Implications of declining donor offers with increased risk of disease transmission on waiting list survival in lung transplantation

Increased-risk versus standard-risk donation in lung transplantation: A United Network of Organ Sharing analysis

OBJECTIVES

Donors with characteristics that increase risk of hepatitis B virus, hepatitis C virus, and HIV transmission are deemed increased-risk donors (IRDs) per Public Health Service guidelines. Compared with organs from standard-risk donors (SRDs), IRD organs are more frequently declined. We sought to investigate the outcomes of IRD lung transplant recipients following the 2013 guideline change.

METHODS

We retrospectively identified lung transplant recipients using the United Network of Organ Sharing registry (February 2014 to March 2020). Patients were divided into 2 cohorts, based on Centers for Disease Control and Prevention risk status of the donor: SRD or IRD. Demographics and clinical parameters were compared across groups. Survival was compared using Kaplan-Meier curves and log-rank tests. Cox proportional hazard model was performed to identify variables associated with survival outcome.

RESULTS

We identified 13,205 lung transplant recipients, 9963 who received allografts from SRDs and 3242 who received allografts from IRDs. In both groups, most donors were White, male, and <30 years old. IRDs demonstrated greater rates of heavy alcohol, cigarette, and cocaine use. SRDs had greater rates of cancer, hypertension, previous myocardial infarction, and diabetes. Survival analysis demonstrated no significant difference in 90-day, 1-year, 3-year, or 5-year survival outcome between SRD and IRD recipients (P = .34, P = .67, P = .40, P = .52, respectively). Cox regression demonstrated that double-lung transplants were associated with 13% decreased mortality risk compared with single-lung (P = .0009).

CONCLUSIONS

IRD and SRD recipients demonstrated equivalent survival outcomes. Our study suggests that IRDs offer a safe approach to expand the donor pool and increase availability of lungs for transplantation.

Donor blood cultures and outcomes after lung transplantation: a single-center report

BACKGROUND

Transplanting lungs from donors with positive blood cultures has not been shown to adversely affect survival. There is limited evidence for potential effects on other outcomes, such as hospital course, graft function, and transmission of infection.

METHODS

This retrospective cohort study included adult patients who underwent lung-only transplantation for the first time between March 2010 and December 2022. Outcomes of patients whose donors had positive blood cultures within 72 h of transplant were compared to patients whose donors had negative blood cultures.

RESULTS

Twenty-five (10.8%) of 232 donors had positive blood cultures, including a single, unexpected case with candidemia. The most commonly isolated bacteria were Enterobacter cloacae (n = 5), Klebsiella pneumoniae (n = 5), Acinetobacter baumannii (n = 3), Pseudomonas aeruginosa (n = 3), and Staphylococcus aureus (n = 3). Eleven donors had identical bacteria in their respiratory cultures. All patients who were transplanted from donors with positive blood cultures survived beyond 90 days. Positive donor blood cultures were not associated with longer hospital stay, in-hospital complications, acute cellular rejection, or the achievement of 80% predicted forced expiratory volume in the first second. Probable transmission of donor bacteremia occurred in only two cases (both with S. aureus). These two donors had positive respiratory cultures with the same organism.

CONCLUSION

The study did not find an increased risk of adverse events when transplanting lungs from donors with positive blood cultures. Allograft cultures may be more predictive of the risk of transmitting infections.

Beyond donation to organ utilization in the USA

PURPOSE OF REVIEW

The deceased donor organ pool has broadened beyond young, otherwise healthy head trauma victims. But an abundance of donated organs only benefits patients if they are accepted, expeditiously transported and actually transplanted. This review focuses on postdonation challenges and opportunities to increase the number of transplants through improved organ utilization.

