Heterogeneous Characteristics of Patients with Inflammatory Abdominal Aortic Aneurysm. Systematic Review of Therapeutic Solutions.

Background: Endovascular repair of inflammatory abdominal aortic aneurysms (IAAAs) has emerged as an alternative to open surgery, but direct comparisons are limited. The aim of the study was to compare clinical outcomes of endovascular and open repair for IAAA according with specific clinical characteristics.

Methods: We performed a literature review of reports describing patients who had open or endovascular repair for IAAA. A literature search was performed in June 2022 by 2 investigators who conducted a review of papers reported in PubMed, Embase, MEDLINE, and Cochrane Database. The strings "Inflammatory aneurysm" and "Abdominal Aortic Aneurysms" were used. There was no language restriction and screened reports were published from March 1972 to December 2021. We identified 2,062 patients who had open (1,586) or endovascular repair (476) for IAAA. Primary outcomes were operative mortality and morbidity. Secondary outcomes were complications during follow-up (mean follow-up: 48 months). Propensity score matching was performed between patients who had open or endovascular surgery.

Results: In Western countries, propensity-weighted postoperative mortality (in-hospital) (1.5% endovascular vs. 6% open) and morbidity rates (6% vs. 18%) were significantly lower in patients who had endovascular repair (P < 0.0001); patients with larger aneurysm (more than 7 cm diameter), signs of active inflammation, and retroperitoneal rupture of the aneurysm had better outcomes after endovascular repair than after open surgery. Hydronephrosis was present in 20% of the patients. Hydronephrosis regressed in most patients when signs of active inflammation were present suggesting an acute onset of the hydronephrosis itself (fever, elevated serum C Reactive Protein) either after endovascular or open surgery. Long-standing hydronephrosis as suggested by the absence of signs of active inflammation rarely regressed after endovascular surgery despite associated steroid therapy. During a mean follow-up of 48 months, propensity-weighted graft-related complications were more common in patients who had endovascular repair (20% vs. 8%). For patients from Asia, short-term and medium-term results were similar after open and endovascular repair. IAAAs related with aortitis were more common in Asia. In Western countries, IAAAs were commonly associated with atherosclerosis.

Conclusions: Patients with IAAA represent a heterogeneous population, suggesting biological differences from continent to continent; conservative therapy and endovascular or open surgery should be chosen according to the patient clinical condition. Endovascular repair presents advantages in patients with signs of active inflammation and contained rupture of the IAAA and larger aneurysms. Hydronephrosis, without signs of active inflammation, rarely regresses after endovascular repair associated with steroid therapy. Further studies are needed to establish the long-term results of endovascular repair.