1216. Statistical Investigation of the Relationship Between the Morphology and Rupture Rate of Very Small Posterior Communicating Artery Aneurysms

Authors: Dong-Jun Lim, MD PhD; Seung-Hwan Lee; Sung-Kon Ha; Sung-Won Jin (Ansan-si Kyounggi-do, Republic of Korea)

Aim: The purpose of this study is to evaluate the relationship between the shape, size of aneurysms and the rupture rate of small posterior communicating artery aneurysms. Material and Methods: We studied 74 patients with posterior communicating artery aneurysms less than 5 mm in diameter. We divided these patients into ruptured and unruptured groups, with 51 and 23 patients, respectively. Further, the radiologic and morphologic findings of the aneurysm (maximum diameter, height, width, neck width, aspect ratio, dome-to-neck ratio, bottleneck factor, size ratio, bleb formation, presence of fetal-type PCoA, and inflow angle) were measured and compared between the two groups. Results: All patients perceived the management of such conservative treatment in 5 cases, endovascular coiling in 27 cases or aneurysm clipping in 42 cases. As a result of statistical analysis, the maximum diameter, aspect ratio, dome-to-neck ratio, size ratio and bleb formation were significantly different between the unruptured group and ruptured one (p = 0.039, p = 0.012, p = 0.001, p = 0.06 and p = 0.015). In regression model, the dome-to-neck ratio and bleb formation were remained and were associated with the ruptured aneurysm (p = 0.045 and p = 0.004). Conclusion: The aneurysm rupture risk of the small posterior communicating artery differs on the basis of the shape and size of the aneurysm. Even if the size of the aneurysm is very small, treatment should be provided when the aneurysm have a bleb formation and a high dome-to-neck ratio on imaging study.