Cerebral Aneurysm Multicenter European Onyx (CAMEO) Trial: Results of a Prospective Observational Study in 20 European Centers

Abstract

BACKGROUND AND PURPOSE: This study was designed to investigate the safety and efficacy of the Onyx liquid embolic system in treating a selected population of patients with intracranial aneurysms that presented difficulties for surgical or endovascular alternatives.

METHODS: A prospective observational study was conducted in 20 European centers enrolling a consecutive series of 119 patients with 123 aneurysms judged suitable for Onyx treatment. The series consists of findings collected in 97 of 119 patients with 100 of 123 aneurysms, because one center declined to provide data to the study sponsor or allow outside audit. Clinical and angiographic outcomes were recorded at discharge, 3 months, and 12 months. All adverse events and re-treatments were recorded. Seventy-nine aneurysms were large or giant.

RESULTS: Twelve-month follow-up angiography findings were available for 71 aneurysms. This angiographic follow-up showed complete occlusion in 56 (79%) aneurysms, subtotal occlusion in nine (13%), and incomplete occlusion in six (8%). Procedure- or device-related permanent neurologic morbidity at final follow-up was present in eight of 97 patients. Seven patients died: two deaths were procedure related; one, disease related; and four, unrelated causes. Seventy-five of the 82 patients alive and with follow-up at 12 months were at Rankin 2 or better status. Delayed occlusion of the parent vessel occurred in nine patients; delayed occlusion was asymptomatic in five and resulted in permanent neurologic deficit in two.

CONCLUSION: In selected patients with aneurysms that are unsuitable for coil treatment or in whom previous treatment has failed to occlude the aneurysm, Onyx treatment offers an endovascular alternative. Aneurysm occlusion rates are superior to reported rates of coil occlusion, and treatment morbidity is comparable to that of published prospective data on endovascular results for this subgroup of patients.