Pediatric Transplantation Using Hearts Refused on the Basis of Donor Quality

Donor sequence number is not associated with worse lung transplant outcomes regardless of transplant center case volume

BACKGROUND

Potential lung transplantation (LTx) recipients are assigned a donor sequence number (DSN) based on their position on the match list. Since a higher DSN offer has already been declined for other recipients, some providers may assume that a high DSN connotates poorer allograft quality. This study evaluated the association between DSN and outcomes, the correlation between transplant program case volume and the utilization of higher DSN lungs, and whether LTx outcomes differ between lower- and higher-volume programs.

METHODS

Using the Scientific Registry of Transplant Recipients database, LTx cases from 2015-2021 were retrospectively reviewed. Recipients were categorized into low (<20), medium (21-50), high (51-100), and very high (>100) DSN groups. The primary outcome was LTx survival. For cases involving high or very high DSN donors, a subgroup analysis compared survival among programs with annual transplant volumes in the bottom, middle 2, and top quartiles.

RESULTS

Median survival was similar among the low (6.9 years), medium (6.1), high (5.9), and very high DSN (6.5) groups (log-rank p = 0.09). Higher DSN donors were more commonly accepted by higher-volume LTx centers. However, the annual case volume of the transplanting institution did not impact survival when high (log-rank p = 0.16) or very high DSN (log-rank p = 0.36) donors were used.

CONCLUSIONS

Higher DSN should not be considered an independent marker of low allograft quality. Additionally, lower-volume centers achieved similar post-transplant outcomes as higher-volume centers for recipients receiving higher DSN lungs. These findings underscore that surgeons must judge each donor offer independent of other programs' assessments.

Donor Characteristics and Outcomes of Pediatric Heart Transplantation in South Korea

BACKGROUND

Heart transplantation is often limited by the availability of transplantable donor heart and understanding of donor aspects that would influence transplant outcomes becomes important. In this study, donor characteristics and their impact on the outcomes of pediatric heart transplantations performed in South Korea were investigated.

METHODS

We reviewed the medical records of patients less than 18 years old who received heart transplantation between 2002 and 2022 in three tertiary hospitals located in South Korea.

RESULTS

A total of 139 cases were enrolled. One-year mortality was 10.4% and total mortality was 33.8%. Forty-nine recipients (35.3%) showed biopsy-proven rejections and 20 (14.4%) showed cardiac allograft vasculopathy during mean follow-up of 6.4 ± 4.9 years. Six recipients (4.5%) showed left ventricle ejection fraction of less than 55% post-transplantation. The mean age of the donors was 23.0 ± 15.4 years. The most common cause of death of the donors was unspecified illness (46.4%). Donors with a history of diabetes, hypertension, smoking, and alcohol consumption were 0%, 3.1%, 32.1%, and 34.4%, respectively. Mean total ischemic time was 191.6 ± 72.7 min, while total ischemic time was over 4 h in 37 patients (26.6%). There were no significant relationship between donor factors and survival. However, donor's history of drinking or cardiopulmonary resuscitation was significantly associated with acute rejection and donor's age with cardiac allograft vasculopathy.

CONCLUSION

Donor factors did not show significant impact on post-transplant survival but some factors were predictive of post-transplant rejection and cardiac allograft vasculopathy.

A modified intraventricular balloon method for functional assessment of hearts from donation after circulatory death

Objective

Functional assessment of hearts during ex-vivo heart perfusion is not well-established. Conventional intraventricular balloon methods for large animals sacrifice the mitral valve. This study assessed the effectiveness of the modified intraventricular balloon method in comparison with other modalities used during working mode in juvenile pigs.

Methods

Following asphyxia circulatory arrest, hearts were ischemic for 15 minutes and then reperfused on an ex-vivo device for 2 hours before switching to working mode. Left ventricular pressure was continuously measured during reperfusion by a saline-filled balloon fixated in the left atrium. Spearman Correlation Coefficients with linear regression lines with confidence intervals were analyzed.

