Program-specific reports: implications and impact on program behavior

Current Techniques and Indications for Machine Perfusion and Regional Perfusion in Deceased Donor Liver Transplantation

Since the advent of University of Wisconsin preservation solution in the 1980s, clinicians have learned to work within its confines. While affording improved outcomes, considerable limitations still exist and contribute to the large number of livers that go unused each year, often for fear they may never work. The last 10 years have seen the widespread availability of new perfusion modalities which provide an opportunity for assessing organ viability and prolonged organ storage. This review will discuss the role of in situ normothermic regional perfusion for livers donated after circulatory death. It will also describe the different modalities of ex situ perfusion, both normothermic and hypothermic, and discuss how they are thought to work and the opportunities afforded by them.

Survival analysis for pediatric heart transplant patients using a novel machine learning algorithm: A UNOS analysis

BACKGROUND

Impact of pretransplantation risk factors on mortality in the first year after heart transplantation remains largely unknown. Using machine learning algorithms, we selected clinically relevant identifiers that could predict 1-year mortality after pediatric heart transplantation.

METHODS

Data were obtained from the United Network for Organ Sharing Database for years 2010-2020 for patients 0-17 years receiving their first heart transplant (N = 4150). Features were selected using subject experts and literature review. Scikit-Learn, Scikit-Survival, and Tensorflow were used. A train:test split of 70:30 was used. N-repeated k-fold validation was performed (N = 5, k = 5). Seven models were tested, Hyperparameter tuning performed using Bayesian optimization and the concordance index (C-index) was used for model assessment.

RESULTS

A C-index above 0.6 for test data was considered acceptable for survival analysis models. C-indices obtained were 0.60 (Cox proportional hazards), 0.61 (Cox with elastic net), 0.64 (gradient boosting), 0.64 (support vector machine), 0.68 (random forest), 0.66 (component gradient boosting), and 0.54 (survival trees). Machine learning models show an improvement over the traditional Cox proportional hazards model, with random forest performing the best on the test set. Analysis of the feature importance for the gradient boosted model found that the top 5 features were the most recent serum total bilirubin, the travel distance from the transplant center, the patient body mass index, the deceased donor terminal Serum glutamic pyruvic transaminase/Alanine transaminase (SGPT/ALT), and the donor PCO2.

CONCLUSIONS

Combination of machine learning and expert-based methodology of selecting predictors of survival for pediatric heart transplantation provides a reasonable prediction of 1- and 3-year survival outcomes. SHapley Additive exPlanations can be an effective tool for modeling and visualizing nonlinear interactions.

Burden of early hospitalization after simultaneous liver-kidney transplantation: Results from the US Multicenter SLKT Consortium

The burden of early hospitalization (within 6 months) following simultaneous liver-kidney transplant (SLKT) is not known. We examined risk factors associated with early hospitalization after SLKT and their impact on patient mortality conditional on 6-month survival. We used data from the US Multicenter SLKT Consortium cohort study of all adult SLKT recipients between 2002 and 2017 who were discharged alive following SLKT. We used Poisson regression to model rates of early hospitalizations after SLKT. Cox regression was used to identify risk factors associated with mortality conditional on survival at 6 months after SLKT. Median age (N = 549) was 57.7 years (interquartile range [IQR], 50.6-63.9) with 63% males and 76% Whites; 33% had hepatitis C virus, 20% had non-alcohol-associated fatty liver disease, 23% alcohol-associated liver disease, and 24% other etiologies. Median body mass index (BMI) and Model for End-Stage Liver Disease-sodium scores were 27.2 kg/m2 (IQR, 23.6-32.2 kg/m2 ) and 28 (IQR, 23-34), respectively. Two-thirds of the cohort had at least one hospitalization within the first 6 months of SLKT. Age, race, hospitalization at SLKT, diabetes mellitus, BMI, and discharge to subacute rehabilitation (SAR) facility after SLKT were independently associated with a high incidence rate ratio of early hospitalization. Number of hospitalizations within the first 6 months did not affect conditional survival. Early hospitalizations after SLKT were very common but did not affect conditional survival. Although most of the risk factors for early hospitalization were nonmodifiable, discharge to SAR after initial SLKT was associated with a significantly higher incidence rate of early hospitalization. Efforts and resources should be focused on identifying SLKT recipients at high risk for early hospitalization to optimize their predischarge care, discharge planning, and long-term follow-up.

