IF04 - Five-year results of side branch embolization revealed continued sac shrinkage and less re-intervention after endovascular aneurysm repair for abdominal aortic aneurysm.

Objectives: Persistent type 2 endoleak (T2EL) after endovascular aneurysm repair (EVAR) is the most significant risk factor for sac enlargement. Side branch embolization is shown to reduce T2EL, but clinical relevance to sac enlargement and re-intervention is unknown.

Methods: Among all patients who underwent EVAR for abdominal aortic aneurysm (AAA) between 2013 and 2021, patients with short neck, solitary iliac artery aneurysms, dissection, inflammatory or infected AAAs and in-hospital death were excluded. IMA embolization was conducted during the whole period, and after April 2018, lumbar artery (LA) embolization was considered. Sac enlargement (>5mm), re-intervention as well as the incidences of T2EL were compared.

Results: There were 214 patients without any side branch embolization (N group), while 228 and 158 patients underwent inferior mesenteric artery (IMA) only (I group) and IMA plus LA embolization (L group). Comparison of the 3 groups revealed statistical differences in age, sex, respiratory impairment, chronic kidney disease, proximal neck length, landing of the right leg and the main body. Overall success rates of LA embolization was 75%. The success rate of the first 10 successive cases was 46%, and cumulative success rate reached 70% after 30 cases. The incidences of T2EL from 1 year through 3 years ranged from 21.1%–29.6%, 23.9%–35.7% and 9.5%–12.0% in the N, I and L groups, respectively (p < .05 for all time points). The initial aneurysmal diameters were 52.6 ± 9.9mm, 49.7 ± 7.8mm, 50.3 ± 7.9mm, (p < .001). % sac shrinkage from the baseline was significantly promoted in the L group at 3 years and thereafter (18.4%–21.6% [L group] versus 9.0%–12.2% [N group] and 9.8%–11.6% [I group], p < .05 for each time point). Sac enlargement ≥5mm during the follow up period was significantly less in the L group (4.4%) compared to the N group (12.6%) and I group (12.3%, p=.02). Multivariate analysis adjusted for the different baseline characteristics confirmed the L group was a significant factor for absence of sac enlargement. Similarly, re-intervention was significantly infrequent in the L group (5.8%) compared to the N group (17.4%) and I group (14.6%, p=.004), which was also affirmed in the multivariate analysis.

Conclusions: IMA and LA embolization at EVAR can reduce T2EL and re-intervention, and promote sac shrinkage during the follow-up period of 5 years. Thirty cases may be necessary to learn LA embolization.