Results

Maximum dp/dt at 90 minutes of reperfusion and minimum dp/dt at 60 minutes of reperfusion showed a moderate positive correlation to that in working mode, respectively (Rs = 0.61, P = .04 and Rs = 0.60, P = .04). At 60 minutes of reperfusion, minimum dp/dt showed moderate positive correlation to tau (Rs = 0.52, P = .08). Myocardial oxygen consumption during reperfusion consistently decreased at least 30% compared to working mode (at 90 minutes as the highest during reperfusion, 3.3 ± 0.8; in working mode, 5.6 ± 1.4, mLO2/min/100 g, P < .001).

Conclusions

Functional parameters of contractility and relaxation measured during reperfusion by the modified balloon method showed significant correlations to respective parameters in working mode. This mitral valve sparing technique can be used to predict viability and ventricular function in the early phase of ex-vivo heart perfusion without loading the heart during working mode.

Risk Index Predicts Pediatric Heart Allograft Non-Utilization

BACKGROUND

Children listed for heart transplantation face the highest waitlist mortality among all solid organ transplant patients (14%). Attempts at decreasing donor allograft non-utilization (41.5%) could potentially decrease waitlist mortality for pediatric heart transplant patients. Our aim was to quantify the non-utilization risk of pediatric donor heart allografts at the time of initial offering.

METHODS

Using the United Network of Organ Sharing (UNOS) database, we retrospectively analyzed 8823 deceased donors (≤18 years old) data through univariable and multivariable analysis and logistic regression models. These factors were divided into a training (n = 5882) and validation set (n = 2941). Donor clinical characteristics and laboratory values were used to predict non-utilization of donor hearts. The multivariable analysis used factors that were significant from the univariable analysis (p-value < .05), and the pediatric non-utilization risk index (pDRSI) included significant factors from the multivariable analysis, producing an overall risk score for non-utilization. With these data, we created a non-utilization risk index to predict likelihood of donor allograft non-utilization.

RESULTS

From the 24 potential factors that were identified from univariable analysis, 17 were significant predictors (p < .05) of pediatric heart non-utilization in the multivariable analysis. Low left ventricular ejection fraction (odds ratio (OR)-35.3), hepatitis C positive donor (OR-23.3), high left ventricular ejection fraction (OR-3.29), and hepatitis B positive donor (OR-3.27) were the most significant risk factors. The phDSRI has a C-statistic of 0.80 for the training set and 0.80 for the validation set.

CONCLUSION

Using over 8000 donors, the phDSRI uses 17 significant risk factors to predict risk of pediatric heart donor allograft non-utilization.

Recent advances in porcine cardiac xenotransplantation: from aortic valve replacement to heart transplantation

INTRODUCTION

Cardiac xenotransplantation presents significant potential to the field of heart failure by addressing the high demand for donor organs. The availability of xenograft hearts would substantially augment the number of life-saving organs available to patients and may ultimately liberalize eligibility criteria for transplantation.

AREAS COVERED

In this review, we will discuss the need for cardiac xenotransplantation and the history of research and clinical practice in this field. Specifically, we address immunologic concepts and clinical lessons learned from heart valve replacement using xenogeneic tissues, the advancement of xenotransplantation using organs from genetically modified animals, and the progression of this research to the first-in-man pig-to-human heart transplantation.

EXPERT OPINION

Cardiac xenotransplantation holds tremendous promise, but the indications for this new treatment will need to be clearly defined because mechanical support with ventricular assist devices and total artificial hearts are increasingly successful alternatives for adults in heart failure. Cardiac xenotransplantation will also serve as temporary bridge to allotransplantation in babies with complex congenital heart disease who are too small for the currently available mechanical assist devices. Moreover, xenotransplantation of the part of the heart containing a heart valve could deliver growing heart valve implants for babies with severe heart valve dysfunction.

Outcomes following use of pediatric and young adult donor hearts with bicuspid aortic valves: A single-center case series

BACKGROUND

Valvular disease in pediatric and young adult donor hearts may be a relative contraindication to graft use. Outcomes following the use of donor hearts with bicuspid aortic valve (BAV) have not been previously reported in children. We describe 4 cases of pediatric heart transplantation (HTx) utilizing a donor heart with a BAV.

