"Age" in lung transplantation: factors related to outcomes and other considerations

Characteristics of human donor lungs utilized for research

Introduction

Many fundamental discoveries have occurred using primary cells from deceased donor lungs. These cells respond differently to injury when there are underlying co-morbidities like diabetes mellitus, hypertension, aging and exposures to cigarette smoke, cocaine and chronic alcohol use. However, the prevalence of these characteristics in donor lungs utilized for research is currently unknown.

Methods

This retrospective cohort study procured data of lung transplant donors from Mid-America Transplant from January 2017 until July 2023. The donors were characterized based on lung utilization into three groups - lungs used for research, lungs used for transplant, and lungs not recovered from donors for either research or transplantation.

Results

The mean age of donors whose lungs were utilized for research was 41±18 years. 25% of them were expanded criteria donors (ECD) while 10% of the donors in the transplant cohort were ECD. 14% of the donors whose lungs were utilized for research had history of diabetes compared to 8% of donors whose lungs were transplanted. A quarter of the research donor population had positive history of cigarette use within the preceding 20 years. At least 40% of donors had a positive history of non-intravenous drug use, of whom a majority had a history of continued non-intravenous drug use.

Conclusions

No strict selection criteria or protocols exist when human donor lungs are obtained for ex-vivo research. There is a high prevalence of diabetes mellitus, history of smoking and non-intravenous drug use along with older age distribution in donors whose lungs used are for research.

A single-centre analysis of lung transplantation outcomes in recipients aged 70 or older

OBJECTIVES

As life expectancies continue to increase, a greater proportion of older patients will require lung transplants (LTs). However, there are no well-defined age cutoffs for which LT can be performed safely. At our high-volume LT centre, we explored outcomes for LT recipients ≥70 vs <70 years old.

METHODS

This is a retrospective single-centre study of survival after LT among older recipients. Data were stratified by recipient age (≥70 vs <70 years old) and procedure type (single versus double LT). Demographics and clinical variables were compared using Chi-square test and 2 sample t-test. Survival was assessed by Kaplan-Meier curves and compared by log-rank test with propensity score matching.

RESULTS

A total of 988 LTs were performed at our centre over 10 years, including 289 LTs in patients ≥70 years old and 699 LTs in patients <70 years old. The recipient groups differed significantly by race (P < 0.0001), sex (P = 0.003) and disease aetiology (P < 0.0001). Older patients were less likely to receive a double LT compared to younger patients (P < 0.0001) and had lower rates of intraoperative cardiopulmonary bypass (P = 0.019) and shorter length of stay (P = 0.001). Both groups had overall high 1-year survival (85.8% vs 89.1%, respectively). Survival did not differ between groups after propensity matching (P = 0.15).

CONCLUSIONS

Our data showed high survival for older and younger LT recipients. There were no statistically significant differences observed in survival between the groups after propensity matching, however, a trend in favour of younger patients was observed.

Kidney Transplantation as a Treatment Option of Chronic Renal Failure Among Lung Transplant Recipients: A Single-Center Experience

INTRODUCTION

Chronic renal failure is one of the most common complications after solid organ transplantation. It is associated with multiple pre-, peri-, and post-transplant factors. In some patients, the available methods of conservative treatment are insufficient and kidney transplantation (KTx) is necessary. The aim of this study was to present our experience in the treatment of renal failure by KTx after lung transplantation (LTx).

METHODS

Our study is a single-center retrospective review of clinical data of all 7 LTx recipients who underwent a KTx between the years 2013 and 2021. Patients' clinical condition, pulmonary function, renal function, and survival were examined.

RESULTS

There were a total of 7 patients with medium age 36 years (±15). In 3 patients, the period of time from LTx to KTx was less than 3 years, and in 4 of them less than 13 years. Dialysis therapy was required in 4 patients. One patient had pre-LTx renal disease, while 6 patients had renal dysfunction related to post-transplant factors, including the use of calcineurin inhibitors.

CONCLUSIONS

Renal protection is a very important aspect among LTx recipients; therefore, physicians must show a holistic and individual approach to patients and minimize exposure to nephrotoxic medication. Patients at high risk of developing chronic renal failure should be identified and, if required, renal replacement therapy should be initiated, including KTx.

