Lung volumes predict survival in patients with chronic lung allograft dysfunction

Bronchiolitis obliterans syndrome after lung or haematopoietic stem cell transplantation: current management and future directions

Bronchiolitis obliterans syndrome (BOS) may develop after either lung or haematopoietic stem cell transplantation (HSCT), with similarities in histopathological features and clinical manifestations. However, there are differences in the contributory factors and clinical trajectories between the two conditions. BOS after HSCT occurs due to systemic graft-versus-host-disease (GVHD), whereas BOS after lung transplantation is limited to the lung allograft. BOS diagnosis after HSCT is more challenging, as the lung function decline may occur due to extrapulmonary GVHD, causing sclerosis or inflammation in the fascia or muscles of the respiratory girdle. Treatment is generally empirical with no established effective therapies. This review provides rare insights and commonalities of both conditions, that are not well elaborated elsewhere in contemporary literature, and highlights the importance of cross disciplinary learning from experts in other transplant modalities. Treatment algorithms for each condition are presented, based on the published literature and consensus clinical opinion. Immunosuppression should be optimised, and other conditions or contributory factors treated where possible. When initial treatment fails, the ultimate therapeutic option is lung transplantation (or re-transplantation in the case of BOS after lung transplantation) in carefully selected candidates. Novel therapies under investigation include aerosolised liposomal cyclosporine, Janus kinase inhibitors, antifibrotic therapies, and (in patients with BOS after lung transplantation) B-cell–directed therapies. Effective novel treatments that have a tangible impact on survival and thereby avoid the need for lung transplantation or re-transplantation are urgently required.

Determinants of survival after lung transplantation in telomerase-related gene mutation carriers: A retrospective cohort

Carriers of germline telomerase-related gene (TRG) mutations can show poor prognosis, with an increase in common hematological complications after lung transplantation (LT) for pulmonary fibrosis. The aim of this study was to describe the outcomes after LT in recipients carrying a germline TRG mutation and to identify the predictors of survival. In a multicenter cohort of LT patients, we retrospectively reviewed those carrying pathogenic TRG variations (n = 38; TERT, n = 23, TERC, n = 9, RTEL1, n = 6) between 2009 and 2018. The median age at LT was 54 years (interquartile range [IQR] 46-59); 68% were male and 71% had idiopathic pulmonary fibrosis. During the diagnosis of pulmonary fibrosis, 28 (74%) had a hematological disease, including eight with myelodysplasia. After a median follow-up of 26 months (IQR 15-46), 38 patients received LT. The overall post-LT median survival was 3.75 years (IQR 1.8-NA). The risk of death after LT was increased for patients with myelodysplasia (HR 4.1 [95% CI 1.5-11.5]) or short telomere (HR 2.2 [1.0-5.0]) before LT. After LT, all patients had anemia, 66% had thrombocytopenia, and 39% had neutropenia. Chronic lung allograft dysfunction frequency was 29% at 4 years. The present findings support the use of LT in TRG mutation carriers without myelodysplasia. Hematological evaluation should be systematically performed before LT.

Multi-omics profiling predicts allograft function after lung transplantation

RATIONALE

Lung transplantation is the ultimate treatment option for patients with end-stage respiratory diseases but bears the highest mortality rate among all solid organ transplantations due to chronic lung allograft dysfunction (CLAD). The mechanisms leading to CLAD remain elusive due to an insufficient understanding of the complex post-transplant adaptation processes.

OBJECTIVES

To better understand these lung adaptation processes after transplantation and to investigate their association with future changes in allograft function.

METHODS

We performed an exploratory cohort study of bronchoalveolar lavage samples from 78 lung recipients and donors. We analysed the alveolar microbiome using 16S rRNA sequencing, the cellular composition using flow cytometry, as well as metabolome and lipidome profiling.

