Kanj, A.N.

Abstract Background Takayasu arteritis (TA) is a rare large-vessel vasculitis that can involve pulmonary arteries, potentially leading to pulmonary hypertension (PH). Noninvasive evaluation by echocardiography is often used, but its reliability in confirming and characterizing PH in TA is unclear. We investigated the role of invasive hemodynamic testing in TA patients with suspected PH. Methods We retrospectively identified 10 patients with TA meeting 2022 ACR criteria and suspected PH based on symptoms and/or echocardiography; all underwent echocardiography followed by right heart catheterization (RHC).PH was defined as mean pulmonary artery pressure (mPAP) >20 mmHg. PH was classified as pre-capillary (pulmonary artery wedge pressure [PAWP] ≤15 mmHg), post-capillary (PAWP >15 mmHg), or combined (PAWP >15 mmHg with elevated pulmonary vascular resistance). Echocardiographic parameters were collected where available, along with invasive hemodynamics, cardiac biomarkers (BNP/NT-proBNP), inflammatory markers (ESR, CRP), NYHA functional class, and outcomes. Results Median age was 44 years (range 18-58), and 90% were female. Based on invasive hemodynamics, pre-capillary PH was present in 5 patients, combined pre-/post-capillary PH in 3, and isolated post-capillary PH in 2. Median mPAP was 38 mmHg (IQR 30-55), median pulmonary vascular resistance 3.5 Wood units (IQR 2.3-8.7), and median PAWP 15 mmHg (IQR 8-24). Echocardiography frequently underestimated disease severity. Several patients with absent or low tricuspid regurgitation velocity (≤1.0 m/s), where measurable, demonstrated severe pre-capillary PH on RHC, including pulmonary vascular resistance >6 Wood units. Among patients with available data, NT-proBNP levels ranged from 59 to 51,968 pg/mL, and inflammatory markers varied widely (CRP <0.3 to 107.9 mg/L). Among patients with available NYHA data, most were class II-III. Conclusions In this TA cohort, RHC was essential to confirm and phenotype PH, which was present in the majority of those with suspected PH. Echocardiography alone often underestimated or misclassified PH in TA - in one case missing severe pre-capillary PH due to an absent TR signal, and in another failing to discern elevated left-heart filling pressure. Invasive assessment prevented missed diagnoses and misclassification, ensuring appropriate management of TA-associated PH This abstract is funded by: None

Abstract Rationale Blood eosinophil count (BEC) has emerged as a marker of inflammatory endotypes in bronchiectasis. We examined whether bacterial and mold respiratory culture profiles differ by BEC, comparing patients with BEC ≥300 cells/μL to those with lower BEC. Methods We analyzed patients with bronchiectasis evaluated at a specialized clinic (2019-2025) who had contemporaneous respiratory bacterial and fungal cultures and BEC. Patients were stratified by BEC <300 vs ≥ 300 cells/μL; those with BEC <300 were further subclassified (<100 and 100-299 cells/μL) for figure presentation only. Cultures were evaluated for overall growth and organism-specific prevalence across eosinophil strata, focusing on the most frequently isolated organisms. Group comparisons were performed using Fisher’s exact test. Results A total of 608 patients met inclusion criteria (median age 69 years [IQR 61-77], 72% female); 138 (22.7%) had BEC ≥300 cells/μL. Bacterial growth occurred in 277 patients (45.6%) and mold growth in 366 (60.2%). The odds of bacterial growth were similar between BEC ≥300 and <300 groups (47.1% vs 45.2%). In contrast, BEC ≥300 was associated with higher odds of mold growth (68.1% vs 58.0%; OR 1.54, p = 0.038). Pseudomonas species (18.9%) were the most common bacterial isolates and comprised a greater proportion of all bacterial isolates in patients with BEC ≥300 compared with lower BEC (44.7% vs 30.0%; OR 1.89, p = 0.019). Penicillium species (27.5%), followed by Aspergillus (26.9%), were the most frequently isolated molds, with no differences in distribution across BEC strata. Conclusions BEC ≥300 cells/μL was associated with increased odds of respiratory mold growth and enrichment of Pseudomonas species, suggesting that eosinophil-defined endotypes may identify patients with distinct airway microbiologic patterns that could inform future phenotyping and treatment strategies. This abstract is funded by: None