CASE SERIES

Of the 469 HTx included in this study, 4 utilized a donor heart with a BAV. All recipients were female; median age was 11 years (range 0.3 to 19 years). In all cases, the BAV was not discovered until after HTx. All donors were less than 30 years old. The patients were followed for a median of 6 years (range 2 to 9 years) with all patients alive at last follow-up. Two patients have transitioned to adult care, and 2 patients continue to follow in our clinic. In follow-up, no patient has required an aortic valve intervention or had infective endocarditis. At last review, no patient had greater than mild aortic insufficiency or more than mild aortic stenosis. Three patients developed mild-to-moderate left ventricular hypertrophy in the first year post-transplant that improved over time. One patient experienced a peri-operative embolic stroke at time of transplant unrelated to the BAV.

CONCLUSION

On short- and intermediate-term follow-up, pediatric and young adult donor hearts with BAV demonstrated acceptable graft longevity and valvular function. A functionally normal BAV in a pediatric heart transplant donor should not be a contraindication to organ acceptance.

Neonatal heart transplant outcomes: A single institutional experience

OBJECTIVE

Neonatal orthotopic heart transplantation was introduced in the 1980s as a treatment for complex congenital heart disease. Progress in single-ventricle palliation and biventricular correction has resulted in a decline in neonatal heart transplant volume. However, limited reports on neonatal heart transplants have demonstrated favorable outcomes. We report the long-term outcomes of patients with neonatal heart transplants at our institution spanning nearly 30 years.

METHODS

A retrospective analysis of neonatal heart transplants and neonates listed for transplant was performed at Children's Hospital Colorado. Primary outcomes were early and late survival. Secondary outcomes were rejection episodes, retransplantation, and development of cardiac allograft vasculopathy or post-transplant lymphoproliferative disease.

RESULTS

A total of 21 neonates underwent orthotopic heart transplantation at our institution. Among these, 10 neonates were transplanted from 1991 to 2000, 8 neonates were transplanted from 2001 to 2010, and 3 neonates were transplanted from 2011 to 2020. The average age of these patients was 17 days, and the average weight was 3.43 kg. Early survival was 95.2%. Survival at 1 and 5 years was 85.7% (confidence interval [CI], 61.9%-95.2%) and 75% (CI, 45.6%-85.5%), respectively. Of eligible patients, the 10-year and 20-year survival was 72.2% (CI, 45.1%-85.3%) and 50% (CI, 25.9%-70.1%), respectively.

CONCLUSIONS

Our institution reports favorable outcomes of neonatal heart transplantation. These results should be considered within the context of outcomes for patients awaiting transplant and the limited donor availability. However, the successful nature of these procedures suggest it may be necessary to reevaluate the indications for neonatal heart transplantation, particularly where risk of mortality and morbidity with palliative or corrective surgery is high.

Evidence-based surgical hypothesis: Partial heart transplantation can deliver growing valve implants for congenital cardiac surgery

Children undergoing congenital cardiac surgery often outgrow the valve implants. These children are thus committed to morbid reoperations for successive exchanges of the vavular implants that they have outgrown. Therefore the holy grail of congenital cardiac surgery is a valve implant that grows with the recipient child. Preserved homografts routinely are used as valve implants, but they do not grow as the child grows because they lose viability during preservation. In contrast, pulmonary autografts and pediatric heart transplants grow with the recipient children. Similarly, partial heart transplantation can deliver growing valve implants for congenital cardiac surgery. Temporary immune suppression would only be needed until the partial heart transplant can be exchanged for an adult-sized prosthetic valve in the grown child.

Impact of Donor-Recipient Age Difference on Graft Function and Survival After Deceased Donor Kidney Transplantation

BACKGROUND

Donor-recipient age difference (DRAD) is one of the reasons why patients on kidney waiting lists refuse to receive the offered organ. However, its impact on deceased donor kidney transplantation (DDKT) outcomes is still controversial.

METHODS

One hundred fifty-three kidney transplant recipients (KTRs) who received their first-time DDKT were enrolled. The KTRs were divided into groups by DRAD: group 1 (n = 74) (DRAD < 0) and group 2 (n = 79) (DRAD ≥ 0). The KTRs in group 2 were divided into 3 subgroups: DRAD 0 to 10 (n = 35), 10 to 20 (n = 32), and ≥ 20 (n = 12). The outcome measures included estimated glomerular filtration rate (eGFR), delayed graft function (DGF), acute rejection (AR), and graft and patient survival.

