Clinical Outcome of Pipeline Embolization Device with and without Coil to Treat Intracranial Aneurysm: A Systematic Review and Meta-Analysis.

Background: The use of a Pipeline Embolization Device (PED) in combination with coils (PEDC) to treat intracranial aneurysms remains unclear as to whether it offers significant benefits for the patients since the results have varied.

Purpose: This study aimed to investigate the clinical outcome of PEDC compared to PED in treating intracranial aneurysms.

Data sources: We systematically searched the articles from PubMed, Web of Science, and the Cochrane Library databases published before January 25, 2024.

Study selection: We selected studies comparing PEDC vs. PED to treat intracranial aneurysms. Patients treated with PEDC but using dense coiling were excluded from the study.

Data analysis: The clinical outcomes observed in this meta-analysis were intraprocedural complications, postoperative complications (stenosis, stroke, hemorrhage, mortality), favorable outcome (mRS ≤ 2), complete occlusion rate, and retreatment rate. Forest plot was used to analyze pooled Odds Ratio (OR) of clinical outcomes.

Data synthesis: A total of 3001 subjects from nine observational studies were included. PEDC was mainly used to treat larger aneurysms. PEDC has a significantly higher complete occlusion rate at 6 months [OR= 2.66, 95% CI(1.26, 5.59), p= 0.01], a lower retreatment rate [OR= 0.18, 95% CI(0.05, 0.07), p= 0.010], higher stroke-related complications [OR= 1.66, 95% CI(1.16, 2.37), p= 0.005], and higher hemorrhage-related complications [OR= 1.98, 95% CI(1.22, 3.21), p = 0.005]. There was no significant difference in intraprocedural complications, stenosis-related complications, mortality, favorable outcomes, and complete occlusion at the end of the study.

Limitations: No randomized controlled trials have been performed comparing PEDC and PED. Considering that all the included studies were observational, the patients' baseline characteristics were not completely balanced.

Conclusions: This meta-analysis study showed that PEDC in large intracranial aneurysms induces a faster complete occlusion rate at 6 months and a lower retreatment rate. However, it increases the risk of stroke-related postoperative complications, and the faster complete aneurysm occlusion rate found in this study did not correlate with a reduction in long-term aneurysm or distal artery ruptures. Thus, this study suggests the need to find a better strategy to improve long-term hemorrhage-related complications in large intracranial aneurysms.

Abbreviations: F = female; FDDs = flow-diverter devices; M = male; NOS = Newcastle-Ottawa Scale; PED = pipeline embolization device; PEDC = pipeline embolization device in combination with coils.