Toward an “Off-the-Shelf” Fenestrated Endograft for Management of Short-Necked Abdominal Aortic Aneurysms: An Analysis of Current Graft Morphological Diversity

Abstract

To examine the feasibility of an "off-the-shelf" fenestrated endograft repository to broaden the applicability of fenestrated endovascular aneurysm repair (f-EVAR) to a greater number of emergent cases. Graft dimensions of 438 consecutive customized fenestrated endografts for juxtarenal aneurysms were obtained from the commercial manufacturer, classified into tolerance ranges, and encoded in a database for statistical analysis. Limits of variability for tolerance ranges were set to maintain target vessel patency within acceptable surgical limits at deployment. Key independent structural variables were identified and analyzed for trends. Detailed analysis was performed of 282 (64%) 3-fenestration endografts, representing 232 structurally unique grafts. Seven key individual structural variables were identified, constituting 21,952 possible combinations. Only 8/232 (3.5%) graft configurations were compatible with > or =3 patients. Nearly a third of the patients (86/282, 30.5%) were treated by a range of 36 customized endografts. Graft dimensions were not uniformly distributed; there were modal sizes that were likely to recur at a median 39 cases (95% CI 17-121). Deploying endografts incorporating double diameter-reducing tie technology increased the tolerance such that 28 grafts would treat 81% of this population. The current design of fenestrated stent-grafts means that an "off-the-shelf" option is not practicable. However, there is evidence of recurrent patterns of morphology. Statistical modeling is capable of predicting demand for graft configurations. Innovations in f-EVAR endograft technology may decrease the required variability in graft morphology, paving the way for ready-to-deploy fenestrated stent-grafts.