Impact of recipient age on mortality among Cytomegalovirus (CMV)-seronegative lung transplant recipients with CMV-seropositive donors

BACKGROUND

Cytomegalovirus (CMV)-seronegative lung transplant recipients (LTRs) with seropositive donors (CMV D+/R-) have the highest mortality of all CMV serostatuses. Due to immunosenescence and other factors, we hypothesized CMV D+/R- status might disproportionately impact older LTRs. Thus, we investigated whether recipient age modified the relationship between donor CMV status and mortality among CMV-seronegative LTRs.

METHODS

Adult, CMV-seronegative first-time lung-only recipients were identified through the Scientific Registry of Transplant Recipients between May 2005 and December 2019. We used adjusted multivariable Cox regression to assess the relationship of donor CMV status and death. Interaction between recipient age and donor CMV was assessed via likelihood ratio testing of nested Cox models and by the relative excess risk due to interaction (RERI) and attributable proportion (AP) of joint effects.

RESULTS

We identified 11,136 CMV-seronegative LTRs. The median age was 59 years; 65.2% were male, with leading transplant indication of idiopathic pulmonary fibrosis (35.6%); and 60.8% were CMV D+/R-. In multivariable modeling, CMV D+/R- status was associated with 27% increased hazard of death (adjusted hazard ratio: 1.27, 95% confidence interval: 1.21-1.34) compared to CMV D-/R-. Recipient age ≥60 years significantly modified the relationship between donor CMV-seropositive status and mortality on the additive scale, including RERI 0.24 and AP 11.4% (p = 0.001), that is, the interaction increased hazard of death by 0.24 and explained 11.4% of mortality in older CMV D+ recipients.

CONCLUSIONS

Among CMV-seronegative LTRs, donor CMV-seropositive status confers higher risk of posttransplant mortality, which is amplified in older recipients. Future studies should define optimal strategies for CMV prevention and management in older D+/R- LTRs.

Outcomes after lung transplantation from selected donors older than 70 years in a single centre: time to close the debate?

OBJECTIVES

The aim of this study was to compare the outcomes of lung transplantations using grafts from donors aged over 70 years against those performed using younger donors.

METHODS

This retrospective single-centre analysis includes lung transplants conducted at our institution from January 2014 to June 2022. Lung recipients were classified into 2 groups based on donor age (group A <70 years; group B ≥70 years). Variables regarding demographics, peri and postoperative outcomes and survival were included. The statistical analysis approach included univariable analysis, propensity score matching to address imbalances in donor variables (smoking status), recipient characteristics (sex, age, diagnosis and lung allocation score) and calendar period and survival analysis.

RESULTS

A total of 353 lung transplants were performed in this period, 47 (13.3%) using grafts from donors aged over 70 years. Donors in group B were more frequently women (70.2% vs 51.6%, P = 0.017), with less smoking history (22% vs 43%, P = 0.002) and longer mechanical ventilation time (3 vs 2 days, P = 0.025). Recipients in group B had a higher lung allocation score (37.5 vs 35, P = 0.035). Postoperative variables were comparable between both groups, except for pulmonary function tests. Group B demonstrated lower forced expiratory volume 1 s levels (2070 vs 2580 ml, P = 0.001). The propensity score matching showed a lower chance of chronic lung allograft dysfunction by 12% for group B. One-, three- and five-year survival was equal between the groups.

CONCLUSIONS

The use of selected expanded-criteria donors aged over 70 years did not result in increased postoperative morbidity, early mortality or survival in this study.

