Aneurysm Sac Thrombus Volume Predicts Aneurysm Expansion with Type II Endoleak After Endovascular Aneurysm Repair

Background: Several studies have analyzed risk factors that may influence the incidence of type II endoleak with sac expansion after endovascular aneurysm repair (EVAR). However, the impact of intraluminal thrombus volume on the incidence of sac expansion with type II endoleak requires further analysis. This study examined the correlation between preoperative intraluminal thrombus and the incidence of type II endoleak and late sac expansion by measuring the thrombus volume. Methods: Between June 2007 and March 2014, 423 patients underwent EVAR at our institution. Two hundred and eighty patients with preoperative and postoperative computed tomography angiography (CTA) were included in this study. Data were collected prospectively and supplemented with a retrospective review of the medical records and radiologic images, and demographic and clinical characteristic profiles were collected. Logistic regression and Cox regression analyses were used to assess each variable's association with the incidences of persistent or new endoleak and sac expansion. Results: Of the 280 patients, 46.7% (131 patients) had persistent type II endoleak, and 19.6% (55 patients) had persistent type II endoleak with significant sac expansion (>= 5 mm). The mean follow-up duration was 60 months (interquartile range, 24-72 months). Cox regression analysis showed that older age (P = 0.001), intraluminal thrombus volume ratio (thrombus volume [T vol]/aortic aneurysm volume [A vol]) (P = 0.042) and IMA diameter (P = 0.004) were significant predictors of the incidence of sac expansion with persistent or new type II endoleak. The receiver operating characteristic curve analysis revealed a cutoff of 51% T vol/A vol (area under the curve [AUC]: 0.59) and 2.9 mm (area under the curve [AUC]: 0.60). The rate of freedom from sac expansion (>= 5 mm) during followup was significantly higher in patients with >= 51% T vol/A vol than in those with a lower T vol/A vol (P = 0.010). Conclusions: Preoperative sac thrombus volume, IMA diameter, and older age predict the incidence of aneurysm expansion with type II endoleak after EVAR.