Network For Organ Sharing Database Research Articles

Use of Machine Learning Consensus Clustering to Identify Distinct Subtypes of Black Kidney Transplant Recipients and Associated Outcomes

Among kidney transplant recipients, Black patients continue to have worse graft function and reduced patient and graft survival. Better understanding of different phenotypes and subgroups of Black kidney transplant recipients may help the transplant community to identify individualized strategies to improve outcomes among these vulnerable groups. To cluster Black kidney transplant recipients in the US using an unsupervised machine learning approach. This cohort study performed consensus cluster analysis based on recipient-, donor-, and transplant-related characteristics in Black kidney transplant recipients in the US from January 1, 2015, to December 31, 2019, in the Organ Procurement and Transplantation Network/United Network for Organ Sharing database. Each cluster's key characteristics were identified using the standardized mean difference, and subsequently the posttransplant outcomes were compared among the clusters. Data were analyzed from June 9 to July 17, 2021. Machine learning consensus clustering approach. Death-censored graft failure, patient death within 3 years after kidney transplant, and allograft rejection within 1 year after kidney transplant. Consensus cluster analysis was performed for 22 687 Black kidney transplant recipients (mean [SD] age, 51.4 [12.6] years; 13 635 men [60%]), and 4 distinct clusters that best represented their clinical characteristics were identified. Cluster 1 was characterized by highly sensitized recipients of deceased donor kidney retransplants; cluster 2, by recipients of living donor kidney transplants with no or short prior dialysis; cluster 3, by young recipients with hypertension and without diabetes who received young deceased donor transplants with low kidney donor profile index scores; and cluster 4, by older recipients with diabetes who received kidneys from older donors with high kidney donor profile index scores and extended criteria donors. Cluster 2 had the most favorable outcomes in terms of death-censored graft failure, patient death, and allograft rejection. Compared with cluster 2, all other clusters had a higher risk of death-censored graft failure and death. Higher risk for rejection was found in clusters 1 and 3, but not cluster 4. In this cohort study using an unsupervised machine learning approach, the identification of clinically distinct clusters among Black kidney transplant recipients underscores the need for individualized care strategies to improve outcomes among vulnerable patient groups.

Computational methods for predicting the outcome of thoracic transplantation

Cardiac disease and the death rates due to coronary heart failure and cardiomyopathy are increasing. Thoracic transplantation is now a widely accepted therapeutic option for end-stage cardiac failure. The survival rate after the organ transplantation is crucial. Survival prediction after heart transplantation is a hot area of research. The use of conventional statistical techniques is computationally expensive and does not provide reliable solutions. Artificial Neural Networks based survival prediction helps surgeons make precise decisions and predict the best outcomes. The proposed system implements multi-layer perceptron algorithm, which shows good performance in survival prediction. We also implemented our work in the Radial Basis Function Network model to prove the accuracy of proposed model. For this research study, data were collected from United Network for Organ Sharing database and extracted the relevant thoracic transplantation survival prediction attributes with the help of suitable data mining techniques. We obtained an accuracy of 97.1% from the multi-layer perceptron model with the evaluation of various performance measures. In order to assure the validity of the proposed model we implemented the Radial Basis Function model and obtained an accuracy of 92.37%. We collated the accuracy of proposed survival prediction models with existing systems and proved that the proposed system appeared to be best for survival prediction with higher accuracy compared to 85.9% in the existing system. The outcome of the model will be an asset for the lifesaving procedures in the medical field.

Determiningoptimal donor heart ischemic times in adult cardiac transplantation.

ObjectivesUnsupervised statistical determination of optimal allograft ischemic time (IT) on heart transplant outcomes among ABO donor heart types.MethodsWe identified 36,145 heart transplants (2000–2018) from the United Network for Organ Sharing database. Continuous and categorical variables were analyzed with parametric and nonparametric testing. Determination of IT cutoffs for survival analysis was performed using Contal and O'Quigley univariable method and Vito Muggeo multivariable segmented modeling.ResultsUnivariable and multivariable IT threshold determination revealed a cutoff at about 3 h. The hourly increase in survival risk with ≥3 h IT is asymmetrically experienced at the early 90 days (hazard ratio [HR] = 1.29, p < .001) and up to 1‐year time point (HR = 1.16, p < .001). Beyond 1 year the risk of prolonged IT is less impactful (HR = 1.04, p = .022). Longer IT was associated with more postoperative complications such as stroke (2.7% vs. 2.3, p = .042), dialysis (11.6% vs. 9.1%, p < .001) and death from primary graft dysfunction (1.8% vs. 1.2%, p < .001). O blood type donor hearts with IT ≥ 3 h has significantly increased hourly mortality risk at 90 days (HR = 1.27, p < .001), 90 days to 1 year (HR = 1.22, p < .001) and >1 year (HR = 1.05, p = .041). For non‐O blood types with ≥3 h IT hourly mortality risk was increased at 90 days (HR = 1.33, p < .001), but not at 90 days to 1 year (HR = 1.09, p = .146) nor ≥1 year (HR = 1.08, p = .237).ConclusionsThe donor heart IT threshold for survival determined from unbiased statistical modeling occurs at 3 h. With longer preservation times, transplantation with O donor hearts was associated with worse survival.

