Predictors of Occlusion, Long-termoutcomes, and Safety in a Large Cohortof 780 Aneurysms Treated with Thepipeline Embolization Device

Introduction: Endovascular treatment for intracranial aneurysms (IA) was revolutionized with the introduction of the detachable coil in the 1990s. Nearly two decades later, 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 (PED), the first flow diverter to be approved by the FDA. We aim to assess the efficacy and safety of 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. The mean age was 56 years and most (83.2%) were female. 85.3% of aneurysms were saccular with the rest being fusiform (7.9%), dissecting (5.9%), and blister (0.9%). The median largest aneurysmal dimension was 6.5 mm (IQR 4 mm – 10 mm). Symptomatic complications occurred at a rate of 6% (1.4% delayed aneurysmal rupture, 1.5% distal intraparenchymal hemorrhage, 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=0.006), increasing aneurysm size (p=0.001), and adjunctive angioplasty (p=0.016) were significantly associated with incomplete aneurysm occlusion. The final mortality rate was 3.1%.

Conclusion : Our findings are in conjunction with those of previous studies and trials. 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.