MEASUREMENTS AND MAIN RESULTS

We established distinct temporal dynamics for each of the analysed data sets. Comparing matched donor and recipient samples, we revealed that recipient-specific as well as environmental factors, rather than the donor microbiome, shape the long-term lung microbiome. We further discovered that the abundance of certain bacterial strains correlated with underlying lung diseases even after transplantation. A decline in forced expiratory volume during the first second (FEV1) is a major characteristic of lung allograft dysfunction in transplant recipients. By using a machine learning approach, we could accurately predict future changes in FEV1 from our multi-omics data, whereby microbial profiles showed a particularly high predictive power.

CONCLUSION

Bronchoalveolar microbiome, cellular composition, metabolome and lipidome show specific temporal dynamics after lung transplantation. The lung microbiome can predict future changes in lung function with high precision.

A randomized controlled trial of liposomal cyclosporine A for inhalation in the prevention of bronchiolitis obliterans syndrome following lung transplantation

Long-term survival after lung transplantation is limited by chronic allograft dysfunction. The aim of this study was to investigate the effect of locally augmented immunosuppression with liposomal cyclosporine A for inhalation (L-CsA-i) for the prevention of bronchiolitis obliterans syndrome (BOS). In a randomized, double-blind, placebo-controlled, multi-center Phase 3 study, 180 LT recipients in BOS grade 0 were planned to receive L-CsA-i or placebo in addition to triple-drug immunosuppression. L-CsA-i was administered twice daily via an Investigational eFlow nebulizer to recipients of single (SLT) and bilateral lung transplants (BLT) within 6-32 weeks posttransplant, and continued for 2 years. The primary endpoint was BOS-free survival. 130 patients were enrolled before the study was prematurely terminated for business reasons. Despite a 2-year actuarial difference in BOS-free survival of 14.1% in favor of L-CsA-i in the overall study population, the primary endpoint was not met (p = .243). The pre-defined per protocol analysis of SLT recipients (n = 24) resulted in a treatment difference of 58.2% (p = .053). No difference was observed in the BLT (n = 48) subpopulation (p = .973). L-CsA-i inhalation was well tolerated. Although this study failed to meet its primary endpoint, the results warrant additional investigation of L-CsA-i in lung transplant recipients.

Polyomavirus exerts detrimental effects on renal function in patients after lung transplantation

INTRODUCTION

Chronic kidney disease (CKD) is associated with significant morbidity and mortality after lung transplantation (LTX). Calcineurin inhibitor (CNI) nephrotoxicity is the leading cause of CKD. After kidney transplantation, polyomavirus-associated nephropathy (PyVAN) is a well-recognized problem. This study aims to evaluate the role of polyomavirus in patients after LTX.

METHODS

From January 2017 to January 2020, all lung transplant recipients who performed follow-up visits in our center were included in the study and retrospectively assessed. We measured renal function (creatinine levels before and after transplantation), JCPyV, and BKPyV load by polymerase chain reaction (PCR) in serum and urine samples after transplantation.

RESULTS

In total, 104 consecutive patients (59 males, 56.7%) with a mean age of 49.6 ± 11.1 years were identified. JCPyV was found in urine of 36 patients (34.6%) and serum of 3 patients (2.9%). BKPyV was found in urine of 40 patients (38.5%) and serum of 4 patients (3.8%), respectively. Urine evidence for JCPyV (p < 0.001, coefficient: +21.44) and BKPyV (p < 0.001, coefficient: +29.65) correlated highly with further kidney function decline.

CONCLUSION

Kidney function deterioration is associated with JCPyV and BKPyV viruria in patients after LTX. This might indicate a role of PyVAN in lung transplant recipients.