Total ventricular mass oversizing +50% or greater was a predictor of worse 1-year survival after heart transplantation

ObjectivesCurrent donor-recipient size matching guidelines rely primarily on body weight, with no specified oversizing cutoff values. Recent literature has explored predicted total ventricular mass matching over body weight matching. We aim to explore the impact of total ventricular mass oversizing on heart transplant outcomes. MethodsThe United Network for Organ Sharing database was queried for adults who underwent primary heart transplant from 1997 to 2017. By using validated equations, donor-recipient total ventricular mass mismatch was calculated. Donor-recipient pairs were divided into 3 groups by total ventricular mass mismatch. Post–heart transplant 1-year survival was analyzed using the Kaplan–Meier method and Cox proportional hazards models. We also investigated post–heart transplant complications, independent predictors for mortality, donor-recipient sex mismatch, and donor-recipient body habitus in total ventricular mass mismatch greater than +50%. ResultsA total of 34,455 donor-recipient pairs were included. Fractional polynomial regression demonstrated increased the risk of mortality with higher total ventricular mass mismatch. Total ventricular mass mismatch of +48.3% maximized the Youden Index. Donor-recipient pairs were subsequently grouped by total ventricular mass mismatch as −20% to +30%, +30% to +50%, and greater than +50%. Total ventricular mass mismatch greater than +50% was an independent risk factor for 1-year mortality (hazard ratio, 1.40, P = .004) and was associated with increased postoperative stroke (P = .002). Some 80.3% of these recipients were smaller female patients with male donors. Total ventricular mass mismatch from +30% to +50% was not associated with worse survival (P = .17). ConclusionsTotal ventricular mass mismatch greater than +50% is associated with worse 1-year survival, although this group comprises a small portion of heart transplant. total ventricular mass mismatch from +30% to +50% is not associated with worse survival. These outcomes should be considered in selecting donors and in efforts to expand the potential donor pool.

Association of center-level temporary mechanical circulatory support use and waitlist outcomes after the 2018 adult heart allocation policy

BackgroundThe present study characterizes the association of center-level temporary mechanical circulatory support use with waitlist outcomes after the 2018 adult heart allocation policy change. MethodsThe United Network for Organ Sharing database was queried for all single-organ, adult heart transplant candidates from November 2015 to October 2021. The study population was divided into 2 cohorts, prepolicy and postpolicy, centered around the rule change on October 18, 2018. The primary study outcome was center-level rate of poor waitlist outcome, defined as death or deterioration on the waitlist. Competing-risks regression was used to generate risk-adjusted rates of poor waitlist outcome at each center, while Pearson’s correlation coefficient (r) was used to assess the significance of center-level temporary mechanical circulatory support use (defined as the proportion listed with temporary mechanical circulatory support) and poor waitlist outcome. ResultsOf 22,077 transplant candidates included in analysis, 50.5% were listed during postpolicy. Compared to prepolicy, postpolicy candidates were more often listed with temporary mechanical circulatory support and less commonly listed with a durable left-ventricular assist device. The proportion of hospitals not using any temporary mechanical circulatory support decreased significantly from prepolicy to postpolicy (15% to 1%, P < .001). During prepolicy, center-level temporary mechanical circulatory support use showed no correlation with adjusted poor waitlist outcome. However, center-level temporary mechanical circulatory support use showed a negative correlation with poor waitlist outcome during postpolicy (r = -0.42, P < .001). ConclusionThe 2018 adult heart allocation policy appears to benefit patients listed at high temporary mechanical circulatory support using centers, with significant interhospital variation in temporary mechanical circulatory support use in the new era. Given the growing role of temporary mechanical circulatory support on the heart transplant waitlist, greater standardization of its application is warranted.

Failure to rescue: obesity increases the risk of mortality following early graft failure in heart transplantation in UNOS database patients.

