Introduction The flow characteristics of bifurcation aneurysms of the posterior communicating artery (PCOM) have rarely been studied. Especially in the presence of a fetal posterior circulation (FPC), the likelihood of complete PCOM aneurysm occlusion after endovascular treatment is reduced. Due to this, PCOM aneurysms in anatomical variations of the posterior circulation represent a major challenge.[1]

Aim of Study Investigating variations in fetal and non-fetal configurations and its hemodynamic impact on PCOM aneurysms.

Methods 3D-DSA data of 18 patients harboring bifurcation aneurysms at the PCOM are collected. 11 patients demonstrate a FPC and 7 patients a non-FPC. Patient-specific 3D models containing at least one bifurcation distal the aneurysm in the anterior circulation as well as the PCOM itself are extracted. Using image-based blood flow simulations, hemodynamics of all aneurysm models are calculated. The outflow of the PCOM is artificially varied representing fetal and non-fetal conditions for every model.

Results PCOM aneurysms generally exhibit a lower wall shear stress on the aneurysm wall compared to the surrounding parent vessels. Due to the increase of the PCOM outflow, indicating a fetal state, higher local wall shear stresses are detected at the distal aneurysm side. Furthermore, fetal configurations show higher velocities in the PCOM itself as well as a slightly higher flow distribution in the aneurysm sac.

Conclusion The presence of posterior anatomical variations affects the hemodynamic parameters of PCOM bifurcation aneurysms. In particular, the presence of an FPC has an unfavourable effect on the intraaneurysmal flow dynamics.

Disclosure of Interest no.