A standardized multi-branched thoracoabdominal stent-graft for endovascular aneurysm repair

Abstract

Purpose: To assess the feasibility of endovascular thoracoabdominal aortic aneurysm (TAAA) repair using a standard off-the-shelf multi-branched stent-graft.

Methods: The aortic anatomy of 66 patients (45 men; mean age 74 years, range 57-87) referred for endovascular repair of TAAA was measured using 3-dimensional reconstructed images from computed tomographic angiograms. In particular, the orientation and longitudinal position of the orifice of each celiac artery, right renal artery, and left renal artery were measured relative to the location of the superior mesenteric artery (SMA) orifice. Based on prior experience, branch insertion with a standard endograft was considered feasible under the following conditions: (1) no more than 4 indispensable (target) arteries to the abdominal viscera, (2) the celiac artery and SMA were 6 to 10 mm in diameter, (3) the renal arteries were 4 to 8 mm in diameter, (4) all target arteries were accessible from a transbrachial approach, (5) the distance between each cuff and the corresponding arterial orifice was <or=50 mm, and (6) the line between the cuff and the orifice deviated by <or=45 degrees from the long axis of the aorta.

Results: Seven (11%) of 66 patients violated conditions 1 through 4: 2 had target arteries that were either too wide or too narrow, 2 had >4 indispensable visceral or renal branches, and 3 patients had inaccessible upward directed renal artery branches. Three of the remaining 59 patients had renal arteries outside the boundaries defined by conditions 5 and 6 when the hypothetical stent-graft was positioned with its SMA cuff 25 mm proximal to the corresponding SMA orifice. However, if the stent-graft were deployed in a more caudal location, only 1 of these 3 renal arteries would have been out of range. Therefore, 58 (88%) of 66 patients met all the eligibility criteria for repair using the off-the-shelf stent-graft.

Conclusion: A standardized, off-the-shelf, multi-branched stent-graft is applicable in 88% of cases of TAAA that would otherwise have been treated using customized stent-grafts. The use of a pre-made stent-graft has the potential to eliminate long manufacturing delays and expand the scope of endovascular repair of TAAA.

Figure 1

♦ Photograph of the standard endograft

Figure 2

♦ Flow diagram of the cohort with determination of applicability of the standardized multi-branched stent-graft

Figure 3

♦ Scatter plot of branch position of the 59 patients meeting the initial 4 criteria with standard endograft overlaid. The angled lines indicate the boundary conditions as outlined in the text. The 3 branches that fall outside the boundary conditions are circled. CA: celiac artery, SMA: superior mesenteric artery, RRA: right renal artery, LRA: left renal artery