Objective To report the clinical results and initial clinical experience of endovascular isolation with the Willis covered stent for carotid siphon aneurysms.

Methods Between November 2013 and December 2016, a total of 57 patients who presented with carotid siphon aneurysms were treated with the Willis covered stent. Results of the procedures, technical events, and complications were recorded. Clinical and imaging follow-ups were performed at 3 months following the endovascular procedures.

Results Placement of the Willis covered stent was successful in all patients. Immediate angiography revealed complete exclusion of aneurysms in 48 patients (84%), while endoleak occurred in nine patients (16%). Procedure-related complications occurred in three cases, including displacement of the covered stent in one patient, acute in-stent thrombosis in one patient, and microwire-related intracranial hemorrhage in one patient. Angiographic follow-ups were done in 49 patients, with complete exclusion of aneurysms in 47 patients. Endoleak was present in two patients. No aneurysm recurrence occurred. Forty-four patients showed good parent artery patency, while the other five patients showed mild to moderate asymptomatic in-stent stenosis. During the follow-up period, no ischemic or hemorrhagic event occurred. The modified Rankin Scale scores at follow-up were 0–2 in 56 patients and >2 in one patient.

Conclusions The treatment of siphon aneurysms with Willis covered stent implantation resulted in satisfactory clinical outcomes. The Willis covered stent seems safe and feasible for the treatment of siphon aneurysms, which still needs to be confirmed by longer follow-up periods and controlled studies with larger samples.