Background Flow diversion introduced a new paradigm shift in neuroendovascular by providing a more physiologic approach for the treatment of IAs. To date, there are many flow diverters on the market, but we report our experience with the pipeline embolization device, the first flow diverter to be approved by the FDA. We aim to assess the efficacy and safety of PED flow diversion for the treatment of a wide range of aneurysms, as well as look at factors affecting occlusion.

Methods This study was a retrospective chart review of a prospectively maintained database for patients treated with flow diversion between January 2011 and December 2019.

Results Our study included 636 patients with 780 aneurysms. Most aneurysms (707) were in the anterior circulation. 85.3% of aneurysms were saccular with the rest being fusiform (7.9%), dissecting (5.9%), and blister (0.9%). Additionally, 738 aneurysms (94.7%) were unruptured while 41 (5.3%) were acutely ruptured. The median largest aneurysmal dimension was 6.5 mm (IQR 4 mm - 10 mm), and 162 aneurysms (20.8%) were larger than 10 mm. Symptomatic complications occurred at a rate of 6% (1.4% delayed aneurysmal rupture, of which, 33% occurred in ruptured cases; 1.5% distal intraparenchymal hemorrhage, of which, 20% occurred in ruptured cases; and 3.1% ischemic complications). The complete occlusion rate was 90.3% at a median follow up of 18.5 months, and 93.8% of patients had a favorable neurological outcome (mRS 0 - 2) at last follow up. On multivariate analysis hypertension (p=0.007) and adjunctive angioplasty (p=0.007) were significantly associated with incomplete aneurysm occlusion. The overall mortality rate was 2.6%, of which, 17% were due to ruptured cases.

Conclusion Our findings are in conjunction with those of previous studies and trials. Our complete occlusion rate was >90% at 24 months follow-up with 94% of patients having favorable functional outcomes (mRS 0 - 2). In addition, our complication rate was low (6%) and occurred mainly in ruptured, non-saccular, and large (>10mm) aneurysms. Thus, Flow diversion is safe and effective for the treatment of IAs. Further research is warranted to accurately delineate factors associated with FD failure and thus improving patient care.

Disclosures R. Abbas: None. E. Atallah: None. K. El Naamani: None. S. Tjoumakaris: 2; C; microvention. M. Gooch: 2; C; Medtronic. P. Jabbour: 2; C; Medtronic.