ARRS 2022 Abstracts

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1269. ILD Patterns in Patients With ANCA Associated Vasculitis
Authors * Denotes Presenting Author
  1. Karen Rodriguez *; Massachusetts General Hospital
  2. Brett Doliner; Massachusetts General Hospital
  3. Sydney Montesi; Massachusetts General Hospital
  4. Xiaoquing Fu; Massachusetts General Hospital
  5. Zachary Wallace; Massachusetts General Hospital
  6. Amita Sharma; Massachusetts General Hospital
Objective:
The aim of this North-American-based retrospective study was to determine the incidence of Interstitial Lung Disease (ILD) and characterize the CT patterns in patients with ANCA-associated vasculitis (AAV). In particular, the study assessed the incidence of recently described signs in connective tissue-related ILD, including the anterior upper lobe sign, straight edge sign, and exuberant honeycombing.

Materials and Methods:
A consecutive inception of a PR3- or MPO-ANCA+ AAV multi-center cohort of 698 patients assembled between 2002 and 2019 was screened for ICD-9/10 codes relevant to the diagnosis of ILD. Thin section chest CT scans were available for review in 110/149 patients. Each patient had an average of 4.6 chest CT scans. Two independent board-certified radiologists evaluated available chest CT images for presence or absence of ILD and characterized findings into ILD patterns. UIP was further divided into UIP-IPF and UIP-CTD based on the presence of anterior upper lobe, exuberant honeycombing or straight edge signs. Non-UIP ILD subtypes, including NSIP, OP, HP, and LIP, were subclassified into fibrotic and nonfibrotic.

Results:
A total of 149 AAV-ILD cases were identified to have ILD (21%). Patients with AAV-ILD were older (67±12 years vs 58±18 years, p<0.001) than those with AAV-non-ILD; sex distribution was similar (55% vs 60% women, p=0.7). CT patterns of ILD were identified in 76/110 patients; 61 patients had features of fibrotic ILD, and 15 patients had non fibrotic ILD. Fibrotic patterns included UIP in 27/61 patients, NSIP/OP in 15/61 patients, NSIP in 6/61 patients, and OP in 13/61 patients. UIP patterns were divided into UIP-IPF (n=5) and UIP-CTD (n=22) based on presence of exuberant honeycombing, anterior upper lobe sign, and straight edge signs. The 34 patients who did not have ILD had consolidation, solid or ground glass nodules, emphysema, and bronchiectasis.

Conclusion:
In our retrospective review, most patients with AAV-ILD had a fibrotic pattern at presentation or follow up, including UIP, fibrotic NSIP, and OP. UIP-CTD fibrotic pattern was more common than UIP-IPF, manifesting as exuberant honeycombing, the anterior upper lobe sign and straight edge sign. AAV-ILD should be included in the differential when these CT signs are identified. Most other patients had OP or NSIP, which may have an association to UIP-CTD pattern. Additional studies are needed to better characterize this possible association.