Underwent Lung Transplantation Research Articles

Influence of acute kidney injury and its recovery subtypes on patient-centered outcomes after lung transplantation

This study aimed to investigate the association between acute kidney injury (AKI) recovery subtypes and days alive out of hospital within the first 3 months (DAOH-90) in patients undergoing lung transplantation. Patients who underwent lung transplantation from January 2012 to December 2021 were retrospectively analyzed and stratified into three groups: no-AKI, early recovery AKI (within 7 days), and non-early recovery AKI group. AKI occurred in 86 (35%) of patients, of which 40 (16%) achieved early recovery, and the remaining 46 (19%) did not. The median DAOH-90 was 21 days shorter in the AKI than in the no-AKI (P = 0.002), and 29 days shorter in the non-early recovery AKI group than in the no-AKI group (P < 0.001). Non-early recovery AKI and preoperative tracheostomy status were independently associated with shorter DAOH-90. The prevalence of CKD (76%), and 1-year mortality (48%) were highest in the non-early recovery AKI group. Postoperative AKI was associated with an adverse patient-centered quality measure for perioperative care, and shorter DAOH-90. The non-early recovery AKI group exhibited the worst prognosis in terms of DAOH-90, CKD progression, and 1-year mortality, highlighting the important role of AKI and early-recovery AKI on both the quality of life and clinical outcomes after lung transplantation.

Longitudinal study on the trajectory and influencing factors of cognitive dysfunction in lung transplantation patients

IntroductionLung transplantation is an effective method for treating end-stage lung disease. It prolongs the survival time of patients, improves the quality of life, and prevents the degree of mental disability. In particular, postoperative cognitive dysfunction (POCD) is one of the complications after lung transplantation. Despite this, longitudinal studies on the identification and heterogeneity of cognitive dysfunction subgroup trajectories in transplant patients are lacking. Therefore, our study aimed to evaluate the factors that influence POCD in lung transplant patients. MethodsThis prospective longitudinal study included patients who underwent lung transplantation at the transplant center of Wuxi People's Hospital from September 2022 to September 2023. Patients with lung transplants were evaluated at 8 days (T1), 1 month (T2), 3 months (T3), and 6 months (T4) after the operation. The general information questionnaire evaluated cognitive functions using the Montreal Cognitive Assessment (MoCA) numerical rating scale (NRS) and the digital pain assessment to obtain the POCD values. Latent category growth model (LCGM) analysis was used to identify heterogeneous POCD subgroups in the four observation periods. Univariate and logistic regression analyses were used to identify factors affecting POCD classification and independent risk factors. ResultsBased on clinical outcomes, 79 patients completed all four surveys, of whom 16 were lost during the follow-up period (loss rate, 16.8%). The cognitive function by MoCA NRS score was 14.18 ± 5.32 points on day 8 (T1), 22.51 ± 5.13 points at 1 month (T2), 25.44 ± 3.61 at 3 months (T3), and 27.04 ± 3.03 points at 6 months (T4) after lung transplantation, showing an increasing trend. The LCGM, used to fit the trajectory of MoCA scores, observed a heterogeneous trajectory of changes in lung transplant patients. Based on this analysis, patients could be divided into two categories: those with high risk (25,32%) and those with low risk (54,68%). The single-factor analysis identified that POCD values were affected by early postoperative rehabilitation exercise, degree of pain, intensive care unit (ICU) stay time, and donor lung cold ischemia time (all P < 0.05). Using the low-risk group as the reference class, logistic regression analysis showed that the model could correctly classify the subjects. ConclusionOur 6-month observation of lung transplant patients showed that the degree of cognitive dysfunction had an overall downward trend and that patients could be divided into two trajectories of high and low risk for POCD. Early postoperative rehabilitation exercise, degree of pain, ICU stay time, and donor lung cold ischemia time were all influencing factors for POCD in lung transplant patients.

