Multidisciplinary diagnosis and management of inflammatory aortic aneurysms

Abstract

Background: Inflammatory abdominal aortic aneurysms (IAAAs) are a variant involving a distinct immunoinflammatory process, with nearly one half believed to be associated with IgG4-related disease (IgG4-RD).

Methods: MEDLINE and Google Scholar searches were conducted for English-language publications relevant to inflammatory aortic aneurysms from January 1970 onward. The search terms included inflammatory aortic aneurysms, aortitis, periaortitis, IgG4-related disease, and retroperitoneal fibrosis. Relevant studies were selected for review based on their relevance.

Results: Morphologically, IAAAs are characterized by a thickened aneurysm wall often displaying contrast enhancement and elevated metabolic activity on fluorine-18 fluorodeoxyglucose-positron emission tomography imaging. A strong association exists with perianeurysmal and retroperitoneal fibrosis. Although the rupture risk appears lower with IAAAs than with noninflammatory abdominal aortic aneurysms (AAAs), the currently recommended diameter threshold for operative management is the same. Open repair has been associated with increased morbidity compared with noninflammatory AAAs, and a retroperitoneal approach or minimal dissection transperitoneal approach has been recommended to avoid duodenal and retroperitoneal structural injuries. Endovascular aneurysm repair has been increasingly used, especially for patients unfit for open surgery. It is important to exclude an infectious etiology before the initiation of immunosuppressive therapy or operative repair. Multimodality imaging follow-up is critical to monitor disease activity and secondary involvement of retroperitoneal structures by the associated fibrotic process. Maintenance of immunosuppressive therapy will be needed postoperatively for most patients with active systemic disease, especially those with IgG4-RD and those with persistent symptoms. Additional interventions aimed at ureteral decompression could also be required, and lifelong follow-up is mandatory.

Conclusions: Preoperative multimodality imaging is a diagnostic cornerstone for assessment of the disease extent and activity. IgG4-RD is an increasingly recognized category of IAAAs, with implications for tailoring adjunctive medical therapy. Open surgical repair remains the procedure of choice, although endovascular aneurysm repair is increasingly being offered. Maintenance immunosuppressive therapy can be offered according to the disease activity as assessed by follow-up imaging studies.

Keywords: Aorta; Aortitis; IgG4-related disease; Inflammatory AAA.