Letermovir in lung transplant recipients with cytomegalovirus infection: A retrospective observational study

Letermovir is a new antiviral drug approved for the prophylaxis of CMV infection in allogeneic stem cell transplants. The aim of the study was to assess the therapeutic efficacy of letermovir in difficult to treat CMV infections in lung transplant recipients. All lung transplant recipients between March 2018 and August 2020, who have been treated with letermovir for ganciclovir-resistant or refractory CMV infection were included in the study and analysed retrospectively. In total, 28 patients were identified. CMV disease was present in 15 patients (53.6%). In 23 patients (82.1%), rapid response was noticed, and CMV-viral load could be significantly decreased (>1 log₁₀ ) after a median of 17 [14-27] days and cleared subsequently in all of these patients. Five patients (17.9%) were classified as non-responder. Thereof, development of a mutation of the CMV UL56 terminase (UL-56-Gen: C325Y) conferring letermovir resistance could be observed in three patients (60%). Common side effects were mild and mostly of gastrointestinal nature. Mild adjustments of the immunosuppressive drugs were mandatory upon treatment initiation with letermovir. In addition to other interventions, letermovir was effective in difficult to treat CMV infections in lung transplant recipients. However, in patients with treatment failure mutation conferring letermovir, resistance should be taken into account.

Diffusing Capacity for Carbon Monoxide (DLCO): Association with long-term outcomes after Lung Transplantation in a 20-year longitudinal study

RATIONALE

The diffusing capacity for carbon monoxide corrected for haemoglobin (DLCO_cor), measures gas movement across the alveolar-capillary interface. We hypothesised that DLCO_cor is a sensitive measure of injurious allograft processes disrupting this interface.

OBJECTIVES

To determine the prognostic significance of the DLCO_cor trajectory on chronic lung allograft dysfunction (CLAD) and survival.

METHODS

A retrospective analysis was conducted of all bilateral lung transplant recipients at a single centre, between Jan-1998 and Jan-2018, with ≥1 DLCO_cor measurements. Low baseline DLCO_cor was defined as the failure to achieve a DLCO_cor >75% predicted. Drops in DLCO_cor were defined as >15% below recent baseline.

RESULTS

1259/1492 lung transplant recipients were included. The median time to peak DLCO_cor was 354 (range 181-737) days and the mean %-predicted DLCO_cor was 80.2% (sd 21.2). Multivariable analysis demonstrated that low baseline DLCO_cor was significantly associated with death (HR 1.68, 95% CI 1.27-2.20, p<0.001). Low baseline DLCO_cor was not independently associated with CLAD after adjustment for low baseline FEV₁ or FVC. Any DLCO_cor declines ≥15% were significantly associated with death, independent of concurrent spirometric decline. Lower %-predicted DLCO_cor values at CLAD onset were associated with shorter post-CLAD survival (HR 0.75 per 10%-unit change, p<0.01).

CONCLUSION

Low baseline DLCO_cor and post-transplant declines in DLCO_cor were significantly associated with survival, independent of spirometric measurements. We propose that DLCO_cor testing may allow identification of a sub-phenotype of baseline and chronic allograft dysfunction not captured by spirometry. There may be benefit in routine monitoring of DLCO_cor after lung transplantation to identify patients at risk of poor outcomes.

Chronic Lung Allograft Dysfunction: Evolving Concepts and Therapies

The primary factor that limits long-term survival after lung transplantation is chronic lung allograft dysfunction (CLAD). CLAD also impairs quality of life and increases the costs of medical care. Our understanding of CLAD continues to evolve. Consensus definitions of CLAD and the major CLAD phenotypes were recently updated and clarified, but it remains to be seen whether the current definitions will lead to advances in management or impact care. Understanding the potential differences in pathogenesis for each CLAD phenotype may lead to novel therapeutic strategies, including precision medicine. Recognition of CLAD risk factors may lead to earlier interventions to mitigate risk, or to avoid risk factors all together, to prevent the development of CLAD. Unfortunately, currently available therapies for CLAD are usually not effective. However, novel therapeutics aimed at both prevention and treatment are currently under investigation. We provide an overview of the updates to CLAD-related terminology, clinical phenotypes and their diagnosis, natural history, pathogenesis, and potential strategies to treat and prevent CLAD.

