Background Chronic periaortitis (CP) is rare disease that involves the aorta which is characterized by a fibro-inflammatory periaortic cuff in imaging studies and adventitia-predominant inflammation and fibrosis in histopathology. Associations between aortitis and idiopathic retroperitoneal fibrosis, inflammatory abdominal aortic aneurysm had been reported, and this spectrum of disorders is now categorized as CP. CP has aroused controversy on the question of incorporating it into the spectrum of primary large vessel vasculitis. Recent investigations have documented significant overlap between CP and the newly recognized systemic inflammatory disorder known as IgG4-related disease (IgG4-RD), suggesting that at least a fraction of cases of CP might be IgG4-RD.

Objectives The aim of this study is to investigate clinical characteristics and treatment outcomes of patients with CP.

Methods A retrospective review was performed on 2,496 patients who visited Samsung Medical Center between January 2004 and December 2014. Patients compatible with CP based on characteristic imaging findings of fibrosclerosing encasing lesions around the aorta were enrolled. The clinical, radiological, histopathological features, treatments and outcomes of patients were analyzed. Additionally, patients were further classified into two subgroups: IgG4-related and non IgG4-related CP according to the comprehensive diagnostic criteria for IgG4-RD proposed by a Japanese study, and comparison of the subgroups was performed. Patients without an initial serum IgG4 level or with a history of prior treatment were excluded from this analysis.

Results A total of 61 patients with CP were identified. Patients showed a male predominance with the median age of 61 at diagnosis. The abdominal aorta was the most commonly involved site (84%), and half of the patients had aortic lesion confined to the abdominal aorta without involvement of the thoracic aorta. The thoracic aorta was involved in 46% of patients. Only 2 (3%) patients had stenotic lesions of the aorta, while 19 (31%) patients had aneurysmal changes of the aorta. Ureteral obstruction was found in 30% of patients. 49 (80%) patients received glucocorticoids with a median initial dose of 50 mg per day as prednisolone. 19 (31%) patients received additional immunosuppressant including azathioprine, methotrexate and mycophenolate. Nine patients underwent vascular surgery including seven cases of surgical abdominal aorta aneurysm repair, two cases of aortic valve replacements and four patients underwent endovascular abdominal aneurysm repair during their disease course. Overall 60% of patients achieved remission without relapse during the course. When the Japanese criteria for IgG4-RD were applied to patients, ten were classified as IgG4-related and twenty-five as non IgG4-related. The overall male predominance did not differ and there were no significant differences in clinical features, treatments and outcomes between two groups, with the exception of older age (median 69 vs. 59 years, p=0.021), higher serum globulin, IgG and IgG4 levels and greater pancreas involvement in IgG4-related patients (30% vs. 0%, p=0.018).

Conclusions We identified 61 patients with CP. Further integrated investigations into pathogenesis, practical diagnostic criteria and markers for disease activity and prognosis are warranted.

Disclosure of Interest None declared