RECENT FINDINGS

We build upon recently proposed changes in terminology for measuring organ utilization. Among organs recovered for transplant, the nonuse rate (NUR REC ) has risen above 25% for kidneys and pancreata. Among donors, the nonuse rate (NUR DON ) has risen to 40% for livers and exceeds 70% for thoracic organs. Programme-level variation in offer acceptance rates vastly exceeds variation in the traditional, 1-year survival benchmark. Key opportunities to boost utilization include donation after circulatory death and hepatitis C virus (HCV)+ organs; acute kidney injury and suboptimal biopsy kidneys; older and steatotic livers.

SUMMARY

Underutilization of less-than-ideal, yet transplant-worthy organs remains an obstacle to maximizing the impact of the U.S. transplant system. The increased risk of inferior posttransplant outcomes must always be weighed against the risks of remaining on the waitlist. Advanced perfusion technologies; tuning allocation systems for placement efficiency; and data-driven clinical decision support have the potential to increase utilization of medically complex organs.

Outcomes following heart or bilateral-lung transplantation from donors who died of drug toxicity in British Columbia, Canada

INTRODUCTION

The illicit drug toxicity (overdose) crisis has worsened across Canada; between 2016 and 2021, more than 28,000 individuals have died of drug toxicity. Organ donation from persons who experience drug toxicity death (DTD) has increased in recent years. This study examines whether survival after heart or bilateral-lung transplantation differed by donor cause of death.

METHODS

We studied transplant recipients in British Columbia who received heart (N = 110) or bilateral-lung (N = 223) transplantation from deceased donors aged 12-70 years between 2013 and 2019. Transplant recipient survival was compared by donor cause of death from drug toxicity or other. Five-year Kaplan-Meier estimates of survival and 3-year inverse probability treatment weighted Cox proportional hazards models were conducted.

RESULTS

DTD donors made up 36% (40/110) of heart and 24% (54/223) of bilateral-lung transplantations. DTD donors were more likely to be young, white, and male. Unadjusted 5-year recipient survival was similar by donor cause of death (heart: 87% for DTD and 86% for non-DTD, p = .75; bilateral- lung: 80% for DTD and 76% for non-DTD, p = .65). Adjusted risk of mortality at 3-years post-transplant was similar between recipients of DTD and non-DTD donor heart (hazard ratio [HR]: .94, 95% confidence interval (CI): .22-4.07, p = .938) and bilateral-lung (HR: 1.06, 95% CI: .41-2.70, p = .908).

CONCLUSION

Recipient survival after heart or bilateral-lung transplantation from DTD donors and non-DTD donors was similar. Donation from DTD donors is safe and should be considered more broadly to increase organ donation.

Increased Risk Donors Utilized in Lung Transplantation At A Single Center

Introduction: In 2013, the US Public Health Service (PHS) updated guidelines for high-risk donor organs and renamed the category increased risk. Project Aims: We compared survival of patients who received increased risk or non-increased risk donor lungs to determine if PHS designated increased risk donor lungs were an underutilized resource. Design: This retrospective cohort analysis compared survival and utilization rates of increased-risk and non-increased-risk donor lungs used in lung transplantation at a single institution over a period of 8 years (Feb-2012 through Mar-2020). Survival was assessed using Kaplan-Meier analysis and compared by log-rank test. Cox proportional hazards modeling was used to analyze impact on survival of variables significantly associated with risk status, including recipient ethnicity, lung allocation score (LAS), donor age, year of transplant procedure, and lung transplant type. Results: Of 744 lung transplant recipients from February 2012 through March 2020, there were 192 (26%) recipients of increased risk designated lungs. In 2012 and 2013, 6% and 0% respectively of the lungs transplanted were increased risk labeled. After the PHS guidelines were nationally implemented in February 2014, the proportion of increased risk lung transplants rose to 7% (2014), 21% (2015), 27% (2016), 35% (2017), 28% (2018), 27% (2019), and 40% (January-March 2020). Kaplan-Meier analysis and log-rank test comparison showed no significant difference in survival between patients that received increased risk versus non-increased risk labeled lungs (P = 0.47). Conclusions: Our analysis suggested the 2013 PHS increased risk designation threatened underutilization of viable donor lungs, providing further support for the 2020 PHS changes.