Hardest-to-place kidney transplant outcomes in the United States

The outcomes of hardest-to-place kidney transplants-accepted last in the entire match run after being refused by previous centers-are unclear, potentially translating to risk aversion and unnecessary organ discard. We aimed to determine the outcomes of hardest-to-place kidney transplants and whether the organ acceptance position on the match run sufficiently captures the risk. This is a cohort study of the United Network for Organ Sharing data of all adult kidney-only transplant recipients from deceased donors between 2007 and 2018. Multiple regression models assessed delayed graft function, graft survival, and patient survival stratified by share type: local versus shared kidney acceptance position scaled by tertile. Among 127 028 kidney transplant recipients, 92 855 received local kidneys. The remaining received shared kidneys at sequence number 1-4 (n = 12 322), 5-164 (n = 10 485) and >164 (n = 11 366). Hardest-to-place kidneys, defined as the latest acceptance group in the match-run, were associated with delayed graft function (adjusted odds ratio 1.83, 95% confidence interval [CI] 1.74-1.92) and all-cause allograft failure (adjusted hazard ratio [aHR] 1.11, 95% CI 1.04-1.17). Results of this IRB-approved study were robust to the exclusion of operational allocation bypass and mandatory shares. The hardest-to-place kidneys accepted later in the match run were associated with higher graft failure and delayed graft function.

Association of low center performance evaluations and pediatric heart transplant center behavior in the United States

BACKGROUND

To date, no study has evaluated the effects of low center performance evaluations (CPE) on pediatric heart transplant center behavior. We sought to assess the impact of low CPE flags on pediatric heart transplant center listing and transplant volumes and center recipient and donor characteristics.

METHODS

We included centers performing at least 10 pediatric (age <18 years) transplants during the Scientific Registry of Transplant Recipients reporting period January 2009-June 2011 and evaluated consecutive biannual program specific reports until the last reporting period January 2016-June 2018. We evaluated changes in center behavior at following time points: a year before flagging, a year and two years after the flag; and at last reporting period.

RESULTS

During our study period, 24 pediatric centers were non-flagged and 6 were flagged. Compared to non-flagged centers, there was a decline in candidate listings in flagged centers at the last reporting period (mean increase of 5.5 ± 12.4 listings vs"?> mean decrease of 14.0 ± 14.9 listings; p = .003). Similarly, the number of transplants declined in flagged centers (mean increase of 2.6 ± 9.6 transplants vs"?> mean decrease of 10.0 ± 12.8 transplants; p = .012). Flagged centers had declines in listings for patients with restrictive cardiomyopathy, re-transplant, renal dysfunction, those on mechanical ventilation and extracorporeal membrane oxygenation. There was no significant change in donor characteristics between flagged and non-flagged centers.

CONCLUSIONS

Low CPE may have unintended negative consequences on center behavior leading to declines in listing and transplant volumes and potentially leading to decreased listing for higher risk recipients.

The Creation of a Novel Low-Cost Bench-Top Kidney Transplant Surgery Simulator and a Survey on Its Fidelity and Educational Utility

Introduction Resident inexperience during time-sensitive vascular anastomoses of a kidney transplant can negatively impact outcomes. In light of this, we created a low-cost bench-top kidney transplant surgery simulator to help residents practice vascular anastomoses. Methods We searched for inexpensive materials to design an iliac fossa and kidney allograft. Eighteen residents with real-life kidney transplant experience trialed the simulator and scored its fidelity and educational utility on a 0-100 visual analog scale (VAS) survey. Results A 35.9 x 19.4 x 12.4 cm plastic box mimicked the iliac fossa. Hooks attached to the box's sidewall held under tension 1.27 and 0.64 cm diameter Penrose drains to replicate the external iliac vein and artery. A modified kidney-shaped stress ball with 1.27 x 4, 0.64 x 4, and 0.64 x 15 cm Penrose drains replicated a kidney allograft with its vein, artery, and ureter, respectively. Residents performed and assisted in vascular anastomoses on the simulator. The iliac fossa and allograft cost $20.20 and each practice run cost $7.20. Residents thought that the simulator was less difficult than real-life procedure, had acceptable fidelity levels, and they highly rated its educational utility. Conclusion Our novel low-cost bench-top kidney transplant surgery simulator focusing on vascular anastomoses received positive educational feedback from residents.

