Epidemiology, risk factors, and outcomes of lung retransplantation: An analysis of the International Society for Heart and Lung Transplantation Thoracic Transplant Registry

[Indications for Lung Transplantation - Updates Since the Last ISHLT Recommendations]

Lung transplantation has evolved continuously since its first successful procedures in the 1960 s. The current guidelines from the International Society for Heart and Lung Transplantation (ISHLT) emphasise increasingly individualised patient assessment, which, in addition to the underlying lung disease, considers factors such as comorbidities, frailty, age, and social aspects. The expanded indications for lung transplantation are reflected in the refined risk assessment, which particularly includes patients with advanced chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and pulmonary arterial hypertension (PAH). Furthermore, the criteria for patients with a history of cancer and those with infections such as HIV or multidrug-resistant organisms have been made more flexible, leading to a more inclusive transplantation policy. A key focus is on early transplant counselling, allowing patients the opportunity for transplantation before they develop acute exacerbations. These updated guidelines aim to maximise both the survival rates and the quality of life of transplant patients, through differentiated and risk-adjusted decision-making.

Active smokers should not be denied access to lung transplantation

International society consensus statements, health insurance policies, and individual transplant programs almost uniformly consider active cigarette smoking an absolute contraindication to lung transplant. This denial is typically supported on utilitarian grounds-active smokers are prohibitively high-risk because of anticipated poor long-term survival-or nonutilitarian grounds related to fairness in resource allocation to smokers. However, the available literature on lung transplant recipients who resume smoking posttransplant does not demonstrate increased mortality. At the same time, other conditions that carry significant short and long-term posttransplant mortality, such as retransplantation, are considered relative contraindications. I also suggest that arguments regarding responsibility and fairness do not support the exclusion of active smokers. Patients with lung disease from other ongoing inhalational exposures, including avian antigens in chronic hypersensitivity pneumonitis, are not automatically excluded from transplant. I argue that active smokers are stigmatized, leading smoking to be treated as an inappropriate proxy for nonadherence. I suggest that the lung transplant community should treat active smoking as a relative, not absolute, contraindication to transplant. Transplant program policy should be revised to improve access for active smokers, particularly those who are in urgent need of a transplant and who will not survive long enough to demonstrate smoking abstinence.

Outcomes of single-lung retransplantation after double-lung transplantation

OBJECTIVE

To compare outcomes of single-lung retransplantation (SLRTx) and double-lung retransplantation (DLRTx) after an initial double-lung transplantation.

METHODS

The Organ Procurement and Transplantation Network/United Network for Organ Sharing database between May 2005 and December 2022 was retrospectively analyzed. Multiorgan transplantations, repeated retransplantations, and lung retransplantations when the status of the initial transplantation was unknown were excluded.

RESULTS

A total of 891 patients were included in the analysis, included 698 (78.3%) with DLRTx and 193 (21.7%) with SLRTx. The mean lung allocation score was higher in the DLRTx group (59.6 ± 20.7 vs 55.1 ± 19.3; P = .007). The use of extracorporeal membrane oxygenation (ECMO) bridge to lung transplantation was similar in the 2 groups (P = .125), as was waitlist time (P = .610). The need for mechanical ventilation (54.6% vs 35.8%; P = .005) and ECMO (17.9% vs 9.0%; P = .069) at 72 hours post-transplantation was greater in the DLRTx group. However, median post-transplantation hospital stay (21.5 [interquartile range (IQR), 12-35] days versus 20 [IQR, 12-35] days; P = .119) and in-hospital mortality (10.9% [n = 76/698] vs 12.4% [n = 24/193]; P = .547) were comparable in the 2 groups. Long-term survival was significantly better in the DLRTx group (P < .001, log-rank test). In the propensity score-weighted multivariable model, the DLRTx group had 28% lower risk of mortality at any point during follow-up compared to the SLRTx group (hazard ratio, 0.72; 95% confidence interval, 0.57-0.91; P = .006).

