Preoperative risk factors for aneurysm sac expansion caused by type 2 endoleak after endovascular aneurysm repair

Purpose: The objective of this study was to investigate the preoperatively definable risk factors which predict the aneurysm sac expansion caused by persistent type 2 endoleak after endovascular aneurysm repair. Methods: Between 2008 and 2014, retrospective analysis was performed to examine the predictive risk factors for aneurysm sac enlargement caused by persistent type 2 endoleak, which was defined as a continuous endoleak present for more than six months. Aneurysm sac expansion was diagnosed if the maximum transverse diameter increased by 5mm or more compared with the preoperative measurement. Results: During the study period, endovascular aneurysm repair was performed in 211 patients with abdominal aortic aneurysm and common iliac artery aneurysm. Sac enlargement for type 2 endoleaks was observed in 20 patients (9.5%). The presence of more than five patent lumbar arteries flowing into aneurysm sac in the preoperative computed tomography (hazard ratio, 3.37; 95% confidence interval, 1.24-10.8; p = 0.017) was a predictive factor for sac expansion caused by persistent type 2 endoleak on Cox regression analysis. The presence of a patent inferior mesenteric artery was not associated with the sac expansion caused by persistent type 2 endoleak. Conclusions: The presence of more than five lumbar arteries flowing into the aneurysm sac was a preoperative risk factor for sac expansion caused by persistent type 2 endoleak.