Al-Itelat, A

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