CONCLUSIONS

The less invasiveness of single-lung transplantation in the retransplantation setting has minimal short-term benefit and is associated with significantly worse long-term survival. Double-lung retransplantation should remain the standard for lung retransplantation after initial double-lung transplantation.

A New Routine Immunity Score (RIS2020) to Predict Severe Infection in Solid-Organ Transplant Recipients

BACKGROUND Infection is a cause of morbidity and mortality in solid-organ transplantation (SOT). We evaluated a new score that is applied during the first month after transplantation. The score comprises biomarkers of innate and acquired immunity to predict infections in SOT. MATERIAL AND METHODS Prospectively collected blood samples from 377 heart, liver, or kidney recipients were analyzed at 2 centers in Madrid (Spain) and Lima (Peru). Biomarkers were tested before transplantation and at days 7 and 30 after transplantation. During the first 6 months after transplantation, 183 (48.5%) patients developed severe infections (bacterial infections and/or CMV disease). Risk for severe infection was assessed using logistic regression analysis. We designed a score, the routine immunity score (RIS2020), which is based on the sum of the hazard ratios (HRs) of each biomarker. RESULTS The risk factors for severe infection were as follows: Moderate IgG hypogammaglobulinemia (IgG <600 mg/dL at days 7 or 30, HR 2.07, 95% CI 1.37-3.12, p=0.0005, 2 points), CD4 <400 cells/uL at day 30 (HR 1.76, 95% CI 1.03-3.04, p=0.039, 2 points), C3 <80 mg/dL at day 30 (HR 2.18, 95%CI 1.16-4.06, p=0.014, 2 points), and CRP >3 mg/dL at day 30 (HR 2.11, 95% CI 1.12-3.97, p=0.02, 2 points). In patients with ≥4 points, the HR for infection was 5.18 (95% CI 3.06-8.75; p<0.001). RIS2020 was an independent predictor of severe infection in multivariate models. CONCLUSIONS An immunological score combining moderate IgG hypogammaglobulinemia and other parameters of innate and acquired immunity could better identify the risk for severe infection in SOT.

Significantly reduced patient and graft survival for left vs right donor lungs for lung transplant recipients

Background

To evaluate the association of right vs left single lung transplants (SLT) from split lung donors with long-term post-transplant recipient outcomes.

Methods

We performed a retrospective review of the Scientific Registry of Transplant Recipients data of split SLT adult recipients comparing right and left lung grafts between 2005 and 2021. We used a paired donor model to account for underlying differences between donors and evaluated post-transplant patient and graft survival with Cox proportional hazard models with robust variance estimates adjusted for recipient characteristics. We also used Wilcoxon signed-rank, McNemar's, and Bowker's tests to evaluate complication rates between donor pairs.

Results

There were 5,180 recipients with 2,590 right and left split allografts. Left SLT had higher rates of mortality (hazards ratio [HR] = 1.17, 95% confidence interval [CI]: 1.08, 1.27) and graft failure (HR = 1.16, 95% CI: 1.06, 1.26) compared to right SLT in adjusted models. There were more early deaths (<13 days post-transplant) among left vs right SLT (n = 52 vs 31, p = 0.018). Estimated 5-year graft survival was 47.1% (95% CI: 45.1, 49.3) and 51.4% (95% CI: 49.4, 53.5) for left and right SLT, respectively. Right SLT was associated with longer length of stay (median 14 days vs 13 days, p = 0.016) and more prolonged ventilation (>5 days) (n = 319, 12.6% vs n = 270, 10.6%; p = 0.030).

Conclusions

Left SLT was associated with significantly worse mortality and graft failure while right SLT was associated with more short-term complications from split lung donors. Organ listing and acceptance decisions should consider donor lung laterality.

Lung transplantation after ex vivo lung perfusion in high-risk recipients: A propensity-score matched analysis of a national database

PURPOSE

We report outcomes associated with ex vivo lung perfusion (EVLP) lungs in high-risk lung transplant recipients utilizing a national database.

