Oversizing of aortic stent grafts for abdominal aneurysm repair: a systematic review of the benefits and risks.

OBJECTIVE: Sizing of aortic endografts is an essential step in successful endovascular treatment of aortic pathology, although consensus regarding the optimal sizing strategy is lacking. Some proximal oversizing is necessary to obtain a seal between the stent graft and the aortic wall and to prevent the graft from migrating, but excessive oversizing might influence the results negatively. In this systematic review, we investigated the current literature to obtain an overview of the risks and benefits of oversizing and to determine the optimal degree of oversizing of stent grafts used for endovascular abdominal aortic aneurysm repair.
METHODS: PUBMED, EMBASE and Cochrane Library databases were searched for articles related to the impact of proximal endograft oversizing on complications after endovascular aneurysm repair. After in- and exclusion, 23 relevant articles reporting on 8415 patients remained for analysis and critical appraisal.
RESULTS: Most studies that investigated neck dilatation are flawed by poor methodology. No clear relationship between proximal oversizing and neck dilatation relative to the first post-operative scan was found. None of the studies described a positive relationship between the degree of oversizing and the incidence of endoleaks. On the contrary, oversizing up to 25% seems to decrease the risk of proximal endoleaks. There are conflicting data regarding the risk of graft migration when oversizing by more than 30%.
CONCLUSIONS: Based on the best available evidence, the current standard of 10-20% oversizing regime appears to be relatively safe and preferable. Oversizing >30% might negatively impact the outcome after EVAR. Studies of higher quality are needed to further assess the relationship between proximal oversizing and the incidence of complications, particularly regarding the impact on aneurysm neck dilatation.