Lung Transplantation Research Articles

Impact of Intravenous Immunoglobulin Replacement Therapy on Hypogammaglobulinemia and Infection in Lung Transplant Recipients

Secondary hypogammaglobulinemia (HGG) from immunosuppression therapy in lung transplant recipients has been associated with increased mortality, morbidity and higher risk of infection. Intravenous immunoglobulin (IVIG) for the treatment of HGG post-lung transplant is not well studied with conflicting evidence regarding efficacy. This single-center, retrospective cohort study analyzed adult lung transplant recipients with HGG receiving ≥1 dose of IVIG 0.3-0.5 g/kg. Resolution of HGG (IgG > 600 mg/dL within 30 days of IVIG) was evaluated for optimal dose and duration of IVIG therapy. Incidence of infection, patient survival, rejection, and chronic lung allograft dysfunction-free survival at 1 year were compared between resolved and persistent HGG. Results demonstrated majority of patients 46/58 (79.3%) achieved HGG resolution. Severe HGG (IgG < 400 mg/dL) was significantly associated with persistent HGG (50.5% vs 15.2%, p = 0.02), with comparable cumulative IVIG dose and duration between both groups (p = 0.96 and p = 0.39, respectively). No other variables correlated with HGG resolution. Overall infection rates were similar between groups (69.6% vs 58.3%, p = 0.50), suggesting HGG resolution did not correlate with incidence of infection. Lastly, use of IVIG for the treatment of HGG appears to be safe with minimal incidence of thrombosis found within each group.

Is Night Surgery a Nightmare for Lung Transplantation?

Night work is frequently associated with sleep deprivation and is associated with greater surgical and medical complications. Lung transplantation (LT) is carried out both at night and during the day and involves many medical healthcare workers. The goal of the study was to compare morbidity and mortality between LT recipients according to LT operative time. We performed a retrospective, observational, single-center study. When the procedure started between 6AM and 6PM, the patient was allocated to the Daytime group. If the procedure started between 6PM and 6AM, the patient was allocated to the Nighttime group. Between January 2015 and December 2020, 253 patients were included. A total of 168 (66%) patients were classified into the Day group, and 85 (34%) patients were classified into the Night group. Lung Donors' general characteristics were similar between the groups. The 90-day and one-year mortality rates were similar between the groups (90-days: n = 13 (15%) vs. n = 26 (15%), p = 0.970; 1year: n = 18 (21%) vs. n = 42 (25%), p = 0.499). Daytime LT was associated with more one-year airway dehiscence (n = 36 (21%) vs. n = 6 (7.1%), p = 0.004). In conclusion, among patients who underwent LT, there was no significant association between operative time and survival.

A novel rat lung transplantation model using venoarterial extracorporeal membrane oxygenation support

ObjectivesExtracorporeal membrane oxygenation (ECMO) has become an important life support technique during lung transplantation. We aimed to develop a rat model for lung transplantation using venoarterial (VA) ECMO support. MethodsAdult male Sprague-Dawley rats weighing 400 to 450 g were used in this study. ECMO circuits were created by obtaining venous access from the femoral vein with subsequent extracorporeal oxygen exchange, which was then returned to the circulatory system through the left carotid artery (ie, VA-ECMO). Simultaneously, the donor lungs were retrieved and immersed in cold, low-potassium dextran lung preservation solution. Orthotopic left lung transplantation supported by VA-ECMO was performed. Thereafter, a respiratory failure rat model was constructed using ventilation with a hypoxic and hypercapnic gas mixture, consisting of 6% oxygen, 8% carbon dioxide, and 86% nitrogen, before lung transplantation. Similarly, left lung transplantation supported by VA-ECMO was performed in rats with respiratory failure. Arterial blood gas levels were measured at designated time points throughout the experiment. ResultsWe found that VA-ECMO provided sufficient oxygenation and carbon dioxide removal to allow for smooth left lung transplantation in healthy rats and those with respiratory failure. ConclusionsWe established a rat model for lung transplantation using VA-ECMO. Left lung transplantation using VA-ECMO support is also feasible and safe in rat models of respiratory failure. These models provide efficient and economical models for translational medicine for lung transplantation using ECMO. Moreover, it will be invaluable to evaluate the physiological and pathophysiological roles of ECMO during lung transplantation.