Cathepsin B promotes collagen biosynthesis, which drives bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is a major complication after lung transplantation (LTx). BOS is characterised by massive peribronchial fibrosis, leading to air trapping-induced pulmonary dysfunction. Cathepsin B, a lysosomal cysteine protease, has been shown to enforce fibrotic pathways in several diseases. However, the relevance of cathepsin B in BOS progression has not yet been addressed. The aim of the study was to elucidate the function of cathepsin B in BOS pathogenesis.We determined cathepsin B levels in bronchoalveolar lavage fluid (BALF) and lung tissue from healthy donors (HD) and BOS LTx patients. Cathepsin B activity was assessed via a fluorescence resonance energy transfer-based assay and protein expression was determined using Western blotting, ELISA and immunostaining. To investigate the impact of cathepsin B in the pathophysiology of BOS, we used an in vivo orthotopic left LTx mouse model. Mechanistic studies were performed in vitro using macrophage and fibroblast cell lines.We found a significant increase of cathepsin B activity in BALF and lung tissue from BOS patients, as well as in our murine model of lymphocytic bronchiolitis. Moreover, cathepsin B activity was associated with increased biosynthesis of collagen and had a negative effect on lung function. We observed that cathepsin B was mainly expressed in macrophages that infiltrated areas characterised by a massive accumulation of collagen deposition. Mechanistically, macrophage-derived cathepsin B contributed to transforming growth factor-β1-dependent activation of fibroblasts, and its inhibition reversed the phenotype.Infiltrating macrophages release active cathepsin B, thereby promoting fibroblast activation and subsequent collagen deposition, which drive BOS. Cathepsin B represents a promising therapeutic target to prevent the progression of BOS.

Current trends in thoracic surgery

Thoracic surgery has evolved drastically in recent years. Although thoracic surgeons mainly deal with tumorous lesion in the lungs, mediastinum, and pleura, they also perform lung transplantation surgery in patients with end-stage lung disease. Herein, we introduce various major current topics in thoracic surgery. Minimally invasive surgical procedures include robot-assisted thoracic surgery and uniportal video-assisted thoracic surgery. Novel techniques for sublobar resection include virtual-assisted lung mapping, image-guided video-assisted thoracic surgery, and segmentectomy using indocyanine green. Three-dimensional (3D) computed tomography (CT) simulation consists of surgeon-friendly 3D-CT image analysis systems and new-generation, dynamic 3D-CT imaging systems. Updates in cadaveric lung transplantation include use of marginal donors, including donation after circulatory death, and ex vivo lung perfusion for such donors. Topics in living donor lobar lung transplantation include size matching, donor issues, and new surgical techniques. During routine clinical practice, thoracic surgeons encounter various pivotal topics related to thoracic surgery, which are described in this report.

Association of CMV-specific T-cell immunity and risk of CMV infection in lung transplant recipients

BACKGROUND

Protecting against CMV infection and maintaining CMV in latent state are largely provided by CMV-specific T-cells in lung transplant recipients. The aim of the study was to assess whether a specific T-cell response is associated with the risk for CMV infection in seronegative patients who are at high risk for delayed CMV infection.

METHODS

All CMV-seronegative recipients (R-) from CMV-seropositive donors (D+) between January 2018 and April 2019 were included and retrospectively screened for CMV infection before and after assessment of CMV-specific cell-mediated immunity.

RESULTS

Thirty-one of the 50 patients (62%) developed early-onset CMV infection. Lower absolute neutrophil counts were significantly associated with early-onset CMV infection. Antiviral prophylaxis was ceased after 137.2 ± 42.8 days. CMV-CMI were measured at a median of 5.5 months after LTx. 19 patients experienced early and late-onset CMV infection after prophylaxis withdrawal within 15 months post transplantation. Positive CMV-CMI was significantly associated with lower risk of late-onset CMV infection after transplantation in logistic and cox-regression analysis (OR=0.05, p = .01; OR=2,369, p = .026).

CONCLUSION

D+/R- lung transplant recipients are at high risk of developing early and late-onset CMV infection. Measurement of CMV-CMI soon after transplantation might further define the CMV infection prediction risk in LTx recipients being at high risk for CMV viremia.