OBJECTIVESEarly graft failure (EGF) is a devastating postoperative complication following heart transplant. Institutional studies have modelled donor and recipient risk factors predictive of graft failure. To date, no studies have assessed specific recipient profiles associated with mortality after recipients suffer from EGF. The objective of this study was to identify this recipient profile.METHODSWe performed a retrospective review of patients in the United Network for Organ Sharing database undergoing heart transplant from August 2000 to September 2019. EGF was defined as graft dysfunction at 24 hours post-heart transplant. The primary outcome was 90-day mortality. To isolate recipient characteristics associated with mortality, we performed the univariate analysis on 24 recipient characteristics adjusted for high-risk donor characteristics (ischaemic time, donor age, race mismatch, BUN/creatinine ratio) predictive of 1-year mortality (P < 0.2). We then performed backward stepwise multivariable regression adjusted for identified donor characteristics to determine recipient characteristics associated with mortality after EGF (P < 0.05).RESULTSWe identified 302 patients diagnosed with post-transplant EGF. Among these patients, mortality was 82% within 90 days of transplantation. Adjusted univariate analysis identified 7 factors associated with mortality. Adjusted backward stepwise multivariable regression identified BMI > 30 as predictive of mortality at 90 days after EGF.CONCLUSIONSPatients who develop EGF after heart transplant are at high risk for mortality. Careful discussion regarding transplant candidacy and risk is warranted in obese patients. In addition, minimizing donor factors associated with graft dysfunction is critical during preoperative planning in these recipients.

Variability in serum creatinine is associated with waitlist and post-liver transplant mortality in patients with cirrhosis.

Kidney function in patients with cirrhosis is dynamic. After controlling for the presence of chronic kidney disease (CKD) and acute kidney injury (AKI), we investigated the impact of variation in clinical function on pre-liver transplantation (LT) and post-LT outcomes. We included adults listed for LT from 2011 through 2018. We excluded those with any exceptions, those on hemodialysis at listing, and those with fewer than three clinical updates in the United Network for Organ Sharing database. Our primary exposure was the serum creatinine coefficient of variation (sCr CoV). Logistic regression determined the associations between our exposures and higher sCr CoV. Competing risk regression determined the associations between our exposures and waitlist mortality, accounting for LT as a competing risk. Cox regression determined the associations between our exposures and either listing for kidney transplant or death. We divided our cohort into tertiles of sCr CoV: low variability, 8.8% (interquartile range [IQR], 6.6%-10.8%); intermediate variability, 17.4% (IQR, 14.8%-20.4%); high variability, 36.8% (IQR, 29.5%-48.8%). We demonstrate that women, those with CKD, and those with advanced liver disease were more likely to have a greater sCr CoV. Compared to those with low variability, those with high variability had significantly higher waitlist mortality (34.7% vs. 19.6% vs. 11.7%, p<0.001). We highlight that the sCr CoV was associated with higher waitlist and post-LT mortality-an association independent of baseline sCr, the degree of underlying liver disease, the presence of AKI, or the presence of CKD. This study informs the long-term impact of the variation in kidney function we all see in clinical practice. These data highlight that all fluctuations in sCr are associated with worse pre-LT and post-LT outcomes.

Varying Utilization Rates but Superior Outcomes in Liver Transplantation From Hepatitis C-positive Donors in the United States: An Analysis of the OPTN/UNOS Database.

Liver transplantation (LT) from hepatitis C virus (HCV)-positive donors [antibody positive (Ab+) or nucleic acid test-positive (NAT+) donors] has been reported to achieve successful outcomes. However, donor and recipient selection has not been well-characterized. Data between 2015 and 2019 were obtained from the United Network for Organ Sharing database. The utilization rates and graft survival among 35 239 potential donors and 23 780 adult LT recipients were reviewed based on donor HCV Ab/NAT status. The utilization of Ab+/NAT+ donors was significantly reduced compared with HCV-negative donors (66.4% versus 80.0%, P < 0.001) among donors aged between 40 and 69 y. Recipients of livers from HCV-positive donors had lower laboratory and allocation Model for End-stage Liver Disease scores (both P < 0.001). HCV-positive donors were younger ( P < 0.001). Kaplan-Meyer survival curves demonstrated significantly superior 1-y graft survival in recipients of HCV-positive grafts compared with those from HCV-negative grafts ( P = 0.004; 97.1% in Ab-/NAT+, 93.9% in Ab+/NAT-, and 93.7% in Ab+/NAT+ versus 91.8% in Ab-/NAT-). Multivariate analysis for 1-y graft survival identified donor age [hazard ratio (HR) = 1.01; 95% confidence interval (CI), 1.00-1.01] and laboratory Model for End-stage Liver Disease score (HR = 1.01; 95% CI, 1.00-1.01) as independent predictors but not donor HCV status: HR 0.77' 95% CI, 0.58-1.02 in Ab+/NAT-; HR 0.82' 95% CI, 0.66-1.03 in Ab+/NAT+; and HR 0.39' 95% CI, 0.10-1.55 in Ab-/NAT+. More widespread utilization of HCV-positive donors, especially Ab+/NAT+ donors of age 40-69 y, may expand the donor pool without impairing short-term outcomes after LT.

