Multi-centric European post-market follow-up study of the Neuroform Atlas Stent System: primary results

Background Few prospective series have described the safety and effectiveness of the Neuroform Atlas Stent System. We aimed to investigate the efficacy and safety of the device in patients treated for unruptured aneurysm. Methods ATLAS EU PMCF is a consecutive, prospective, multicentric study that included patients with unruptured saccular aneurysm of all sizes. Follow-up visits were scheduled at 3–6 months and 12–16 months with digital subtraction angiography (DSA) or MRI imaging follow-up as per the site standard of care. The primary efficacy endpoint was adequate aneurysm occlusion (Raymond Roy occlusion grade I and II) on 12 month angiography. The primary safety endpoint was any major stroke or ipsilateral stroke or neurological death within 12 months. Results Of the 106 patients consented, 105 were treated with at least one Neuroform Atlas stent. There was a failed implantation attempt in 1 patient, 85 patients received lateral stenting, and 19 patients received Y-stenting. Mean aneurysm neck size was 4.2 mm (range 1.9–33 mm). Adequate occlusion was observed in 95.1% immediately after the procedure and in 98.9% of cases at 1 year DSA follow-up. Overall, 1.0% (1/102; 95% CI 0.0% to 5.3%) of patients experienced a primary safety endpoint of major stroke. Three minor strokes resulted in a modified Rankin Scale score of 2. Conclusions In this multicentric, prospective study, stent-assisted coiling of medium size unruptured aneurysms with the Neuroform Atlas stent resulted in a favorable rate of satisfactory occlusion. In our findings, the use of the Y-stenting technique was associated with increased rates of procedural complications. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT02783339 .