Treatment of Distal Internal Carotid Artery Aneurysm with the Willis Covered Stent: A Prospective Pilot Study

Purpose: To evaluate the flexibility and efficacy of the Willis covered stent in the treatment of distal internal carotid artery (DICA) aneurysms. Materials and Methods: The study was approved by the authors' institutional review board, and the research was conducted by the authors' institution and the MicroPort Medical Company (Shanghai, China). Thirty-one patients with 33 DICA aneurysms were considered for treatment with a Willis covered stent. The angiographic assessments were categorized as complete or incomplete occlusion. The data on technical success, initial and final angiographic results, mortality, morbidity, and final clinical outcome were collected, and follow-up was performed at 1, 3, 6, and 12 months and yearly after the procedures. Results: Navigation and deployment of the covered stents were successful in 97.6% (41 of 42; 95% confidence interval [CI]: 93%, 102%) of the attempted stent placement procedures. The initial angiographic results showed a complete occlusion in 23 patients with 25 aneurysms (of 32 aneurysms, 78.1% [95% CI: 63%, 93%]) and an incomplete occlusion in seven patients with seven aneurysms (21.9%). The angiographic follow-up (mean, 14 months [95% CI: 12, 15 months]) findings exhibited a complete occlusion in 27 patients with 29 aneurysms (of 31 aneurysms, 93.5% [95% CI: 84%, 103%]) and an incomplete occlusion in two aneurysms (6.5%), with a mild in-stent stenosis in two patients. The clinical follow-up (mean, 27 months [95% CI: 23, 30 months]) demonstrated that 15 patients experienced a full recovery and 14 patients improved. Conclusion: The preliminary results demonstrate good flexibility and efficacy of the Willis covered stent in the treatment of DICA aneurysms in selected patients; longer follow-up and expanded clinical trials are needed. (C) RSNA, 2009