Predictors of aneurysmal occlusion in the period immediately after endovascular treatment with detachable coils: a multivariate analysis.

BACKGROUND AND PURPOSE Complete intracranial aneurysmal occlusion by endovascular techniques is required for successful treatment and is presumably influenced by several parameters. The purpose of this study was to investigate whether operator experience and angiographic characteristics of intracranial aneurysms correspond to the degree of endovascular occlusion in the period immediately after treatment with Guglielmi detachable coils (GDCs).

METHODS Pre- and posttreatment angiograms of 72 patients undergoing GDC treatment were reviewed retrospectively. The following angiographic characteristics of the aneurysms were evaluated: largest diameter of the sac, volume, neck size, shape, type, cerebrovascular site, surroundings, and likely direction of aneurysmal inflow as judged by a score developed by measuring aneurysm/parent artery angulation. The chronological sequence in which the aneurysms were treated was used as a measure of operator experience. A chi2-test was used to identify parameters that correlated with outcomes of total (100%) or partial (<100%) occlusion. A multivariate analysis was used to determine the factors most predictive of aneurysmal occlusion at therapy.

RESULTS Parameters that correlated with the unsatisfactory result of partial occlusion were large aneurysmal diameter, volume, and neck size, more direct inflow (ie, increasingly obtuse aneurysm/parent artery angulation), and early chronological presentation in the series. The three factors most predictive of partial occlusion were large aneurysmal diameter, more direct inflow, and early chronological order of treatment.

CONCLUSION Several morphologic features of aneurysms were identified to help predict the immediate outcome of occlusion with GDCs. This study underscores the existence of a steep learning curve associated with GDC use in treating aneurysms and the importance of operator experience in achieving optimal therapeutic results.