Geometric changes in aortic endografts over a 2-year observation period

To report geometric changes in bifurcated aortic endografts observed over a 2-year follow-up period.

Twenty-two patients (21 men; mean age 68 years, range 57-83) with abdominal aortic aneurysms were treated with an endovascular stent-graft. Follow-up examinations included spiral computed tomographic scanning postoperatively and at 3, 6, 9, 12, 18, and 24 months after treatment. Geometric changes were measured using 3-dimensional reconstructed images in anteroposterior (AP) and lateral projections. Locations for the measurements were the proximal neck, the midportion of the endograft, and the graft limbs at the origin of the iliac arteries.

Lateral changes predominated, demonstrating maximum angles on the side of the inserted left limb. For the proximal neck, the stent angle changed by a mean -0.71 degrees in the AP and 4.0 degrees in the lateral projection. At the midgraft, changes were -0.56 degrees for AP and 12.5 degrees for lateral. The right limb showed an angle of 6.43 degrees in AP and -0.43 degrees in lateral, whereas the left limb angles changed 1.38 degrees in AP and 11.71 degrees in the lateral plane after 2 years. There was no statistically significance difference in these changes from baseline.

Aortic endografts are exposed to a significant amount of movement after insertion, but the resultant changes are very inhomogeneous, unpredictable, and ongoing even after 2 years. The most vulnerable location seems to be the attachment zone of the modular graft limb. These geometric changes might be one cause for late complications, including leaks and limb dislocations.