredictably or negatively impacted by allocation policy changes, we must explicitly account for pediatric-specific decision making in LSAM.

Background/UNASSIGNED:) transplantation involves ethical considerations related to safety, consent, stigma, and privacy, which could be better understood through studying patients' actual experiences. Methods/UNASSIGNED:transplantation at 4 centers regarding their decision-making process, the informed consent process, and posttransplant experiences. Participants were interviewed at-transplant (≤3 wk after transplant), posttransplant (≥3 mo after transplant), or both time points. Interviews were analyzed thematically using constant comparison of inductive and deductive coding. Results/UNASSIGNED:transplant candidates were unable to receive HIV-noninfected donor organs. Conclusions/UNASSIGNED:transplant candidates regarding available treatment options and for transplant teams regarding privacy and stigma concerns would be beneficial.

BACKGROUND:Although the population of older transplant recipients has increased dramatically, there are limited data describing the impact of immunosuppression regimen choice on outcomes in this recipient group. METHODS:National data for US Medicare-insured adult kidney recipients (N = 67 362; 2005-2016) were examined to determine early immunosuppression regimen and associations with acute rejection, death-censored graft failure, and mortality using multivariable regression analysis in younger (18-64 y) and older (>65 y) adults. RESULTS:The use of antithymocyte globulin (TMG) or alemtuzumab (ALEM) induction with triple maintenance immunosuppression (reference) was less common in older compared with younger (36.9% versus 47.0%) recipients, as was TMG/ALEM + steroid avoidance (19.2% versus 20.1%) and mammalian target of rapamycin inhibitor (mTORi)-based (6.7% versus 7.7%) treatments. Conversely, older patients were more likely to receive interleukin (IL)-2-receptor antibody (IL2rAb) + triple maintenance (21.1% versus 14.7%), IL2rAb + steroid avoidance (4.1% versus 1.8%), and cyclosporine-based (8.3% versus 6.6%) immunosuppression. Compared with older recipients treated with TMG/ALEM + triple maintenance (reference regimen), those managed with TMG/ALEM + steroid avoidance (adjusted odds ratio [aOR], 0.440.520.61) and IL2rAb + steroid avoidance (aOR, 0.390.550.79) had lower risk of acute rejection. Older patients experienced more death-censored graft failure when managed with Tac + antimetabolite avoidance (adjusted hazard [aHR], 1.411.782.25), mTORi-based (aHR, 1.702.142.71), and cyclosporine-based (aHR, 1.411.782.25) regimens, versus the reference regimen. mTORi-based and cyclosporine-based regimens were associated with increased mortality in both older and younger patients. CONCLUSIONS:Lower-intensity immunosuppression regimens (eg, steroid-sparing) appear beneficial for older kidney transplant recipients, while mTORi and cyclosporine-based maintenance immunosuppression are associated with higher risk of adverse outcomes.

UNLABELLED:Kidney transplantation (KT) is controversial in patients with pretransplant pulmonary hypertension (PtPH). We aimed to quantify post-KT graft and patient survival as well as survival benefit in recipients with PtPH. METHODS/UNASSIGNED:Using UR Renal Data System (2000-2018), we studied 90 819 adult KT recipients. Delayed graft function, death-censored graft failure, and mortality were compared between recipients with and without PtPH using inverse probability weighted logistic and Cox regression. Survival benefit of KT was determined using stochastic matching and stabilized inverse probability treatment Cox regression. RESULTS/UNASSIGNED: < 0.01) compared with those who remained on the waitlist. CONCLUSIONS/UNASSIGNED:Although PtPH is associated with inferior post-KT outcomes, KT is associated with better survival compared with remaining on the waitlist. Therefore, KT is a viable treatment modality for appropriately selected patients with PtPH.

BACKGROUND:Transplant surgery fellowship has evolved over the years and today there are 66 accredited training programs in the US and Canada. There is growing concern, however, about the number of US-trained general surgery residents pursuing transplant surgery. In this study, we examined the transplant surgery pipeline, comparing it with other surgical subspecialty fellowships, and characterized the resident transplantation experience. METHODS:Datasets were compiled and analyzed from surgical fellowship match data obtained from the National Resident Matching Program and ACGME reports and relative fellowship competitiveness was assessed. The surgical resident training experience in transplantation was evaluated. RESULTS:From 2006 to 2018, a total of 1,094 applicants have applied for 946 transplant surgery fellowship positions; 299 (27.3%) were US graduates. During this period, there was a 0.8% decrease per year in US-trained surgical residents matching into transplant surgery (p = 0.042). In addition, transplant surgery was one of the least competitive fellowships compared with other National Resident Matching Program surgical subspeciality fellowships, as measured by the number of US applicants per available fellowship position, average number of fellowship programs listed on each applicant's rank list, and proportion of unfilled fellowship positions (each, p < 0.05). Finally, from 2015 to 2017, there were 57 general surgery residency programs that produced 77 transplant surgery fellows, but nearly one-half of the fellows (n = 36 [46.8%]) came from 16 (28.1%) programs. CONCLUSIONS:Transplant surgery is one of the least competitive and sought after surgical fellowships for US-trained residents. These findings highlight the need for dedicated efforts to increase exposure, mentorship, and interest in transplantation to recruit strong US graduates.

BACKGROUND AND AIMS:Scores from the Model for End-Stage Liver Disease (MELD), which are used to prioritize candidates for deceased donor livers, are widely acknowledged to be negatively correlated with the 90-day survival rate without a liver transplant. However, inconsistent and outdated estimates of survival probabilities by MELD preclude useful applications of the MELD score. APPROACH AND RESULTS:Using data from all prevalent liver waitlist candidates from 2016 to 2019, we estimated 3-day, 7-day, 14-day, 30-day, and 90-day without-transplant survival probabilities (with confidence intervals) for each MELD score and status 1A. We used an adjusted Kaplan-Meier model to avoid unrealistic assumptions and multiple observations per person instead of just the observation at listing. We found that 90-day without-transplant survival has improved over the last decade, with survival rates increasing >10% (in absolute terms) for some MELD scores. We demonstrated that MELD correctly prioritizes candidates in terms of without-transplant survival probability but that status 1A candidates' short-term without-transplant survival is higher than that of MELD 40 candidates and lower than that of MELD 39 candidates. Our primary result is the updated survival functions themselves. CONCLUSIONS:We calculated without-transplant survival probabilities for each MELD score (and status 1A). The survival function is an invaluable tool for many applications in liver transplantation: awarding of exception points, calculating the relative demand for deceased donor livers in different geographic areas, calibrating the pediatric end-stage liver disease score, and deciding whether to accept an offered liver.