Lung Transplant Type & Donor Age in Idiopathic Pulmonary Fibrosis: A Single Center Study

BACKGROUD

Idiopathic pulmonary fibrosis (IPF) accounts for a marked proportion of diagnoses on the US lung transplant (LTx) list. The effects of single (SLT) versus double LTx (DLT) and lung donor age on survival in IPF remain unclear and were investigated in this study.

METHODS

We retrospectively assessed survival of LTx recipients with IPF at a single institution from February 2012-March 2020. Survival was analyzed and compared between LTx types (SLT and DLT), donor ages, and the combined groups (LTx type & donor age) using Kaplan-Meier survival analysis and compared by log-rank test. P-values less than 0.05 were considered significant.

RESULTS

Of 744 LTx patients at our institution, 307 (41.3%) were diagnosed with IPF, of which 208 (67.8%) were SLT, and 97 (31.6%) were DLT (2 excluded patients underwent heart-lung transplantation). There was no significant difference in survival due to LTx type (P = 0.41) or for patients with donor age <50 or ≥50 y (P = 0.46). Once stratified by both LTx type and donor age, analysis showed no significant difference in survival between the four groups (P = 0.69).

CONCLUSIONS

With ethical consideration for organ allocation, as the average age of the US population increases, donor lungs aged ≥50 are an increasingly useful resource in LTx. Our findings suggest donor age and LTx type do not significantly affect survival. Therefore, SLT, and donor lungs aged ≥50 ought to be more readily considered as non-inferior options for LTx in patients with IPF.

Decline of increased risk donor offers increases waitlist mortality in paediatric heart transplantation

BACKGROUND

Increased risk donors in paediatric heart transplantation have characteristics that may increase the risk of infectious disease transmission despite negative serologic testing. However, the risk of disease transmission is low, and refusing an IRD offer may increase waitlist mortality. We sought to determine the risks of declining an initial IRD organ offer.

METHODS AND RESULTS

We performed a retrospective analysis of candidates waitlisted for isolated PHT using 20072017 United Network of Organ Sharing datasets. Match runs identified candidates receiving IRD offers. Competing risks analysis was used to determine mortality risk for those that declined an initial IRD offer with stratified Cox regression to estimate the survival benefit associated with accepting initial IRD offers. Overall, 238/1067 (22.3%) initial IRD offers were accepted. Candidates accepting an IRD offer were younger (7.2 versus 9.8 years, p < 0.001), more often female (50 versus 41%, p = 0.021), more often listed status 1A (75.6 versus 61.9%, p < 0.001), and less likely to require mechanical bridge to PHT (16% versus 23%, p = 0.036). At 1- and 5-year follow-up, cumulative mortality was significantly lower for candidates who accepted compared to those that declined (6% versus 13% 1-year mortality and 15% versus 25% 5-year mortality, p = 0.0033). Decline of an IRD offer was associated with an adjusted hazard ratio for mortality of 1.87 (95% CI 1.24, 2.81, p < 0.003).

CONCLUSIONS

IRD organ acceptance is associated with a substantial survival benefit. Increasing acceptance of IRD organs may provide a targetable opportunity to decrease waitlist mortality in PHT.

Aggressive pursuit and utilization of non-ideal donor lungs does not compromise post-lung transplant survival

BACKGROUND

Organ procurement organizations (OPOs) vary in willingness to pursue and utilize non-ideal donor lungs; implications of these practices for lung transplant (LTx) recipients remain unclear. We examined associations between OPO-level behavior toward non-ideal donors and post-LTx outcomes.

METHODS

Adult lung donors and corresponding adult first-time LTx recipients in the 2008-2019 UNOS registry were included. Non-ideal donors had any of age > 50, smoking history ≥20 pack-years, PaO₂ /FiO₂ ratio ≤350, donation after circulatory death, or increased risk status. OPOs were classified as least, moderately, or most aggressive based on non-ideal donor pursuit, consent attainment, lung recovery, and transplantation. Post-transplant outcomes were compared among aggressiveness strata.