Assessment of the Kidney Donor Profile Index in a European cohort

Background

Recently, transplant societies have had to change their allocation policies to counter global organ shortages. However, strategies differ significantly and long-term outcomes and cross-regional applicability remain to be evaluated.

Methods

Therefore, we retrospectively analysed the Kidney Donor Profile Index (KDPI) of 987 adult kidney transplants at our centre using data from the Organ Procurement and Transplantation Network (OPTN) as a reference.

Results

In our cohort, the median KDPI was 66%, with a higher proportion of >85% KDPI kidneys compared with the US cohort (32.3% versus 9.2%). Among elderly patients (≥65 years of age), 62% received >95% KDPI kidneys, which were primarily allocated within the Eurotransplant Senior Program (ESP). After 10 years, the rate of death-censored graft survival was 70.5%. Recipients of >85% KDPI kidneys were significantly older, demonstrating higher mortality, poorer graft survival and lower estimated glomerular filtration rate. Patients receiving ≥99% KDPI kidneys had a satisfactory 5-year death-censored graft survival (72.9%). The 5-year survival rate of patients living with a functioning graft exceeded the matched OPTN data in the whole KDPI range, despite a higher proportion of elderly recipients. Multivariate analysis revealed KDPI as an independent risk factor for graft loss (hazard ratio 1.14/10%, P < 0.001), although C-statistics of 0.62 indicated limited discriminative ability for individuals.

Conclusion

The analysis demonstrated KDPI as a potentially useful tool for donor quality assessment in a European cohort. Most importantly, our analysis revealed acceptable outcomes even for very high KDPI kidneys.

Do Social Determinants Define "Too Sick" to Transplant in Patients With End-stage Liver Disease?

BACKGROUND

Delisting for being "too sick" to be transplanted is subjective. Previous work has demonstrated that the mortality of patients delisted for "too sick" is unexpectedly low. Transplant centers use their best clinical judgment for determining "too sick," but it is unclear how social determinants influence decisions to delist for "too sick." We hypothesized that social determinants and Donor Service Area (DSA) characteristics may be associated with determination of "too sick" to transplant.

METHODS

Data were obtained from the Scientific Registry of Transplant Recipients for adults listed and removed from the liver transplant waitlist from 2002 to 2017. Patients were included if delisted for "too sick." Our primary outcome was Model for End-Stage Liver Disease (MELD) score at waitlist removal for "too sick." Regression assessed the association between social determinants and MELD at removal for "too sick."

RESULTS

We included 5250 delisted for "too sick" at 127 centers, in 53 DSAs, over 16 years. The mean MELD at delisting for "too sick" was 25.8 (SD ± 11.2). On adjusted analysis, social determinants including age, race, sex, and education predicted the MELD at delisting for "too sick" (P < 0.05).

CONCLUSIONS

There is variation in delisting MELD for "too sick" score across DSA and time. While social determinants at the patient and system level are associated with delisting practices, the interplay of these variables warrants additional research. In addition, center outcome reports should include waitlist removal rate for "too sick" and waitlist death ratios, so waitlist management practice at individual centers can be monitored.

Prediction of mortality following pediatric heart transplant using machine learning algorithms

BACKGROUND

Optimizing transplant candidates' priority for donor organs depends on the accurate assessment of post-transplant outcomes. Due to the complexity of transplantation and the wide range of possible serious complications, recipient outcomes are difficult to predict accurately using conventional multivariable regression. Therefore, we evaluated the utility of 3 ML algorithms for predicting mortality after pediatric HTx.