Inspiratory Muscle Training for Lung Transplant Candidates and Recipients.

Inspiratory muscle training is used in rehabilitation to exercise respiratory muscles in various conditions associated with limited ventilatory reserve. In this review, we investigated inspiratory muscle training in lung transplant candidates and recipients. We searched 5 primary databases from inception through April 2024. Two key word entries, "lung transplantation" and "inspiratory muscle training," were matched using the Boolean operator AND. No filters were applied for document type, age, sex, publication date, language, and subject. The searched databases returned 119 citations. Seven articles that considered 64 patients (47% female) were included in the final analysis, with 1 study involving a pediatric patient. Lung transplant recipients used a threshold trainer at 15% to 60% of maximal inspiratory pressure and mostly exercised twice daily for 10 to 15 minutes per session. Lung transplant candidates exercised at 30% to >50% of maximal inspiratory pressure twice daily, performing 30 to 60 inspirations or for 15 minutes. The highest inspiratory muscle strength was observed in a series of adult lung transplant recipients whose mean value improved by 31.8 ± 14.6 cmH2O versus baseline after treatment. To the same extent, the highest value of maximal inspiratory pressure was detected in a pediatric patient who scored 180 cmH2O after training. Overall, participants obtained improvements in lung function (forced expiratory volume in 1 second, forced vital capacity), functional performance, dyspnea intensity, and exercise tolerance. Inspiratory muscle training is easy to perform and can be done at home without specific supervision (in adults) before or after a lung transplant. Nevertheless, additional rigorous investigations should aim to replicate the positive effects reported in the present review.

Risk factors for mid- and long-term mortality in lung transplant recipients aged 70 years and older.

With increased lung transplantation in those aged 70 and older, limited literature addresses risk factors affecting their survival. Our study aims to identify independent factors impacting mid- and long-term mortality in this elderly population. This study analyzed lung transplant patients over 70 from May 2005 to December 2022 using United Network for Organ Sharing data. The 3- or 5-year cohort excluded multi-organ, secondary transplantation and loss to follow-up. Univariable Cox analysis was conducted to assess recipient, donor and transplant factors. Factors with a significance level of P < 0.2 were subsequently included in a multivariable Cox model to identify correlations with 3- and 5-year mortality in patients aged over 70. Multivariable analysis has identified key factors affecting 3- and 5-year mortality in elderly lung transplant patients over 70. Common notable factors include recipient total bilirubin, intensive care unit status at the time of transplantation, donor diabetes, Cytomegalovirus(CMV) mismatch and single lung transplantation. Additionally, Hispanic/Latino patients and ischaemia time of the transplant significantly impact the 3-year mortality, while recipient age, diabetes, nitric oxide use before transplantation and creatinine were identified as unique independent risk factors affecting the 5-year morality. The study identified several independent risk factors that impact the mid- and long-term survival of lung transplantation for individuals over 70 years. These findings can contribute to the optimization of lung transplant treatment strategies and perioperative management in elderly patients, thereby enhancing the survival rate of this age group.

Long-term air pollution exposure and the risk of primary graft dysfunction after lung transplantation

Background: Primary graft dysfunction (PGD) contributes substantially to both short and long-term mortality after lung transplantation but the mechanisms that lead to PGD are not well understood. Exposure to ambient air pollutants is associated with adverse events during waitlisting for lung transplantation, and chronic lung allograft dysfunction but its association with PGD has not been studied. We hypothesized that long-term exposure of the lung donor and recipient to high levels of ambient air pollutants would increase the risk of PGD in lung transplant recipients. Methods: Using data from 1428 lung transplant recipients and their donors enrolled in the Lung Transplant Outcomes Group (LTOG) observational cohort study, we evaluated the association between the development of PGD and zip-code based estimates of long-term exposure to six major air pollutants (ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, PM2.5 and PM10) in both the lung donor and the lung recipient. Exposure estimates used daily EPA air pollutant monitoring data and were based on the geographic centroid of the each subject’s residential zip code. Associations were tested in both univariable and multivariable models controlling for known PGD risk factors. Results: We did not find strong associations between air pollutant exposures in either the donor or the recipient and PGD. Conclusions: Exposure to ambient air pollutants, at the levels observed in this study, may not be sufficiently harmful to prime the donor lung or the recipient to develop PGD particularly when considering the robust associations with other established PGD risk factors.

