Abstract TP90: Effect of Smoking on Morphological Variables for Ruptured and Unruptured Intracranial Aneurysms

Abstract

Introduction: Management of unruptured intracranial aneurysms remains controversial in neurosurgery. The contribution of morphological parameters has been gradually included in the treatment paradigm. Smoking is associated with increased risk of cerebral aneurysm formation and rupture, but the effect of smoking on morphological features of an aneurysm is unclear. We present a large sample of aneurysms that were assessed using morphological variables to investigate how smoking status affects the parameters associated with aneurysm rupture. Methods: Pre-operative CT angiograms (CTA) were evaluated with 3D Slicer© to generate three-dimensional models of the aneurysms and surrounding vascular architecture. Morphological parameters examined in each model included aneurysm volume, size, aspect ratio, aneurysm angle, flow angle, size ratio, and parent-daughter angle. Univariate and multivariate statistical analyses were performed to determine statistical significance. Results: From 2006-2010, 114 ruptured and 89 unruptured aneurysms were treated in a single institution, including 72 anterior communicating artery aneurysms, 79 middle cerebral artery aneurysms, and 52 internal carotid artery aneurysms. Ruptured aneurysms were associated with greater aspect ratio and size ratio, larger aneurysm angle, and smaller parent-daughter angle (p<0.05). While no difference in aneurysm angle and parent-daughter angle was observed based on smoking status, ruptured aneurysms in smokers are more likely to be smaller in size, have narrower neck diameters, and possess larger aspect ratios (p<0.05) when compared to ruptured aneurysms in nonsmokers. Multivariate logistic regression revealed aspect ratio was the strongest parameter associated with aneurysm rupture in patients who smoke after adjusting for demographic and other clinical risk factors. Conclusion: Aspect ratio, aneurysm angle, and parent-daughter angle have a greater association with aneurysm rupture than size. Smoking status does not affect parameters related to the vascular architecture (i.e. aneurysm angle and parent-daughter angle), but is associated with increased aspect ratio and smaller size in ruptured aneurysms.