Type II Endoleak and Aortic Aneurysm Sac Shrinkage following Pre-emptive Embolization of Aneurysm Sac Side Branches.

OBJECTIVE Type II endoleak (T2EL) is the most common endoleak after endovascular aneurysm repair (EVAR). Its optimal management is controversially discussed. Thus, preliminary selective embolization of aneurysm sac side branches (ASSBs) has been adopted to prevent T2EL. Our goal was to determine the rate of T2EL, and diameter decrease of abdominal aortic aneurysm (AAA) after EVAR following pre-emptive embolization of ASSBs. METHODS Between September 2014 and September 2019, 139 patients with AAA underwent percutaneous ASSBs embolization before EVAR. Imaging follow-up was performed at 1 and 6 months, and yearly thereafter. Endpoints included freedom from T2EL, AAA sac shrinkage, T2EL-related reinterventions, and all-cause mortality. RESULTS Mean follow-up was 23 ± 16 months (range, 1-61 months). Patients had a median of 5 (range 1-8) patent ASSBs on pre-operative imaging. After completion of embolization, 76.4% of initially patent ASSBs were occluded, with no major procedure-related complications. Follow-up imaging showed T2EL in 7 (5%) patients and increase of the aneurysm sac was seen in 6 of these patients. The number of ASSBs remained patent after embolization was the only discriminative factor in patients with and without T2EL. Six T2EL-related reinterventions were performed during follow-up. The majority of patients (n=91, 86.7%) exhibited aneurysm sac shrinkage and mean diameter reduction was 9.2 ± 7.7mm (p<.001) in all patients with follow-up. One aneurysm-related death occurred within 30 days after EVAR. CONCLUSIONS Pre-emptive embolization of ASSBs for patients with AAA is safe and effective in preventing T2EL after EVAR. Aneurysm sac shrinkage was observed in a high proportion of patients.