Treatment of Patients After Lung Transplantation With Covid Infection During Long-Term Follow-Up

BackgroundPatients undergoing lung transplantation are routinely managed with lifelong immunosuppression associated with heightened risk for infections. This study delves into the therapeutic challenges and strategies employed in managing lung transplant recipients (LTRs) who were infected with COVID-19 during long-term follow-up. Patients and MethodsThe study is conducted as a case series analysis, among which non-standard therapies consisting of either targeted antibody treatment or antiviral drugs or anti-IL-6 drugs were applied in patients after lung transplantation. Additional analysis of laboratory test results for systemic inflammation and imaging studies was also carried out. The study was limited to a dedicated COVID-19 center, commonly known as a temporary hospital and included patients infected with Covid-19 in the late post-lung transplant period (home related infection). Results15 patients after LTx (lung transplantation) with current COVID-19 infection were treated with antibodies like tocilizumab, casirivimab and imdevimab and regdanvimab. 6,7 % (n=1) of the patients were given tocilizumab, 53,3% (n=8) casirivimab and imdevimab and 13,3 % (n=2) regdanvimab. Of the 15 LTRs studied, 53,3 % presented COVID-19 associated lung changes in CT scans. Common clinical manifestations included dyspnea, fever, and fatigue. Antiviral agents, like remdesivir, were employed in the remaining 26,7% (n:4) cases, and adjunctive therapies, such as corticosteroids and anticoagulants, were utilized selectively. All treated patients survived the infection without complications; the treatment proved to be effective and safe.

Heparin-free veno-arterial extracorporeal membrane oxygenation in lung transplantation: a retrospective cohort study

BackgroundIn lung transplantation (LTx) surgery, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can provide mechanical circulatory support to patients with cardiopulmonary failure. However, the use of heparin in the administration of ECMO can increase blood loss during LTx. This study aimed to evaluate the safety of heparin-free V-A ECMO strategies.MethodsFrom September 2019 to April 2022, patients who underwent lung transplantation at the First Affiliated Hospital of Guangzhou Medical University were retrospectively reviewed. A total of 229 patients were included, including 117 patients in the ECMO group and 112 in the non-ECMO group.ResultThere was no significant difference in the incidence of thrombus events and bleeding requiring reoperation between the two groups. The in-hospital survival rate after single lung transplantation (SLTx) was 81.08%in the ECMO group and 85.14% in the Non-ECMO group, (P = 0.585). The in-hospital survival rate after double lung transplantation (DLTx) was 80.00% in the ECMO group and 92.11% in the Non-ECMO groups (P = 0.095).ConclusionsIn conclusion, the findings of this study suggest that the heparin-free V-A ECMO strategy in lung transplantation is a safe approach that does not increase the incidence of perioperative thrombotic events or bleeding requiring reoperation.

Risk Factors for and Outcomes Following Early Acquisition of Mycobacterium abscessus Complex After Lung Transplantation.

Lung transplant recipients are at increased risk of Mycobacterium abscessus complex (MABC) acquisition and invasive infection. We analyzed risk factors and outcomes of early post-lung transplant MABC acquisition. We conducted a retrospective matched case-control study of patients who underwent lung transplant from 1/1/2012 to 12/31/2021 at a single large tertiary care facility. Cases had de novo MABC isolation within 90 days post-transplant. Controls had no positive MABC cultures and were matched 3:1 with cases based on age and transplant date. Recipient demographics and pre-/peri-operative characteristics were analyzed, and a regression model was used to determine independent risk factors for MABC acquisition. We also assessed 1-year post-transplant outcomes, including mortality. Among 1145 lung transplants, we identified 79 cases and 237 matched controls. Post-transplant mechanical ventilation for >48 hours was independently associated with MABC acquisition (adjusted odds ratio, 2.46; 95% CI, 1.29-4.72; P = .007). Compared with controls, cases required more days of hospitalization after the MABC index date (28 vs 12 days; P = .01) and had decreased 1-year post-transplant survival (78% vs 89%; log-rank P = .02). One-year mortality appeared highest for cases who acquired M. abscessus subsp. abscessus (31% mortality) or had extrapulmonary infections (43% mortality). In this large case-control study, prolonged post-transplant ventilator duration was associated with early post-lung transplant MABC acquisition, which in turn was associated with increased hospital-days and mortality. Further studies are needed to determine the best strategies for MABC prevention, surveillance, and management.

