Systematic review and meta-analysis of prophylactic aortic side branch embolization to prevent type II endoleaks

Type II endoleaks are the most common type of endoleak after endovascular aneurysm repair (EVAR) and may cause late sac expansion and rupture. To prevent this, prophylactic embolization of aortic side branches has been suggested. The aim of this review was to assess the current evidence for this prophylactic treatment and its association with sac size enlargement as well as rate of and reintervention for type II endoleak.

This was a systematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The MEDLINE and Scopus databases were used to search for related articles until March 2019. After screening, original studies reporting outcome comparing patients having prophylactic embolization with those undergoing EVAR without prophylactic embolization were included. An assessment of the quality of the included studies as well as data extraction was performed by two independent observers. Statistical analysis was performed using Review Manager 5.3 (The Nordic Cochrane Center, Copenhagen, Denmark).

There were 3777 publications identified. After elimination of duplicate entries and review of titles and abstracts, 13 retrospective cohort studies including 1427 patients comparing prophylactic embolization with standard EVAR therapy were identified. No randomized trials were available. Five of these 13 studies reported sac growth, with a frequency of 7.4% (14/90) in the embolization group vs 13.4% in controls (odds ratio [OR], 0.54; 95% confidence interval [CI], 0.29-1). The rate of type II endoleak was 18.5% (100/540) in the embolization group vs 38.6% in the control group (342/887; OR, 0.34; 95% CI, 0.26-0.44). Based on 10 studies, the rate of reintervention was 1.5% (7/468) in the embolization group vs 12.4% (80/646) in the control group (OR, 0.12; 95% CI, 0.06-0.24). Nine of these 13 studies showed that technical success of inferior mesenteric artery and lumbar artery embolization was 82.3% and 69.1%, respectively. Regarding complications, 10 of 108 patients (9.3%) in one study reported nonspecific abdominal pain after embolization, and all resolved with overnight rehydration. Only one patient, who previously had right hemicolectomy, died after inferior mesenteric artery embolization of ischemic colitis.

This systematic review and meta-analysis suggests that prophylactic aortic side branch embolization may be associated with lower rate of sac enlargement, incidence of type II endoleaks, and reinterventions. However, high-quality unbiased studies are lacking in this field, and this review and meta-analysis may be affected by selection bias and residual confounders remaining in the retrospective studies. To conclude whether prophylactic embolization should be routinely performed, a prospective, randomized trial is required.