RESULTS

There were no significant differences in clinical outcomes between group 1 and 2 except eGFR until 5 years after DDKT. Among the subgroups of group 2, DGF, AR, patient survival, and eGFR until 5 years showed no significant differences. However, graft survival was significantly different (P = .015); in addition, in the DRAD ≥ 20 subgroup, graft survival decreased compared with that in the DRAD 10 to 20 subgroup and DRAD 0 to 10 subgroup (P = .020, P = .012, respectively). In a multivariate Cox proportional hazards analysis, the DRAD ≥ 20 subgroup showed a higher risk for graft failure than the DRAD 0 to 10 subgroup.

CONCLUSIONS

Although donors were of the same age or older than recipients, DDKT showed acceptable graft outcomes. However, because donors over 20 years older than recipients showed a decreased graft survival, it might be important to consider this point in donor-recipient matching of DDKT.

Review of interactions between high-risk pediatric heart transplant recipients and marginal donors including utilization of risk score models

BACKGROUND

Donor organ acceptance practices vary among pediatric heart transplant professionals. We sought to understand what is known about the interactions between the "high-risk" recipient and the "marginal donor," and how donor risk scores can impact this discussion.

METHODS

A systematic review of published literature on pediatric HTx was undertaken with the assistance of a medical librarian. Two authors independently assessed search results, and papers were reviewed for inclusion.

RESULTS

We found that there are a large number of individual factors, and clusters of factors, that have been used to label individual recipients "high-risk" and individual donors "marginal." The terms "high-risk recipient" and "marginal donor" have been used broadly in the literature making it virtually impossible to make comparisons between publications. In general, the data support that patients who could be easily agreed to be "sicker recipients" are at more risk compared to those who are clearly "healthier," albeit still "sick enough" to need transplantation. Given this variability in the literature, we were unable to define how being a "high-risk" recipient interplays with accepting a "marginal donor." Existing risk scores are described, but none were felt to adequately predict outcomes from factors available at the time of offer acceptance.

CONCLUSIONS

We could not determine what makes a donor "marginal," a recipient "high-risk," or how these factors interplay within the specific recipient-donor pair to determine outcomes. Until there are better risk scores predicting outcomes at the time of organ acceptance, programs should continue to evaluate each organ and recipient individually.

Review of the discard and/or refusal rate of offered donor hearts to pediatric waitlisted candidates

We aimed to review current literature on the discard rate of donor hearts offered to pediatric recipients and assess geographical differences. Consequences and ways to reduce the discard rate are discussed. A systemic review on published literature on pediatric transplantation published in English since 2010 was undertaken. Additionally, a survey was sent to international OPOs with the goal of incorporating responses from around the world providing a more global picture. Based on the literature review and survey, there is a remarkably wide range of discard and/or refusal for pediatric hearts offered for transplant, ranging between 18% and 57% with great geographic variation. The data suggest that that the overall refusal rate may have decreased over the last decade. Reasons for organ discard were difficult to identify from the available data. Although the refusal rate of pediatric donor hearts seems to be lower compared to that reported in adults, it is still as high as 57% with geographic variation.

ISHLT consensus statement on donor organ acceptability and management in pediatric heart transplantation

The number of potential pediatric heart transplant recipients continues to exceed the number of donors, and consequently the waitlist mortality remains significant. Despite this, around 40% of all donated organs are not used and are discarded. This document (62 authors from 53 institutions in 17 countries) evaluates factors responsible for discarding donor hearts and makes recommendations regarding donor heart acceptance. The aim of this statement is to ensure that no usable donor heart is discarded, waitlist mortality is reduced, and post-transplant survival is not adversely impacted.

Paediatric heart transplantation: an update

Heart transplantation is a standard treatment for selected paediatric patients with end-stage heart disease. With improvement in surgical techniques, organ procurement and preservation strategies, immunosuppressive drugs, and more sophisticated monitoring strategies, survival following transplantation has increased over time. However, rejection, infection, renal failure, post-transplant lymphoproliferative disease and post-transplant cardiac allograft vasculopathy still preclude long-term survival. Therefore, continued multidisciplinary scientific efforts are needed for future gains. This review focuses on the current status, outcomes and ongoing challenges including patient selection, indications and contraindications, national and international survivals, post-transplant complications and quality of life.