Anesthesia for lung transplantation in children under 12 years of age: a single center experience of China

PurposeThis study aims to provide a comprehensive overview of anesthesia management strategies employed in pediatric lung transplantation.MethodsA retrospective analysis was conducted on data from 14 pediatric patients who underwent lung transplantation at the Wuxi Center between September 2019 and November 2022. Patient demographics, surgical particulars, airway management, utilization of extracorporeal support, fluid administration, blood gas and electrolyte profiles, and postoperative outcomes were systematically documented and subsequently summarized.ResultsOf the 14 patients, 7 received extracorporeal membrane oxygenation (ECMO) and 1 received cardiopulmonary bypass (CPB). The average operation time was 303 ± 53 min, with the median extubation time of 26 h. The entirety of pediatric lung transplant procedures was executed successfully, resulting in the discharge of thirteen patients postoperatively. Regrettably, one patient died due to infectious shock on the fourth postoperative day.ConclusionThe achievement of successful pediatric lung transplantation necessitates effective perioperative anesthesia management, with a focal emphasis on circulatory control. Real-time measurements serve as the cornerstone for decision-making. Proactive administration of vasoactive agents is integral to sustaining hemodynamic stability. The judicious assessment of ECMO necessity is paramount, favoring central ECMO during the surgical intervention.

Prognostic factors in lung transplantation after extracorporeal membrane oxygenation bridging therapy: a systematic review and meta-analysis.

Extracorporeal membrane oxygenation (ECMO) has recently emerged as a critical support system for lung function in patients awaiting lung transplantation. This meta-analysis investigates the prognostic factors of lung transplantation following ECMO bridging therapy. A comprehensive search was conducted in PubMed, Cochrane Library, Embase, CINAHL, Web of Science, Scopus, and ProQuest databases from inception to August 11, 2023. Included were cohort or case-control studies focusing on prognostic factors of lung transplantation with ECMO bridging therapy. Data extraction was performed independently, and study quality was assessed. A meta-analysis was carried out using RevMan 5.4 and Stata17.0 software to aggregate mortality rates and pertinent prognostic factors of ECMO as a bridge to lung transplantation. The search identified eight trials encompassing 1,086 participants. The prognosis of patients undergoing lung transplantation with ECMO bridging was significantly associated with several factors: prolonged ECMO support [odds ratio 1.07, 95% confidence interval (CI): 1.02-1.12, I2=77%], deterioration in liver and kidney function (odds ratio 3.62, 95% CI: 2.37-5.54, I2=0%), and complications during ECMO (odds ratio 2.24, 95% CI: 1.45-3.44, I2=5%). Prolonged ECMO support, declining liver and kidney functions, and complications during ECMO are vital prognostic factors in lung transplantation following ECMO bridging therapy.

(1404) - Assessing the Relationship Between Pre-Operative Opioid Use and Outcomes of Patients with Cystic Fibrosis Undergoing Lung Transplantation

(1404) - Assessing the Relationship Between Pre-Operative Opioid Use and Outcomes of Patients with Cystic Fibrosis Undergoing Lung Transplantation

(938) - Fundoplication in Patients with Connective Tissue Disease Undergoing Lung Transplantation

(938) - Fundoplication in Patients with Connective Tissue Disease Undergoing Lung Transplantation

Defining Optimal Settings for Lung Cryobiopsy in End-Stage Pulmonary Disease. A Human, Ex Vivo, Diseased Lung Clinical Trial.

