Role of type II endoleak in sac regression after endovascular repair of infrarenal abdominal aortic aneurysms.

ABSTRACT

OBJECTIVE: Endovascular repair (EVAR) of infrarenal aortic aneurysms (AAA) is increasingly used in patients with suitable aortic morphology conforming to device-specific instructions for use. Despite improvements in graft design, type II endoleak (EL-2) from the inferior mesenteric artery (EL-IMA) or the lumbar artery (EL-LA) remains the Achilles' heel of EVAR. The objective of this study was to evaluate the natural history of the AAA sac after EVAR. We hypothesized that persistent EL-2 would be associated with inferior AAA sac volume regression. METHODS: A retrospective analysis was performed on all nonruptured AAA treated by elective EVAR using Food and Drug Administration-approved endografts from January 2005 to December 2008 in our facility. Review of medical records and preoperative and follow-up computed tomography angiograms at 1, 6, and 12 months was performed. Patients with type I, III, and IV endoleaks were excluded, as were those lost to all follow-up. AAA size and volume were analyzed using TeraRecon software (Aquarius Intuition, Foster City, Calif). Change in AAA sac volume was compared in patients with and without EL-2, and with an occluded vs patent IMA. RESULTS: The study cohort comprised 191 patients (161 men, 30 women) with a mean age of 74 years. The mean preoperative AAA diameter was 5.5 cm (range, 4-11 cm), and mean volume was 137.45 cm(3). EL-2 was present in 24% at completion of EVAR and in 9% at a mean follow-up of 6 months (range 4-8 months). Completion angiography at 1 month showed 63% of EL-2 had resolved. Those with EL-2 present at 1 month had statistically inferior sac regression compared with those who did not (23% reduction vs 2% increase at 1 year; P = .002). Preoperatively, the IMA was occluded by coils or was chronically occluded in 82 patients vs 109 patients who had a patent IMA. At the 6-month follow-up, patients with an occluded IMA had an EL-2 rate of 2.4% vs 14.7% in those with a patent IMA (P = .005 by t-test). Sac volume regression was 21.8% in those with an occluded IMA vs 13.2% in those with a patent IMA (P = .004 by t-test). Regression in AAA sac volume was highly significant in patients with occluded IMA, at 30% vs 16% at 1 year (P = .0018 by two-sided t-test). CONCLUSIONS: The presence of persistent EL-2 after EVAR results in inferior AAA sac regression. A preoperatively patent IMA is associated with increased rates of EL-2 and inferior AAA sac regression. Consideration should be given to preoperative occlusion of a patent IMA before EVAR.