Immediate Anatomic Results after the Endovascular Treatment of Unruptured Intracranial Aneurysms: Analysis of the ATENA Series

BACKGROUND AND PURPOSE: A precise analysis of the immediate postoperative anatomic results in a large series of unruptured intracranial aneurysms treated by endovascular approach has not previously been presented. This study aimed to assess the efficacy of endovascular treatment of unruptured intracranial aneurysms in light of immediate postoperative anatomic results in a prospective, multicenter study (the Analysis of Treatment by Endovascular Approach of Nonruptured Aneurysms study; ATENA). MATERIALS AND METHODS: Postoperative anatomic results from digital subtraction angiography (DSA) were evaluated with the Montreal scale by the treating physician and by 2 anonymous, independent, experienced neuroradiologists. RESULTS: The analysis included 622 patients (449 women, 173 men; age range, 22-83 years; mean age, 51.2 +/- 11.3 years) harboring 694 aneurysms. Evaluation of the postoperative anatomic results by the 2 independent reviewers indicated total occlusions in 437 aneurysms (63.0%), neck remnants in 156 aneurysms (22.5%), and aneurysm remnants in 101 aneurysms (14.6%). Several factors favorably affected the quality of the aneurysm occlusion with treatment, including patient age (< 65 years old; P < .0001), aneurysm diameter (<= 6 mm; P = .0049), aneurysm dome-to-neck ratio (> 1.5; P = .0388), and endovascular technique (coiling or remodelling compared with stent placement; P = .0001). CONCLUSIONS: The endovascular treatment of unruptured aneurysms provided satisfactory postoperative occlusion rates, with a high percentage of complete occlusion or neck remnants (85.4%). Postoperative anatomic results were significantly affected by aneurysm size and neck size, but not aneurysm location.