To evaluate optimal settings of probe size, freezing time, and distance to the pleura that influence the size and quality of biopsy specimens during transbronchial lung cryobiopsies in ESPD. We prospectively recruited 17 patients undergoing lung transplantation. We created a nonperfused ex vivo bronchoscopy setting to perform multiple cryobiopsies with different probe sizes (1.7, 1.9, and 2.4mm), freezing times (3, 5, 7, 10, 20, 30 seconds), and probe distance from pleura (5, 10, and 20mm). Alveolated pulmonary parenchyma area≥50% in histology was considered a good quality biopsy, with a minimum procedural artifact. We used logistic regression to identify independent parameters as risk factors for histologic adequacy. A total of 545 cryobiopsies were obtained from 34 explanted lungs after pneumonectomy for lung transplantation. The mean maximum diameter of the specimen achieved with the 1.7 probe was larger (13.5mm) than those obtained with 1.9 and 2.4mm probes (11.3 and 10.7mm, P= 0.07). More pleural macroscopic damage and pleural tissue in histology occurred with the 2.4mm probe ( P <0.001). There was no difference in the quality of specimens between the different freezing times and the distance from the pleura. Freezing time and distance from the pleura did not affect the histologic quality for diagnosing ESPD in severely damaged lungs. Smaller cryoprobe size did not negatively affect sample adequacy.

Elucidating immune cell dynamics in chronic lung allograft dysfunction: A comprehensive single-cell transcriptomic study

Chronic Lung Allograft Dysfunction (CLAD) is a critical post-transplant complication that predominantly determines the long-term survival rates and quality of life of patients undergoing lung transplantation. The limited efficacy of current immunosuppressive strategies underscores our incomplete understanding of the immunological aspects of CLAD. Hence, there is an urgent need for more comprehensive and targeted research to unravel the complex interplay of immune cells in the development and progression of CLAD. This study conducts an in-depth analysis of the immune environment in CLAD. By examining the gene expression profiles of T cells, natural killer cells, B cells, macrophages, and monocytes, we have elucidated a unique immunological landscape in CLAD compared to healthy controls. We highlight the heterogeneity within the immune populations and provide a comprehensive understanding of the immune mechanisms driving CLAD. Enrichment analysis identified specific pathways that are either overactive or suppressed in CLAD, revealing potential molecular targets for therapeutic intervention. Our findings emphasize the crucial role of T cells in the pathophysiology of CLAD, coordinating the immune response and revealing an amplified immune cell network, potentially leading to maladaptive tissue responses. By integrating a comprehensive cellular and molecular portrait of the immune environment, our research not only deepens our understanding of the pathogenesis of CLAD but also lays a foundational approach for the development of targeted therapies.

Chronic interstitial lung disease associated with systemic lupus erythematosus: A multicentric study of 89 cases.

Chronic interstitial lung disease (ILD) occurs rarely with systemic lupus erythematosus (SLE) as compared with other connective tissue diseases. This multicentric retrospective study of patients with SLE-ILD from the OrphaLung and French SLE networks during 2005-2020 aimed to describe the characteristics of patients with SLE-ILD and analyse factors associated with prognosis. We analysed data for 89 patients with SLE-ILD (82 women, 92.1%) (median age at SLE diagnosis: 35 years [interquartile range 27-47]). All patients met the 2019 EULAR/ACR criteria for the diagnosis of SLE. Forty two (47.2%) patients were positive for anti-ribonuclear protein antibodies and 45 (50.6%) for anti SSA/Ro antibodies. A total of 58 (65.2%) patients had another connective tissue disease: Sjögren's syndrome (n = 33, 37.1%), systemic sclerosis (n = 14, 15.7%), inflammatory myopathy (n = 6, 6.7%), or rheumatoid arthritis (n = 6, 6.7%). ILD was diagnosed along with SLE in 25 (28.1%) patients and at a median of 6 (0-14) years after the SLE diagnosis. The most frequent CT pattern was suggestive of non-specific interstitial pneumonia (n = 41, 46.0%) with or without superimposed organizing pneumonia. After a median follow-up of 86.5 [39.5-161.2] months, 18 (20.2%) patients had died and 6 (6.7%) underwent lung transplantation. The median 5-year and 10-year transplantation-free survival were 96% (92-100) and 87% (78-97). In total, 44 (49.4%) patients showed ILD progression. Cutaneous manifestations and Raynaud's phenomenon were associated with better survival. Only forced vital capacity was significantly associated with survival and ILD progression. ILD is a rare manifestation of SLE with good overall prognosis but with possible risk of ILD progression. Patients with SLE-ILD frequently have another connective tissue disease.

