Role of Type II Endoleak in Abdominal Aortic Aneurysm Sac Regression After Endovascular Repair

Abstract

Endovascular repair (EVAR) of infrarenal aortic aneurysms (AAAs) is increasingly used in patients with suitable aortic morphology. Despite improvements in graft design, type II endoleak (EL-2) from the inferior mesenteric artery (EL-IMA) or lumbar artery (EL-LA) remains the Achilles' heel of EVAR. This study evaluated the natural history of the AAA sac after EVAR. Our hypothesis was that persistent EL-2 is associated with inferior AAA sac regression. A retrospective analysis of all nonruptured AAA treated by elective EVAR using Food and Drug Administration-approved endografts from January 2005 to December 2008 in our facility was performed. Review of medical records and preoperative and follow-up computed tomography angiograms (CTA) at 1, 6, and 12 months were performed. Patients with type I, III, and IV endoleaks were excluded. Persistent EL-2 was defined as EL-2 present on CTA at 6 months post-EVAR. AAA size and volume were analyzed using Aquarius TeraRecon software. Changes in AAA sac volume at 6 and 12 months were compared in patients (1) with and without EL-2 and (2) with an occluded vs patent IMA. The study cohort comprised 197 patients (164 men, 33 women) who were a mean age of 74 years. Mean preoperative AAA diameter was 5.5 cm, and volume was 137.45 cm3 (range 4-11 cm). EL-2 was present in 27% at completion of EVAR and persisted in 9% at a mean follow-up of 6 months (range, 4-8 months). EL-LA resolved in 94% on follow-up vs 55% of EL-IMA (P = .01 by Fisher exact test). Preoperatively, the IMA was occluded by coils or chronically occluded in 92 patients vs 105 patients who had a patent IMA. At the 6-month follow-up, patients with an occluded IMA had an EL-2 rate of 2.5% vs 13% in those with a patent IMA (P = .007 by t-test). Sac volume regression was 39.5% in those with an occluded IMA vs 29% in those with a patent IMA (P = .04 by Fisher test). Regression in AAA sac volume was highly significant in patients with occluded IMA at 60% vs 41.6% at 1 year (P = .0010, two- sided t-test). The presence of persistent EL-2 after EVAR results in inferior AAA sac regression. The majority of EL-LA spontaneously thrombose by 6 months; however, 45% of EL-IMA are persistent. Consideration should be given to preoperative coiling of a patent IMA before EVAR.