Longitudinal lung function measurements in single lung transplant recipients with chronic lung allograft dysfunction

BACKGROUND

Phenotyping chronic lung allograft dysfunction (CLAD) in single lung transplant (SLTX) recipients is challenging. The aim of this study was to assess the diagnostic and prognostic value of longitudinal lung function tests in SLTX recipients with CLAD.

METHODS

A total of 295 SLTX recipients were analyzed and stratified according to native lung physiology. In addition to spirometry, measurements of static lung volumes and lung capacities were used to phenotype patients and to assess their prognostic value. Outcome was survival after CLAD onset. Patients with insufficient clinical information were excluded (n = 71).

RESULTS

Of 224 lung transplant recipients, 105 (46.9%) developed CLAD. Time to CLAD onset (hazard ratio [HR]: 0.82, 95% CI: 0.74-0.90; p < 0.001), severity of CLAD at onset (HR: 0.97, 95% CI: 0.94-0.99; p = 0.009), and progression after onset of CLAD (HR: 1.03, 95% CI: 1.00-1.05; p = 0.023) were associated with outcome. Phenotypes at onset were bronchiolitis obliterans syndrome (BOS) (59.1%), restrictive allograft syndrome (RAS) (12.4%), mixed phenotype (6.7%), and undefined phenotype (21.9%). Survival estimates differed significantly between phenotypes (p = 0.004), with RAS and mixed phenotype being associated with the worst survival, followed by BOS and undefined phenotype. Finally, a higher hazard for mortality was noticed for RAS (HR: 2.34, 95% CI: 0.99-5.52; p = 0.054) and mixed phenotype (HR: 3.30, 95% CI: 1.20-9.11; p = 0.021) while controlling for time to CLAD onset and severity of CLAD at onset.

CONCLUSIONS

Phenotyping CLAD in SLTX remains challenging with a high number of patients with an undefined phenotype despite comprehensive lung function testing. However, phenotyping is of prognostic value. Furthermore, early, severe, and progressive CLADs are associated with worse survival.

Chronic lung allograft dysfunction: light at the end of the tunnel?

PURPOSE OF REVIEW

Chronic lung allograft dysfunction (CLAD) has been recently introduced as an umbrella-term encompassing all forms of chronic pulmonary function decline posttransplant with bronchiolitis obliterans syndrome and restrictive allograft syndrome as the most important subtypes. Differential diagnosis and management, however, remains complicated.

RECENT FINDINGS

Herein, we provide an overview of the different diagnostic criteria (pulmonary function, body plethysmography and radiology) used to differentiate bronchiolitis obliterans syndrome and restrictive allograft syndrome, their advantages and disadvantages as well as potential problems in making an accurate differential diagnosis. Furthermore, we discuss recent insights in CLAD management and treatment and advances in the search for accurate biomarkers of CLAD.

SUMMARY

Careful dissection of CLAD phenotypes is of utmost importance to assess patient prognosis, but uniform diagnostic criteria are desperately needed. There is a long way ahead, but the first steps towards this goal are now taken; tailored individualized therapy will be the golden standard to treat CLAD in the future, but randomized placebo-controlled and multicentre trials are needed to identify new and powerful therapeutic agents.

An update on chronic lung allograft dysfunction

Chronic lung allograft dysfunction (CLAD) remains a significant challenge and the major determinant of morbidity and mortality post lung transplantation (LTx). The definition of CLAD has evolved significantly over the last ten years, reflecting better understanding of pathophysiology and different phenotypes. While there is an agreed consensus approach to CLAD, questions remain regarding the limitations of lung function parameters as well as the role of imaging and histopathology. Here we present a current snapshot of the definition of CLAD, its evolution and future directions.

Identification and characterization of chronic lung allograft dysfunction patients with mixed phenotype: A single-center study

RATIONALE

Patients can change chronic lung allograft dysfunction (CLAD) phenotype, especially from BOS to mixed phenotype. Our aim was to further characterize these patients.

METHOD

Mixed CLAD was defined as a restrictive physiology with persistent CT opacities, after initial bronchiolitis obliterans syndrome (BOS) diagnosis. The incidence, prognosis, pulmonary function, radiology, pathology, and airway inflammation were compared between patients with restrictive allograft syndrome (RAS) and mixed CLAD.

