Introduction <p>Flow diverters (FD) are used for the treatment of intracranial aneurysms, by redirecting flow and serving as a scaffold for endothelial coverage of the aneurysm ostium. However, in-stent stenosis has been observed in some patients treated with these devices, the cause of which and the epidemiology remaining elusive. In the current study we aimed to elucidate potential factors leading to higher degree of in-stent stenosis including gender, location, and type of FD.</p> Methods <p>The authors queried their institutional Electronic Health Record (EHR) for all patients undergoing FD for intracranial saccular aneurysms. We excluded cases where an FD was performed for a dissecting aneurysm, or other indications. We also excluded patients who had no available follow up.</p> Results <p>We identified 161 patients undergoing FD for aneurysms, with a mean age of 57.4 (SD = 12.94) and141 (87.6%) of which were females. A total of 24 patients (14.9%) had an in-stent stenosis at a median interval of 10&#xa0;months; 9 (5.6%) had a severe (i.e. symptomatic or requiring treatment) stenosis. When subsetting for females, we found that females with any in-stent stenosis were significantly younger compared to those without stenosis (51.045, SD = 15.7 vs 58.5, SD = 12.31, p = 0.013). Females with severe in-stent stenosis were even younger (42.2, SD = 14.2 vs 58.3, SD = 12.54; p &lt; 0.001) compared to the rest of the females. Patients presenting with ruptured aneurysm had a higher rate of severe in-stent stenosis (16.7%, n = 4/24, p = 0.014). Regarding devices, patients who underwent treatment with a high-braid FD were more likely to have severe in-stent stenosis (18.8%, n = 3/16; p = 0.016).</p> Conclusion <p>Our findings indicate that younger age, presentation with rupture and high-braid FD may be associated with higher risk of severe in-stent stenosis. These findings may provide more insight into the selection of treatment modality and/or device in patients undergoing management of their cerebral aneurysms.</p>