Increasing donor sequence number is not associated with inferior outcomes in lung transplantation

BACKGROUND

Donor sequence number (DSN) represents the number of recipients to whom an organ has been offered. The impact of seeing numerous prior refusals may potentially influence the decision to accept an organ. We sought to determine if DSN was associated with inferior posttransplant outcomes.

METHODS

Using the United Network for Organ Sharing database, a retrospective analysis was performed on 22 361 patients who received a lung transplant between 2005 and 2017. Patients were grouped into low DSN (1-24, n = 16 860) and high DSN (>24, n = 5501) categories. Baseline characteristics and posttransplant outcomes were analyzed. An institutional subgroup was also analyzed to compare rates of primary graft dysfunction (PGD) posttransplant.

RESULTS

The DSN ranged from 1 to 1735 (median, 7; interquartile range, 2-24). A total of 18 507 recipients received an organ with at least one prior refusal. Recipients of donors with a higher DSN were older (58 vs 55 years; P < .01) but had lower lung allocation scores (43.5 vs 47.5; P < .01). On adjusted analysis, high DSN was not associated with increased mortality (hazard ratio, 0.99; 95% confidence interval, 0.94-1.04; P = .77). There was no difference in the incidence of graft failure (P = .37) or retransplantation (P = .24). Recipient subgroups who received donors with an increasing DSN >50 and >75 also demonstrated no difference in mortality when compared with a low DSN (P = .86 and P = .97). There was no difference in PGD for patients with a low vs a high DSN at any time posttransplant.

CONCLUSIONS

DSN is not associated with increased mortality in patients undergoing lung transplantation and should not negatively influence the decision to accept a lung for transplant.

Pediatric heart transplantation in the current era

PURPOSE OF REVIEW

To provide an international perspective and current review of pediatric heart transplantation (PHTx).

RECENT FINDINGS

Waitlist survival and long-term outcomes in PHTx continue to improve. Strategies to maximize donor pool utilization include ABO incompatible listing for infants and expanded donor-to-recipient weight ranges. However, there is a high degree of practice variation internationally, from listing strategies and donor acceptance practices to chronic immunosuppression regimens, long-term graft surveillance, and consideration for retransplantation.

SUMMARY

Common indications for PHTx include end-stage congenital heart disease and cardiomyopathy. Current median graft survival among PHTx recipients ranges from 13 to 22 years. Common morbidities include infection, rejection, renal dysfunction, coronary allograft vasculopathy, and posttransplant lymphoproliferative disease. International registry data, collaborative initiatives to standardize management, and multicenter studies continue to improve knowledge and advancement of the field.

Variability in donor selection among pediatric heart transplant providers: Results from an international survey

There is considerable variability in donor acceptance practices among adult heart transplant providers; however, pediatric data are lacking. The aim of this study was to assess donor acceptance practices among pediatric heart transplant professionals. The authors generated a survey to investigate clinicians' donor acceptance practices. This survey was distributed to all members of the ISHLT Pediatric Council in April 2018. A total of 130 providers responded from 17 different countries. There was a wide range of acceptable criteria for potential donors. These included optimal donor-to-recipient weight ratio (lower limit: 50%-150%, upper limit: 120%-350%), maximum donor age (25-75 years), and minimum acceptable left ventricular EF (30%-60%). Non-US centers demonstrated less restrictive donor selection criteria and were willing to accept older donors (50 vs 35 years, P < 0.001), greater size discrepancy (upper limit weight ratio 250% vs 200%, P = 0.009), and donors with a lower EF (45% vs 50%, P < 0.001). Recipient factors were most influential in the decision to accept marginal donors including recipients requiring ECMO support, ventilator support, and highly sensitized patients with a negative XM. However, programmatic factors impacted the decision to decline marginal donors including recent programmatic mortalities and concerns for programmatic restrictions from regulatory bodies. There is significant variation in donor acceptance practices among pediatric heart transplant professionals. Standardization of donor acceptance practices through the development of a consensus statement may help to improve donor utilization and reduce waitlist mortality.