Randomized trial of routine versus on-demand intraoperative extracorporeal membrane oxygenation in lung transplantation: A feasibility study

In most centers, extracorporeal membrane oxygenation (ECMO) is the preferred means to provide cardiopulmonary support during lung transplantation. However, there is controversy about whether intraoperative venoarterial (VA) ECMO should be used routinely or selectively. A randomized controlled trial is the best way to address this controversy. In this publication, we describe a feasibility study to assess the practicality of a protocol comparing routine versus selective VA ECMO during lung transplantation. This prospective, single-center, randomized controlled trial screened all patients undergoing lung transplantation. Exclusion criteria include retransplantation, multi-organ transplantation, and cases where ECMO is mandatory. We determined that the trial would be feasible if we could recruit 19 participants over six months with less than 10% protocol violations. Based on the completed feasibility study, we conclude that the protocol is feasible and safe, giving us the impetus to pursue a multicenter trial with little risk of failure due to low recruitment.

Intracellular Pseudomonas aeruginosa within the Airway Epithelium of Cystic Fibrosis Lung Tissues.

Pseudomonas aeruginosa (P.a.) is the major bacterial pathogen colonizing the airways of adult cystic fibrosis (CF) patients and causes chronic infections that persist despite antibiotic therapy. Intracellular bacteria may represent an unrecognized reservoir of bacteria that evades the immune system and antibiotic therapy. While the ability of P.a. to invade and survive within epithelial cells has been described in vitro in different epithelial cell models, evidence of this intracellular lifestyle in human lung tissues is currently lacking. To detect and characterize intracellular P.a. in CF airway epithelium from human lung explant tissues. We sampled the lung explant tissues from CF patients undergoing lung transplantation and non-CF lung donor control. We analyzed lung tissue sections for the presence of intracellular P.a. by quantitative culture and microscopy, in parallel to histopathology and airway morphometry. P.a. was isolated from the lungs of 7 CF patients undergoing lung transplantation. Microscopic assessment revealed the presence of intracellular P.a. within airway epithelial cells in 3 out of the 7 patients analyzed, at a varying but low frequency. We observed those events occurring in lung regions with high bacterial burden. This is the first study describing the presence of intracellular P.a. in CF lung tissues. While intracellular P.a. in airway epithelial cells are likely relatively rare events, our findings highlight the plausible occurrence of this intracellular bacterial reservoir in chronic CF infections.

Plasma concentrations of histidine-rich glycoprotein in primary graft dysfunction after lung transplantation.