METHODS

We performed a retrospective analysis of the United Network for Organ Sharing Database (January 1, 2018-March 31, 2024). High-risk status was defined as mean pulmonary arterial pressure >35 mm Hg, lung retransplantation, or bridge to transplant. In addition to univariable analysis, propensity-score matched analysis was performed on predictors of donor and recipient characteristics.

RESULTS

Risk of dying on the waitlist was significantly higher for high-risk candidates (hazard ratio, 1.69; 95% CI, 1.51-1.89; P < .001). Following matching, 203 EVLP cases were matched to 609 standard procurement recipients. The EVLP group was associated with higher rates of postoperative acute kidney injury requiring renal replacement therapy (27% vs 16%; P < .001), higher mortality on index admission (13% vs 8%; P = .04), and longer length of stay (29 vs 25 days; P = .006). EVLP modality was associated with survival time (P < .001) with portable EVLP having significantly shorter survival (2.7 years) relative to standard cases (4.7 years; P < .02). A subgroup analysis found that this survival effect was limited to bridge and retransplant recipients.

CONCLUSIONS

EVLP lungs were associated with higher rates of postoperative acute kidney injury and portable EVLP was associated with shorter survival in high-risk lung transplant recipients. However, given the high waitlist mortality in this candidate population, EVLP lungs should still be considered an alternative.

The Year in Cardiothoracic Transplant Anesthesia: Selected Highlights From 2022 Part I: Lung Transplantation

These highlights focus on the research in lung transplantation (LTX) that was published in 2022 and includes the assessment and optimization of candidates for LTX, donor optimization, the use of organs from donation after circulatory death, and outcomes when using marginal or novel donors; recipient factors affecting LTX, including age, disease, the use of extracorporeal life support; and special situations, such as coronavirus disease2019, pediatric LTX, and retransplantation. The remainder of the article focuses on the perioperative management of LTX, including the perioperative risk factors for acute renal failure (acute kidney injury); the incidence and management of phrenic nerve injury, delirium, and pain; and the postoperative management of hyperammonemia, early postoperative infections, and the use of donor-derived cell-free DNA to detect rejection.

Unraveling the spectrum of airway complications following lung transplantation: a comprehensive overview

PURPOSE OF REVIEW

This review delves into the intricate landscape of airway complications post lung transplantation. With the rising prevalence of end-stage lung disease and the increasing number of lung transplantation worldwide, understanding and effectively managing airway complications are crucial. Given the nuanced nature of these complications and the array of treatment options available, this review aims to provide a comprehensive overview of how to identify, classify, mitigate risk factors for, and manage these complications.

RECENT FINDINGS

Several donor, recipient, and surgical risk factors are associated with the increased risk of airway complications. In managing these complications, bronchoscopic interventions, notably balloon dilation and stenting, are pivotal. Although self-expanding metallic stents offer versatility, silicone stents are preferred in certain scenarios for their durability. Emerging techniques such as biodegradable stents and advancing imaging modalities show promise in mitigating complications and improving outcomes.

SUMMARY

These findings underscore the significance of a multidisciplinary approach and personalized treatment algorithms in managing airway complications post lung transplantation. By elucidating specific indications and complications of treatment modalities, this review serves as a valuable resource for optimally managing airway complications. Ongoing research into novel interventions holds promise for further enhancing outcomes in this challenging clinical setting.

