Abstract TP77: Simple Morphological Parameters Associated With The Rupture Risk Of Posterior Communicating Artery Aneurysms.

Abstract

Introduction: The contribution of morphological characteristics to the treatment decision of unruptured aneurysms has not been established in a systematic and location specific manner. We present a large sample of posterior communicating (PComm) aneurysms that were assessed using a diverse array of morphological variables to determine the parameters associated with aneurysm rupture. Methods: Demographic and clinical risk factors of aneurysm rupture were obtained viachart review. Pre-operative CT angiograms (CTA) were evaluated with 3D Slicer© to generate 3-D models of the aneurysms and surrounding vascular architecture. Morphological parameters examined in each model included aneurysm volume, aspect ratio, size ratio, distance to bifurcation and origin points, aneurysm angle, vessel angles, flow angles, and parent-daughter angles. Univariate and multivariate analyses were performed to determine statistical significance. Results: From 2005-2011, 141 PComm aneurysms were treated in a single institution, and preoperative CTAs from 48 patients (32 ruptured, 16 unruptured) were analyzed. Those that underwent reoperation, were associated with arteriovenous malformations, or lacked a preoperative CTA were excluded. Ruptured aneurysms were associated with smaller volume, greater aspect ratio, greater size ratio, smaller internal carotid artery (ICA) to aneurysm neck angle, larger PComm flow angle, larger ICA to PComm angle, and smaller PComm to daughter vessel angle. Multivariate logistic regression revealed that a larger neck diameter, greater aspect ratio, greater size ratio, and shorter ICA bifurcation to aneurysm distance were the most strongly associated with rupture after adjusting for all other variables. Interestingly, volume of the aneurysm had a smaller effect size than most other variables and rupture risk was associated with smaller volumes. Conclusion: We found that larger neck diameter, greater aspect ratio, greater size ratio, and smaller ICA bifurcation to aneurysm distance to be highly associated with PComm aneurysm rupture. These are easily measured and physically intuitive parameters. They are more strongly associated with PComm aneurysm rupture than size alone and can be readily applied in clinical practice.