Safety and efficacy of flow-diverter stents in endovascular treatment of intracranial aneurysm: interest of the prospective DIVERSION observational study.

Endovascular treatment using detachable coils is now a well-established technique for intracranial aneurysms (IA) occlusion following the publication of the results of the International Subarachnoid Aneurysm Trial (ISAT) [1]. However, the treatment of large or giant IA remains challenging with low initial angiographic occlusion rates [2] and high rates of recanalization [2—4]. In this situation, the flow-diverter stents (FDS) appeared recently as an alternative therapeutic option [5]. The concept of these stents is to divert the blood flow allowing progressive aneurysm thrombosis. These devices are deployed in an increasing number of patients. Efficacy of FDS in IA occlusion is high. Szikora et al. reported a complete occlusion and a partial filling at 6 months in 17 and 1 out of 18 patients, respectively [6]. In the series of Lubicz et al., angiographic follow-up at 6 months showed 20 complete occlusions out of 29 aneurysms (69%), 1 neck remnant (3.5%), and 8 incomplete occlusions (27.5%) [7]. In a recent meta-analysis of 29 studies including 1451 patients with 1654 aneurysms, the rate of complete occlusion was 76% at 6 months [8]. However, the safety of FDS remains a crucial concern. The safety results of FDS vary widely across reported studies. In the first Argentine series of 53 patients, no stroke or death were encountered, and 3 patients (5%) experienced transient exacerbations of preexisting cranial neuropathies [9]. In other reports, morbidity and mortality rates after treatment with FDS were found to be high [6,10—16]. In the series of Szikora et al. dealing with 18 patients, one patient died due to rupture of a coexisting aneurysm, one patient experienced abrupt in-stent thrombosis resulting in a transient neurologic deficit, and one patient presented visual deficit due to ophtalmic artery occlusion [6]. The same year, Lubicz et al. reported mortality and morbidity rates of 4% (1 out of 26 patients) and 15% (4 patients), respectively [7]. Results from the recent meta-analysis found procedurerelated morbidity and mortality of 5% and 4%, respectively [8]. o m I t