Image-guided endovascular intervention (EIGI), using new flow modifying endovascular devices for intracranial
aneurysm treatment is an active area of stroke research. The new polyurethane-asymmetric vascular stent (P-AVS), a
vascular stent partially covered with a polyurethane-based patch, is used to cover the aneurysm neck, thus occluding
flow into the aneurysm. This study involves angiographic imaging of partially covered aneurysm orifices. This
particular situation could occur when the vascular geometry does not allow full aneurysm coverage. Four standard in-vivo
rabbit-model aneurysms were investigated; two had stent patches placed over the distal region of the aneurysm
orifice while the other two had stent patches placed over the proximal region of the aneurysm orifice. Angiographic
analysis was used to evaluate aneurysm blood flow before and immediately after stenting and at four-week follow-up.
The treatment results were also evaluated using histology on the aneurysm dome and electron microscopy on the
aneurysm neck. Post-stenting angiographic flow analysis revealed aneurysmal flow reduction in all cases with faster
flow in the distally-covered case and very slow flow and prolonged pooling for proximal-coverage. At follow-up,
proximally-covered aneurysms showed full dome occlusion. The electron microscopy showed a remnant neck in both
distally-placed stent cases but complete coverage in the proximally-placed stent cases. Thus, direct flow (impingement
jet) removal from the aneurysm dome, as indicated by angiograms in the proximally-covered case, was sufficient to
cause full aneurysm healing in four weeks; however, aneurysm healing was not complete for the distally-covered case.
These results support further investigations into the treatment of aneurysms by flow-modification using partial