Laboratory "In-vitro" Evaluation of the Parallel Stent Graft Association for the Iliac Sandwich Technique

The Iliac Sandwich is an off-label technique that uses parallel stent grafts to treat aortoiliac aneurysms. The purpose of this experimental study is to evaluate the conformability and juxtaposition of stent grafts combinations used in this technique through in-vitro mechanical evaluation, computed tomography (CT) analyses, and a controlled pulsatile flow system.

The combinations of two Viabahn® ("V-V") or Viabahn® and Excluder® iliac extension ("V-E") were analysed using CT imaging with measurement of the gutter area by two independent analysts before and after balloon angioplasty. In a second phase, the parallel stent combinations were also evaluated using CT imaging after being implanted in the aortic aneurysm model with a pulsatile flow system with controlled temperature, viscosity, and density.

The "V-E" group had a better conformability when compared to the "V-V" group, ensuring smaller gutter areas (0.0064 cm² ± 0.01 vs. 0.0228 cm² ± 0.03, p < 0.001). Post dilatation with two non-compliant balloons resulted in enlargement of the gutter area (Area A, p 0.065; Area B, p 0.071). Conversely, post dilatation with a non-compliant balloon for the internal iliac component and a compliant balloon for the external iliac device reduced the gutter area (Area A, p 0.008; Area B, p 0.010).

The combination of Viabahn® and Excluder® iliac extension device ("V-E") had a smaller gutter area compared to two Viabahn® parallel stents for the Iliac Sandwich Technique. Post dilatation using a non-compliant balloon for the internal iliac device and a compliant balloon for the external iliac provided superior conformability and juxtaposition.