RESULT

A total of 268 (44%) patients developed CLAD of which 47 (18%) were diagnosed with RAS "ab initio," 215 (80%) with BOS, and 6 (2%) an undefined phenotype. Twenty-five patients developed a mixed CLAD phenotype (24 BOS to mixed and 1 RAS to mixed). Survival after mixed phenotype diagnosis was comparable (P = .39) to RAS. More emphysema patients developed a mixed phenotype (P = .020) compared to RAS ab initio, while mixed CLAD patients had a lower FEV₁ (P < .0001) and FEV₁ /FVC (P = .0002) at diagnosis compared to RAS ab initio. CT scans in patients with the mixed phenotype demonstrated apical predominance of the opacities (P = .0034) with pleuroparenchymal fibroelastosis on histopathology.

CONCLUSION

We further characterized patients with a mixed phenotype of CLAD. Although the survival after diagnosis was comparable to RAS ab initio patients, there was a difference in demography, pulmonary function, radiology, and pathology.

Variation in Time to Peak Values for Different Lung Function Parameters After Double Lung Transplantation

BACKGROUND

Establishment of baseline values for forced expiratory volume in the first second (FEV₁), forced vital capacity (FVC), or total lung capacity (TLC) is required when diagnosing and phenotyping chronic lung allograft dysfunction after lung transplant. It is generally accepted that the baseline (peak) values of these parameters occur simultaneously, but this assumption has not been substantiated for TLC.

METHODS

All lung function measurements in all double lung transplant recipients from a single center in the period from 1992-2014 were included. Time to baseline FEV₁ was assessed according to standards from the International Society for Heart and Lung Transplantation, and time to peak FVC, TLC, and diffusion capacity for carbon monoxide were evaluated.

RESULTS

A total of 288 double lung transplants surviving more than 3 months after transplant were included. Baseline FEV₁ occurred at a median of 0.77 years post transplant and was statistically different from median times to the peak FVC (1.02 years), to peak TLC (1.37 years), and to peak diffusion capacity for carbon monoxide 1.04 years post transplant (all log-rank P < .001). At the time of baseline FEV1, FVC, and TLC were at a mean of 96% and 95% of their peak values, respectively.

CONCLUSION

The peak lung function is reached at different time points for different parameters post transplant with FEV₁ baseline occurring first. For most patients values of FVC and TLC obtained at time for baseline FEV₁ is a good estimate of peak values, but in a small percentage of patients this procedure may jeopardize phenotyping of chronic lung allograft dysfunction based solely on lung function parameters.

Pirfenidone exerts beneficial effects in patients with IPF undergoing single lung transplantation

Pirfenidone demonstrated pleiotropic antiinflammatory effects in various experimental and clinical settings. The aim of this study was to assess the impact of previous treatment with pirfenidone on short-term outcomes after single lung transplantation (SLTx). Therefore, patients with idiopathic pulmonary fibrosis (IPF) who were undergoing SLTx were screened retrospectively for previous use of pirfenidone and compared to respective controls. Baseline parameters and short-term outcomes were recorded and analyzed. In total, 17 patients with pirfenidone were compared with 26 patients without antifibrotic treatment. Baseline characteristics and severity of disease did not differ between groups. Use of pirfenidone did not increase blood loss, wound-healing, or anastomotic complications. Severity of primary graft dysfunction at 72 hours was less (0.3 ± 0.6 vs 1.4 ± 1.3, P = .002), and length of mechanical ventilation (37.5 ± 34.8 vs 118.5 ± 151.0 hours, P = .016) and intensive care unit (ICU) stay (6.6 ± 7.1 vs 15.6 ± 20.3, P = .089) were shorter in patients with pirfenidone treatment. An independent beneficial effect of pirfenidone was confirmed by regression analysis while controlling for confounding variables (P = .016). Finally, incidence of acute cellular rejections within the first 30 days after SLTx was lower in patients with previous pirfenidone treatment (0.0% vs 19.2%; P = .040). Our data suggest a beneficial role of previous use of pirfenidone in patients with IPF who were undergoing SLTx.