Repeat Pediatric Heart Transplantation in the United States: United Network for Organ Sharing Database Analysis

<h3>Purpose</h3> National data on the efficacy of re-transplantation in children, in whom waitlist mortality approaches 20%, is scarce. <h3>Methods</h3> The United Network for Organ Sharing (UNOS) Database was used to identify 6,244 patients aged <18 years undergoing isolated heart transplant from 2004-2021, including 5,913 (94.7%) primary transplants and 331 (5.3%) re-transplants. The primary outcome was all-cause mortality. Multivariable cox regression was used to assess the impact of re-transplantation on survival, adjusting for patient, donor and hospital characteristics. Median follow-up was 4.5 (range 0.0-16.2) years. <h3>Results</h3> Re-transplant patients were older (median age 12 vs 4 years; p<0.01), more likely to be female (54.1%, n=179 vs 44.1%, n=2609; p<0.01), and less likely to be in UNOS status 1A (67.7%, n=224 vs 83.4% n=4932; p<0.01) than those undergoing primary transplants. The main indication for re-transplantation was allograft vasculopathy (60.7% n=201), followed by chronic rejection (10.6%, n=35) and primary failure (8.8%, n=29). The overall 90-day survival was 94.8% (95% confidence interval (CI) 94.2-95.3), this was similar between the groups (p=0.28). The unadjusted 10-year survival was 48.4% (95% CI 41.2-55.7%) among re-transplants and 71.6% (95% CI 70.0-73.2%) among primary transplants (p<0.01) (Figure 1). Re-transplantation was an independent predictor of long-term mortality in multivariable analysis (hazard ratio (HR) 1.8, 95% CI 1.4-2.2), other predictors included earlier transplant year (HR 0.9, 95% CI 0.8-0.9 per 5-years). <h3>Conclusion</h3> Despite advancements in overall outcomes, late survival following pediatric heart re-transplantation is significantly worse than primary transplantation. Increased awareness, prevention, diagnosis and management of coronary disease in pediatric heart transplant patients may improve patient outcomes and organ stewardship.

Outcomes of Heart Transplant Recipients with Class II Obesity: A United Network for Organ Sharing Database Analysis.

In the 2016 ISHLT listing criteria guidelines for heart transplantation, recipients were recommended to have a body mass index (BMI) <35 kg/m². However, outcomes data for subgroups of transplant recipients with a BMI >35 kg/m² are limited. We examined the outcomes of heart transplant recipients who had a BMI of 35 to 39.9 kg/m² or ≥40 kg/m² and compared their outcomes with recipients who had a BMI <35 kg/m2. Using data from the United Network for Organ Sharing database, we performed a retrospective cohort analysis of 23,009 adults who underwent cardiac transplantation between 2009 and 2018. Transplant recipients were stratified by BMI categories (<35 kg/m², 35-39.9 kg/m², and ≥40 kg/m²). Patient survival was depicted by Kaplan-Meier curves. Cox proportional-hazards modeling was used to determine the prognostic factors associated with mortality within 90 days, 1 year, and 5 years after transplantation. Survival at 90 days, 1 year, and 5 years after transplantation was better in recipients who had a BMI <35 kg/m² than in those who had a BMI of 35 to 39.9 kg/m² (P values ranged from 0.01 to < 0.001) or ≥40 kg/m² (P < 0.001). Additionally, survival at 90 days (P < 0.001) and 1 year (P=0.002) was significantly better in recipients who had a BMI of 35 to 39.9 kg/m² than in those who had a BMI ≥40 kg/m². In multivariate analysis, a BMI of 35 to 39.9 was significantly associated with increased 90-day mortality (HR=1.53; 95% CI 1.12, 2.08; P=0.01) but not increased 1-year (HR=1.28; 95% CI 0.99, 1.66; P=0.06) or 5-year mortality (HR=1.11; 95% CI 0.91, 1.36; P=0.29). Although heart transplant recipients with class II obesity (BMI 35-39.9 kg/m²) may have suboptimal survival compared with those who have a BMI <35 kg/m², these patients have better outcomes than do those with class III obesity (BMI ≥40 kg/m²). Thus, contrary to current guidelines, selected patients with class II obesity should be considered for transplantation.