Hospital-free days in the first year after lung transplantation and subsequent survival

RationaleComplications occurring during the first post-operative year after lung transplantation increase the risk of long-term mortality. These events often lead to prolonged and repeated hospitalizations. ObjectivesWe sought to assess the relationship between days outside the hospital or hospital-free days (HFD) during the first post-transplant year among 1-yr survivors and subsequent retransplant-free survival. MethodsIn a single-center study, we derived total inpatient days (initial transplant episode, readmission, and emergency room/observation) from the electronic medical record of lung transplant recipients who survived one year. The cohort was divided into HFD quartiles and Kaplan-Meir curves of subsequent transplant-free survival were compared with log-rank analysis. A Cox proportional hazards model was used to test the association of HFD with outcome and adjusted for selected variables. ResultsAmong 238 patients, 42 deaths and 2 retransplants occurred after a median of 3.6 yr post-transplant. The median HFD was 341 (IQR:324, 348). Estimated transplant-free survival at 3 and 5 yrs post-transplant in the lowest quartile of HFD (79% and 56%, respectively) was considerably worse compared with the first quartile (98% and 94%; P < 0.01). Fewer hospital-free days were associated with subsequent death or retransplant [HR: 0.90 (95% CI: 0.85, 0.94; P < 0.001) for each 10-day increase] and remained significant after adjusting for several potentially confounding variables. ConclusionsHFD during the first year after lung transplantation is a predictor of subsequent long-term outcome and may be a useful surrogate marker for clinical trials during the early post-operative period.

A cost-free approach to evaluating vertebral body bone density and height loss in lung transplant recipients using routine chest CT

BackgroundTo assess changes in bone density and vertebral body height of patients undergoing lung transplant surgery using computed tomography (CT). MethodsThis institutional review board (IRB) approved retrospective observational study enrolled patients with a history of lung transplant who had at least two chest CT scans. Vertebral body bone density (superior, middle, and inferior sections) and height (anterior, middle, and posterior sections) were measured at T1-T12 at baseline and follow up CT scans. Changes in the mean bone density, mean vertebral height, vertebral compression ratio (VBCR), percentage of anterior height compression (PAHC), and percentage of middle height compression (PMHC) were calculated and analyzed. ResultsA total of 93 participants with mean age of 58 ± 12.3 years were enrolled. The most common underlying disease that led to lung transplants was interstitial lung diseases (57 %). The inter-scan interval was 34.06 ± 24.8 months. There were significant changes (p-value < 0.05) in bone density at all levels from T3 to T12, with the greatest decline at the T10 level from 163.06 HU to 141.84 HU (p-value < 0.05). The average VBCR decreased from 96.91 to 96.15 (p-value < 0.05). ConclusionRoutine chest CT scans demonstrate a gradual decrease in vertebral body bone density over time in lung transplant recipients, along with evident anatomic changes such as vertebral body bone compression. This study shows that utilizing routine chest CT for lung transplant recipients can be regarded as a cost-free tool for assessing the vertebral body bone changes in these patients and potentially aiding in the prevention of complications related to osteoporosis.

Pretransplant NT-proBNP levels are associated with mortality among lung transplant recipients.