The effect of primary graft dysfunction after lung transplantation on parenchymal remodeling detected by quantitative computed tomography

Background

Regional analysis by computed tomography (CT) is an attractive technique to interpret lung patterns after transplantation (LTx). We evaluated the application of CT functional mask derived parameters to determine whether development of primary graft dysfunction (PGD) is associated with short and/or long-term postoperative evidences of pulmonary function alterations.

Methods

A total of 38 patients who underwent bilateral LTx were evaluated at 24, 48 and 72 hours after the end of surgery to establish PGD occurrence and grading. CT scans at 3 and 12 months after LTx were analyzed to measure specific gas volume (SV_g) changes normalized on expiratory SVgEXP of the whole lung (ΔSV_g/SV_gEXP) and to obtain functional masks of density variation, namely maps of low ventilation (LV), consolidation (C), air trapping (AT) and healthy parenchyma (H).

Results

Our main result was the evidence of a marked decrease in ΔSV_g/SV_gEXP in all subjects, irrespectively on PGD, at each time point after LTx, indicating a high degree of ventilation defects versus healthy. High percentages of LV were found in all subjects while percentages of AT and C were negligible.

Conclusions

We demonstrate that quantification of ventilation defects by CT functional mask offers insights into the correlation between PGD and pulmonary function after LTx at short and mid-term.

Prognostic significance of early pulmonary function changes after onset of chronic lung allograft dysfunction

BACKGROUND

Chronic lung allograft dysfunction (CLAD), including the phenotypes of bronchiolitis obliterans syndrome (BOS) and restrictive CLAD (R-CLAD), represents the leading cause of late death after lung transplantation. Little is known, however, regarding the natural history or prognostic significance of pulmonary function changes after the onset of these conditions. We examined changes in forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) over the first 18 months after CLAD. We also sought to determine whether lung function changes occurring early after CLAD impact longer term outcomes.

METHODS

We performed a retrospective analysis of 216 bilateral lung recipients with CLAD, which included those with R-CLAD (n = 65) or BOS (n = 151). The course of FEV₁ and FVC after CLAD was described. Cox proportional hazards models were used to evaluate the impact of a ≥10% decline in FEV₁ or FVC within the first 6 months of CLAD on graft loss after that time.

RESULTS

Lung recipients with CLAD, whether BOS or R-CLAD, had the largest decreases in FEV₁ and FVC within the first 6 months after onset. Moreover, a decline in FEV₁ or FVC of ≥10% within the first 6 months after CLAD was associated with a significantly increased hazard for graft loss after that time (hazard ratio [HR] = 3.17, 95% confidence interval [CI] 1.56 to 6.42, p = 0.001, and HR = 2.80, 95% CI 1.66 to 4.70, p ≤ 0.001, respectively), an effect observed in both BOS and R-CLAD patients.

CONCLUSIONS

Early physiologic changes after CLAD were independently associated with graft loss. This suggests lung function changes after CLAD, specifically a ≥10% decline in FEV₁ or FVC, could be a surrogate measure of graft survival.

Combined diffusing capacity for nitric oxide and carbon monoxide as predictor of bronchiolitis obliterans syndrome following lung transplantation

BACKGROUND

There is a need for non-invasive parameters that are sensitive to the development of the bronchiolitis obliterans syndrome (BOS) in lung transplantation (LTx) patients. We studied whether the pulmonary diffusing capacity for inhaled nitric oxide is capable of detecting BOS stages.

METHODS

Sixty-one LTx patients were included into this cross-sectional study (19/29/7/3/3 in BOS stages 0/0-p/1/2/3). For analysis stages 0/0-p versus 1/2/3 ("BOS binary-early"), and stages 0/0-p/1 versus 2/3 ("BOS binary-late") were summarized. Measurements of the combined diffusing capacity for nitric oxide (DLNO) and carbon monoxide (DLCO) were compared with spirometry and bodyplethysmography, and their relative importance was evaluated by discriminant analysis.