Monitoring regulatory T cells as a prognostic marker in lung transplantation

Lung transplantation is the major surgical procedure, which restores normal lung functioning and provides years of life for patients suffering from major lung diseases. Lung transplant recipients are at high risk of primary graft dysfunction, and chronic lung allograft dysfunction (CLAD) in the form of bronchiolitis obliterative syndrome (BOS). Regulatory T cell (Treg) suppresses effector cells and clinical studies have demonstrated that Treg levels are altered in transplanted lung during BOS progression as compared to normal lung. Here, we discuss levels of Tregs/FOXP3 gene expression as a crucial prognostic biomarker of lung functions during CLAD progression in clinical lung transplant recipients. The review will also discuss Treg mediated immune tolerance, tissue repair, and therapeutic strategies for achieving in-vivo Treg expansion, which will be a potential therapeutic option to reduce inflammation-mediated graft injuries, taper the toxic side effects of ongoing immunosuppressants, and improve lung transplant survival rates.

Two Staged Single Lung Transplants in the Current Era: A United Network for Organ Sharing Study

BACKGROUND

We hypothesized that outcomes after 2 staged, contralateral single lung transplantation procedures (SSLTs) may be equivalent to those of double lung transplantation (DLT) by capitalizing on the known long-term survival advantages of DLT.

METHODS

Using the United Network for Organ Sharing data set (1987-2018), the largest national data set available, the outcomes of 278 SSLTs were retrospectively analyzed and compared with the outcomes of 21,121 standard DLTs.

RESULTS

During SSLT, the median interval between the 2 transplants was 960 days, and the indication for the second transplant was most often chronic lung allograft dysfunction (n = 148; 53.2%) or the same disease that necessitated the first transplant (n = 81; 29.1%). The patients who underwent SSLT were significantly older and had a higher baseline creatinine level than the patients who underwent DLT. Most posttransplantation short-term outcomes were equivalent between the second stage of SSLT and DLT, but renal insufficiency requiring hemodialysis was notably higher after SSLT. There were no differences in long-term survival. In multivariate analysis, baseline creatinine, O2 support at rest, ventilator support at the time of the second transplantation, and posttransplantation renal insufficiency requiring dialysis were independent predictors of 1-year mortality after SSLT.

CONCLUSIONS

Over a study period of 30 years, long-term survival after SSLT was comparable with survival after DLT. With further analysis of individual risk profiles, including the contributions of preoperative renal function and functional status, SSLT can be a valuable option for patients who would have undergone single lung transplantation to reap the long-term benefits of a second transplant.

Lung Transplantation Outcomes in Recipients Aged 70 Years or Older and the Impact of Center Volume

OBJECTIVE

To evaluate trends and outcomes of lung transplants (LTx) in recipients ≥ 70 years.

METHODS

We performed a retrospective analysis of the UNOS database identifying all patients undergoing LTx (May 2005-December 2022). Baseline characteristics and postoperative outcomes were compared by age (<70 years, ≥70 years) and center volume. Kaplan-Meier analyses were performed with pairwise comparisons between subgroups.

RESULTS

34,957 patients underwent LTx, of which 3236 (9.3%) were ≥70 years. The rate of LTx in recipients ≥ 70 has increased over time, particularly in low-volume centers (LVCs); consequently, high-volume centers (HVCs) and LVCs perform similar rates of LTx for recipients ≥ 70. Recipients ≥ 70 had higher rates of receiving from donor after circulatory death lungs and of extended donor criteria. Recipients ≥ 70 were more likely to die of cardiovascular diseases or malignancy, while recipients < 70 of chronic primary graft failure. Survival time was shorter for recipients ≥ 70 compared to recipients < 70 old (hazard ratio (HR): 1.36, 95% confidence interval (CI): 1.28-1.44, p < 0.001). HVCs were associated with a survival advantage in recipients < 70 (HR: 0.91, 95% CI: 0.88-0.94, p < 0.001); however, in recipients ≥ 70, survival was similar between HVCs and LVCs (HR: 1.11, 95% CI: 0.99-1.25, p < 0.08). HVCs were more likely to perform a bilateral LTx (BLT) for obstructive lung diseases compared to LVCs, but there was no difference in BLT and single LTx likelihood for restrictive lung diseases.

CONCLUSIONS

Careful consideration is needed for recipient ≥ 70 selection, donor assessment, and post-transplant care to improve outcomes. Further research should explore strategies that advance perioperative care in centers with low long-term survival for recipients ≥ 70.