Abstract Background Single breath diffusing capacity of the lung for carbon monoxide (DLCO) remains the most widely used test to assess pulmonary gas exchange. GLI DLCO reference equations are based on a larger, more diverse dataset and offer age-specific and internally consistent reference values. However, their impact on interpretation in a real-world population remains uncertain. Research Question Describe the direction and magnitude of DLCO interpretation changes resulting from our multicenter PFT laboratory transition from Miller to GLI reference equations. Study Design and Methods In this multicenter cross-sectional study, we reanalyzed 88,060 DLCO measurements in a large pulmonary function laboratory database performed between 2016 and 2022 using GLI and Miller reference equations, stratified by self-reported race and ethnicity. Baseline patient characteristics and lung function measurements were summarized with continuous characteristics as median (IQR) and categorical variables as n (%). Kruskal-Wallis test was used to evaluate the difference between GLI and Miller DLCO % predicted difference between races, and two-by-two and four-by-four tables were generated to summarize the proportion of concordance and discordance of GLI to Miller severity levels. A repeated measures multivariable logistic regression was used to evaluate discordance between GLI and Miller severity and patient characteristics (age, sex, race, and BMI). Results We included 63,357 individuals with 88,060 PFT visits; 91.6% (58,076) identified as Caucasian, 5.2% (3,262) as Black, 1.4 % (895) as Asian, and 1.8% (1,113) as mixed/other race. Fifty-one percent were female with an median age of 64 years (range: 5- 85). 7.4% (6509) of DLCO results were discordant, with 0.5% (n = 439) abnormal by GLI only, and 6.9% (n = 6070) abnormal by Miller only. Compared to the Miller, GLI interpretations were associated with a greater shift toward normal interpretations. Younger age, lower BMI, female sex, and being of NE Asian, SE Asian, or Other/mixed race compared to Caucasian were associated with higher odds of discordance in DLCO severity/normal classification. Interpretation The use of GLI reference equations substantially alters the interpretation of DLCO results, shifting a meaningful subset of patients from abnormal to normal classification. While GLI reference equations offer more comprehensive, population-based approach, it is crucial to place these interpretations within the context of the patient presentation until further investigations more clearly define the clinical implications of these transitions. This abstract is funded by: none

Abstract Rationale Gastroesophageal reflux disease (GERD) is a common comorbidity in non-cystic fibrosis bronchiectasis (NCFB), yet its impact on clinical outcomes remains poorly defined. We sought to determine whether GERD is associated with worse clinical outcomes in patients with NCFB using a large, real-world database. Methods We conducted a retrospective cohort study using the TriNetX platform, identifying patients with NCFB (ICD-10 J47*) with and without concurrent GERD (ICD-10 K21*), excluding those with cystic fibrosis (ICD-10 E84*). Propensity score matching (PSM) was performed using 1:1 nearest neighbor matching without replacement, controlling for age, sex, race/ethnicity, obesity, socioeconomic risk factors, and tobacco use. Primary outcomes included pneumonia, bronchiectasis exacerbations, intensive care unit admission, mechanical ventilation, and mortality. Statistical analyses included risk ratios and Cox proportional hazards modeling for survival outcomes. Results Out of 421,710 patients with NCFB in the dataset from January 2000 to September 2025, 186,874 (44%) had a diagnosis of GERD. After propensity score matching, 179,753 patients with NCFB+GERD and 179,753 patients with NCFB-only were included (mean age 74.0±13.1 years, 58.8% female, 67.1% White). Baseline characteristics were well-balanced after matching. Median follow-up was approximately 2.5 years for both cohorts (898 vs 889 days; similar means and IQR), ensuring balanced observation time. Compared to NCFB-only, NCFB+GERD was associated with increased risks for mortality (risk ratio 1.04, 95% CI 1.02-1.05; p < 0.001), pneumonia (risk ratio 1.06, 95% CI 1.05-1.08; p < 0.001), bronchiectasis exacerbations (risk ratio 1.03, 95% CI 1.01-1.06; p = 0.006), and mechanical ventilation (risk ratio 1.14, 95% CI 1.10-1.18; p < 0.001). Intensive care unit admission rates were comparable between groups (risk ratio 1.00; p = 0.65). Conclusions In this large propensity score-matched analysis, concurrent GERD in NCFB is independently associated with increased mortality, pneumonia, bronchiectasis exacerbations, and mechanical ventilation requirements. These findings suggest GERD may represent a modifiable risk factor warranting aggressive management in NCFB patients. Study limitations include retrospective design, reliance on ICD-10 coding accuracy, and potential unmeasured confounders. Our results support systematic screening and treatment of GERD in NCFB, but whether targeted GERD management can modify the natural history of NCFB future investigation. This abstract is funded by: None

