Ab0781 large vessel involvement in antineutrophil cytoplasmic antibody-associated vasculitis

Background Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is currently categorized under the small vessel vasculitides and includes granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA) [1]. There is limited knowledge about large vessel involvement in AAV (L-AAV); mainly described in case reports and small series. L-AAV can involve temporal arteries (TA-AAV), aorta (A-AAV), and periaortic soft tissue (PA-AAV). Objectives The objective of this study was to investigate the characteristics of L-AAV. Methods Patients older than 18 years at diagnosis of TA-AAV, A-AAV and PA-AAV seen at a single institution between January 1, 2000, and December 31, 2021, were identified through a proprietary medical text search algorithm. Patients were included if diagnosed with L-AAV by the treating physician, fulfilled 2022 American College of Rheumatology/ European Alliance of Associations for Rheumatology classification criteria for GPA, MPA or EGPA, had positive ANCA, and had more than one outpatient or inpatient visit. Arteritis of the temporal artery was based on histopathology whereas the diagnosis of aortitis and periaortitis could be either based on radiology or histopathology. Results The study cohort consists of 36 patients with L-AAV. Of those, 23 had p-ANCA/ MPO-ANCA and 13 had c-ANCA/ PR3- ANCA. Mean (SD) age at AAV diagnosis was 63.4 (12.79); 20 (56%) were male. Seventeen patients had TA-AAV, 10 had A-AAV and 9 had PA-AAV (Table 1). Most of the patients (n=25, 69%) were diagnosed with large vessel involvement and AAV within a one-year timespan. Inflammatory markers were elevated at the time of diagnosis of large vessel involvement. Twenty-five (69%) patients had histopathologic confirmation of AAV diagnosis. There was no overlap between TA-AAV, A-AAV and PA-AAV groups. Of the 17 patients with TA-AAV, 6 had inflammation of a temporal artery branch vessel. The most frequent site of involvement in the A-AAV group was the ascending thoracic aorta, whereas in the PA-AAV group, the abdominal aorta was most frequently involved. Glucocorticoids (36/36), rituximab (19/36), and methotrexate (18/36) were the most frequent treatments. During the study period 8 patients died (4 in TA-AAV, 3 in A-AAV, and 1 in PA-AAV). There was no difference in mortality between this cohort of L-AAV patients and the general population (standardized mortality ratio: 0.98; 95% CI, 0.42- 1.93). Conclusion This is the largest single-center cohort of patients with L-AAV to date. Clinicians should consider L-AAV in the differential diagnosis of vasculitides especially in the context of positive ANCA and atypical organ manifestations. References [1]Jennette JC, Falk RJ, Bacon PA, et al. 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Arthritis Rheum 2013; 65 :1–11. doi:10.1002/art.37715 Table 1. Features of L-AAV cohort Temporal Artery Vasculitis (N=17) Aortitis (N=10) Periaortitis (N=9) Total (N=36) Demographics Mean (SD) age at AAV diagnosis 68.8 (7.07) 56.2 (16.64) 61.2 (13.05) 63.4 (12.79) Sex, male n (% ) 9 (53) 4 (40) 7 (78) 20 (56) Race, white n (% ) 17 (100) 9 (90) 7 (78) 33 (92) Duration of follow-up from AAV diagnosis years, median (IQR ) 4.5 (0.1- 12.6) 9.5 (2.2 – 16.9) 4.7 (1.8 – 6.2) 4.7 (1.0 – 11.8) AAV GPA, n (% ) 3 (18) 6 (60) 6 (67) 15 (42) MPA, n (% ) 13 (76) 4 (40) 3 (33) 20 (56) EGPA, n (% ) 1 (6) 0 (0) 0 (0) 1 (3) Histological confirmation of AAV, n (%) * 11 (65) 6 (60) 8 (89) 25 (69) Clinical manifestations before or at AAV diagnosis Constitutional symptoms, n (% ) 16 (94) 6 (60) 7 (78) 29 (81) Cutaneous, n (% ) 1 (6) 1 (10) 0 (0) 2 (6) Mucous membranes/ eyes, n (% ) 1 (6) 2 (20) 1 (11) 4 (11) ENT, n (% ) 5 (29) 8 (80) 5 (56) 18 (50) Cardiovascular, n (% ) 1 (6) 0 (0) 0 (0) 1 (3) Gastrointestinal, n (% ) 0 (0) 1 (10) 0 (0) 1 (3) Pulmonary, n (% ) 5 (29) 2 (20) 5 (56) 12 (33) Renal, n (% ) 6 (35) 0 (0) 4 (44) 10 (28) Nervous system, n (% ) 8 (47) 1 (10) 0 (0) 9 (25) *Histological confirmation of AAV, other than large vessel pathology Acknowledgements: NIL. Disclosure of Interests Mahmut Kaymakci: None declared, Mohanad Elfishawi: None declared, Hannah Langenfeld: None declared, Andrew Hanson: None declared, Cynthia S. Crowson: None declared, Umar Ghaffar: None declared, Matthew Koster: None declared, Ulrich Specks Shareholder of: AbbVie, Pfizer, Johnson & Johnson, Consultant of: AstraZeneca, ChemoCentryx, Grant/research support from: Genentech, AstraZeneca, GSK, Bristol Myer Squibb, Kenneth J Warrington Consultant of: Chemocentryx, Sanofi, Grant/research support from: Eli Lilly, Kiniksa, GSK.