Background and purpose Low profile braided stents have facilitated the endovascular treatment of broad-based intracranial aneurysms.

Methods Between 2013 and June 2018, we attempted 104 Leo baby stent placements in 101 patients. Locations were the anterior communicating artery (AcomA) (37 aneurysms, 35.6%), middle cerebral artery (MCA) bifurcation (29 aneurysms, 27.9%) and basilar artery (23aneurysms, 22.1%). Mean neck size was 4.9 mm (2.2–8.2). 60 aneurysms were incidental, 31 of 37 recurrent aneurysms had ruptured before.

Results Stent deployment was successful in 89.4% of cases. Common reasons for failure were inability to access the parent artery (n=5) or to deploy the stent across the aneurysm neck (n=4). Two patients had poor outcomes within 24 hours. One patient developed a brain hemorrhage caused by guide wire perforation (MRS 5), the other an early thrombotic stent occlusion (MRS 4). No patient died. Nine (8.7%) patients experienced transient neurological deficits with ischemic lesions on diffusion weighted imaging (DWI). Initially Raymond-Roy class 1 occlusion was achieved in 23 aneurysms (24.7%), class 2 occlusion in 40 (43%), class 3a occlusion in 14 (15.0%), and 3b occlusion in 16 aneurysms (17.2%). Follow-up imaging in 87 patients showed stable or improved occlusion grades in 76%. Six patients required retreatment while the rest were managed conservatively. Four delayed stent occlusions occurred in three patients, with severe morbidity in one patient (MRS 5). There were no aneurysm ruptures or deaths.

Conclusion Stent assisted treatment of broad-based aneurysms with the Leo baby stent is safe and effective. The frequency of delayed thrombotic complications is low and similar to other stents.