Abstract Background Sputum color is a visual marker of airway inflammation and disease activity in bronchiectasis, ranging from clear or light gray (mucoid) to yellow-green (purulent), the latter largely reflecting neutrophil myeloperoxidase release. This study evaluated associations between sputum color and common clinical markers of disease activity to determine which parameters differed most between color categories. Methods Forty spontaneous sputum samples were analyzed from 80 consecutive adults with non-cystic fibrosis bronchiectasis (median age 70 years [IQR 12]; 74% female) enrolled between January 2024 and April 2025 in an observational study. Sputum color was graded using the Murray Sputum Color Chart and classified as mucoid (color #1) or purulent (colors #2-4). Clinical parameters, including blood cell counts, C-reactive protein (CRP), fractional exhaled nitric oxide (FeNO), and results of bacterial and acid-fast bacillus cultures (induced or bronchoscopic), were obtained from medical records if available within one month of enrollment. Categorical variables were analyzed using chi-square or Fisher’s exact tests and continuous variables with the Mann-Whitney U test. A secondary analysis compared patients who could versus could not produce spontaneous sputum. Results Of 40 samples, 20 (50%) were purulent. Blood neutrophil counts (median 4.5 vs. 3.9 x109/L), neutrophil-to-lymphocyte ratios (2.5 vs. 2.6), and eosinophil counts (1.7 vs. 1.7 x109/L) did not differ significantly between groups (n = 26). FeNO was normal in all 10 patients with available data and was not analyzed further. CRP was higher among patients with purulent sputum (4.6 vs. <3 mg/L; n = 20; p = 0.044). Bacterial growth was more frequent in purulent than mucoid samples (73% vs. 31%; n = 31; p = 0.032). Isolates in the purulent group included Klebsiella, Pseudomonas, Staphylococcus, and Streptococcus (n = 2 each), and single isolates of Acetobacter, Acinetobacter, Chryseobacterium, Delftia, Enterobacter, Escherichia, and Moraxella. In the mucoid group, Pseudomonas, Staphylococcus (n = 2 each), and Stenotrophomonas (n = 1) were identified. Mycobacterial growth did not differ significantly (20% vs. 12.5%; n = 31; p = 0.65). Patients unable to produce spontaneous sputum had a higher rate of mycobacterial isolation on induced/bronchoscopic samples (43% vs. 16%; n = 54; p = 0.027), though other parameters were similar. Over 90% of measurements were obtained within three days of enrollment, and freezing did not appear to alter sputum color. Conclusions Even within a small cohort, purulent sputum was associated with higher CRP and greater bacterial growth, supporting sputum color as a rapid, inexpensive marker of disease activity in bronchiectasis. Further research should clarify whether sputum color primarily reflects bacterial colonization, airway inflammation, or both. This abstract is funded by: None

