Impact of Stent Graft Design on External Iliac Artery Limb Occlusion Rates After Endovascular Aneurysm Repair: Post-hoc Analysis of a Japanese Multicentre Database

Abstract

WHAT THIS PAPER ADDS External iliac artery (EIA) limb deployment during endovascular aortic aneurysm repair (EVAR) is associated with an increased risk of limb occlusion. Japanese patients are thought to have a higher incidence of EIA limb deployment during EVAR and a higher incidence of limb occlusion than Caucasians. It is suggested that a helical stent with expanded polytetrafluoroethylene should be used in patients with a small EIA, such as Japanese patients, to reduce the risk of EIA limb occlusion. Clinicians can put these findings to immediate clinical use. This study also serves as a baseline for similar studies of other stent graft designs. Objective/Background: It was hypothesised that a helical stent with expanded polytetrafluoroethylene (ePTFE) grafts could provide a preventive effect for external iliac artery (EIA) limb occlusion following endovascular aortic aneurysm repair (EVAR). Therefore, a post-hoc analysis of a Japanese multicentre database was conducted to assess the impact of the stent graft design on EIA limb occlusion rates. Methods: Patients who underwent EVAR with EIA limb deployment between 2008 and 2016 were evaluated. The stent graft limbs were divided into two groups: group A comprised stent graft limbs made of a helical stent with ePTFE grafts (Excluder; n ¼ 255), and group B comprised stent graft limbs made of a Z stent with polyester grafts (Zenith, Flex and Endurant; n ¼ 173). The main outcome was the incidence of limb occlusion and severe limb stenosis (EIA related limb complications). The risk factors for EIA related limb complications were analysed and the midterm results between groups A and B compared. FineeGray generalisation of the proportional hazards model was used after propensity score matching to calculate the hazard ratio (HR). Results: One complication occurred in group A and 10 complications occurred in group B. The risk factors for EIA related limb complications for the entire group were a stent graft limb size 10 mm (HR 5.41; p ¼ .01) and inclusion in group B (HR 14.9; p ¼ .009). After propensity matching, group A (n ¼ 159) was matched with group B (n ¼ 159). The cumulative incidence function of EIA related limb complications at five years was 0.66% in group A and 7.8% in group B (HR 8.67; p ¼ .039). Conclusion: Stent graft design can affect limb patency in EIA limb deployment. When EIA limb deployment is necessary for patients with a small EIA, such as Japanese patients, stent graft limbs made of a helical stent with ePTFE should be used to reduce the risk of limb occlusion.

Aneurysm Sac Shrinkage After EVAR Can Lead to Complications: A Case Report of Complete Endograft Thrombosis Due to Kinking

“…Also, small diameter limbs are described in the literature as a risk factor. 16 In this regard, Bogdanovic et al described the endograft device type as an independent risk factor for limb occlusion; in their study, the Zenith Alpha ® (Cook Medical, Bloomington, IN, USA) showed an increased risk (12.4%) of occlusion compared with the Excluder ® endograft (W. L. Gore & Assoc., Flagstaff, AZ, USA) which reports a much lower occlusion rate (.7%). 17 The literature specifically addressing predisposing factors for bilateral limb occlusion as an independent entity is scarce.…”

Long-term Outcomes of the Endurant and Excluder Stent Grafts for Endovascular Aneurysm Repair in a Japanese Cohort

“…As for the more frequent bilateral hypogastric artery embolizations observed in the Excluder stent graft, this system is believed to perform better in cases that require deployment in the external iliac artery. 20 Shintani et al 20 reported that implantation of stent grafts made from a Z stent with polyester grafts, including the Endurant stent graft system, in the external iliac artery was a risk factor for external iliac artery occlusion. In contrast, although the size of the delivery system is similar for both stent grafts, the Endurant tended to be used in cases with smaller external iliac arteries, and IFU violations due to poor access were significantly more frequent.…”

Early Clinical Outcomes of Initial Launch of the Zenith Alpha Abdominal Endovascular Graft in Japan

“…[23][24][25] As for the graft material, expanded polytetrafluoroethylene grafts with spiral stent configuration perform better compared with dacron grafts with independent Z stent configuration. 26 Furthermore, it has been reported that the iliac arteries of the Asian population have a more complex anatomy with a shorter CIA, smaller diameter, and more tortuosity and calcification compared with Caucasian populations, resulting in more complications after EVAR. [27][28][29] As for the newly developed Zenith Alpha Spiral-Z Endovascular Leg, not much evidence is around; however, there has been a report with strikingly high occlusion rate (12.4%) from Sweden.…”

“…Considering the fact that this study was conducted in the Japanese population, and 30 patients (38.0%) had limb deployment in the EIA, the present result is satisfactory and comparable with previous reports. 20,21,22,26,30,31 Among 30 patients who had limb deployed in the EIA, 9 patients had bare nitinol stent placed for the reinforcement, which may have affected the result favorably.…”