RESULTS

Regarding the recognition of "BOS binary-early", among spirometric parameters forced expiratory volume in 1 s (FEV1) was best, among bodyplethysmographic parameters airway resistance, and among diffusing parameters DLNO. Regarding "BOS binary-late", DLNO was inferior to bodyplethysmographic parameters.

CONCLUSION

Although the study comprised only measurements at a single time point and no follow-up, DLNO outperformed FEV1, the time course of which is used in detecting BOS. Together with its pathophysiological plausibility, this result suggests that the measurement of DLNO, possibly over time, could be an easily applicable tool for the monitoring of LTx patients and should be evaluated in larger studies.

Radiological findings of complications after lung transplantation

Abstract

Complications following lung transplantation may impede allograft function and threaten patient survival. The five main complications after lung transplantation are primary graft dysfunction, post-surgical complications, alloimmune responses, infections, and malignancy. Primary graft dysfunction, a transient ischemic/reperfusion injury, appears as a pulmonary edema in almost every patient during the first three days post-surgery. Post-surgical dysfunction could be depicted on computed tomography (CT), such as bronchial anastomosis dehiscence, bronchial stenosis and bronchomalacia, pulmonary artery stenosis, and size mismatch. Alloimmune responses represent acute rejection or chronic lung allograft dysfunction (CLAD). CLAD has three different forms (bronchiolitis obliterans syndrome, restrictive allograft syndrome, acute fibrinoid organizing pneumonia) that could be differentiated on CT. Infections are different depending on their time of occurrence. The first post-operative month is mostly associated with bacterial and fungal pathogens. From the second to sixth months, viral pneumonias and fungal and parasitic opportunistic infections are more frequent. Different patterns according to the type of infection exist on CT. Malignancy should be depicted and corresponded principally to post-transplantation lymphoproliferative disease (PTLD). In this review, we describe specific CT signs of these five main lung transplantation complications and their time of occurrence to improve diagnosis, follow-up, medical management, and to correlate these findings with pathology results.

Key Points

• The five main complications are primary graft dysfunction, surgical, alloimmune, infectious, and malignancy complications.

• CT identifies anomalies in the setting of unspecific symptoms of lung transplantation complications.

• Knowledge of the specific CT signs can allow a prompt diagnosis.

• CT signs maximize the yield of bronchoscopy, transbronchial biopsy, and bronchoalveolar lavage.

• Radiopathological correlation helps to understand CT signs after lung transplantation complications.

Three-dimensional image in lung transplantation

Three-dimensional computed tomography (3D-CT) technologies have been developed and, recently, high-speed and high-quality 3D-CT technologies have been introduced to the field of thoracic surgery. The purpose of this manuscript is to demonstrate the clinical application of 3D-CT technologies in lung transplantation. In Japan, because of the severe donor shortage, living-donor lobar lung transplantation (LDLLT) is essential, in addition to cadaveric lung transplantation. In LDLLT, size matching is a grave issue, since ideal size matching between donor and recipient is usually difficult because of the limited population of potential donor. Size matching using pulmonary function test results has been widely used as a gold standard, but anatomical size matching using 3D-CT volumetry data has also been utilized in LDLLT. In donor lobectomy, 3D-CT images provided a variety of information regarding anatomical variation of pulmonary vessels and bronchial trees preoperatively. These images ensure surgical quality and safety, and they also affect surgical procedures for the recipient. 3D-CT images are also utilized in various aspects of postoperative care, such as detection of chronic lung allograft dysfunction and clarification of its subtypes. Furthermore, preoperative 3D-CT simulation is useful in developing and performing a special surgical procedure, such as right-to-left inverted LDLLT. In conclusion, following the introduction of 3D-CT to the field of thoracic surgery, various 3D-CT images and their application to preoperative simulations have been introduced in lung transplantation. In the near future, this technique will become more prevalent, and frequent use by thoracic surgeons will be seen worldwide in daily practice.