Histidine-rich glycoprotein has been reported as an anti-inflammatory glycoprotein that inhibits acute lung injury in mice with sepsis and as a prognostic biomarker in patients with sepsis. We investigated the relationship between plasma concentrations of histidine-rich glycoprotein and the risk of occurrence of primary graft dysfunction. According to the primary graft dysfunction grade at post-transplant 72 h, patients who underwent lung transplantation were divided into three groups: non-primary graft dysfunction group (grade 0-1), moderate primary graft dysfunction group (grade 2), and severe primary graft dysfunction group (grade 3). The plasma concentrations of histidine-rich glycoprotein measured daily during the first post-transplant 7 days were compared among the three groups. Appropriate cutoff values of the concentrations were set for survival analyses after lung transplantation. A total of 68 patients were included. The plasma histidine-rich glycoprotein concentration at post-transplant 72 h was significantly lower in the severe primary graft dysfunction group (n = 7) than in the other two groups [non-primary graft dysfunction group (n = 43), P = 0.042; moderate primary graft dysfunction group (n = 18), P = 0.040]. Patients with plasma histidine-rich glycoprotein concentration ≥34.4 µg/ml at post-transplant 72 h had significantly better chronic lung allograft dysfunction-free survival (P = 0.012) and overall survival (P = 0.037) than those with the concentration <34.4 µg/ml. Plasma histidine-rich glycoprotein concentrations at post-transplant 72 h might be associated with the risk of development of primary graft dysfunction.

Lung Transplantation in Pulmonary Arterial Hypertension: The Portuguese Experience

In patients with pulmonary arterial hypertension (PAH), refractory to medical therapy, lung transplantation emerges as an option. This study describes the outcomes of 8 PAH patients who underwent lung transplantation. A retrospective, single-center study was conducted among patients with PAH who underwent lung transplantation in our center. Patients had a median age of 46 years, with female sex predominance (75%). Causes of HAP were pulmonary veno-occlusive disease (n = 5, 62.5%), idiopathic PAH (n = 2, 25%), and heritable PAH (n = 1, 12.5%). Pre-transplant hemodynamics revealed a median mean pulmonary artery pressure of 58.5 mm Hg (48-86). All patients received bilateral lung transplants with extracorporeal membrane oxygenation support, displaying immediate post-transplant hemodynamic improvement. Primary graft dysfunction grade 3 (PGD 3) was observed in 75% of patients. Five patients (62.5%) died, with a 72.9% survival at 12 months and 29.2% at 24 months post-transplantation. Our study reveals the complexity and challenges of lung transplants in patients with PAH. Despite notable immediate hemodynamic improvements, high rates of PGD 3 and the survival rate remain a concern. Further research to define optimal peri and post-transplant management to improve survival is required.

Comparison of the safety and cost-effectiveness of nebulized liposomal amphotericin B and amphotericin B deoxycholate for antifungal prophylaxis after lung transplantation

IntroductionFungal infection after lung transplantation can lead to poor clinical outcome, for which lung transplant recipients require prophylaxis. One of the antifungal agents used after lung transplantation is nebulized amphotericin B (AMB). Nebulized AMB causes adverse events such as dyspnea and airway irritation, and long-term use leads to high economic costs. So far, prophylactic regimens employing AMB deoxycholate (AMB-d) and liposomal AMB (L-AMB) have been developed. This study compared the efficacy, safety, and cost of AMB-d and L-AMB. Patients and methodsPatients who underwent lung transplantation at Kyoto University Hospital from January 2021 to May 2023 were included in this study. Thirty-three patients received nebulized AMB-d, whereas 29 received nebulized L-AMB. ResultsBoth regimens maintained comparable prophylactic efficacy regarding the development of fungal infection in the AMB-d and L-AMB groups (3.0% vs. 3.4%, P = 0.877). Patients treated with nebulized L-AMB experienced fewer respiratory-related adverse reactions than those treated with nebulized AMB-d (6.9% vs. 30.3%, P < 0.05), leading to a longer treatment duration with L-AMB than with AMB-d. Additionally, the daily cost of administering L-AMB was lower than that of administering AMB-d (3609 Japanese yen vs. 1792.3 Japanese yen, P < 0.05). DiscussionThese results suggest that nebulized L-AMB is safer and more cost-effective than nebulized AMB-d, with comparable efficacy.

PM10 increases mortality risk in rheumatoid arthritis-associated interstitial lung disease

ObjectivesThe effect of air pollution on the prognosis of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) remains poorly understood. We aimed to evaluate the effect of long-term exposure to particulate matter...