Lung transplantation: Current insights and outcomes

Until now, the ability to predict or retard immune-mediated rejection events after lung transplantation is still limited due to the lack of specific biomarkers. The pressing need remains to early diagnose or predict the onset of chronic lung allograft dysfunction (CLAD) and its differential phenotypes that is the leading cause of death. Omics technologies (mainly genomics, epigenomics, and transcriptomics) combined with advanced bioinformatic platforms are clarifying the key immune-related molecular routes that trigger early and late events of lung allograft rejection supporting the biomarker discovery. The most promising biomarkers came from genomics. Both unregistered and NIH-registered clinical trials demonstrated that the increased percentage of donor-derived cell-free DNA in both plasma and bronchoalveolar lavage fluid showed a good diagnostic performance for clinically silent acute rejection events and CLAD differential phenotypes. A further success arose from transcriptomics that led to development of Molecular Microscope® Diagnostic System (MMDx) to interpret the relationship between molecular signatures of lung biopsies and rejection events. Other immune-related biomarkers of rejection events may be exosomes, telomer length, DNA methylation, and histone-mediated neutrophil extracellular traps (NETs) but none of them entered in registered clinical trials. Here, we discuss novel and existing technologies for revealing new immune-mediated mechanisms underlying acute and chronic rejection events, with a particular focus on emerging biomarkers for improving precision medicine of lung transplantation field.

Performance status at the time of lung retransplant predicts long-term function

BACKGROUND

Lung retransplantation is offered to select patients with chronic allograft dysfunction. Given the increased risk of morbidity and mortality conferred by retransplantation, post-transplant function should be considered in the decision of who and when to list. The aim of this study is to identify predictors of post-operative disability in patients undergoing lung retransplantation.

METHODS

Data were collected from the UNOS national dataset and included all patients who underwent lung retransplant from May 2005-March 2023. Pre- and post-operative function was reported by the Karnofsky Performance Status (KPS) and patients were stratified based on their needs. Cumulative link mixed effects models identified associations between pre-transplant variables and post-transplant function.

RESULTS

A total of 1275 lung retransplant patients were included. After adjusting for between-group differences, pre-operative functional status was predictive of post-transplant function; patients requiring Total Assistance ( n = 740) were 74% more likely than No/Some Assistance patients (n = 535) to require more assistance in follow-up (OR 1.74, 95% CI 1.13-2.68, p = .012). Estimated one year survival of Total Assistance patients is lower than No/Some Assistance Recipients (72% vs. 82%, CI 69%-75%; 79%-86%) but similar to overall re-transplant survival (76%, CI 74%-79%).

CONCLUSION

Both survival and regain of function in patients requiring Total Assistance prior to retransplant may be higher than previously reported. Pre-operative functional status is predictive of post-operative function and should weigh in the selection, timing and post-operative care of patients considered for lung retransplantation.

Rehabilitative goals for patients undergoing lung retransplantation

Lung retransplantation (LRT) involves a second or subsequent lung transplant (LT) in a patient whose first transplanted graft has failed. LRT is the only treatment option for irreversible lung allograft failure caused by acute graft failure, chronic lung allograft dysfunction, or postoperative complications of bronchial anastomosis. Prehabilitation (rehabilitation before LT), while patients are on the waiting list, is recognized as an essential component of the therapeutic regimen and should be offered throughout the waiting period from the moment of listing until transplantation. LRT is particularly fraught with challenges, and prehabilitation to reduce frailty is one of the few opportunities to address modifiable risk factors (such as functional and motor impairments) in a patient population in which there is clearly room to improve outcomes. Although rehabilitative outcomes and quality of life in patients receiving or awaiting LT have gained increased interest, there is a paucity of data on rehabilitation in patients undergoing LRT. Frailty is one of the few modifiable risk factors of retransplantation that is potentially preventable. As such, it is imperative that professionals involved in the field of retransplantation conduct research specifically exploring rehabilitative techniques and outcomes of value for patients receiving LRT, because this area remains unexplored.

Off-pump lung re-transplantation avoiding clamshell thoracotomy is feasible and safe: a single-center experience

Background

Lung re-transplantation (re-LTx) is the only therapeutic option for selected patients with advanced allograft dysfunction. This study aims to describe our center's experience to illustrate the feasibility and safety of off-pump re-LTx avoiding clamshell incision.

