What are the characteristics of an inflammatory aortic aneurysm, specifically regarding its rupture risk, clinical presentation, and effects on the aorta?

From the Guidelines

The correct answer is (d) inflammatory aortic aneurysm may present with abdominal pain in the absence of rupture. Inflammatory aortic aneurysms are characterized by chronic inflammation and fibrosis of the outer aortic wall, which can cause significant abdominal or back pain even without rupture occurring. This pain results from the inflammatory process itself and from the aneurysm's tendency to adhere to and irritate adjacent structures. Some key points to consider:

• Inflammatory aneurysms frequently cause symptoms due to the inflammatory component, unlike regular aneurysms which are often asymptomatic until rupture 1.
• They typically show a thickened aortic wall with periaortic fibrosis rather than circumferential thickening.
• Regarding rupture risk, inflammatory aneurysms actually have a lower rupture rate compared to non-inflammatory aneurysms of similar size 1.
• While surgical repair can be more challenging due to inflammatory adhesions to surrounding structures, there is no increased incidence of graft infection associated with inflammatory aortic aneurysm repair 1. Key considerations for management include:
• Screening or imaging surveillance is widely used to detect AAA that requires repair, with a generally accepted threshold of an aneurysm diameter exceeding 5.5 cm in men and 5.0 cm in women 1.
• Elective surgical repair is considered the best way to prevent rupture and can be performed using an open surgical or endovascular approach 1.
• Centralizing complex procedures in centers with a high level of expertise in aortic diseases and a multidisciplinary team is advisable 1.

From the Research

Inflammatory Aortic Aneurysm Characteristics

• Inflammatory aortic aneurysm is characterized by marked thickening of the aneurysm wall, fibrosis of the adjacent retroperitoneum, and rigid adherence of the adjacent structures to the anterior aneurysm wall 2
• It is almost never associated with inflammation of other arteries, and male sex and smoking are stronger risk factors for the inflammatory variant than for atherosclerotic AAA 2
• The presenting symptoms are often idiosyncratic and include severe abdominal or back pain, or both, and ureteral obstruction 3

Rupture Risk and Graft Infection

• Inflammatory AAA appears less likely to rupture than atherosclerotic AAA 2, 3
• Graft infection is a potential complication of repair, and patients with inflammatory abdominal aneurysms frequently develop postoperative graft complications requiring secondary surgical treatment 4

Diagnosis and Treatment

• Computed tomography and magnetic resonance imaging are both sensitive for demonstrating the cuff of soft tissue inflammation surrounding the aneurysm that is characteristic of inflammatory AAA 2
• A mantle sign on computed tomography angiography (CTA) is highly suggestive of the diagnosis 5
• Open surgical repair (OSR) and endovascular aortic aneurysm repair (EVAR) are treatment options, with EVAR associated with lower 30-day mortality and fewer intra-operative complications, but more late fibrosis-related adverse events 5
• Corticosteroids may be considered a basic treatment that all patients should receive initially, leading to complete pain relief and a reduction in peri-aortic inflammation within 6-18 months 5

Clinical Presentation

• Inflammatory aortic aneurysm may present with abdominal pain in the absence of rupture 2, 3
• A triad of chronic abdominal or back pain, weight loss, and elevated inflammatory markers is highly suggestive of the diagnosis, but rarely present 5