Tomographic Measurement of Gutters and Analysis of the Conformability of Stent Grafts in the Octopus Technique for Endovascular Thoracoabdominal Aneurysm Repair.

BACKGROUND: The Octopus technique is an off-label and off-the-shelf strategy used as an option in the management of some specific and selected cases of thoracoabdominal aortic aneurysms (TAAA). We sought to compare 2 different methods of measurements on computed tomography (CT) slices and to evaluate the accommodation and conformability, before and after ballooning, of the components used in the Octopus technique.

METHODS: The CT gutter analysis between the 3 stent grafts within the short docking limb of the Excluder(®) was made using Viabahns(®) of 8, 7, and 6 mm in diameter. Each of the 10 possible combinations underwent a CT established protocol. The best axial image of the docking limb was submitted for an evaluation by 2 independent analysts, using 2 different methods. We also performed a postballooning evaluation, and the same CT protocol was used.

RESULTS: There was no significant difference between the formats of measurement type "A" and type "B." Furthermore, there was no significant difference between the measurements made by the independent analysts. The tomography analyses demonstrated that the combination of stent grafts (Viabahn) of 8 and 7 mm diameter, inside the short docking limb of the bifurcated endoprosthesis, had the best possible relationship between the diameters used. These combinations showed better conformability and juxtaposition, with smaller areas of gutters and theoretically less possibility of endoleak. In addition, we found that postimplant balloon dilatation impaired the conformability and juxtaposition of the stent grafts (Viabahn) in the optimum combinations.

CONCLUSIONS: In this analysis, we demonstrated a feasible, reliable, and reproducible form of CT measurement of the gutters in the Octopus technique for endovascular repair of TAAAs. Based on these measurements, there is a preferable combination of Viabahn sizes to be used in the Octopus technique and that postdilatation impairs the conformability and juxtaposition.