METHODS

We identified patients <18 years of age receiving HTx in 2006-2015 in the UNOS Registry database. Mortality within 1, 3, or 5 years was predicted using classification and regression trees, RFs, and ANN. Each model was trained using cross-validation, then validated in a separate testing set. Model performance was primarily evaluated by the area under the receiver operating characteristic (AUC) curve.

RESULTS

The training set included 2802 patients, whereas 700 were included in the testing set. RF achieved the best fit to the training data with AUCs of 0.74, 0.68, and 0.64 for 1-, 3-, and 5-year mortality, respectively, and performed best in the testing data, with AUCs of 0.72, 0.61, and 0.60, respectively. Nevertheless, sensitivity was poor across models (training: 0.22-0.58; testing: 0.07-0.49).

DISCUSSION

ML algorithms demonstrated fair predictive utility in both training and testing data, but the sensitivity of these algorithms was generally poor. With the registry missing data on many determinants of long-term survival, the ability of ML methods to predict mortality after pediatric HTx may be fundamentally limited.

Poor Performance Flagging Is Associated With Fewer Transplantations at Centers Flagged Multiple Times

BACKGROUND

Lung transplantation outcomes are heavily scrutinized, given the high stakes of these operations, yet the Center for Medicare and Medicaid Services (CMS) method of using Scientific Registry of Transplant Recipients (SRTR) risk-adjusted outcomes to identify underperforming centers is controversial. We hypothesized that CMS flagging results in conservative behavior for recipient and organ selection, resulting in fewer patients added to the waitlist and fewer transplantations performed.

METHODS

SRTR reports from July 2012 through July 2017 were included. Center characteristics were compared, stratified by number of flagging events. The impact of flagging for underperformance on risk aversion outcomes was analyzed using a mixed-effects regression model.

RESULTS

A total of 72 centers had reported SRTR data during the study period. Of these, 21 centers (29%) met flagging criteria a median of 2 times (interquartile range, 1 to 4 times) for a total of 53 events. Flagging had no statistically significant impact on waitlist or transplantation volume and patient selection by mixed-effects modeling. Despite similar average expected 1-year survival (86.6% versus 87.7%, p = 0.27), centers that were flagged only once added more patients per year to the waitlist (16.3 patients versus 7.8 patients, p = 0.01) and performed more transplantations per year (28.4 transplantations versus 11.1 transplantations, p = 0.01).

CONCLUSIONS

This analysis defines center-level trends in lung transplantation after CMS flagging. Contrary to our primary hypothesis, flagging did not result in temporal center-level changes. However, programs on prolonged probation demonstrated reduced activity, which likely indicates a shift to higher performing centers.

Quality-based ratings in Medicare and trends in kidney transplantation

OBJECTIVE

To assess the relationship between the 2007 Medicare regulation enforcing quality standards for transplant centers and trends in kidney transplantation.

DATA SOURCES

Transplant centers' biannual reports and the national registry for kidney transplantation from 2003 to 2010.

STUDY DESIGN

Non-compliant (low-performing) centers were compared with centers in compliance with quality standards according to: number of transplants, waiting-list registrations, and rates of graft failures, transfers, and deaths. Multivariate regressions were estimated to evaluate the association between the regulation and transplantation outcomes.

DATA EXTRACTION METHODS

Patient characteristics and outcomes were aggregated to six-month periods and linked to centers' reports.

PRINCIPAL FINDINGS

Relative to average-performing centers, 12 percent of transplants shifted away from low-performing centers and high-performing centers captured 6 percent of this decline. Low-performing centers experienced a 2-percentage point per period decline in 1-year graft failure rates and a 15-percent decrease in registrations post-regulation, whereas high-performing centers incurred a 5-percent decrease in registrations relative to average-performing centers.

CONCLUSIONS

Government oversight in kidney transplantation was associated with a small downward shift in overall kidney transplants. Reductions in graft failure rates at low-performing centers may imply an increase in quality or a decline in transplantation of either marginal organs or riskier patients; whereas reductions in registrations may indicate risk aversion toward high-risk patients. Policy makers should consider making less punitive requirements for programs, which employ new transplantation techniques to expand access.