The prognostic significance of pretransplant N-terminal pro-brain (B)-type natriuretic peptide (NT-proBNP) level has not been investigated in lung transplant recipients. The electronic files of 173 patients with chronic lung disease who underwent lung transplantation in 2018-2022 at a tertiary medical center were retrospectively reviewed. Right heart catheterization (RHC) and NT-proBNP determination were performed preoperatively in all cases. Pretransplant demographic, clinical, and laboratory data were compared between posttransplant survivors and nonsurvivors. Correlations of NT-proBNP values with lung function and RHC parameters and all-cause mortality were analyzed. NT-proBNP level correlated positively with mean pulmonary artery pressure (R = 0.51, p < 0.001) and pulmonary vascular resistance (PVR) (R = 0.45, p = 0.0013), and negatively with diffusing lung capacity for carbon monoxide (R = -0.25, p = 0.0017), cardiac index (R = -0.26, p = 0.001), and cardiac output (R = -0.23, p = 0.004). Over a median follow-up time of 23.22 months, 74 patients died. On univariate analysis, mortality was significantly associated with higher log-NT-proBNP (hazard ratio [HR] = 0.54, 95% confidence interval [CI] 1.15-2.05, p = 0.016), older age at transplant registration (HR = 1.033, 95% CI 1.009-1.058, p = 0.0068), higher PVR (HR 1.15, 95% CI 1.07-1.23, p = 0.015), and lower cardiac output (HR = 0.62, 95% CI 0.42-0.92, p = 0.045). On multivariate analysis adjusted for age, sex, and body mass index, mortality significance was maintained only for higher log-NT-proBNP (HR = 1.54, 95% CI 1.12-2.11, p = 0.007). Among lung transplant recipients, pretransplant NT-proBNP levels correlated well with RHC parameters and were strongly associated with posttransplantation mortality. Assessment of NT-proBNP may improve risk stratification of lung transplant candidates.

Pseudomonas aeruginosa infection correlates with high MFI donor-specific antibody development following lung transplantation with consequential graft loss and shortened CLAD-free survival

BackgroundDonor-specific antibodies (DSAs) are common following lung transplantation (LuTx), yet their role in graft damage is inconclusive. Mean fluorescent intensity (MFI) is the main read-out of DSA diagnostics; however its value is often disregarded when analyzing unwanted post-transplant outcomes such as graft loss or chronic lung allograft dysfunction (CLAD). Here we aim to evaluate an MFI stratification method in these outcomes.MethodsA cohort of 87 LuTx recipients has been analyzed, in which a cutoff of 8000 MFI has been determined for high MFI based on clinically relevant data. Accordingly, recipients were divided into DSA-negative, DSA-low and DSA-high subgroups. Both graft survival and CLAD-free survival were evaluated. Among factors that may contribute to DSA development we analyzed Pseudomonas aeruginosa (P. aeruginosa) infection in bronchoalveolar lavage (BAL) specimens.ResultsHigh MFI DSAs contributed to clinical antibody-mediated rejection (AMR) and were associated with significantly worse graft (HR: 5.77, p < 0.0001) and CLAD-free survival (HR: 6.47, p = 0.019) compared to low or negative MFI DSA levels. Analysis of BAL specimens revealed a strong correlation between DSA status, P. aeruginosa infection and BAL neutrophilia. DSA-high status and clinical AMR were both independent prognosticators for decreased graft and CLAD-free survival in our multivariate Cox-regression models, whereas BAL neutrophilia was associated with worse graft survival.ConclusionsP. aeruginosa infection rates are elevated in recipients with a strong DSA response. Our results indicate that the simultaneous interpretation of MFI values and BAL neutrophilia is a feasible approach for risk evaluation and may help clinicians when to initiate DSA desensitization therapy, as early intervention could improve prognosis.

