Pos0866 Large-Vessel Involvement in Anca-Associated Vasculitis: A Multicenter Case-Control Study

Background: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) primarily affects small vessels. Large-vessel involvement (LVI) is rare. Objectives: We aimed to describe the characteristics of LVI, to identify associated risk factors, and to describe its therapeutic management. Methods: This multicenter case-control (1:2) study included patients with AAV according to the ACR/EULAR classification [1] and LVI as defined by the Chapel Hill nomenclature [2], together with controls matched for age, sex, and AAV type. Results: We included 26 patients, 15 (58%) of whom were men, with a mean age of 56.0 ±17.1 years. The patients had granulomatosis with polyangiitis (n=20), or microscopic polyangiitis (n=6). LVI was inaugural in 18 of 26 patients, but occurred after the diagnosis of AAV in the remaining eight patients. The affected vessels included the aorta (n=18; 69%) supra-aortic trunks (n=9; 35%), lower-limb arteries (n=5; 19%), mesenteric arteries (n=5; 19%), renal arteries (n=4; 15%), and upper-limb arteries (n=2; 8%). The diagnosis of LVI was incidental in 15 patients (58%), occurring during imaging for a flare-up of AAV. In patients with symptoms (n=11), pain was the most common symptom (n=10), particularly back or abdominal pain for aortic injury (n=6), neck pain for carotid injury (n=1), inguinal pain for iliac injury (n=1), and abdominal pain for mesenteric artery injury with ischemia (n=2). Imaging showed wall thickening (n=10; 38%), perivascular inflammation (n=8; 31%), aneurysms (n=5; 19%), and stenosis (n=4; 15%). Comparisons with the control group (52 patients) revealed that LVI was significantly associated with neurological manifestations (OR=3.23 [95% CI: 1.11-10.01, p=0.03]), but not with cardiovascular risk factors (OR=0.70 [95% CI: 0.23-2.21, p=0.60]), or AAV relapse (OR=2.01 [95% CI: 0.70-5.88, p=0.16]). All patients received corticosteroids, in combination with an immunosuppressant in 24 (92%), mostly cyclophosphamide (n=10, 38%) or rituximab (n=9, 35%). Conclusion: Regardless of distinctions based on vessel size, clinicians should consider LVI as a potential manifestation of AAV, with the aorta commonly affected. The risk of developing LVI appears to be greater for clinical phenotypes of AAV with neurological involvement. Standard AAV treatment can be used to manage LVI. References: [1] Robson JC, Grayson PC, Ponte C, Suppiah R, Craven A, Judge A, et al. 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria for granulomatosis with polyangiitis. Ann Rheum Dis. 2022 Mar;81(3):315–20. [2] Jennette JC, Falk RJ, Bacon PA, Basu N, Cid MC, Ferrario F, et al. 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Arthritis Rheum. 2013 Jan;65(1):1–11. Acknowledgements: NIL. Disclosure of Interests: None declared.