National Heart, Lung, and Blood Institute and American Association for Thoracic Surgery Workshop Report: Identifying collaborative clinical research priorities in lung transplantation

This report summarizes the discussion and recommendations from the June 2017 NHLBI-AATS Workshop on Identifying Collaborative Clinical Research Priorities in Lung Transplantation.

Factors leading to the discard of deceased donor kidneys in the United States

The proportion of deceased donor kidneys procured for transplant but subsequently discarded has been growing steadily in the United States, but factors contributing to the rising discard rate remain unclear. To assess the reasons for and probability of organ discard we assembled a cohort of 212,305 deceased donor kidneys recovered for transplant from 2000-2015 in the SRTR registry that included 36,700 kidneys that were discarded. 'Biopsy Findings' (38.2%) was the most commonly reported reason for discard. The median Kidney Donor Risk Index of discarded kidneys was significantly higher than transplanted organs (1.78 vs 1.12), but a large overlap in the quality of discarded and transplanted kidneys was observed. Kidneys of donors who were older, female, Black, obese, diabetic, hypertensive or HCV-positive experienced a significantly increased odds of discard. Kidneys from donors with multiple unfavorable characteristics were more likely to be discarded, whereas unilaterally discarded kidneys had the most desirable donor characteristics and the recipients of their partner kidneys experienced a one-year death-censored graft survival rate over 90%. There was considerable geographic variation in the odds of discard across the United States, which further supports the notion that factors beyond organ quality contributed to kidney discard. Thus, while the discard of a small fraction of organs procured from donors may be inevitable, the discard of potentially transplantable kidneys needs to be avoided. This will require a better understanding of the factors contributing to organ discard in order to remove the disincentives to utilize less-than-ideal organs for transplantation.

County socioeconomic characteristics and pediatric renal transplantation outcomes

BACKGROUND

Existing risk adjustment models for solid organ transplantation omit socioeconomic status (SES). With limited data available on transplant candidates' SES, linkage of transplant outcomes data to geographic SES measures has been proposed. We investigate the utility of county SES for understanding differences in pediatric kidney transplantation (KTx) outcomes.

METHODS

We identified patients < 18 years of age receiving first-time KTx using United Network for Organ Sharing registry data in two eras: 2006-2010 and 2011-2015, corresponding to periods of county SES data collection. In each era, counties were ranked by 1-year rates of survival with intact graft, and by county SES score. We used Spearman correlation (ρ) to evaluate the association between county rankings on SES and transplant outcomes in each era and consistency between these measures across eras. We also evaluated the utility of county SES for improving prediction of individual KTx outcomes.

RESULTS

The analysis included 2972 children and 108 counties. County SES and transplant outcomes were not correlated in either 2006-2010 (ρ = 0.06; p = 0.525) or 2011-2015 (ρ = 0.162, p = 0.093). County SES rankings were strongly correlated between eras (ρ = 0.99, p < 0.001), whereas county rankings of transplant outcomes were not correlated between eras (ρ = 0.16, p = 0.097). Including county SES quintile in individual-level models of transplant outcomes did not improve model predictive utility.

CONCLUSIONS

Pediatric kidney transplant outcomes are unstable from period to period at the county level and are not correlated with county-level SES. Appropriate adjustment for SES disparities in transplant outcomes could require further collection of detailed individual SES data.

Expanding clarity or confusion? Volatility of the 5-tier ratings assessing quality of transplant centers in the United States

Outcomes of patients receiving solid organ transplants in the United States are systematically aggregated into bi-annual Program-Specific Reports (PSRs) detailing risk-adjusted survival by transplant center. Recently, the Scientific Registry of Transplant Recipients (SRTR) issued 5-tier ratings evaluating centers based on risk-adjusted 1-year graft survival. Our primary aim was to examine the reliability of 5-tier ratings over time. Using 10 consecutive PSRs for adult kidney transplant centers from June 2012 to December 2016 (n = 208), we applied 5-tier ratings to center outcomes and evaluated ratings over time. From the baseline period (June 2012), 47% of centers had at least a 1-unit tier change within 6 months, 66% by 1 year, and 94% by 3 years. Similarly, 46% of centers had at least a 2-unit tier change by 3 years. In comparison, 15% of centers had a change in the traditional 3-tier rating at 3 years. The 5-tier ratings at 4 years had minimal association with baseline rating (Kappa 0.07, 95% confidence interval [CI] -0.002 to 0.158). Centers had a median of 3 different 5-tier ratings over the period (q1 = 2, q3 = 4). Findings were consistent for center volume, transplant rate, and baseline 5-tier rating. Cumulatively, results suggest that 5-tier ratings are highly volatile, limiting their utility for informing potential stakeholders, particularly transplant candidates given expected waiting times between wait listing and transplantation.