Abstract Introduction: We present a case of constrictive bronchiolitis with paraneoplastic autoimmune multi-organ syndrome (PAMS) treated with lung transplantation. To our knowledge, this is the first reported case of PAMS with constrictive bronchiolitis managed with this approach. Presentation: A 45-year-old woman presented with 3 months of dyspnea. PFTs showed severe airflow obstruction with air trapping and no immediate bronchodilator response. [FEV1 0.94L (z: -3.9), FVC 2.98L (z: -0.515), TLC 4.89L (z: 1.0), RV 1.70L (z: 2.4) and DLCO 22 ml/min/mmhg (z: 0.58)] CT chest with expiratory views showed air trapping in the left upper lobe and ground glass opacities, consistent with constrictive bronchiolitis. 6 months prior, she was diagnosed with abdominal grade 1 follicular lymphoma, treated with Bendamustine and Rituximab. One month into treatment, she developed a lichenoid rash involving the oro-gential mucosa and erythematous papular skin eruptions. Her eruptions and constrictive bronchiolitis were consistent with PAMS with pulmonary involvement. The rash improved with oral steroids and topical therapies, but her pulmonary symptoms did not. The likelihood of progression was low, so lymphoma was not a contraindication for lung transplantation. To ensure complete metabolic remission, she was further treated with R-CHOP and maintained on Rituximab. During transplant evaluation, FEV1 was 30% with NYHA class II, Karnofsky score 60 and she required 4L oxygen. She grew mycobacterium abscessus subspecies abscessus on 3 different sets of induced sputum. Secondary to radiographic findings consistent with NTM-PD (bronchial wall thickening and mucoid impaction) and pending lung transplant, she was treated with omadacycline, tedizolid, amikacin and clofazimine until sputum culture negativity (3-months). She underwent lung transplantation and received pre-operative Mycophenolate and Methylprednisolone without induction immunosuppression. Post-operatively she was started on Tacrolimus, Mycophenolate Mofetil and Prednisone. M. Abscessus therapy continued for 2 months post-transplant. At 6 months post-transplant, she is well, and PFTs are improving without evidence of organ rejection, lymphoma recurrence, or M. abscessus infection. Discussion: Pulmonary involvement in PAMS is associated with high mortality and is not reversed by treatment of the neoplasm, due to non-reversible destruction of small airways. The only disease modifying therapy is lung transplant. Her lymphoma recurrence risk was very low after 2 years of remission following initial treatment, and as her lymphoma was not associated with immunosuppression, post-transplant immunosuppression likely does not increase risk of recurrence. Additionally, while mycobacterium abscessus poses significant risks, intensive treatment in the peri-transplant period can help allow for safe transplantation.

Abstract RATIONALE: Understanding co-isolation patterns between fungi and other potentially pathogenic microorganisms in the airways of bronchiectasis patients is important for uncovering possible microbial interactions and informing treatment. Although numerous organisms have been identified in respiratory cultures, the specific patterns of their co-isolation are underexplored. OBJECTIVES: To examine the patterns of co-isolation between fungi and bacteria or mycobacteria in respiratory samples from patients with bronchiectasis across a large national health system. METHODS: We reviewed 58,170 respiratory culture tests from 8,194 patients with bronchiectasis (identified using ICD-10-CM codes J47.0, J47.1, and J47.9) across Mayo Clinic. These tests were analyzed for fungal, bacterial, and mycobacterial growth, focusing on co-isolation from the same sample. Chi-square statistics were used to compute p-values. RESULTS: Of all 18,983 samples cultured for fungi, 59% were positive. Of these, 72% yielded yeasts and 40% molds. Among the 11,372 samples cultured for both fungi and bacteria, 681 (6%) showed co-isolation, representing 54% of positive bacterial cultures. The odds of bacterial co-isolation with fungi were 1.4 (95% CI: 1.3-1.6; p < 0.01), driven by yeasts (OR: 1.5, 95% CI: 1.3-1.7; p < 0.01), rather than molds (OR: 1.0, 95% CI: 0.9-1.2; p = 0.8). Pseudomonas species, the most common bacterial isolate, had a higher likelihood of co-isolation with fungi (OR: 1.6, 95% CI: 1.3-1.9; p < 0.01), particularly yeasts (OR: 1.6, 95% CI: 1.4-2.0; p < 0.01). Molds, including those from genera such as aspergillus and penicillium, did not show a significant association with the isolation of pseudomonas. On the other hand, among the 15,859 samples cultured for both fungi and mycobacteria, 1352 (9%) showed co-isolation, representing 62% of positive mycobacterial cultures. Odds of co-isolation were 1.7 (95% CI: 1.5-1.8; p < 0.01). Molds showed a stronger association with isolation of mycobacteria (OR: 1.7, 95% CI: 1.5-1.9; p < 0.01) compared to bacteria, while yeasts also had elevated odds (OR: 1.4, 95% CI: 1.2-1.5). CONCLUSIONS: Distinct patterns of fungal co-isolation with bacteria and mycobacteria have been observed in bronchiectasis, which may influence key aspects of the disease, such as inflammation and mucociliary dysfunction. Advanced metagenomic and immunoprofiling techniques could provide deeper insights into these co-isolation patterns while considering other factors like clinical demographics, previous antibiotic exposure, and disease severity. Understanding whether altering the mycobiome could modify these aspects and improve outcomes remains an important avenue for research.