Introduction | Purpose Flow diversion (FD) has changed the landscape for minimally invasive treatment of intracranial aneurysms. Long-term safety and efficacy of this treatment modality is still underinvestigation particularly for those used for off-label indications. The purpose of this study is to examine the safety and efficacy of FD in a real-world setting.

Methods Data from 200 patients across 7 institutions with a procedure date between January 2015 and January 2020 were retrospectively abstracted. Descriptive analyses of patient demographics, aneurysm characteristics and follow-up appointments at 6-months and most recent follow-up (or last appointment date within the study period) were examined. Primary outcomes included aneurysm incidence, mortality, complications, occlusion and functional or neurological outcomes as measured by modified Rankin Scale (mRS), the National Institutes of Health Stroke Scale score (NIHSS), and World Federation of Neurosurgical Societies (WFNS) score post procedure, at 6-months, or most recent follow-up appointment.

Results 200 patients underwent 210 stent placements for treatment of 234 aneurysms. Patients were majority female (78.5%), with a mean age of 58.3 years (SD 12.9), with comorbidities of hypertension (52%), diabetes (9.5%), current/previous tobacco use (15.5%, 40.0%), and family history of subarachnoid hemorrhage (SAH, 11%). Ethnicity and race breakdown: American Indian/Alaskan Native (8.5%), Asian (9%), Hispanic/Latino (13.5%), or white (59.5%). Only 32.5% of patients presented with headaches/dizziness, 16% with neurological deficits and 18% with a combination therein. Nine individuals (4.5%) presented with SAH, none had a post-procedural WFNS score > 1 at any follow-up. Most patients received a single stent (89%) and 16.5% were considered off-label due to location or morphology. Of all aneurysms treated, 18.6% had been previously coiled, and 15.3% received adjunctive coiling during stent placement. Complete occlusion among patients with a 6-month follow-up appointment was 66.7% and overall patients improved further at their most recent follow-up appointment (median 27.7 months) with 83.9% with complete occlusion. Frequency of complications was comparable to other studies (table 1). Precent of NIHSS scores of ≥ 1 at pre- or post-procedure were similar 11.2% and 16.7% respectively. 25.2% had mRS scores ≥ 1 at the 6-month follow-up. Nine individuals died (4.3%), with 3 (1.4%) of those deaths occurring within 30 days of stent placement and being deemed FD-associated.

Conclusion This report characterizes patient demographics, aneurysm characteristics, procedure complications and long-term angiographic and clinical outcomes for a large patient population across multiple medical centers treated with flow diversion. Overall, procedures resulted in a high rate of occlusion and low rate of serious complications. Continued iterative outcomes analysis is warranted particularly as flow diversion technology evolves. Despite diverse hospital settings, differences in presentation, patient characteristics and the inclusion of off-label treatments, flow diversion procedures remained safe and effective in treating aneurysms.

Disclosures R. Meister: None. A. Lesko: None. H. Marginean: None. V. Deshmukh: None.