Effect of Remote Ischemic Conditioning on Organ Transplantation: A Meta-Analysis of Randomized Controlled Trials

BackgroundRemote ischemic conditioning (RIC) has shown great advantages in protecting organs from ischemia-reperfusion loss and applied research on RIC continues to increase. We performed a systematic review and meta-analysis to comprehensively investigate the value of RIC for different organ transplantation. MethodsWe searched PubMed, EMBASE, and the Cochrane Library from inception to November 1, 2023, for randomized controlled trials investigating whether RIC has an advantage in organ transplantation (including heart, lung, liver, and kidney) compared with controls. The primary outcomes varied according to the transplanted organ, including liver transplantation (graft loss, early allograft dysfunction, acute kidney injury, days in hospital, and mortality); kidney transplantation (delayed graft function, acute rejection (AR), graft loss, 50% decrease in serum creatinine, glomerular filtration rate, days in hospital, and mortality); heart and lung transplantation (AR, mortality). Two investigators independently selected suitable trials, assessed trial quality, and extracted the data. ResultsA total of 11 randomized controlled trials were included in this study, including six kidney transplants, three liver transplants, and one heart and lung transplant each, with 561 RIC cases and 564 controls, and a total of 1125 patients. The results showed that RIC did not reduce mortality in transplant patients compared with controls (liver transplant: RR0.9, 95% confidence interval [0.31-2.66]; kidney transplant: RR 0.76, 95% confidence interval [0.17-3.33]), graft failure rate (liver transplantation: RR 0.3, 95% confidence interval [0.07, 1.19]; kidney transplantation: RR 0.89, 95% confidence interval [0.35, 2.27]), length of hospital stay (liver transplantation: standard mean difference [SMD] 0.14, 95% confidence interval [−0.15, 0.42]; kidney transplantation: SMD −0.1, 95% confidence interval [−0.3, 0.11]). In addition, RIC did not improve early liver function after liver transplantation (RR 0.97, 95% confidence interval [0.55,1.7]), acute kidney injury after liver transplantation (RR 1.17 95% confidence interval [0.9, 1.54]), delayed functional recovery after renal transplantation (RR 0.84, 95% confidence interval [0.62, 1.15]), AR rate (RR 1.04, 95% confidence interval [0.72, 1.49]), 50% serum creatinine decline rate (RR 1.1, 95% confidence interval [0.88, 1.37]), glomerular filtration rate 3 months after surgery (SMD 0.13, 95% confidence interval [−0.05, 0.31]) and postoperative 12 months glomerular filtration rate (SMD 0.13, 95% confidence interval [−0.06, 0.31]). ConclusionRemote ischemic modulation does not improve clinical outcomes in patients undergoing organ transplantation (heart, lung, liver, and kidney).

Recurrent treatment of refractory acute cellular rejection with alemtuzumab after lung transplantation

We present an exceptional case of a lung transplant recipient successfully treated by multiple courses of alemtuzumab for refractory acute cellular rejection.The patient experienced multiple episodes of acute cellular rejection following the transplantation procedure. Alemtuzumab was initiated as third-line rejection treatment and was repeated six times. Each treatment course resulted in complete recovery of the pulmonary function and depletion of T- and B-lymphocytes and NK cells. The onset of rejection was consistently preceded by the recovery of NK cells, while T- and B-lymphocytes remained depleted. This suggests a rejection process mediated by NK cells.This case contributes to recent research findings suggesting that NK cells play a significant role in acute cellular rejection in lung transplant recipients and stresses the importance to further investigate the role of NK cells in rejection. Furthermore, it demonstrates that acute cellular rejection following lung transplantation can be repeatedly managed by treatment with alemtuzumab. Data availability statementThe authors confirm that the data supporting the findings of this study are available within the article.

Systematic Reporting of Eosinophils in Transbronchial Biopsies After Lung Transplantation Defines a Distinct Inflammatory Response

