The challenge of gate cannulation during endovascular aortic repair: A hypothesis of simplification

One of the technical problems which can be encountered during the endovascular repair (EVAR) of abdominal aortic aneurysms, is represented by the challenge of cannulation of the contralateral gate after the opening of the main body of the endograft, especially in case of tortuous aorta-iliac anatomy. Aim of this work is to propose a hypothesis of simplification, verifying the possibility to maximize the area available for the cannulation of the contralateral gate by simulating an oblique distal end of the leg of the most used devices, without affecting the correct sealing between the main body and the iliac extension.

Data about the contralateral gate of the main body of endografts most used for EVAR were analyzed. The elliptical sectional area resulting from the simulation of the oblique cut was calculating with some geometric formulas. Then the gain of "disposable area" for the cannulation of the contralateral gate was calculated as a percentage of the elliptical area resulting in maximum distal oblique cut, with respect to the nominal circular area of the base.

The only endografts which could undergo an oblique cut without losing the sealing between the main body and the contralateral limb were the Incraft, the Treovance and the Ovation, for which it would be possible to obtain a surface gain up to 84%, 22.8% and 14.4% respectively (being 9.8% in case of Ovation with the main body 29 and 34). A simulation of oblique cut was also performed on the endografts which currently do not allow to do so without a loss of sealing, assuming to lengthen the contralateral gate of an arbitrary measure of 10mm. In these cases, the percentage of surface gain was greater for endoprostheses which had a smaller diameter of the contralateral leg.

The oblique cut of the contralateral gate allowed a gain of the surface available for the cannulation, however it was not applicable to all models of currently available endoprostheses, unless of a loss of sealing between the main body and the contralateral iliac limb.