Table 1 Characteristics of the Included Studies and Outcome Events

Regions

22 centers in 2 countries

25 centers in 6 countries

1 centers in 1 country

24 centers in 7 countries

Publication

Stroke

Am J Neuroradiol

European Journal of Radiology

Lancet

Inclusion Criteria

Ruptured or unruptured IAs; WFNS grade: 0–3; Age: 18–75 years; IA size: 4-12 mm in diameter; Endovascular occlusion is deemed possible; Neurointerventionist is content to use either HC or BPC.

Ruptured or unruptured IAs; WFNS grade: 0–3; Age: > 18 years; Life expectancy: > 2 years

Endovascular occlusion is considered possible by both coils; Neurointerventionist is satisfied with using either HC or BPC but not other type.

Only unruptured IAs; Endovascular occlusion is considered possible by both coils; Neurointerventionist is satisfied with using either HC or BPC but not other type.

Ruptured or unruptured IAs; Previously untreated IAs; Not pregnant; WFNS grade: 0–3; Age: 18–75 years; IA size: 2-25 mm in maximum diameter; Endovascular occlusion is deemed possible; Neurointerventionist is content to use either HC or BPC.

Exclusion Criteria

Patients already randomized in this trials; Pre-treated IA by coiling or clipping; More than one IAs need to be treated at the same treatment episode.

Other IAs requiring to be treated at the same treatment episode; Presence of AVM; Absolue contraindication to endovascular treatment.

Ruptured IAs; Intolerance to heparin or resistance to antiplatelet therapy, coagulopathies and abnormal platelet outcome.

Patients already randomized in this trials; More than one IAs need to be treated at the same treatment episode.

Study Design

Second-generation hydrogel coil (HydroSoft and/or HydroFrame) vs. Bare platinum coil

First or Second-generation hydrogel coil vs. Bare platinum coil

Hydrogel-coated coil vs. Bare platinum coil

First-generation hydrogel coil vs. Bare platinum coil

Efficacy outcomes

Complete occlusion, residual neck and residual aneurysm at periprecedure and 6–18 months; Recurrence, retreatment and mRS responese at 6–18 months.

Complete occlusion, residual neck and residual aneurysm at periprecedure; Recurrence, retreatment and mRS responese at 18 months.

Complete occlusion, residual neck and residual aneurysm at periprecedure and 12 months; Recurrence, retreatment and mRS responese at 12 months.

Complete occlusion, residual neck and residual aneurysm at periprecedure and 18 months; Recurrence, retreatment and mRS responese at 18 months.

Safety outcomes

Thromboembolic complications, coil migration, peforation, etc. at periprecedure; AEs, SAEs and death at periprocedure and 6-18 months.

Thromboembolic complications, hydrocephalus, peforation, etc. at periprecedure; AEs, SAEs and death at periprocedure and 18 months.

Thromboembolic complications, hydrocephalus, cerebral edema, etc. at periprecedure; AEs and death at periprocedure and 12 months.

Thromboembolic complications, artery occlusion, peforation, etc. at periprecedure; AEs and death at periprocedure and 18 months.