Background. Descriptions of eosinophils in transbronchial biopsy (TBBx) pathology reports after lung transplantation (LTx) are associated with poor long-term outcomes. The absence of routine reporting and standardization precludes accurate assessment of this histologic predictor. A systematic reporting scheme for the presence of TBBx eosinophils after LTx was implemented. This report aims to assess this scheme by describing the presence, pattern, and gradation of TBBx eosinophils and clinical associations. Methods. A prospective cross-sectional study of all TBBx reports was performed including all patients presenting for a surveillance or diagnostic TBBx between January 2020 and June 2023. Each TBBx was systematically reported in a blinded manner. Mixed-effects logistic regression was performed to measure the association between concurrent clinical and histologic features, and the presence of TBBx eosinophils. Results. A total of 410 TBBx reports from 201 patients were systematically reported. In 43.8% recipients, any TBBx eosinophils were detected and in 17.1% recipients, higher-grade eosinophils (≥3 per high power field) were present. Adjusted analysis showed that retransplantation, A- and B-grade cellular rejection, positive bronchoalveolar lavage (BAL) bacterial microbiology, and elevated blood eosinophil count were independently associated with the presence of any TBBx eosinophils. Diagnostic “for-cause” procedures were independently associated with higher quantities of TBBx eosinophils. Conclusions. Systematic reporting demonstrates that TBBx eosinophils are a distinct inflammatory response associated with rejection, infection, and peripheral eosinophilia. Although these findings require multicenter external validation, standardized reporting for TBBx eosinophils may assist in identifying recipients at risk of poor outcomes and provides a platform for mechanistic research into their role after lung transplantation.

Donor-derived Mycoplasma and Ureaplasma infections in lung transplant recipients: A prospective study of donor and recipient respiratory tract screening and recipient outcomes

Mycoplasma hominis and Ureaplasma species are urogenital mollicutes that can cause serious donor-derived infections in lung transplant recipients. Best practices for mollicute screening remain unknown. We conducted a single-center prospective study analyzing lung transplants performed from October 5, 2020, to September 25, 2021, whereby donor and recipient bronchoalveolar lavage (BAL) samples obtained at time of transplant underwent mollicute screening via culture and polymerase chain reaction (PCR). Of 115 total lung transplants performed, 99 (86%) donors underwent combined mollicute BAL culture and PCR testing. The study cohort included these 99 donors and their matched recipients. In total, 18 (18%) of 99 donors screened positive via culture or PCR. Among recipients, 92 (93%) of 99 had perioperative BAL screening performed, and only 3 (3%) had positive results. After transplant, 9 (9%) recipients developed mollicute infection. Sensitivity of donor screening in predicting recipient mollicute infection was 67% (6/9) via culture and 56% (5/9) via PCR. Positive predictive value for donor culture was 75% (6/8), compared with 33% (5/15) for PCR. Donor screening via culture predicted all serious recipient mollicute infections and had better positive predictive value than PCR; however, neither screening test predicted all mollicute infections. Independent of screening results, clinicians should remain suspicious for posttransplant mollicute infection.

Induction immunosuppression strategies and outcomes post-lung transplant: A single center experience

PurposeCurrently 80% of lung transplant centers use induction immunosuppression. However, there is a lack of standardization of induction protocols within and across lung transplant centers. This study explores the association of two different induction immunosuppression strategies used at our center [single dose rabbit antithymocyte globulin (rATG) vs. alemtuzumab] compared to no induction with immunologic and clinical outcomes after lung transplantation. MethodsA total of 174 consecutive lung transplant recipients (LTR) between 2016 and 2019 were included in the analysis. Twenty nine LTR (16.7%) received no induction, 22 LTR (12.6%) received alemtuzumab, 123 LTR (70.6%) received a single dose of rATG; 1.5 mg/kg within 24 h of transplant for induction. All LTR had a negative flow cytometry crossmatch on the day of the transplant. All LTR were assessed for de novo HLA donor-specific antibodies (DSA) development and clinical outcomes, including the risk of acute cellular rejection (ACR), antibody-mediated rejection (AMR), chronic lung allograft dysfunction (CLAD), and overall survival post-transplant. ResultsThe median lung allocation score (LAS) was significantly higher in LTR that did not receive Induction immunosuppression (76; range = 35.3–94.3) compared to induction with rATG (41.6; range = 31.6–91) and alemtuzumab (51; range = 33.1–88.2) (p < 0.001). De novo HLA DSA were detected in 50/174 (28.7%) LTR within 12 months post-transplant. They were detected in 13/29 (44.8%) LTR without induction immunosuppression compared to 28/123 (22.8%) and 9/22 (40.9%) LTR with rATG and alemtuzumab induction, respectively (p = 0.02). The percent freedom from ACR rates between LTR who received alemtuzumab induction was significantly higher compared to LTR who received rATG or no induction at 1 (p = 0.02), 2 (p = 0.01) and 3 (p = 0.05) years post-transplant. In addition, the overall 1-year survival rates were significantly higher in LTR who received rATG or alemtuzumab induction compared to LTR without induction immunosuppression (p = 0.02). ConclusionInduction immunosuppression strategies utilizing rATG or Alemtuzumab have unique and contrasting benefits in LTR. Combination of alemtuzumab induction and a lower dose of maintenance immunosuppression may reduce the incidence of ACR in LTR. Single-dose rATG or alemtuzumab induction immunosuppression may also improve the 1 year overall LTR survival compared to no induction.