RESULTS

Of 22,795 recipients, 6229 (27.3%), 8256 (36.2%), and 8310 (36.5%) received lungs from least, moderately, and most aggressive OPOs, respectively. Moderately aggressive OPOs had the highest recipient rates of pre-discharge acute rejection, grade 3 primary graft dysfunction, postoperative extracorporeal membrane oxygenation, and longest lengths of stay. After adjustment, moderately and most aggressive OPOs had similar risks of recipient mortality as least aggressive OPOs.

CONCLUSIONS

The most and least aggressive OPOs achieve similar patient survival and short-term post-LTx outcomes. Aggressive pursuit and utilization of non-ideal donor lungs by less aggressive OPOs would likely expand the donor pool, without compromising recipient outcomes.

Outcomes of Lung Transplantation from HCV Viremic Donors

BACKGROUND

Direct-acting antiviral (DAA) therapy for hepatitis C (HCV) has encouraged lung transplantation with HCV+ donors. Early trials have been promising(1, 2), however nationwide data has not been previously examined.

METHODS

The United Network for Organ Sharing registry was queried for adult patients receiving lung transplants from 2016-2019. We excluded multiorgan transplants, incomplete data, and loss to follow-up. Nucleic acid testing (NAT) determined HCV status. Propensity matching was performed for comparison of outcomes.

RESULTS

HCV NAT+ lungs were transplanted in 189 patients, compared to 9511 recipients of NAT- lungs. HCV NAT+ donors were younger (mean: 33 vs 35 years, p=0.017) with higher rates of PaO2/FiO2 >300 (83.6% vs 76.5%, p=0.029). Recipients of NAT+ lungs had lower lung allocation scores (mean: 39.3 vs 42.4; p=0.009). Distance traveled was significantly further for HCV viremic donor lungs (mean: 416 vs 206 miles, p<0.001). Kaplan Meier survival analysis demonstrated no difference in survival (p=0.56). There were no differences in airway dehiscence (p-0.629), acute rejection (p>0.999) or reintubation (p=0.304). At mean follow-up of 395 days, 63 recipients of NAT+ lungs (40.0%) seroconverted, 14 with viremia. 1-year mortality rates among seroconverted patients was 6.0% and did not differ significantly from 14.0% in non-seroconverted patients or 13.2% in recipients of HCV-negative lungs.

CONCLUSIONS

Short-term outcomes of lung transplantation from HCV viremic donors are promising, with no difference in early complications or survival. The effects of seroconversion and long-term outcomes including chronic rejection and infection need to be further explored.

Pushing the Envelope for Donor Lungs

The shortage of organ donors remains the major limiting factor in lung transplant, with the number of patients on the waiting list largely exceeding the number of available organ donors. Another issue is the low utilization rate seen in some types of donors. Therefore, novel strategies are continuously being explored to increase the donor pool. Advanced age, smoking history, positive serologies, and size mismatch are common criteria that decrease the rate of use when it comes to organ utilization. Questioning these limitations is one of the purposes of this review. Challenging these limitations by adapting novel donor management strategies could help to increase the rate of suitable lungs for transplantation while still maintaining good outcomes. A second goal is to present the latest advances in organ donation after controlled and uncontrolled cardiac death, and also on how to improve these lungs on ex vivo platforms for assessment and future specific therapies. Finally, pushing the limit of the donor envelope also means reviewing some of the recent improvements made in lung preservation itself, as well as upcoming experimental research fields. In summary, donor lung optimization refers to a global care strategy to increase the total numbers of available allografts, and preserve or improve organ quality without paying the price of early-, mid-, or long-term negative outcomes after transplantation.