A novel patient-centered "intention-to-treat" metric of U.S. lung transplant center performance

Despite the importance of pretransplantation outcomes, 1-year posttransplantation survival is typically considered the primary metric of lung transplant center performance in the United States. We designed a novel lung transplant center performance metric that incorporates both pre- and posttransplantation survival time. We performed an ecologic study of 12 187 lung transplant candidates listed at 56 U.S. lung transplant centers between 2006 and 2012. We calculated an "intention-to-treat" survival (ITTS) metric as the percentage of waiting list candidates surviving at least 1 year after transplantation. The median center-level 1-year posttransplantation survival rate was 84.1%, and the median center-level ITTS was 66.9% (mean absolute difference 19.6%, 95% limits of agreement 4.3 to 35.1%). All but 10 centers had ITTS values that were significantly lower than 1-year posttransplantation survival rates. Observed ITTS was significantly lower than expected ITTS for 7 centers. These data show that one third of lung transplant candidates do not survive 1 year after transplantation, and that 12% of centers have lower than expected ITTS. An "intention-to-treat" survival metric may provide a more realistic expectation of patient outcomes at transplant centers and may be of value to transplant centers and policymakers.

Analysis of local versus imported expanded criteria donor kidneys: A single-center experience with 497 ECD kidney transplants

BACKGROUND

The value of importing expanded criteria donor (ECD) kidneys is uncertain.

METHODS

We retrospectively reviewed our single-center experience with ECD kidney transplants (KT).

RESULTS

Over 12.8 years, we performed 497 ECD KTs including 247 local and 250 imported from other donor service areas. The import ECD group had more donors (16% vs 9%) ≥ age 70, more zero human leukocyte antigen mismatches (14% vs 2%), more KTs with a cold ischemia time >30 hours (46% vs 19%), and fewer kidneys managed with pump preservation (78% vs 92%, all P≤.05) compared to the local ECD group. Mean Kidney Donor Profile Index were 80% import vs 84% local. With a mean follow-up of 55 months, actual patient and graft survival rates were 71% and 58% in import vs 76% and 58% in local ECD KTs, respectively. Death-censored graft survival rates were 70% in import vs 69% in local ECD KTs. Delayed graft function occurred in 28% import vs 23% local ECD KTs (P=NS) whereas the incidence of primary nonfunction was slightly higher with import ECD kidneys (4.8% vs 2.4%, P=.23).

CONCLUSIONS

Midterm outcomes are remarkably similar for import vs local ECD KTs, suggesting that broader sharing of ECD kidneys may improve utilization without compromising outcomes.

Measuring transplant center performance: The goals are not controversial but the methods and consequences can be

PURPOSE OF REVIEW

Risks of regulatory scrutiny has generated widespread concern about increasingly risk averse transplant center behaviors regarding both donor and candidate acceptance patterns. To address potential unintended consequences threatening access to care, we discuss recent changes in regulatory metrics and potential improvements in quality oversight of transplant centers.

RECENT FINDINGS

Despite many recent changes to one-year patient and graft survival regulatory criteria, the capacity to accurately identify true underperforming centers and avoiding false positive flagging remains an area of great concern. Numerous studies have demonstrated restrictions in transplant volume and access following transplant center flagging.

SUMMARY

Current regulatory criteria are limited in their capacity to accurately identify poorly performing centers and potentially encourage risk-averse behavior by transplant centers. Efforts to address these concerns should focus on (1) improving risk-adjustment models with better data which captures the acuity of candidate and donor risk, (2) reconsidering primary outcomes measured to assess comprehensive transplant center performance, (3) improving education to address rational or perceived disincentives, and (4) using data more effectively to share best practices.

