Inflammatory Abdominal Aortic Aneurism: Still a Quandary

Inflammatory abdominal aortic aneurysm (IAAA) is rare—approximately 10% of abdominal aneuryms present sheathed in peri-aneurysmal and retroperitoneal fibrosis, thick aortic walls and dense adhesions involving adjacent abdominal organs. Life-threatening, IAAA has been a puzzle for decades. When patients have a simple abdominal aortic aneurysm, surgeons try to prevent or correct a rupture using open or endovascular repair; the procedures used are well-studied. In contrast, IAAA sometimes leads to iatrogenic injury during open repair or increased inflammatory response to endoprosthesis implantation. Open surgery replaces the aneurysm with an artificial graft, while endovascular repair involves placing an artificial stent graft inside the aneurysm via a blood vessel in the groin. But which poses less risk or offers best outcome? Investigators at the Cochrane Collaboration combed the literature for studies. Their findings indicate this is still an open question.

Most IAAA are identified with abdominal computed tomography scans, with a typical mantle sign. During surgery, surgeons observe a white, shiny exterior. IAAA, due to inflammation and frequent involvement of the ureters or gastrointestinal tract, is complicated. Most surgeons hold that endovascular repair may not endure or might exacerbate inflammation, but are uncertain if open repair is any better.

In assessing differences between elective endovascular versus open repair for inflammatory abdominal aortic aneurysms, the investigators used the standard comprehensive process mandated by the Cochrane Peripheral Vascular Diseases Group. As always, they looked aggressively for published and unpublished trials of high quality.

The EUROpean collaborators on Stent-graft Techniques for abdominal aortic Aneurysm Repair registry analysis indicates endovascular repair of IAAAs have been associated with a higher incidence of stent stenosis (3.9%) than that found in non-inflammatory AAA (0.3%). As this information is not a study, it could not be included in the review.

A single study that failed to meet the criteria for inclusion found that endovascular and open surgical repairs had similar outcomes at 30 days. These procedures, however, were done at high volume centers and the study only included 121 patients. The study period is also quite short.

No studies that met the inclusion criteria for this Cochrane review. The authors conclude that high-quality studies looking at immediate (30-day), intermediate (up to one-year follow-up) and long-term (more than one-year follow-up) mortality or complications rates are needed.