A three-tier system for evaluation of organ procurement organizations' willingness to pursue and utilize nonideal donor lungs

Lungs from "nonideal," but acceptable donors are underutilized; however, organ procurement organization (OPO) metrics do not reflect the extent to which OPO-specific practices contribute to these trends. We developed a comprehensive system to evaluate nonideal lung donor avoidance, or risk aversion among OPOs. Adult donors in the UNOS registry who donated ≥1 organ for transplantation between 2007 and 2018 were included. Nonideal donors had any of age>50, smoking history ≥20 pack-years, PaO₂ /FiO₂ ratio ≤350, donation after circulatory death, or increased risk status. OPO-level risk aversion in donor pursuit, consent attainment, lung recovery, and transplantation was assessed. Among 83916 donors, 70372 (83.9%) were nonideal. Unadjusted OPO-level rates of nonideal donor pursuit ranged from 81 to 100%. In a three-tier system of overall risk aversion, tier 3 OPOs (least risk-averse) had the highest rates of nonideal donor pursuit, consent attainment, lung recovery, and transplantation. Tier 1 OPOs (most risk-averse) had the lowest rates of donor pursuit, consent attainment, and lung recovery, but higher rates of transplantation compared to tier 2 OPOs (moderately risk-averse). Risk aversion varies among OPOs and across the donation process. OPO evaluations should reflect early donation process stages to best differentiate over- and underperforming OPOs and encourage optimal OPO-specific performance.

Extracorporeal membrane oxygenation as a bridge vs. non-bridging for lung transplantation: A systematic review and meta-analysis

Whether extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (BTT) can achieve a similar survival to non-BTT remains controversial. We conducted this meta-analysis to compare the outcomes between ECMO BTT and non-BTT to facilitate better clinical decision-making. Seven databases were searched for eligible studies comparing ECMO BTT and non-BTT. The primary endpoints included survival, intraoperative indicators, postoperative hospitalization indicators, and postoperative complications. Nineteen studies (involving 7061 participants) were included in the final analysis. The outcomes of overall survival, overall survival rate, graft survival rate, in-hospital mortality, postoperative hospital days, postoperative intensive care unit days, postoperative ventilation time, blood transfusion volume, and postoperative complications were all better in the non-BTT group. The total mortality in ECMO bridging was 23.03%, in which the top five causes of death were right heart failure (8.03%), multiple organ failure (7.03%), bleeding (not cranial) (4.67%), cranial bleeding (3.15%), and sepsis (2.90%). In summary, Non-BTT is associated with better survival and fewer complications compared to BTT. When ECMO may be the only option, the patient and medical team need to realize the increased risk of ECMO by complications and survival.

Assessing Solid Organ Donors and Monitoring Transplant Recipients for Human Immunodeficiency Virus, Hepatitis B Virus, and Hepatitis C Virus Infection - U.S. Public Health Service Guideline, 2020

The recommendations in this report supersede the U.S Public Health Service (PHS) guideline recommendations for reducing transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) through organ transplantation (Seem DL, Lee I, Umscheid CA, Kuehnert MJ. PHS guideline for reducing human immunodeficiency virus, hepatitis B virus, and hepatitis C virus transmission through organ transplantation. Public Health Rep 2013;128:247-343), hereafter referred to as the 2013 PHS guideline. PHS evaluated and revised the 2013 PHS guideline because of several advances in solid organ transplantation, including universal implementation of nucleic acid testing of solid organ donors for HIV, HBV, and HCV; improved understanding of risk factors for undetected organ donor infection with these viruses; and the availability of highly effective treatments for infection with these viruses. PHS solicited feedback from its relevant agencies, subject-matter experts, additional stakeholders, and the public to develop revised guideline recommendations for identification of risk factors for these infections among solid organ donors, implementation of laboratory screening of solid organ donors, and monitoring of solid organ transplant recipients. Recommendations that have changed since the 2013 PHS guideline include updated criteria for identifying donors at risk for undetected donor HIV, HBV, or HCV infection; the removal of any specific term to characterize donors with HIV, HBV, or HCV infection risk factors; universal organ donor HIV, HBV, and HCV nucleic acid testing; and universal posttransplant monitoring of transplant recipients for HIV, HBV, and HCV infections. The recommendations are to be used by organ procurement organization and transplant programs and are intended to apply only to solid organ donors and recipients and not to donors or recipients of other medical products of human origin (e.g., blood products, tissues, corneas, and breast milk). The recommendations pertain to transplantation of solid organs procured from donors without laboratory evidence of HIV, HBV, or HCV infection. Additional considerations when transplanting solid organs procured from donors with laboratory evidence of HCV infection are included but are not required to be incorporated into Organ Procurement and Transplantation Network policy. Transplant centers that transplant organs from HCV-positive donors should develop protocols for obtaining informed consent, testing and treating recipients for HCV, ensuring reimbursement, and reporting new infections to public health authorities.

