Strategies to reduce the rate of type II endoleaks: Routine intraoperative embolization of the inferior mesenteric artery and thrombin injection into the aneurysm sac

Purpose: To determine whether the rate of type II endoleaks following endovascular aneurysm repair (EVAR) can be decreased using a branch vessel management strategy. Methods: The branch vessel management strategy consisted of routine intraoperative embolization of all patent inferior mesenteric arteries (IMA) and thrombin injection into all aneurysm sacs that showed branch vessel filling on the "sacogram." Sixty-nine consecutive patients (65 men; median age 77 years, range 58-90) undergoing elective EVAR since the protocol was introduced in July 2003 were included; 69 consecutive patients (65 men; median age 76 years, range 60-90) who underwent EVAR immediately prior to the protocol were used as controls. Primary outcome measures were type II endoleak rates and secondary intervention rates. Results: The median follow-up was 36 months (range 0.25-72) for the pre-protocol group and 12 months (range 0.25-24) for the post-protocol group. The type II endoleak rate for the pre-protocol group was 26% compared to 14% for the post-protocol group (p=0.114) This difference was not significant on Kaplan-Meir analysis (p=0.23). The 18 type II endoleaks in the pre-protocol group included 14 lumbar endoleaks, 1 IMA endoleak, and 3 combined lumbar and IMA endoleaks. The 10 type II endoleaks in the post-protocol group included 9 lumbar artery endoleaks and 1 IMA endoleak. Ten (14%) patients in the pre-protocol group required 15 interventions for type II endoleak compared to 2 (3%) in the post-protocol group who required 3 secondary procedures for type II endoleak (p=0.03). This difference was not significant on Kaplan-Meier analysis (p=0.22). Of the 12 interventions for lumbar endoleaks, only 5 (42%) were successful. Conclusion: Although there was a trend toward lower type II endoleak rates with our branch vessel management strategy, this did not reach statistical significance. Our data also indicated that there is a high incidence of lumbar endoleaks, and they are difficult to treat. Therefore, we believe there should be ongoing research into means to prevent lumbar endoleaks.