Separation of Components in Fenestrated and Branched Endovascular Grafting – Branch Protection or a Potentially New Mode of Failure?

ObjectivesModular component separation following endovascular aortic repair is recognized as a potential source of late failure. The aim of this study was to establish the extent of component separation occurring in branched and fenestrated endografts and to ascertain any factors that predict its occurrence.DesignAn analysis of component relationships following fenestrated and branched endovascular aneurysm repair was conducted on all patients with >1 year of digital imaging data. A mathematical model was developed, and retrospectively applied, to determine the minimum stentgraft overlap required to preclude any risk of component separation.ResultsOf the 184 patients treated prior to 2006, data (for patients with greater than 1 year follow-up) were available for 106 patients. Fourteen (13%) had evidence of inter-component movement of which 8 developed component separation (<2 stent overlap). All 8 patients with component separation, in addition to 38% of the total cohort, were identified as being at risk for eventual component separation using the mathematical model.ConclusionsComponent movement is commonly observed in modular devices, but clinical consequences are rare. The degree of overlap, aneurysm diameter, aneurysm length, and stentgraft diameter can be used to predict the risk of inter-component movement which may result in component separation.