Should Age-Based Eligibility Thresholds Differ for Repeat Heart Transplantation? Analysis of the United Network of Organ Sharing Database

<h3>Purpose</h3> Risk-adjusted survival after cardiac re-transplantation may be comparable to primary transplant, but the efficacy of re-transplantation in older candidates is not established. We evaluated outcomes after re-transplantation in recipients > 60 years. <h3>Methods</h3> The United Network for Organ Sharing Database identified 1295 adult patients undergoing heart re-transplants between 2003 and 2020 (excluding heart-lung transplants). Unadjusted 5-year survival of older recipients (> 60 years, n=212) was compared to younger recipients (<= 60 years, n=1083). Adjusted Cox model using restricted cubic splines explored the non-linear relationship between recipient age and mortality risk after re-transplantation. A separate multivariate Cox model analyzed recipients>60 years undergoing either primary transplant (n=12826) or re-transplantation (n=181, excluding re-transplants for acute/hyperacute rejection or primary graft dysfunction) to evaluate the impact of re-transplantation on mortality. <h3>Results</h3> In patients undergoing re-transplantation, older recipients had more pre-transplant ECMO use (9.9% vs. 5.8%, p=0.027) and received grafts from older donors (34, IQR 24-46 vs. 28, IQR 21-38 years, p<0.0001). Recipient age >60 was associated with inferior unadjusted survival (Figure 1A). Restricted cubic spline (Figure 1B) showed a significant increase in mortality risk when recipient age becomes older than 61.8 years (corresponding HR 1.35, 95% CI 1.01-1.79). In recipients >60 years undergoing either primary transplant or re-transplantation, re-transplantation was independently associated with increased risk of mortality (HR 1.33, 95% CI 1.07-1.65, p=0.01) compared to primary transplant. <h3>Conclusion</h3> Re-transplanting patients greater than 60 years old is independently associated with increased risk of mortality. More conservative age-based thresholds for re-transplantation may be appropriate.

Risk Factors for Failure to Recover Normal Left Ventricular Function in Transplanted Donor Hearts with Low Ejection Fraction

<h3>Purpose</h3> Previous work has demonstrated that carefully selected donor hearts with low ejection fraction (EF) can be transplanted with outcomes equivalent to hearts with normal left ventricular (LV) function and most, but not all, will recover at one year. In an effort to help guide selection of these hearts, we sought to determine whether there are risk factors for failure to recover normal LV function at one year. <h3>Methods</h3> Using the United Network for Organ Sharing database, we reviewed all adult heart transplants between January 2000 and June 2021. Patients who received a first-time single organ transplant using a donor heart with EF < 50 were included. Recovery of EF was defined as EF ≥ 50 at one year from transplant. Baseline characteristics were compared between donor hearts that had recovery of EF (R group) and those that did not (NR group). Univariate analysis included Chi square test for categorical variables and Independent samples t test, or Mann Whitney U test where appropriate, for continuous variables. A logistic regression model was utilized to determine whether breath death mechanism significantly contributed to recovery rates after adjustment for other covariates. Data analysis was performed using R v4.1.1. <h3>Results</h3> Of the 97,990 donor hearts that were transplanted during the study period, 717 (7.3%) met criteria. Of these, 656 (91.5%) had recovery of EF ≥ 50 at one year. We found no statistically significant differences in baseline characteristics between groups. On univariate analysis, mean ischemic time (3.5 vs 3.1 hrs, p = 0.005) and recipient total bilirubin (1.9 vs 1.0 mg/dL, p = 0.004) were higher in the NR group. Mean recipient pulmonary capillary wedge pressure at registration was higher in the R group (23.7 vs 20.7 mmHg, p = 0.02). However, these variables did not remain significant on multivariate analysis. After adjusting for selected recipient and donor factors, we found that mechanism of brain death (anoxia, head trauma, or CVA/stroke) did not predict recovery of EF. <h3>Conclusion</h3> Of the donor hearts transplanted with low EF, mechanism of brain death does not predict recovery of EF at one year. Other risk factors for failure to recover EF were not identified. The decision to exclude a heart from transplant should not be made solely on the basis of poor EF or mechanism of brain death.

The Utilization of Marginal Donors for Cardiac Re-Transplantation

<h3>Purpose</h3> The global shortage of available donor organs and the poor clinical outcomes of re-transplant patients raise the ethical and economic concerns. In this study, we examined the difference in post-transplant survival of re-transplant (re-HTx) patients with and without the use of marginal donor hearts. <h3>Methods</h3> The United Network of Organ Sharing database was retrospectively queried from January 2000 to March 2020 to identify adult (17 > years) patients underwent re-HTx. Recipients were divided into early (≦6 months after previous transplant)and late (>6 months after previous transplant) groups based on the timing of re-transplantation. Demographic data and outcomes were compared with and without the use of marginal donors in each group. Marginal donors were those who met at least one of the following characteristics: age greater than 55 years, cocaine or other intravenous drug use, hepatitis C positive, ejection fraction less than 0.45, and donor: recipient weight less than 0.8. <h3>Results</h3> There were 111 early and 1133 late re-transplantation.10-year mortality was significantly higher in the early transplantation compared with the late transplantation (Early 61.0% vs. Late 44.9%, log-rank P<0.001). There was no difference in preoperative patient background between the Marginal and non-Marginal groups in the early transplant group, while the Marginal group had a higher BMI (p<0.001), higher PRA (p=0.005), and longer total waiting time (0.018) than non-marginal group in the late transplant group. There was no significant difference in 10-year mortality between the marginal and non-marginal groups in either the early or late transplant groups. (Early: non-MD 58.5% vs. MD 62.0%, log-rank P=0.827; Late: non-MD 43.2% vs. MD 46.6%, log-rank P=0.699). <h3>Conclusion</h3> Utilization of marginal donor in patients undergoing re-HTx is not associated with worse outcomes both for early and late graft failure.

