Antithrombotic Therapy and Freedom From Bridging Stent Occlusion After Elective Branched Endovascular Repair: A Multicenter International Cohort Study

Abstract

The risk of bridging stent occlusion after branched endovascular aortic repair (BEVAR) remains an issue. Currently, there is no clear recommendation on what kind of antithrombotic therapy should be installed after BEVAR. The aim of the study was to estimate the impact of postoperative antithrombotic therapy on bridging stent occlusion rate after elective BEVAR. An international multicenter retrospective analysis was performed in 4 European tertiary vascular units. All reno-visceral target vessels treated with bridging stents of patients undergoing elective BEVAR with the use of off-the-shelf or custom-made branched stent-grafts for pararenal aortic aneurysms (PAAs), type Ia endoleaks after previous EVAR, and thoracoabdominal aortic aneurysms (TAAA) between January 2014 and December 2022 were included. Primary outcome was freedom from bridging stent occlusion and its correlation with postoperative antithrombotic therapy. Secondary outcomes were overall survival and identifying target vessel and bridging stent characteristics, which may have a higher risk for bridging stent occlusion according to the PRINCE2SS recommendation. Follow-up information was obtained for all patients per 31st of December 2022. In total, 120 patients (90 male) with a median age of 72 (interquartile range [IQR]=67-77) years were included. Two hundred eighty-nine external and 127 internal branches were used for 416 target vessels. The median follow-up was 21 months (IQR=9-48) with a follow-up index of 1.0. During follow-up, 24 (5.8%) primary bridging stent occlusions (left renal artery [LRA]=10, right renal artery [RRA]=7, superior mesenteric artery [SMA]=3, truncus coeliacus [TC]=4) were found. The risk of renal bridging stent occlusion is significantly higher compared with visceral bridging stent, p=0.013. The occlusion rate was 7.8% for renal branches and 1.5% for visceral branches at 1 year and 10.6% and 3.7% at 5 years, respectively. The multivariable Cox proportional hazard model on bridging stent occlusion showed that there was no significant difference between the used antithrombotic strategies. No antithrombotic therapy was significantly associated with bridging stent occlusion, whereas no evidence for superiority of any other antithrombotic therapy was found. Overall, the bridging stents’ occlusion rate was low. We found a significantly higher occlusion rate in renal arteries compared with the visceral ones. Clinical Impact Based on our study, no antithrombotic therapy is significantly associated with bridging stent occlusion, and no evidence of the superiority of other antithrombotic therapy exists. Nevertehless, due to the low number of bridging stent occlusions, this study can neither support nor reject the PRINCE2SS recommendations. Further studies with larger cohorts are needed to determine clear guideliness of the best antithrombotic treatment regimen after complex enfovascular aortic repair.