Maximizing proximal seal zone in fenestrated endografting: Evolution in the approach to graft configuration

Abstract

Objective: Fenestrated endografting for juxtarenal and pararenal abdominal aortic aneurysms affords the ability to seal stent grafts in normal aorta at and above the renal arteries. The Zenith fenestrated graft (ZFEN; Cook Medical, Bloomington, Ind) is custom-made to surgeon specifications, subject to certain manufacturing limitations. The most common configuration in the pivotal trial and in commercial use after approval has been as a scallop for the superior mesenteric artery (SMA) and two small fenestrations for the renal arteries (configuration A). An alternative configuration to maximize the seal zone length, consisting of a large fenestration for the SMA and two small fenestrations for the renal arteries (configuration B) has been routinely adopted at our institutions to potentially prevent type IA endoleak.

Methods: The present retrospective cohort study examined 100 consecutive ZFEN grafts designed for patients at two university centers from 2012 through 2019. The proximal seal length, measured from the top of the graft to the beginning of the aneurysm, was determined from the preoperative computed tomography angiograms. Alternative configurations were evaluated to determine whether they would have provided a longer proximal seal length.

Results: The two most common configurations were B (n = 45) and A (n = 38). For the cases in which A had been chosen but B could have been built, 5.8 ± 1.9 mm of seal zone length was lost. For the cases in which B was chosen but A could have been built, 5.8 ± 2.8 mm of seal zone length was gained. Owing, in part, to the increased proximal seal length with configuration B, this configuration has been used more frequently in the past 4 years of the present study compared with the first four (53% vs 25%; P = .004). Of 95 patients who had completed surgery and follow-up, type IA endoleaks were observed in 12 (13%) on completion angiography, all of which had resolved on follow-up imaging without intervention. No SMA was compromised by misalignment of the large fenestration in configuration B.

Conclusions: A significantly longer proximal seal length can be obtained using a ZFEN with a large fenestration for the SMA and two small fenestrations for the renal arteries. Whenever possible, surgeons should consider this configuration to maximize the proximal seal length and potentially reduce the risk of proximal endoleak. An additional advantage of this approach is that stenting of the SMA to prevent shuttering will be unnecessary or impossible, making the procedure more technically facile.

Keywords: Abdominal aortic aneurysm; Endograft; Fenestrated; Fenestrated stent graft; Juxtarenal aortic aneurysm; Stent graft.