Increased Donor Organ Size and Age is Associated with Reduced Survival in Female Lung Transplant Recipients

BackgroundOrgan selection in lung transplantation (LTx) is still controversial. We here analyze the impact of mismatches in size, age, and gender on early and long-term outcome after LTx. MethodsRetrospective analysis of donor and recipient characteristics of patients who underwent double lung transplantation (DLTx) between 03/2003 and 12/2021. Statistical analysis was performed using SPSS and GraphPad software. Results203 patients were included (94 female and 109 male). In the whole cohort, oversizing donor organs 10%-20% compared to the recipients’ predicted total lung capacity (pTLC) led to a decreased incidence of severe primary graft dysfunction (PGD2/3) (15% vs. 41%, p=0.03), and further oversizing >20% was associated with reduced long-term survival (HR 2.33, p=0.011). Analysing donor and recipient age, we found that increased donor age correlated with reduced long-term survival (p=0.013). In this cohort, female recipients received older organs (median 57 vs. 46 years, p=0.0003) and had a higher incidence of >20% oversizing (13% vs. 4%, p=0.019) of donor lungs which resulted in a significantly reduced long-term survival (p=0.02) compared to male recipients. Median LAS scores were similar in both groups. ConclusionMismatch of donor age and size can be important for organ function and survival in lung transplant recipients. Particularly female recipients seem to have a higher risk for unfavourable long-term outcome when transplanting organs of increased size and age. Multicentre studies are warranted to further address this question.

Diaphragmatic palsy following lung transplantation.

Diaphragmatic palsy after lung transplantation has been reported infrequently. Given the role of the diaphragm in respiration, the palsy may play a significant role in the post-surgical recovery as well as morbidity and mortality. This review summarises the current literature to better understand diaphragmatic palsy in the post lung-transplant setting among adults. A thorough literature search was conducted through multiple databases and 91 publications were identified that fit the research question. The review aimed to report the burden of this problem, explore different modalities of diagnosis reported, the effect of various clinical factors and treatment modalities, as well as their effects on outcomes. Additionally, it aimed to highlight the variability, limitations of reported data, and the absence of a standardised approach. This review emphasises the crucial need for more dedicated research to better address this clinical challenge.

What Happens to Frailty in the First Year After Lung Transplantation?

Frailty is prevalent in lung transplant (LTx) candidates, but the impact and subsequent frailty trajectory is unclear. This study aimed to investigate frailty over the first year after LTx. Post-LTx recipients completed a thrice weekly 12-week directly supervised exercise rehabilitation program. Edmonton Frail Scale (EFS) was used to assess frailty. Primary outcome was 6-Minute Walk Distance (6MWD) measured at pre-LTx, prerehabilitation, postrehabilitation, and 1 year post-LTx. 106 of 139 recruited participants underwent LTx: mean age 58 years, 48% male, 52% with chronic obstructive pulmonary disease. Mean (± SD) frailty scores pre-LTx and 1 year post-LTx were 5.54 ± 2.4 and 3.28 ±1.5. Mean 6MWD improved significantly for all: prerehabilitation 326 m (SD 116), versus postrehabilitation 523 m (SD 101) (p < 0.001) versus 1 year 512 m (SD 120) (p < 0.001). There were significant differences between an EFS > 7 (frail) and EFS ≤ 7 (not frail) for 6MWD, grip strength (GS), anxiety, and depression. Postrehabilitation, there were no significant differences in 6MWD, GS, anxiety, or depression while comparing EFS > 7versus ≤ 7. At 1 year, there was a significant difference in depression but not 6MWD, GS, or anxiety between those EFS ≤ 7and > 7 (p = 0.017). Participants in a structured post-LTx rehabilitation program improved in functional exercise capacity (6MWD), GS, depression, and anxiety. For frail participants exercise capacity, depression, anxiety, and GS were well managed in rehabilitation with no significant differences between those who were not frail. Pre-LTx frailty may be reversible post-LTx and should not be an absolute contraindication to LTx.