Clinical Outcomes Of Patients With Peripartum Cardiomyopathy Listed For Heart Transplantation.

<h3>Background</h3> In patients with peripartum cardiomyopathy (PPCMP) who do not recover but advance to end-stage heart failure, treatment with heart transplantation (HT) or a durable left ventricular assist device (LVAD) as a bridge to HT is an alternative. We describe the characteristics and clinical outcomes of PPCMP patients listed for HT from a national registry. <h3>Methods</h3> The United Network for Organ Sharing database was used to identify end-stage HF patients with PPCMP as the etiology of HF who were listed for HT between 2008 and 2020. Baseline clinical characteristics were compared between those listed with or without an LVAD. The primary outcome was waitlist mortality evaluated with competing risk analysis for death, transplant, or recovery. Post-transplant survival at 5-years was compared between both groups with Kaplan Meier survival curves in HT candidates. Cox proportional Hazard modelling was used to identify independent predictors of 5-year post-transplant survival. <h3>Results</h3> A total of 620 PPCMP patients (Non-LVAD; n=390; LVAD: n=230) were listed for HT during the study period. Of these 379 (68%) successfully reached HT, 66 (11%) died or were delisted due to deteriorating clinical status and 40 (7%) recovered while on the waitlist. Compared to Non-LVAD patients, LVAD candidates were younger (median age: 36 vs. 33 years, p=0.02), had a higher BMI (29 vs. 27 kg/m², p=0.01) and more likely ≤ high school graduates (55% vs. 44%; p=0.01). Waitlist mortality at 1-year after listing was similar in both groups. (Non-LVAD vs. LVAD; 11.6% vs. 9.5%; Fine-Gray test: p=0.53) (Figure A) with no difference in 5-year post-transplant survival. [Log rank test: p=0.72]. (Figure B). On Cox proportional hazard modelling, level of education (≥ College) HR: 95% C.I [1.5 (1.1, 2.2; p=0.01)] was associated with 5-year post-transplant survival. <h3>Conclusions</h3> About two-thirds of PPCMP patients who were listed for HT were successfully transplanted, despite a low rate of myocardial recovery. Waitlist mortality at 1 year and 5-year post-transplant survival was comparable regardless of treatment approach.

Heart Transplant Recipients of Donors with Intracranial Hemorrhage Have Worse Survival

<h3>Purpose</h3> A significant proportion of heart transplant donors suffer death from intracranial hemorrhage. We sought to determine if recipients of donors who die due to intracranial hemorrhage have worse outcomes post heart transplant. <h3>Methods</h3> The United Network for Organ Sharing database was queried from 2006 to 2020 for all adult recipients who underwent heart transplant. Survival was compared for recipients of donors with intracranial hemorrhage versus all other causes of death. Recipients were then identified if the donor cause of death was cerebrovascular, stroke or head trauma. Survival was compared for recipients of donors with intracranial hemorrhage and donors with nonhemorrhagic stroke or head trauma within this sub-group. <h3>Results</h3> A total of 31,599 patients underwent heart transplant during the study time period, with 6362 patients whose donor died due to intracranial hemorrhage. A total of 15,914 patients received a heart from a donor with an intracranial cause of death. Demographic information is shown in table 1. Survival was significantly worse for recipients of donors who died from intracranial hemorrhage (Figure 1, p<0.001). When survival was compared for recipients whose donor had an intracranial cause of death, intracranial hemorrhage resulted in worse survival compared with a nonhemorrhagic cause of death (p<0.001). Analysis of the cause of death showed a higher rate of graft failure in recipients of donors with intracranial hemorrhage (N=257, 13.4% vs. N=699, 11.9%, p<0.001). <h3>Conclusion</h3> Donors who die from intracranial hemorrhage should be considered with caution and should be matched carefully with the appropriate recipient.