Pediatric marginal donor hearts: Trends in US national use, 2005-2014

Pediatric patients awaiting heart transplant face high mortality rates due to donor organ shortages, including non-use of marginal donor hearts. We examined national trends in pediatric marginal donor heart use over time. UNOS data were queried for heart donors <18 years from 2005 to 2014. The proportion of donor hearts considered marginal was determined using previously cited marginal characteristics: left ventricular ejection fraction (LVEF) <50%, use of ≥2 inotropes, cerebrovascular death, CDC high-risk status, and eGFR < 30 mL/min/1.73 m² . Disposition of donor hearts was determined and stratified by marginal donor status. Of 6778 pediatric hearts offered from 2005 to 2014, 2373 (35.0%) were considered marginal. Non-use of marginal donor hearts was significantly higher than that of donor hearts without any marginal characteristics (59.5% vs 20.3%, P < .001). In particular, LVEF < 50% and donor inotropes were associated with high rates of organ non-use among pediatric donors. Yet, non-use of marginal donor organs decreased from 67% to 48% from 2005 to 2014 (P < .001). Although the proportion of pediatric donor hearts used for pediatric patients has increased, more than half of donor hearts are declined for use in pediatric recipients due, in part, to perceived marginal status.

Outcome of pediatric heart transplantation in blood culture positive donors in the United States

Active donor infection at the time of organ procurement poses a potential infection risk and may increase post-transplant morbidity and mortality in recipients. Our hypothesis was that pediatric heart transplant recipients from blood culture positive donors (BCPD) would have increased morbidity and mortality compared to non-blood culture positive donors (NBCPD). A retrospective analysis of pediatric heart transplant recipients using the organ procurement and transplant network (OPTN) between 1987 and 2015 was conducted. Recipient as well as donor data were analyzed. Propensity score matching with 1:2 ratios was performed for recipient variables. Post-transplant morbidity and mortality were compared for recipients of BCPD and NBCPD. Among 9618 heart transplant recipients, 450 (4.7%) were from culture positive donors. Recipients of BCPD had longer duration of listing as Status 1; diagnosis of congenital heart disease or restrictive cardiomyopathy and required support (IV inotropes, Inhaled NO and LVAD) prior to transplant. Post-transplant survival between the 2 groups was not different. Propensity-matched recipients had similar length of stay; stroke rate; need for dialysis; pacemaker implantation and treated rejection episodes in the first year post-transplant. Careful acceptance of BCPD may have the potential to increase availability of donor hearts in the pediatric population.

Is there an optimal organ acceptance rate for pediatric heart transplantation: "A sweet spot"?

Despite a limited supply of donors, potential donor hearts are often declined for subjective concerns regarding organ quality. This analysis will investigate the relationship between donor heart AR and patient outcome at pediatric transplant centers. The UNOS database was used to identify all match runs for pediatric candidates (age < 18 years) from 2008 through March 2015 in which a heart offer was ultimately placed. Centers which received ≥10 offers/y were included (10 634 offers, 38 centers). Transplant centers were stratified based on their AR: low (<20%, n = 13), medium (20%-40%, n = 16), or high (>40%, n = 9). Low AR centers experienced worse negative WL outcome compared with medium (P = .022) and high (P = .004) AR centers. Low AR centers had similar post-transplant graft survival to medium (P = .311) or high (P = .393) AR centers; however, medium AR centers had better post-transplant graft survival than high AR centers (P = .037). E-F survival from listing regardless of transplant was worse for low AR centers compared with medium (P < .001) or high (P = .001) AR centers. Low AR centers experience worse WL outcomes without improvement in post-transplant outcomes. High AR centers experience higher post-transplant graft failure than medium AR centers. AR of 20%-40% appears to have optimal WL and post-transplant outcomes.

Pediatric Heart Donor Assessment Tool (PH-DAT): A novel donor risk scoring system to predict 1-year mortality in pediatric heart transplantation

BACKGROUND

In this study we sought to quantify hazards associated with various donor factors into a cumulative risk scoring system (the Pediatric Heart Donor Assessment Tool, or PH-DAT) to predict 1-year mortality after pediatric heart transplantation (PHT).