Methods

We performed a retrospective analysis of 42 patients who underwent bilateral re-LTx between 2007 and 2021. Patients were classified according to their surgical approach and extracorporeal life support (ECLS)-use. Demographics, surgical technique, and short- and long-term outcomes were compared between groups. Continuous data were examined with an independent-sample t-test or non-parametric test. Pearson's chi-squared and Fisher's exact were used to analyze categorical data.

Results

Twenty-six patients (61.9%) underwent re-LTx by anterior thoracotomy without ECLS. Compared to the more invasive approach (thoracotomy with ECLS and clamshell with/without ECLS, n=16, 38.1%), clamshell-avoiding off-pump re-LTx patients had a shorter operative time (471.6±111.2 vs. 704.0±273.4 min, P=0.010) and less frequent grade 3 primary graft dysfunction (PGD-3) at 72 h (7.7% vs. 37.5%, P=0.038). No significant difference was found in PGD-3 incidence within 72 h, mechanical ventilation, intensive care unit (ICU) and hospital stay, and the incidence of reoperation within 90 days between groups (P>0.05). In the long-term, the clamshell-avoiding and off-pump approach resulted in similar 1- and 5-year patient survival vs. the more invasive approach.

Conclusions

Our experience shows that clamshell-avoiding off-pump re-LTx is feasible and safe in selected patients on a case-by-case evaluation.

Incidence of malignancies after lung transplantation and their effect on the outcome. 26 years' experience

Background

Malignancy is a significant, life-limiting complication after lung transplantation (LuTx) and the second common long-term cause of death. We aimed to investigate its incidence and effect on the outcome.

Methods

This is a retrospective observational study. Between 1996 and 2022, n = 627 lung transplantations (LuTx) were performed in our department. We used our institutional database to identify recipients with malignancies after LuTx and examined the malignancies' incidence and mortality.

Results

N = 59 malignancies occurred in n = 55 (8.8%) LuTx recipients. The post-LTx malignancies incidence was 9.4% (59/627). We report the following rates based on their location: n = 17/55 (28,8% of all recipients diagnosed with malignancies) skin, n = 10/55 (16,95%) gastrointestinal, n = 9/55 (15,3%) respiratory, n = 5/55 (8,48%) lymphatic, n = 13/55 (23,6%) other, n = 5 (8,48%) multiple synchronous.During this study period, a total of n = 328 deaths after LuTx was determined. N = 29 (8,84% of all deaths) were malignancy induced, corresponding to a total malignancy-induced mortality of 4.6% (n = 29/627). The majority of deaths were attributed to GI adenocarcinoma and PTLD. Malignancies' origin, primary COPD diagnosis, type, and specific age group were significantly survival-related (p-values <0.05). The most affected organ was skin and showed the best prognosis. PTLD had the fastest and pancreatic the latest onset.

Conclusions

This is the first report of its kind in a large cohort of german LuTx recipients. The prevalence ranking of the three commonest malignancy were skin > colorectal > PTLD. Post-LTx malignancy was the second commonest cause of death. Further studies are needed, while post-LuTx malignomas remain a serious impairment of long-term LuTx survival.

[Chronic lung allograft dysfunction in 2022, past and updates]

INTRODUCTION

While short-term results of lung transplantation have improved considerably, long-term survival remains below that achieved for other solid organ transplants.

CURRENT KNOWLEDGE

The main cause of late mortality is chronic lung allograft dysfunction (CLAD), which affects nearly half of the recipients 5 years after transplantation. Immunological and non-immune risk factors have been identified. These factors activate the innate and adaptive immune system, leading to lesional and altered wound-healing processes, which result in fibrosis affecting the small airways or interstitial tissue. Several phenotypes of CLAD have been identified based on respiratory function and imaging pattern. Aside from retransplantation, which is possible for only small number of patients, no treatment can reverse the CLAD process.

PERSPECTIVES

Current therapeutic research is focused on anti-fibrotic treatments and photopheresis. Basic research has identified numerous biomarkers that could prove to be relevant as therapeutic targets.

CONCLUSION

While the pathophysiological mechanisms of CLAD are better understood than before, a major therapeutic challenge remains.