Listing Dilemmas: Age, Frailty, Weight, Preexisting Cancers, and Systemic Diseases

Selection of lung transplant candidates is an evolving field that pushes the boundaries of what is considered the norm. Given the continually changing demographics of the typical lung transplant recipient as well as the growing list of risk factors that predispose patients to poor posttransplant outcomes, we explore the dilemmas in lung transplant candidate selections pertaining to older age, frailty, low and high body mass index, preexisting cancers, and systemic autoimmune rheumatic diseases.

International Pediatric Transplant Association (IPTA) position statement supporting prioritizing pediatric recipients for deceased donor organ allocation

A position statement of the International Pediatric Transplant Association endorsing prioritizing pediatric recipients for deceased donor organ allocation, examining the key ethical arguments that serve as the foundation for that position, and making specific policy recommendations to support prioritizing pediatric recipients for deceased donor organ allocation globally.

Body Function and Structure, Activity, and Participation Limitations of Lung Transplant Recipients Within the Scope of the International Classification of Functioning, Disability, and Health

OBJECTIVES

There is no study in the literature that specifically evaluates lung transplant recipients in the long-term under the framework of the International Classification of Functioning, Disability, and Health. The aim of this study was to evaluate the relationships between lung transplant recipient age, age at transplant, and comorbidity levels and the body structure and functions and the activity and participation levels of patients within the scope of the International Classification of Functioning, Disability, and Health.

MATERIALS AND METHODS

We evaluated 27 lung transplant recipients according to the International Classification of Functioning, Disability, and Health items in domain b (body functions), domain s (body structures), and domain d (activities and participation). For domain b, sleep functions, psychosocial status, respiratory functions, and upper and lower extremity exercise capacity were evaluated. Posture was evaluated for the s domain. Balance, arm functional capacity, health-related quality of life, and physical activity were evaluated for domain d.

RESULTS

As the age of lung transplant recipients and the age at transplant increase, their sleep quality and respiratory functions decreased, and postural impairment increased. There was a negative correlation between age at transplant and functional exercise capacity (P < .05). As the comorbidity level of the recipient increases, the upper and lower extremity exercise capacity, physical activity level, and quality of life declined. There was a moderately positive correlation between the level of comorbidity and balance disorder (P < .05).

CONCLUSIONS

We found the International Classification of Functioning, Disability, and Health framework to be useful for the evaluation and for planning pulmonary rehabilitation for lung transplant recipients; it can bring a new perspective to physiotherapists specialized in cardiopulmonary rehabilitation.

Lung transplantation and severe coronary artery disease: results from a single-centre experience

OBJECTIVES

The management of severe coronary artery disease at the time of lung transplantation remains a challenge. We analyzed the short- and long-term-outcomes of lung transplant recipients with severe coronary artery disease.

METHODS

Records of adult patients transplanted at our institution between April 2010 and February 2021 were retrospectively reviewed. Severe coronary artery disease was defined by coronary stenosis ≥70% (main stem ≥50%) at the coronary angiography performed before or at the time of listing. Patient characteristics, perioperative- and long-term-outcomes were compared between patients with and without severe coronary artery disease.

RESULTS

Among 896 lung-transplanted patients who had undergone a coronary angiography before transplantation, 77 (8.5%) showed severe coronary artery disease, the remaining 819 (91.5%) did not. Patients with severe coronary artery disease were older (p < 0.0001), more often male (p < 0.0001) and were transplanted more often for pulmonary fibrosis (p = 0.0007). The median (interquartile range) follow-up was 46 (20-76) months. At the Cox multivariable analysis severe coronary artery disease was not associated with mortality. Patients with pretransplant percutaneous transluminal coronary angioplasty and patients with coronary artery bypass graft surgery concomitant to transplantation had equivalent survival compared to patients without severe coronary artery disease (p = 0.513, p = 0.556).

CONCLUSIONS

Severe coronary artery disease was not associated with decreased survival after lung transplantation. Concomitant coronary artery bypass graft surgery and pretransplant percutaneous transluminal coronary angioplasty can be used for revascularization.