Variability in donor organ offer acceptance and lung transplantation survival

BACKGROUND

Lung transplantation offers a survival benefit for patients with end-stage lung disease. When suitable donors are identified, centers must accept or decline the offer for a matched candidate on their waitlist. The degree to which variability in per-center offer acceptance practices impacts candidate survival is not established. The purpose of this study was to determine the degree of variability in per-center rates of lung transplantation offer acceptance and to ascertain the associated contribution to observed differences in per-center waitlist mortality.

METHODS

We performed a retrospective cohort study of candidates waitlisted for lung transplantation in the US using registry data. Logistic regression was fit to assess the relationship of offer acceptance with donor, candidate, and geographic factors. Listing center was evaluated as a fixed effect to determine the adjusted per-center acceptance rate. Competing risks analysis employing the Fine-Gray model was undertaken to establish the relationship between adjusted per-center acceptance and waitlist mortality.

RESULTS

Of 15,847 unique organ offers, 4,735 (29.9%) were accepted for first-ranked candidates. After adjustment for important covariates, transplant centers varied markedly in acceptance rate (9%-67%). Higher cumulative incidence of 1-year waitlist mortality was associated with lower acceptance rate. For every 10% increase in adjusted center acceptance rate, the risk of waitlist mortality decreased by 36.3% (sub-distribution hazard ratio 0.637; 95% confidence interval 0.592-0.685).

CONCLUSIONS

Variability in center-level behavior represents a modifiable risk factor for waitlist mortality in lung transplantation. Further intervention is needed to standardize center-level offer acceptance practices and minimize waitlist mortality.

The impact of change in definition of increased-risk donors on survival after lung transplant

OBJECTIVES

To study the impact of using the US Public Health Service broadened definition of "increased-risk" donors (2013) in comparison with "high-risk" (1994) and standard infectious risk donors on lung transplant recipient outcomes.

METHODS

Patients who underwent lung transplant between January 1, 2006, and May 31, 2017, in the Scientific Registry of Transplant Recipients were divided into 2 cohorts, recipients of: (1) high-risk donors: January 1, 2006, to October 1, 2013, and (2) increased-risk donors: January 1, 2014, to May 31, 2017, and compared with matched recipients who received standard-risk donors. Risks for acute rejection, patient, and graft survival using propensity score matched cohorts, multivariable logistic, and Cox models were examined.

RESULTS

In total, 18,490 lung transplant recipients were analyzed with 36% transplanted during the increased-risk donor definition period. The proportion of donors classified as nonstandard infectious risk increased with the definition change (8% high-risk donors vs 22% increased-risk donors; P < .001). In both cohorts, male patients with a lower forced expiratory volume in 1 second and greater creatinine were more likely to receive an organ from increased risk donors. Neither graft nor patient survival differed by donor type in either period. Acute treated rejection within 1 year did not differ by period for recipients of increased risk donors (odds ratio, 0.87; P = .23) or recipients of high-risk donors (odds ratio, 1.2; P = .27).

CONCLUSIONS

The 2013 broadened definition of donor risk increased the proportion of nonstandard infectious risk donors. Recipients of increased/high-risk donors had similar graft and patient survival compared with standard-risk donors.