METHODS

PHT data with complete donor information (5,732) were randomly divided into a derivation cohort and a validation cohort (3:1). From the derivation cohort, donor-specific variables associated with 1-year mortality (exploratory p-value < 0.2) were incorporated into a multivariate logistic regression model. Scores were assigned to independent predictors (p < 0.05) based on relative odds ratios (ORs).

RESULTS

The final model had an acceptable predictive value (c-statistic = 0.62). The significant 5 variables (ischemic time, stroke as the cause of death, donor-to-recipient height ratio, donor left ventricular ejection fraction, glomerular filtration rate) were used for the scoring system. The validation cohort demonstrated a strong correlation between the observed and expected rates of 1-year mortality (r = 0.87). The risk of 1-year mortality increases by 11% (OR 1.11 [1.08 to 1.14]; p < 0.001) in the derivation cohort and 9% (OR 1.09 [1.04 to 1.14]; p = 0.001) in the validation cohort with an increase of 1-point in score. Mortality risk increased 5 times from the lowest to the highest donor score in this cohort. Based on this model, a donor score range of 10 to 28 predicted 1-year recipient mortality of 11% to 31%.

CONCLUSION

This novel pediatric-specific, donor risk scoring system appears capable of predicting post-transplant mortality. Although the PH-DAT may benefit organ allocation and assessment of recipient risk while controlling for donor risk, prospective validation of this model is warranted.

Donors' characteristics and impact on outcomes in pediatric heart transplant recipients

Organ availability and acceptability limit pediatric HTx. What characteristics define an unacceptable or high-risk pediatric donor remains unclear. The purpose of this study was to characterize a large cohort of pediatric donors and determine the donor risk factors, including cumulative risk, that affect recipient survival. Data from the PHTS, a prospective multicenter study, were used to examine the impact of donor factors on the outcomes of patients listed <18 yr of age who received a HTx between 1993 and 2009. Donor data were available for 3149 of 3156 HTx (99.8%). Donor cause of death, need for inotropes, or CPR did not affect survival outcomes (p = 0.05). Ischemic time also did not have an impact on overall recipient survival; however, longer ischemic times negatively impacted one-yr post-transplant survival (p < 0.0001). There was no impact of cumulative risk factors on survival (p = 0.8). Although used in a minority of cases, hormonal therapy in the donor positively impacted survival (p = 0.03). In multivariate analysis, the only donor factor associated with decreased survival was smaller donor BSA, the other factors being related to the recipient characteristics. When analyzed by recipient age, there were no donor-related factors that affected survival for those who received a transplant at <6 months of age. Longer ischemic time (p < 0.0001) and greater age difference between the recipient and donor (p = 0.0098) were donor-related factors impacting early-phase survival for recipients who received a graft at ≥10 yr of age. Factors perceived to define a marginal or high-risk pediatric heart donor including inotrope use, CPR and donor cause of death may have less impact on outcomes than previously thought. Longer ischemic times did impact one yr, but not overall survival, and this impact was much greater with older donors. Parameters for accepting a donor heart can potentially be expanded, especially in the infant age group, but strong consideration should always be given to the interaction between ischemic time and donor age.

Pediatric cardiac transplantation using hearts previously refused for quality: a single center experience

Pediatric donor hearts are regularly refused for donor quality with limited evidence as to which donor parameters are predictive of poor outcomes. We compare outcomes of recipients receiving hearts previously refused by other institutions for quality with the outcomes of recipients of primarily offered hearts. Data for recipients aged ≤18 and their donors were obtained. Specific UNOS refusal codes were used to place recipients into refusal and nonrefusal groups; demographics, morbidity and mortality were compared. Kaplan-Meier analysis with log-rank test was used to determine differences in graft survival. A multivariable Cox proportional hazards model was constructed to determine independent risk factors for postoperative mortality. From July 1, 2000 to April 30, 2011, 182 recipients were transplanted and included for analysis. One hundred thirty received a primarily offered heart; 52 received a refused heart. No difference in postoperative complications or graft survival between the two groups (p = 0.190) was found. Prior refusal was not an independent risk factor for recipient mortality. Analysis of this large pediatric cohort examining outcomes with quality-refused hearts shows that in-hospital morbidity and long-term mortality for recipients of quality-refused hearts are no different than recipients of primarily offered hearts, suggesting that donor hearts previously refused for quality are not necessarily unsuitable for transplant and often show excellent outcomes.

