Visceral stent patency after fenestrated endovascular aneurysm repair using bare-metal stent extensions versus covered stents only

Abstract

Objective: Fenestrated endovascular aneurysm repair (FEVAR) is an alternative to treat complex abdominal aortic aneurysms. Patency of visceral vessels remains high when covered stents are used. The use of distal uncovered stents to prevent kinking has been associated with loss of branch patency. The aim of this study was to evaluate branch-related outcomes of FEVAR using covered stents only vs the use of uncovered stents distal to covered stents. Methods: During a 4-year period, 142 patients underwent FEVAR. Patients with suprarenal, juxtarenal, and type IV thoracoabdominal aneurysms were included. Patients treated with side branch devices were excluded. Covered iCAST (Maquet, Hudson, NH) stents were used as bridging stents in all cases. The primary end point was primary patency, defined as the absence of stenosis or occlusion that required intervention. Secondary end points included secondary patency, branch-related outcomes (kidney injury and gastrointestinal complications), branch instability, and mortality rates. Results: A total of 442 target vessels were incorporated (49 scallops and 393 fenestrations). Uncovered stents were used in 38 (9.6%) visceral vessels. Median follow-up time was 11 (interquartile range, 6-13) months. Overall, visceral vessel primary patency was 91% at 12 and 24 months. The overall primary patency rate was 86% in the distal extension group vs 93% when only covered stents were used at 12 and 24 months (P ¼ .8). Similarly, the rate of branch-related reinterventions at 12 months was 9% and 15% for each group, respectively, and 22% vs 32% at 24 months, respectively (P ¼ .5). Overall, freedom from branch instability was 87% at 12 months and 81% at 24 months. Freedom from branch instability in the distal extension group was 82% at 12 and 24 months vs 89% at 12 months and 81% at 24 months when only covered stents were used (P ¼. 08). Mortality rate at 24 months was 15% for the bare-metal stent extension group vs 14% for the covered stent only group (P ¼ .4). We found no statistical difference in acute kidney injury at any Kidney Disease: Improving Global Outcomes stage (P ¼ 1.0) or gastrointestinal complications (P ¼ 1.0) between the groups. Conclusions: The use of distal uncovered stents to prevent kinks was not associated with decreased early branch patency. The long-term outcomes of bare-metal stents remain to be determined. For now, the use of uncovered stents distal to covered stents may be considered to prevent kinks in complex anatomy.

Insights on Bridging Stent Grafts in Fenestrated and Branched Aortic Endografting

“…Additionally, studies also reported fewer fractures with covered stents than with uncovered stents [26,29]. A possible reason for this observation could be that the polytetrafluoroethylene (PTFE) layers in the covered stents create high radial strength by connecting the stent struts, wherefore covered stents might be less prone to fatigue fracture [29,30]. For the aforementioned reasons, covered stents are preferred in branch endografting.…”

“…Moreover, studies do not support this concept. In a series incorporating 442 target vessels, Khoury et al [30] evaluated whether the use of distal extension with uncovered stents influences vessel patency. They found that at 12 months, the overall primary patency rate was 86% in the distal extension group vs. 93% when covered stents only (P=0.8), and the rate of branch-related reinterventions was 9% and 15%, respectively (P=0.5), suggesting the use of distal uncovered stents to prevent kinks was not associated with decreased early branch patency [30].…”

“…In a series incorporating 442 target vessels, Khoury et al [30] evaluated whether the use of distal extension with uncovered stents influences vessel patency. They found that at 12 months, the overall primary patency rate was 86% in the distal extension group vs. 93% when covered stents only (P=0.8), and the rate of branch-related reinterventions was 9% and 15%, respectively (P=0.5), suggesting the use of distal uncovered stents to prevent kinks was not associated with decreased early branch patency [30]. Panuccio et al [7] also failed to confirm the efficacy of the relining strategy as crimping of the BSG was the most frequent source of problems (type 1 endoleak and restenosis of the BSGs) in their series, despite the extensive use of relining stents (64.6%).…”

Preliminary Outcomes of Viabahn Balloon-Expandable Endoprosthesis as Bridging Stent in Renal Arteries During Fenestrated Endovascular Aortic Repair

“…However, the systematic use of BMS to reinforce balloon expandable stent graft (BESG) does not seem a definitive solution, especially in long-term outcomes. 31 Independently by the stent-graft used for TV, we consider the suprarenal fixation of previous EVAR a challenge and an independent risk factor for TAI.…”

Comparison of the Biomechanical Properties of the Advanta V12/iCast and Viabahn Stent-Grafts as Bridging Devices in Fenestrated Endografts: An In Vitro Study

“…4 Moreover, as there is no ideal stent-graft available for this purpose, it is common practice to implant more than one stent in a target vessel, for example, relining a covered stent with a nitinol self-expanding stent. 10 These factors confound comparison of different devices, especially when attempting to extrapolate the long-term performance of new stent-grafts. This in vitro experiment sought to compare the VBX and Advanta/iCast on an isolated biomechanical basis in order to produce indicators for the future performance of the VBX as a bridging device.…”