Optimizing the initial tacrolimus dosage in Chinese children with lung transplantation within normal hematocrit levels.

The appropriate initial dosage of tacrolimus is undefined in Chinese pediatric lung transplant patients with normal hematocrit values. The purpose of this study is to optimize the initial dose of tacrolimus in Chinese children who are undergoing lung transplantation and have normal hematocrit levels. The present study is based on a published population pharmacokinetic model of tacrolimus in lung transplant patients and uses the Monte Carlo simulation to optimize the initial tacrolimus dosage in Chinese children with lung transplantation within normal hematocrit levels. Within normal hematocrit levels, for children with lung transplantation who do not carry the CYP3A5*1 gene and have no coadministration with voriconazole, it is recommended to administer tacrolimus at a dosage of 0.02 mg/kg/day, divided into two doses, for children weighing 10-32 kg, and a dosage of 0.03 mg/kg/day, also divided into two doses, for children weighing 32-40 kg. For children with lung transplantation who carry the CYP3A5*1 gene and have no coadministration with voriconazole, tacrolimus dosages of 0.02, 0.03, and 0.04 mg/kg/day split into two doses are recommended for children weighing 10-15, 15-32, and 32-40 kg, respectively. For children with lung transplantation who do not carry the CYP3A5*1 gene and have coadministration with voriconazole, tacrolimus dosages of 0.01 and 0.02 mg/kg/day split into two doses are recommended for children weighing 10-17 and 17-40 kg, respectively. For children with lung transplantation who carry the CYP3A5*1 gene and have coadministration with voriconazole, a tacrolimus dosage of 0.02 mg/kg/day split into two doses is recommended for children weighing 10-40 kg. It is the first time to optimize the initial dosage of tacrolimus in Chinese children undergoing lung transplantation within normal hematocrit.

Small airways morphological alterations associated with functional impairment in lymphangioleiomyomatosis

BackgroundLymphangioleiomyomatosis (LAM) is a rare neoplastic and cystic pulmonary disease characterized by abnormal proliferation of the so-called LAM cells. Despite the functional obstructive pattern observed in most patients, few studies investigated the morphological changes in the small airways, most of them in patients with severe and advanced LAM undergoing lung transplantation. Understanding the morphological changes in the airways that may occur early in the disease can help us understand the pathophysiology of disease progression and understand the rationale for possible therapeutic approaches, such as the use of bronchodilators. Our study aimed to characterize the morphological alterations of the small airways in patients with LAM with different severities compared to controls, and their association with variables at the pulmonary function test and with LAM Histological Score (LHS).MethodsThirty-nine women with LAM who had undergone open lung biopsy or lung transplantation, and nine controls were evaluated. The histological severity of the disease was assessed as LHS, based on the percentage of tissue involvement by cysts and infiltration by LAM cells. The following morphometric parameters were obtained: airway thickness, airway closure index, collagen and airway smooth muscle content, airway epithelial TGF-β expression, and infiltration of LAM cells and inflammatory cells within the small airway walls.ResultsThe age of patients with LAM was 39 ± 8 years, with FEV1 and DLCO of 62 ± 30% predicted and 62 ± 32% predicted, respectively. Patients with LAM had increased small airway closure index, collagen and smooth muscle content, and epithelial TGF-beta expression compared with controls. Patients with LAM with the more severe LHS and with greater functional severity (FEV1 ≤ 30%) presented higher thicknesses of the airways. Bronchiolar inflammation was mild; infiltration of the small airway walls by LAM cells was rare. LHS was associated with an obstructive pattern, air trapping, and reduced DLCO, whereas small airway wall thickness was associated with FEV1, FVC, and collagen content.ConclusionLAM is associated with small airway remodelling and partial airway closure, with structural alterations observed at different airway compartments. Functional impairment in LAM is associated with airway remodelling and, most importantly, with histological severity (LHS).