Impact of donor cardiopulmonary resuscitation on pediatric heart transplant outcome

Mortality is the highest of any solid organ in pediatric patients awaiting heart transplantation. Strategies to increase the donor pool are needed if survival to transplant is to improve. There can be reluctance to accept pediatric hearts for transplantation if the donor has received cardiopulmonary resuscitation (CPR). This study asked if donor CPR impacts the survival of pediatric heart transplant recipients. Analysis of the UNOS database was performed for all cardiac transplants performed in patients aged 0-18 yr, with donors classified as to whether they received CPR (CPR+) or not (CPR-). We compared overall survival and survival at 30 days, one yr, and five yr between groups. Within the CPR+ group, the impact of duration of CPR on survival was compared. The need for inotropic support and ejection fraction was compared between donor groups as a measure of organ function. Overall survival and survival at 30 days, one yr, and five yr did not differ in the CPR+ compared to the CPR- group. Within the CPR+ group, duration of CPR was unrelated to post-transplant survival. The need for inotropic support at procurement was similar, and ejection fraction did not differ between the CPR+ and CPR- groups. Donor CPR does not have a negative impact on pediatric heart transplant survival.

Association of graft ischemic time with survival after heart transplant among children in the United States

BACKGROUND

Previous studies have found no association between graft ischemic time (IT) and survival in pediatric heart transplant (HTx) recipients. However, previous studies were small or analyzed risk only at the extremes of IT, where observations are few. We sought to determine whether graft IT is independently associated with graft survival in a large cohort of children with no a priori assumptions about where the risk threshold may lie.

METHODS

All children aged <18 years in the U.S. undergoing primary HTx (1987 to 2008) were included. The primary end point was graft loss (death or retransplant) within 6 months. Multivariate analysis was performed to analyze the association between graft IT and graft loss within 6 months after transplant. A secondary end point of longer-term graft loss was assessed among recipients who survived the first 6 months after transplant.

RESULTS

Of 4,716 pediatric HTxs performed, the median IT was 3.5 hours (interquartile range, 2.7-4.3 hours). Adjusted analysis showed that children with an IT > 3.5 hours were at increased risk of graft loss within 6 months after transplant (hazard ratio, 1.3; 95% confidence interval, 1.1-1.5; p = 0.002). Among 6-month survivors, IT was not associated with longer-term graft loss.

CONCLUSIONS

IT beyond 3.5 hours is associated with a 30% increase in risk of graft loss within 6 months in pediatric HT recipients. Although the magnitude of risk associated with IT is small compared with the risk associated with recipient factors, these findings may be important during donor assessment for high-risk transplant candidates.

Heart transplantation for congenital heart disease in the first year of life

Successful infant heart transplantation has now been performed for over 25 years. Assessment of long term outcomes is now possible. We report clinical outcomes for322 patients who received their heart transplant during infancy. Actuarial graft survival for newborn recipients is 59% at 25 years. Survival has improved in the most recent era. Cardiac allograft vasculopathy is the most important late cause of death with an actuarial incidence at 25 years of 35%. Post-transplant lymphoma is estimated to occur in 20% of infant recipients by25 years. Chronic kidney disease grade 3 or worse is present in 31% of survivors. The epidemiology of infant heart transplantation has changed through the years as the results for staged repair improved and donor resources remained stagnant. Most centers now employ staged repair for hypoplastic left heart syndrome and similar extreme forms of congenital heart disease. Techniques for staged repair, including the hybrid procedure, are described. The lack of donors is described with particular note regarding decreased donors due to newer programs for appropriate infant sleep positioning and infant car seats. ABO incompatible donors are a newer resource for maximizing donor resources, as is donation after circulatory determination of death and techniques to properly utilize more donors by expanding the criteria for what is an acceptable donor. An immunological advantage for the youngest recipients has long been postulated, and evaluation of this phenomenon may provide clues to the development of accommodation and/or tolerance.