INTERVENTIONAL NEURORADIOLOGY Leo stent for endovascular treatment of intracranial aneurysms: very long-term results in 50 patients with 52 aneurysms and literature review Boris Lubicz 1 & Alexandre Kadou 1 & Ricardo Morais 1 & Benjamin Mine 1 Received: 16 August 2016 /Accepted: 6 February 2017 # Springer-Verlag Berlin Heidelberg 2017 Abstract Introduction The Leo stent was the first retrievable stent for endovascular treatment of intracranial aneurysms (IAs). We report our experience with this device with emphasis on very long-term follow-up. Methods This study was approved by authors’ ethical com- mittee. A retrospective review of our prospectively main- tained database identified all patients treated for a saccular IA with this stent in our institution. Technical issues and im- mediate and long-term outcomes (at least 12 months) were evaluated. Results Between 2004 and 2015, 50 patients with 52 IAs were identified. In two patients, the stent could not safely be placed (failure rate = 3.8%). Among 48 treated patients with 50 IAs, there were 44 women and 4 men (mean age, 53 years). Mean aneurysm diameter was 7.2 mm. All IAs but six were wide- necked. There was no immediate morbidity or mortality. Anatomical results included 76% complete occlusions, 22% neck remnants, and 2% incomplete occlusions. Mean follow- up was 50.2 months (range, 12–139 months). Two patients had delayed TIAs but long-term morbidity rate remained = 0%. At follow-up, occlusion was stable in 68% IAs, showed thrombosis in 12%, and recanalization in 20% IAs. Complementary treatment was required in 8% IAs. Final re- sults showed 70% complete occlusions, 24% neck remnants, and 6% incomplete occlusions. Asymptomatic stent occlusion and significant stenosis occurred in one and two cases, respectively. Conclusion The Leo stent is safe and effective for treatment of wide-necked saccular IAs. Very long-term results show high rates of adequate and stable occlusion. Moreover, the stent is well tolerated. Keywords Intracranial aneurysms . Stent . Coiling Introduction Endovascular treatment (EVT) is now the first-intention treat- ment for both ruptured and unruptured intracranial aneurysms (IAs) [1–4]. However, wide-necked IAs remain technically more challenging for classic EVT (i.e., coiling and balloon- assisted coiling). Furthermore, aneurysm recanalization is an important issue in EVT, with approximately 20% of coiled aneurysms recanalized and 10% retreated [5]. Aneurysm neck size was identified as the most important factor in the quality of aneurysm occlusion at midterm follow-up after EVT [6]. The stent-assisted coiling (SAC) technique was developed to treat wide-necked IAs by creating a scaffold that prevents coil protrusion into the parent artery. Compared with classic EVT, SAC showed significantly lower rate of retreatment and better anatomical stability [7, 8]. Several self-expandable intracrani- al stents were introduced in the past decade including laser-cut open-cell stent (Neuroform, Stryker, MI, USA), laser-cut closed-cell stent (Enterprise, Codman, MA, USA), and braid- ed stent (Leo, Balt, Montmorency, France; and Lvis, MicroVention, CA, USA). Among them, the Leo stent was the first available retrievable stent. Several authors have re- ported satisfying results with mid- to long-term follow-up with this device [9–19]. However, very long-term results are still missing in order to evaluate the stability of anatomical results as well as the tolerance of the stent over the years. Indeed, at the beginning of the Bstent^ era, one of the major * Boris Lubicz blubicz@ulb.ac.be 1 Department of Interventional Neuroradiology, Erasme University Hospital, 808 route de Lennik, 1070 Bruxelles, Belgium Neuroradiology DOI 10.1007/s00234-017-1805-3