Studying the factors affecting and contributing to the degree of angular remodeling following SAC.

We reviewed 43 bifurcation aneurysms treated by SAC [coiling following stent deployment, Neuroform(n=28), Enterprise(n=8), and Lvis(n=7)]. The bifurcation angle between the mother and stented daughter vessel was measured in 4 settings: pre-treatment, post-stenting, post-coiling, and at delayed follow-up (average 12months). Degree of stent-induced angular remodeling was calculated by subtraction of the post-stenting from the pretreatment angel, while the coil-induced angular remodeling was calculated by subtraction of the post-coiling from the post-stenting angle. The degree of immediate post-procedural angular remodeling equals the sum of the stent and coil-induced angular remodeling.

We analyzed the effect of the aneurysm site, intra-aneurysmal coils size, stent type, diameter of parent vessel, stent length in the daughter vessel.  

The mean stent-induced angular remodeling was 10.2(0-47), coil-induced angular remodeling was 4.53(-7-30), immediate post-procedural angular remodeling was 14.8 (-4-47), and delayed contributing remodeling was 4.75(-12-40). Degree of immediate remodeling is significantly affected by the intra-aneurysmal coils size (P=0.017), and the pretreatment bifurcation angle (p=0.024). Pre-treatment angle was defined as a predictor on regression analysis. The degree of delayed remodeling is significantly affected only by the pretreatment bifurcation angle (p=.011). Aneurysm site, stent type, diameter of parent vessel, and length of the stent in the daughter vessel didn't statistically affect the degree of immediate or delayed angular remodeling.

For years, it was thought that the stent alone is responsible for the angular remodeling in SAC. To our knowledge, this is the first study reporting the role of the coils as an additional factor beside the stent in inducing the immediate angular remodeling.