Management of the obese kidney transplant candidate

Obesity is an increasingly common condition that can exclude end stage renal disease patients from consideration of kidney transplantation. The optimal management of obese transplant candidates is uncertain, especially the use of pharmacologic therapies or bariatric surgery. We review the rationale to consider transplantation in obese patients, the impact of obesity on access to kidney transplantation, the evidence for obese patients to lose weight loss prior to kidney transplantation, peri-operative management considerations and specific weight loss strategies prior to transplantation. We also propose an algorithm for pre-transplant management of obese transplant candidates that takes into consideration the patient's peri-operative risk, the anticipated time to transplantation and the risk of delayed graft function. Finally, we suggest a number of areas in need of further research as well as health policy considerations to improve the care of obese kidney transplant candidates.

Factors Associated With Major Adverse Cardiovascular Events After Liver Transplantation Among a National Sample

Assessment of major adverse cardiovascular events (MACE) after liver transplantation (LT) has been limited by the lack of a multicenter study with detailed clinical information. An integrated database linking information from the University HealthSystem Consortium and the Organ Procurement and Transplant Network was analyzed using multivariate Poisson regression to assess factors associated with 30- and 90-day MACE after LT (February 2002 to December 2012). MACE was defined as myocardial infarction (MI), heart failure (HF), atrial fibrillation (AF), cardiac arrest, pulmonary embolism, and/or stroke. Of 32 810 recipients, MACE hospitalizations occurred in 8% and 11% of patients at 30 and 90 days, respectively. Recipients with MACE were older and more likely to have a history of nonalcoholic steatohepatitis (NASH), alcoholic cirrhosis, MI, HF, stroke, AF and pulmonary and chronic renal disease than those without MACE. In multivariable analysis, age >65 years (incidence rate ratio [IRR] 2.8, 95% confidence interval [95% CI] 1.8-4.4), alcoholic cirrhosis (IRR 1.6, 95% CI 1.2-2.2), NASH (IRR 1.6, 95% CI 1.1-2.4), pre-LT creatinine (IRR 1.1, 95% CI 1.04-1.2), baseline AF (IRR 6.9, 95% CI 5.0-9.6) and stroke (IRR 6.3, 95% CI 1.6-25.4) were independently associated with MACE. MACE was associated with lower 1-year survival after LT (79% vs. 88%, p < 0.0001). In a national database, MACE occurred in 11% of LT recipients and had a negative impact on survival. Pre-LT AF and stroke substantially increase the risk of MACE, highlighting potentially high-risk LT candidates.

Decade-Long Trends in Liver Transplant Waitlist Removal Due to Illness Severity: The Impact of Centers for Medicare and Medicaid Services Policy

BACKGROUND

The central tenet of liver transplant organ allocation is to prioritize the sickest patients first. However, a 2007 Centers for Medicare and Medicaid Services regulatory policy, Conditions of Participation (COP), which mandates publically reported transplant center performance assessment and outcomes-based auditing, critically altered waitlist management and clinical decision making. We examine the extent to which COP implementation is associated with increased removal of the "sickest" patients from the liver transplant waitlist.

STUDY DESIGN

This study included 90,765 adult (aged 18 years and older) deceased donor liver transplant candidates listed at 102 transplant centers from April 2002 through December 2012 (Scientific Registry of Transplant Recipients). We quantified the effect of COP implementation on trends in waitlist removal due to illness severity and 1-year post-transplant mortality using interrupted time series segmented Poisson regression analysis.

RESULTS

We observed increasing trends in delisting due to illness severity in the setting of comparable demographic and clinical characteristics. Delisting abruptly increased by 16% at the time of COP implementation, and likelihood of being delisted continued to increase by 3% per quarter thereafter, without attenuation (p < 0.001). Results remained consistent after stratifying on key variables (ie, Model for End-Stage Liver Disease and age). The COP did not significantly impact 1-year post-transplant mortality (p = 0.38).