Mitigation of Post-Transplant Mortality Risk by Appropriate Donor-to-Recipient Size Matching Using Predicted Heart Mass

<h3>Purpose</h3> Obesity is a known risk factor for post-transplant mortality. Obesity epidemic in U.S. has led to a higher prevalence of obese patients as potential heart transplant recipients. It is unclear if appropriate size matching of donor-to-recipient using predicted heart mass (PHM) can mitigate this risk among obese recipients. <h3>Methods</h3> We selected all recipients with heart transplants performed between 1995 and 2020 (n=34,812) using the United Network for Organ Sharing database to examine the risk of death in 6 separate categories of recipient's BMI (Table) according to PHM matching. PHM-based appropriate match happened when Donor PHM/Recipient PHM x 100% was within 86% to 114% whereas under- and over-match were defined as <86% and >114%, respectively. Multivariable Cox regression models were created examining long-term risk of death in appropriately matched and over-matched categories compared to under-matched category in the overall cohort and separately within each BMI group. <h3>Results</h3> Upon follow-up (mean 5.29 years), 9,810 patients died. Recipients appropriately matched to donor hearts had an 8% lower risk of death compared to recipients matched with underweight donors by PHM (Table). Compared to those who had under-matched hearts, normal or overweight recipients who received appropriately matched donor hearts based on PHM had a 10-13% lower risk of death post-transplant (Table). In addition, morbidly obese recipients who were appropriately matched with donor hearts also had a 17% lower risk of death post-transplant (borderline statistically significant p=0.06; Table). The risk of death among obese or severely obese recipients did not differ with appropriate PHM matching or over matching compared to under-matching. <h3>Conclusion</h3> Although pretransplant obesity continues to be a risk factor for death post-transplant, appropriate size matching for donor hearts by PHM may lower the risk of death compared to under-matching specifically among normal and overweight recipients.

Morbid Obesity is Associated with Significantly Higher Risk of Death After Lung Transplant in Recipients Bridged on Extra-Corporeal Support

<h3>Purpose</h3> Critically ill patients requiring mechanical ventilation (MV) and extra-corporeal support (ECMO) require an abundance of resources and have a high risk of death after lung transplant. To help guide selection, we studied the effect of obesity on mortality in this cohort. <h3>Methods</h3> The United Network for Organ Sharing database (1987-2021) was queried to identify adult lung transplant recipients (n=41,920) bridged on MV (n=2,186, 5.2%) and/or ECMO (n=1,307, 3.1%). Among body mass index (BMI) categories, overall survival (OS) was analyzed using Kaplan-Meier estimation and compared using log-rank tests. Cox regression analyses were used to identify risk factors for death. <h3>Results</h3> Obese (BMI Class I: 30-34.9) and morbidly obese (BMI Class II/III: >35) cohorts were identified. In the MV group, 316 (14.5%) had class I and 62 (2.8%) had class II/III obesity. In the ECMO group, 228 (17.4%) had class I and 37 (2.8%) had class II/III obesity. Median lung allocation scores were 87.0 [IQR 67.5-90.5] in the MV group and 89.2 [IQR 86.6-90.8] in the ECMO group. In the MV group, 30 day, 1, 3 and 5-year OS were 89%, 72%, 53% and 40% in class I patients and decreased to 87%, 56%, 37% and 35% in class II/III patients. In the ECMO group, 30 day, 1, 3 and 5-year OS were 93%, 78%, 58% and 44% in class I patients and decreased to 81%, 43%, 28% and 23% in class II/III patients (Figure 1). Risk factors for death included: class I obesity (HR=1.13, p=0.00), class II/III obesity (HR=1.27, p=0.01), BMI<18.5 (HR 1.16, p=0.00), bridging on MV (HR=1.18, p=0.00), pulmonary hypertension (HR=1.17, p=0.032), diabetes (HR=1.15, p=0.013), history of dialysis (HR=2.05, p=0.00), creatinine (HR=1.11, p=0.00), and donor diabetes (HR=1.13, p=0.00). <h3>Conclusion</h3> Morbidly obese (BMI>35) lung transplant recipients bridged on MV and ECMO carry an extremely high risk of death after transplant. These findings likely reflect non-modifiable challenges in perioperative care and should be considered during evaluation for listing.

Survival Benefit of Lung Transplant in Septuagenarians: A United Network of Organ Sharing Database Analysis

<h3>Purpose</h3> The benefit of lung transplant in septuagenarians is questioned on the grounds that recipients must be so highly selected that their baseline survival negates any benefit of transplant. This study evaluated the short-term outcomes and survival benefit of lung transplant in septuagenarians compared to waitlist patients that did not receive a transplant. <h3>Methods</h3> Using the United Network for Organ Sharing database, lung transplant recipients and waitlist candidates from 1991-2021 were analyzed. Dual organ transplant candidates/recipients and those without validated records were excluded. The cohort consisted of 3109 patients, 12.9% (400) were waitlist candidates and 87.1% (2709) were lung transplant recipients all seventy years of age and older. Propensity matching on eleven demographic characteristics, year of waitlist/surgery, and waitlist time produced 384 pairs with correction of baseline differences. Short-term survival was compared with a Cox regression model. Median follow-up of the lung transplants was 2 years (interquartile range (IQR) 0.8-4) versus 0.3 (IQR 0.1-0.6) for waitlist candidates. <h3>Results</h3> Lung transplants in septuagenarians increased from 0.14% (1) in 1991 to 12.2% (193) transplants in 2021, p<0.001. The median age of the unmatched waitlist candidates and recipients was 71 (IQR 70-73), with a listing lung allocation score of 38.7 (IQR 34-48.5) and 37.8 (IQR 34.1-44.8), respectively, all p>0.5. In the unmatched cohort, there was a higher proportion of females in the waitlist group (37.3% (149) vs 25% (677)), p<0.0001. In matched patients, six-month survival was lower in the waitlist group 42% (95% CI 36.4-47.4) versus 91.1% (95% CI 87.6-93.7), p<0.0001 (Figure). <h3>Conclusion</h3> Lung transplant can be offered in septuagenarians with survival benefit in those eligible for lung transplant. These findings may inform the transplant community that selection bias due to age should be reconsidered.

