FRED-UK: Multicentre UK experience of FRED and FRED Jr flow re-direction endoluminal device for intracranial aneurysms: 6 months and 1 year clinical and anatomical results.

Background: Flow diverting stents (FDS) are an established endovascular treatment for intracranial aneurysms but are reported to have varying rates of adequate occlusion and thromboembolic complications. This study reports clinical safety and efficacy results of the FRED and FRED Jr FDS in clinical practice in the UK at 6 months and 1 year.

Methods: The FRED-UK study is a single arm, multicentre, prospective, observational study conducted in the UK. Safety was reviewed by evaluating morbidity (modified Rankin Score ≤2) and mortality. Efficacy was assessed as adequate occlusion of the treated aneurysm. A clinical event committee and core laboratory independently assessed clinical and anatomical results.

Results: Seven neurointerventional centers treated 61 patients, 57 of which met the full inclusion and exclusion criteria. Of these, 75.4% were treated with FRED and 24.6% with FRED Jr. The aneurysms were located on the cavernous or supraclinoid internal carotid artery (ICA) in 75.4%, on the anterior cerebral artery (ACA) or anterior communicating artery (Acom) in 21.1%, and on the middle cerebral artery (MCA) in 3.5%. 57.9% of aneurysms were small (<10 mm), 40.4% were large (10-24 mm) and 1.8% were giant (≥25 mm). All-cause morbidity and mortality were 0% at 6 and 12 months, and adequate occlusion was 86.7% at 12 months in the per protocol population.

Conclusions: The FRED and FRED Jr devices are safe and efficacious in the treatment of intracranial aneurysms.