Endovascular treatment of distal internal carotid artery aneurysms and vertebral artery dissecting aneurysms with the Willis covered stent: A single-center, retrospective study

Background More data is needed on the short- and medium-term efficacy and safety of the Willis covered stent in treating distal internal carotid artery (DICA) aneurysms and vertebral artery dissecting aneurysms (VADAs). Methods Records of all 42 patients with DICA aneurysms or VADAs treated with the Willis covered stents at our institute between July 2014 and January 2019 were retrospectively examined. The patients' demographic information, symptoms, diagnosis, treatment procedure, immediate and follow-up clinical and angiographic outcomes were extracted. Results 46 Willis covered stents were successfully implanted in all of the 42 patients (total 43 aneurysms). Immediate complete aneurysm occlusion was achieved in 37 patients (38 aneurysms) (88.4%), and endoleak occurred to 5 patients (5 aneurysms) (11.6%). 2 patients died post-operatively from procedure-related complications, another one died from reasons unrelated to the procedure. Among the remaining 39 patients, non-lethal complications occurred in 4 patients including ptosis and diplopia of the right eye, intra-operative hemorrhage and carotid cavernous fistulas (CCF). Angiographic and clinical follow-ups (means +/- standard deviation: 8.8 +/- 5.3 months) were done for 32 patients (33 aneurysms). Complete occlusion was maintained in all of the 33 aneurysms. 2 of the 32 patients had significant though asymptomatic parent artery (PA) occlusion. No ischemic or hemorrhagic event occurred during the follow-up period. The modified Rankin Scale (mRS) score was 0 in 31 patients and 1 in the remaining 1 patient. Conclusions The Willis covered stent could be a safe and effective treatment for complex DICA aneurysms with excellent durability. In addition, the Willis covered stent treated all of the 3 cases of VADAs in the study with complete success without any complications, however, as the number of the VADA cases was small, more cases are needed to further confirm the efficacy and safety of the Willis covered stent in treating VADAs.