Purpose Stent assisted coiling techniques have improved the endovascular treatment of wide necked (neck >4 mm or dome to neck ratio <2) and fusiform/dissecting intracranial aneurysms. The Enterprise stent (Cordis Endovascular, Miami Lakes, Florida, USA) is the first commercially available closed cell stent in the USA specifically designed for the treatment of intracranial aneurysms. We evaluate the safety and efficacy of the Enterprise stent at our center.

Materials and methods Between June 2007 and February 2010, 102 wide necked and fusiform/dissecting intracranial aneurysms in 92 patients were treated endovascularly using the Enterprise stent. Seventeen (17%) aneurysms were located in the posterior circulation. Ten (11%) were treated acutely following subarachnoid hemorrhage. The aneurysms were defined as wide neck (79, 77%), dissecting or fusiform (16, 16%) or blister (seven, 7%) aneurysms. Some aneurysms included in this group were treated due to recanalization following primary coiling (24, 24%) or clipping (two, 2%). The mean aneurysm diameter and neck size was 6.0 mm (SD 4.0 mm, range 2–25 mm) and 4.8 mm (SD 2.6 mm, range 2–15 mm), respectively. The mean dome to neck ratio was 1.3. All patients were pretreated with aspirin and clopidogrel and maintained on both of these medications for 6 months. Follow-up catheter angiography was available for 48 patients (52%) at a mean of 9.7 months (range 6–18 months). Immediate postprocedure control and follow-up angiograms were evaluated using the Raymond scale by investigators not involved in the coiling procedure. Clinical evaluations were performed using a modified Rankin scale.

Results Immediate control angiography demonstrated total aneurysm occlusion in 38 aneurysms (37%), neck filling was seen in 32 aneurysms (32%) and dome filling was seen in 31 aneurysms (31%). The mean packing density was 44% (SD 27%). There were 13 (13%) intraoperative thromboembolic complications that were successfully treated with intra-arterial thrombolytics (tissue plasminogen activator and abciximab). There was one case of acute stent migration during the treatment of a basilar tip aneurysm and another case of intraoperative aneurysm perforation. There was no periprocedural morbidity. One patient that presented with a ruptured aneurysm died from subarachnoid hemorrhage shortly after treatment (mortality 1%), and aneurysm rebleeding could not be excluded. Angiography at follow-up demonstrated total occlusion in 39 aneurysms (82%), six neck remnants (12%) and three residual aneurysms (6%). Four cases showed recanalization secondary to coil compaction of which three aneurysms have been retreated. In the follow-up period, there have been no cases of stent migration, two cases of mild, asymtomatic in-stent stenosis, six cases of delayed thromboembolic complications and one case of symptomatic parenchymal hemorrhage following shunt placement for hydrocephalous treatment 30 days post-coiling. Median modified Rankin scale at follow-up is 0.

Conclusion This large series adds to the growing evidence demonstrating the safety, effectiveness and maneuverability of the Enterprise stent in the treatment of intracranial aneurysms. Although initial complete occlusion rates determined from the Raymond scale were not favorable, most aneurysms (82%) imaged at a mean of 9.7 months after stent assisted coil embolization are completely occluded. Data on long term occlusion and in-stent stenosis rates are pending.