A multicenter analysis of lung transplantation outcomes comparing donation after circulatory death and donation after brain death

BackgroundDonor organ shortage is a barrier to lung transplantation. Donation after circulatory death (DCD) may offer a solution, although it is underutilized. The objective of this study was to compare survival and other postoperative outcomes between DCD and donation after brain death (DBD). MethodsWe performed a multi-center analysis of Multi-Institutional Extracorporeal Life Support (ECLS) Registry data from 11 lung transplant centers in the United States and Europe. Demographics and clinical parameters were compared using Chi-square test and Fisher's exact test. Survival was assessed by Kaplan-Meier curves and compared by log-rank test with propensity score matching. ResultsOf 1585 patients included in the study, 135 (8.5%) received DCD lungs and 1450 (91.5%) received DBD lungs. DCD recipients had higher rates of obstructive lung disease (p=0.042), longer total ischemic time (p<0.0001), and higher rates of primary graft dysfunction (PGD) at t0h (p<0.0001) and t24h (p=0.0005). PGD at t48h and t72h was not significantly different between DCD and DBD recipients. 90-day survival was lower among DCD recipients (91.2%) compared to DBD recipients (97.4%, p=0.038). Survival was higher without ECLS (p=0.014), whereas EVLP (p=0.47) did not affect survival. ConclusionOverall, our data showed excellent 90-day survival for DCD and DBD recipients, although DCD recipients had relatively lower survival. EVLP was not associated with survival, which may guide future strategies to optimize DCD utilization.

Differential effects of donor factors on post-transplant survival in lung transplantation

BackgroundPredicting post-transplant (PT) survival in lung allocation remains an elusive goal. We analyzed the impact of donor factors on PT survival and how these relationships vary among transplant recipients. MethodsWe studied primary bilateral lung transplant recipients (n=7,609) from the US Scientific Registry of Transplant Recipients (19 February 2015 - 1 February 2020). Main and interaction effects were evaluated and adjusted across candidate age, sex, and diagnosis. Models predicting PT survival were compared to the PT composite allocation score model (PT-CAS): 1. Cox regression donor multivariable model (COX), 2. COX + PT-CAS, 3. random forest model (RF), 4. RF + PT-CAS. Model discrimination and calibration measures were compared. ResultsInteractions between donor and recipient factors emerged by – age: lower survival for DCD organs for recipients aged 55-69 years, donor smoking for recipients aged 30-54 and 70+, Hispanic donor for recipients < 30, non-Hispanic Black (NHB) donor for recipients aged 30+; sex: CMV mismatch for males; diagnosis: higher donor recipient weight ratio for diagnosis Group C (e.g.CF), donor diabetes for diagnosis Group D (e.g. IPF). COX and RF models performed similarly to PT-CAS; however, the combined COX PT-CAS model had improved discrimination (1y AUC PT-CAS 0.609 vs. 1y AUC COX + PT-CAS 0.626) and improved calibration across a broader range of predicted risk. ConclusionThe influence of donor factors on recipient post-transplant survival differed by age, sex, and diagnosis. The addition of donor factors to existing models predicting posttransplant survival led to only modest improvement in prediction accuracy. Future efforts may focus on optimizing matching strategies to improve donor utilization.