Sequence of refusals for donor quality, organ utilization, and survival after lung transplantation

BACKGROUND

Lung donor utilization rates remain low, with many organs refused for donor quality. However, some centers have successfully transplanted these organs despite multiple refusals for donor quality (RDQs) by other centers. We hypothesized that the number of refusals due to donor quality does not impact post-transplant outcomes.

METHODS

Lung transplants (LTxs) from 2006 to 2015, identified using the United Network for Organ Sharing (UNOS) database, were matched against the potential transplant recipient (PTR) data set by donor identification. Transplants were categorized into 2 groups: low RDQ (0 to 3 RDQs) and high RDQ (>3 RDQs). Post-transplant survival and predictors for high RDQ were observed using Kaplan‒Meier and logistic regression analyses, respectively.

RESULTS

Of 10,126 adult (>18 years) LTxs, 77% had at least 1 RDQ, with a median of 4 RDQs. Post-transplant 1-year survival was similar for both the low and high RDQ groups (p = 0.49). Furthermore, groups of recipients who received donors with an increasing number of RDQs (>3, >6, or >10) also had similar post-transplant 1-year survival (p = 0.77). Treatment for rejection within 1 year and intubation at 72 hours post-transplant were higher in the high RDQ group (p < 0.01). An inverse relationship was identified between the number of RDQs and likelihood of utilization. After 10 RDQs, the likelihood of utilization varied significantly by donor characteristics.

CONCLUSIONS

Lung transplant survival is not associated with number of refusals due to donor quality. When determining whether an organ is suitable for transplant, the number of refusals due to donor quality should not influence one's decision, especially in this era of limited donor supply.

Immunosuppression for Lung Transplantation: Current and Future

Purpose of the review

The number of lung transplantations performed worldwide continues to increase. There is a growing need in these patients for more effective immunosuppressive medications with less toxicity.

Recent findings

This review article summarizes the recent studies and developments in lung transplant immunosuppression. Novel immunosuppressive medications and strategies used in other solid organ transplantations are being trialed in lung transplantation. This includes the use of co-stimulation blockers like belatacept and mTOR inhibitors like everolimus. Calcineurin sparing regimens have been described in an attempt to minimize nephrotoxicity. Assays to measure the bioactivity of immunosuppressive medications to determine the global immune competence, such as Immuknow assay and Gamma interferon response are gaining traction.

Summary

Immunosuppression in lung transplant is evolving with the development of newer drugs and promising strategies to optimize immunosuppression. Further studies with multicenter randomized trials are required to increase the strength of the evidence.

Perioperative factors associated with 1-year mortality after lung transplantation: a single-center experience in Korea

Background

Most studies about the risk factors of 1-year mortality after lung transplantation were performed on non-Asians. This study aimed to evaluate the perioperative factors related to the 1-year mortality after lung transplantation in Korea.

Methods

Sixty-eight consecutive patients who underwent lung transplantation without preoperative extracorporeal membrane oxygenation treatment at 1 tertiary hospital in South Korea between October 24, 2012, and October 16, 2015, were analyzed retrospectively.

Results

Forty-four patients (64.7%) lived for >1 year after lung transplantation. The median age of all patients was 55 years (range, 16-75 years), and men accounted for 57.4%. The major cause of lung transplantation was idiopathic pulmonary fibrosis (48.5%); the other causes were interstitial lung disease related to connective tissue disease (17.6%) and bronchiolitis obliterans after stem cell transplantation (14.7%). In univariate analysis, higher median age (52 vs. 61.5 years, P<0.001), male sex (45.5% vs. 79.2%, P=0.007), lower preoperative albumin level (<3 g/dL) (22.7% vs. 45.8%, P=0.049), need for renal replacement therapy (RRT) after surgery (4.5% vs. 37.5%, P=0.001), and postoperative delta neutrophil index (DNI) >5.5 higher than the preoperative DNI (22.7% vs. 70.8%, P<0.001) were significantly related to 1-year mortality. After adjustments, old age, postoperative increased DNI, and need for RRT after transplantation were the independent perioperative risk factors for 1-year mortality after lung transplantation.

Conclusions

Recipients with advanced age should be carefully selected, and patients who need RRT or with increased DNI after transplantation should be managed accordingly.