Comparison of idiopathic (isolated) aortitis and giant cell arteritis-related aortitis. A French retrospective multicenter study of 117 patients

International audience; Objectives: The aim of the study was to compare clinical/imaging findings and outcome in patients with idiopathic (isolated aortitis, IA) and with giant cell arteritis (GCA)-related aortitis.Methods: Patients from 11 French internal medicine departments were retrospectively included. Aortitis was defined by aortic wall thickening > 2 mm and/or an aortic aneurysm on CT-scan, associated to inflammatory syndrome. Patients with GCA had at least 3 ACR criteria. Aortic events (aneurysm, dissection, aortic surgeries) were reported, and free of aortic events-survival were compared.Results: Among 191 patients with non-infectious aortitis, 73 with GCA and 44 with IA were included. Patients with IA were younger (65 vs 70y, p = 0.003) and comprised more past/current smokers (43 vs 15%, p = 0.0007). Aortic aneurisms were more frequent (38% vs 20%, p = 0.03) and aortic wall thickening was more pronounced in IA. During follow-up (median = 34 months), subsequent development of aortic aneurysm was significantly lower in GCA when compared to IA (p = 0.009). GCA patients required significantly less aortic surgery during follow-up than IA patients (p = 0.02). Mean age, sex-ratio, inflammatory parameters and free of aortic aneurism-survival were equivalent in patients with IA ≥ 60y when compared to patients with GCA-related aortitis.Conclusions: IA is more severe than aortitis related to GCA, with higher proportions of aortic aneurism at diagnosis and during follow-up. IA is a heterogeneous disease and its prognosis is worse in younger patients < 60y. Most patients with IA ≥ 60y share many features with GCA-related aortitis.