Introduction Flow diversion using the Pipeline Embolization Device (PED) has been a paradigm shift for anterior circulation (AC) aneurysms. However, only a few studies report the long-term (≥1 year) angiographic and clinical outcomes for posterior circulation (PC) aneurysms. This study aimed to compare the morbidity and long-term occlusion rate between AC and PC aneurysms treated with PED.

Methods We performed a systematic review of the literature and meta-analysis of studies of any design that reported purely AC or PC aneurysms treated with PED. Studies with at least 10 patients and 1-year follow-up were included. The primary safety endpoints were the incidence of cumulative symptomatic stroke, intracranial hemorrhage, and aneurysm rupture. The primary efficacy endpoint was the complete aneurysm occlusion rate.

Results Twenty-four studies met the eligibility criteria for inclusion. There were 1,835 patients with 1,952 aneurysms of which 1,547 (79.25%) were in the AC, and 405 (20.75%) in the PC. The one-year occlusion rate was 78% (95% CI, 70%-84%) in AC compared to 73% (95% CI, 67%-78%) in PC (P<0.01). The silent stroke rate was 3% (95% CI, 2%-6%) in AC vs 5% (95% CI, 2%-8%) in PC aneurysms (P=0.01). The symptomatic infarct rate was 5% (95% CI, 4%-7%) in AC compared to 13% (95% CI, 7%-23%) in PC aneurysms (P<0.01). While the long-term rupture rate was 1% (95% CI, 1%-2%) in AC compared to 4% (95% CI, 2%-9%) in PC aneurysms (P=0.01), the rate of intracranial hemorrhage was 2% for both (P=0.99).

Conclusion The long-term occlusion rate after PED was higher in AC aneurysms and the cumulative incidence of ischemic complications and aneurysm rupture was significantly higher in PC. The intracranial hemorrhage rate was not different. More extensive studies are required to identify factors predisposing to incomplete occlusion and postprocedural complications.

Disclosures E. Greco: None. A. Ghaith: None. J. Rios-Zermeno: None. M. Ghanem: None. C. Perez- Vega: None. S. Kashyap: None. D. Freeman: None. E. Middlebrooks: None. S. Sandhu: None. M. Bydon: None. R. Tawk: None.