Early changes in abdominal aortic aneurysm diameter after endovascular repair

PURPOSE: Endovascular repair of abdominal aortic aneurysm (AAA) is expected to alter the natural progression of diameter increase and rupture. The purpose of this study is to determine the rate of diameter change in AAA treated by endovascular repair. MATERIALS AND METHODS: Sixty-three patients underwent endovascular repair of AAA and 12-month median follow-up by computed tomographic (CT) angiography or magnetic resonance (MR) angiography. The maximum cross-sectional outer diameters of aneurysms were measured with serial CT angiography and MR angiography. Immediate postrepair CT angiography and MR angiography were used for comparison to follow-up studies. Endoleak was also evaluated. RESULTS: The mean and median follow-up interval was 12 months (range, 7-21 mo). There was a significant decrease in maximum diameter at follow-up (6.0 cm vs 5.1 cm; P <.001). The mean annual decrease of AAA diameter was 8.4 mm. Endoleak occurred immediately after repair in 12 patients (19%). Endoleak was detected in four patients at follow-up examination (6%). Two patients with persistent endoleaks had a mean diameter increase of 2.1 mm per year. Ten patients (16%) with successfully treated endoleak had a mean decrease in diameter of 11 mm per year. There is a significant difference in mean annual diameter change between patients with treated endoleak and those with persistent endoleak (P <.05). There was no difference in mean annual rate of change between patients with no endoleak and those with treated endoleak (8.4 mm/y vs 11 mm/y; P = NS). Seventeen of 21 patients without an appreciable decrease in aneurysm diameter had no endoleak. CONCLUSIONS: Patients with resolved endoleak exhibit a similar shrinkage rate to patients who never had endoleak during imaging follow-up. There remains a group of patients without significant sac shrinkage after endovascular aneurysm repair (EVAR) yet have no endoleak on follow-up imaging (ie, endotension). It is still unclear whether these patients have received protection from AAA rupture from EVAR.