Predicting Survival in Combined Heart-Liver Transplantation Compared to Heart Transplantation Alone

<h3>Purpose</h3> As the number of heart-liver transplants increases, an understanding of the benefits and risks becomes increasingly important for appropriate multiorgan allocation. The model for end-stage liver disease and serum sodium level (MELD-Na) score is used as a predictor of survival in patient with liver disease. It is used to prioritize liver transplant recipients on the waitlist. We expected that patients with higher MELD-Na scores who underwent heart-liver transplant would have a higher postoperative survival than those patients with high MELD-Na scores who underwent heart transplant alone. The goal of our study was to determine if MELD-Na is a useful metric for allocating heart-liver transplants. <h3>Methods</h3> We retrospectively analyzed both heart-liver transplant recipients enrolled in the United Network for Organ Sharing database and all heart transplant recipients from the Stanford University with complete data for the covariates used in our model. Recipient MELD-Na scores were calculated for transplant recipients in both groups. The risk of death was assessed using a multivariable Cox proportional hazard model with adjustment for age of donor, age of recipient, recipient diabetes, and recipient intra-aortic balloon pump at time of transplant. We investigated whether MELD-Na predicted survival in heart-liver recipients. <h3>Results</h3> A total of 326 patients enrolled in UNOS underwent heart-liver transplantation and a total of 278 patients underwent heart transplantation at Stanford. The interaction effect of the type of transplant received (heart-liver vs heart alone) and MELD-Na was not significant for survival at 30 days (p = 0.812), 1 year (p = 0.859), 3 years (p = 0.621), and 5 years (p = 0.448). Furthermore, in the heart-liver cohort, MELD-Na did not significantly predict survival at 30 day (p = 0.461), 1 year (p = 0.153), 3 years (p = 0.169), and 5 years (0.169). <h3>Conclusion</h3> We found that patients with higher MELD-Na scores who underwent heart-liver transplantation did not have a higher postoperative survival when compared to those patients with high MELD-Na who underwent heart transplant alone. Therefore, MELD-Na is not a useful metric for allocating heart-liver transplants.

Outcomes of Patients Undergoing Combined Heart-Kidney Transplantation with or without Prior Ventricular Assist Device

<h3>Purpose</h3> Both combined heart-kidney transplantation and ventricular assist devices (VAD) pose significant challenges including sensitization, immunosuppressive treatment, and infrastructure demands. Despite these challenges, we hypothesized that the recipients of combined heart-kidney transplants with and without VADs would have equivalent survival. Our aim was to compare the survival of heart-kidney transplant recipients with and without prior VAD placement. <h3>Methods</h3> We retrospectively analyzed all patients enrolled in the United Network for Organ Sharing database who underwent heart-kidney transplants. The heart-kidney transplant recipients were divided into two groups: those patients who had a VAD prior to transplantation and those who did not have a VAD prior to transplantation. We created a matched cohort of patients undergoing heart-kidney transplantation with or without prior VAD using 1:1 optimal propensity-score matching with preoperative variables. <h3>Results</h3> In the propensity-matched cohort, 399 patients (50%) underwent heart-kidney transplantation with prior VAD and 399 (50%) underwent heart-kidney transplantation without prior VAD. The estimated survival of heart-kidney recipients with prior VAD was 84.8% at one year, 81.2% at three years, and 75.3% at five years. The estimated survival of heart-kidney recipients without prior VAD was 88.7% at one year, 86.1% at three years, and 81.4% at five years. There was no statistically significant difference in the survival of heart-kidney transplant recipients with or without prior VAD at one year (p = 0.1; Figure 1), three years (p = 0.065), or five years (p = 0.05). <h3>Conclusion</h3> Despite the increased challenge of heart-kidney transplantation in recipients with prior VAD, we demonstrated that these patients have similar survival to those patients who underwent heart-kidney transplantation without previous VAD placement.