CONCLUSIONS

Although the 2007 Centers for Medicare and Medicaid Services COP policy was a quality initiative designed to improve patient outcomes, in reality, it failed to show beneficial effects in the liver transplant population. Patients who could potentially benefit from transplantation are increasingly being denied this lifesaving procedure while transplant mortality rates remain unaffected. Policy makers and clinicians should strive to balance candidate and recipient needs from a population-benefit perspective when designing performance metrics and during clinical decision making for patients on the waitlist.

Debating Organ Procurement Policy Without Illusions

In this perspective, I review and critique claims that the transplant waiting list overstates the demand for kidneys and correct a few mischaracterizations of some structural barriers to increasing rates of transplantation. The solutions to the shortage of organs proffered by opponents of financial incentives fail to account for a panoply of clinical, regulatory, and financial realities of transplantation centers in the United States in ways that undermine the thesis that a trial of financial incentives for organ procurement is not warranted at this time. I conclude with some personal pessimistic reflections on the progress of this debate.

The combined risk of donor quality and recipient age: higher-quality kidneys may not always improve patient and graft survival

BACKGROUND

The Kidney Donor Profile Index (KDPI) is a more precise donor organ quality metric replacing age-based characterization of donor risk. Little prior attention has been paid on the outcomes of lower-quality kidneys transplanted into elderly recipients. Although we have previously shown that immunological risks associated with older organs are attenuated by advanced recipient age, it remains unknown whether risks associated with lower-quality KDPI organs are similarly reduced in older recipients.

METHODS

Donor organ quality as measured by the KDPI was divided into quintiles (very high, high, medium, low, and very low quality), and Cox proportional hazards was used to assess graft and recipient survival in first-time adult deceased donor transplant recipients by recipient age.

RESULTS

In uncensored graft survival analysis, recipients older than 69 years had demonstrated comparable outcomes if they received low-quality kidneys compared to medium-quality kidneys. Death-censored analysis demonstrated no increased relative risk when low-quality kidneys were transplanted into recipients aged 70 to 79 years (hazard ratio [HR], 1.11; P=0.19) or older than 79 years (HR, 1.08; P=0.59). In overall survival analysis, elderly recipients gained no relative benefit from medium-quality kidneys over low-quality kidneys (70-79 years: HR, 1.03, P=0.51; >79 years: HR, 1.08; P=0.32).

CONCLUSION

Our analysis demonstrates that transplanting medium-quality kidneys into elderly recipients does not provide significant advantage over low-quality kidneys.

High early cardiovascular mortality after liver transplantation

Cardiovascular disease (CVD) contributes to excessive long-term mortality after liver transplantation (LT); however, little is known about early postoperative CVD mortality in the current era. In addition, there is no model for predicting early postoperative CVD mortality across centers. We analyzed adult recipients of primary LT in the Organ Procurement and Transplantation Network (OPTN) database between February 2002 and December 2012 to assess the prevalence and predictors of early (30-day) CVD mortality, which was defined as death from arrhythmia, heart failure, myocardial infarction, cardiac arrest, thromboembolism, and/or stroke. We performed logistic regression with stepwise selection to develop a predictive model of early CVD mortality. Sex and center volume were forced into the final model, which was validated with bootstrapping techniques. Among 54,697 LT recipients, there were 1576 deaths (2.9%) within 30 days. CVD death was the leading cause of 30-day mortality (40.2%), and it was followed by infection (27.9%) and graft failure (12.2%). In a multivariate analysis, 9 significant covariates (6 recipient covariates, 2 donor covariates, and 1 operative covariate) were identified: age, preoperative hospitalization, intensive care unit status, ventilator status, calculated Model for End-Stage Liver Disease score, portal vein thrombosis, national organ sharing, donor body mass index, and cold ischemia time. The model showed moderate discrimination (C statistic = 0.66, 95% confidence interval = 0.63-0.68). In conclusion, we provide the first multicenter prognostic model for the prediction of early post-LT CVD death, the most common cause of early post-LT mortality in the current transplant era. However, evaluations of additional CVD-related variables not collected by the OPTN are needed in order to improve the model's accuracy and potential clinical utility.