FRED™ Flow Diverter: Dual-Layer Flow Diversion for Large and Giant Cerebral Aneurysms
By Modern Medical Solutions Editorial Team
The FRED™ (Flow Re-Direction Endoluminal Device) from MicroVention Terumo is a dual-layer flow diverter combining an outer low-density scaffold with an inner high-density mesh for large and giant cerebral aneurysms, delivered via Headway 27 microcatheter in parent artery diameters from 3.5 to 5.5 mm, with DAPT required post-procedure.
What Is the FRED™ Flow Diverter?
The FRED™ (Flow Re-Direction Endoluminal Device) is a dual-layer self-expanding flow diverter from MicroVention Terumo designed for the treatment of large, giant, fusiform, and complex cerebral aneurysms of the intracranial circulation. Flow diversion treats aneurysms by reconstructing the parent artery wall across the aneurysm neck with a high-mesh-density device that redirects blood flow along the reconstructed artery wall rather than into the aneurysm sac. The reduced intra-aneurysmal flow velocity promotes progressive thrombosis within the sac over 3–12 months, ultimately leading to complete aneurysm occlusion.
The FRED’s dual-layer architecture consists of an outer low-density nitinol scaffold that provides radial force and vessel wall apposition, combined with an inner high-density nitinol mesh that provides the flow-diversion effect. The inner mesh has approximately 30–35% metallic surface area coverage across the aneurysm neck, the established threshold for effective hemodynamic alteration in flow diversion. The two-layer design allows each layer to be optimised independently: the outer layer for mechanical support, the inner layer for flow diversion.
Technical Specifications and Catalog Reference
The FRED is available in implant diameters from 3.5 mm to 5.5 mm, in lengths from 7 mm to 26 mm. Standard catalog numbers span FRED3507 (3.5 mm diameter, 7 mm length) through FRED5526 (5.5 mm diameter, 26 mm length). All FRED devices are delivered via Headway 27 microcatheter over a standard 0.014 in guidewire (ASAHI CHIKAI or Gladius MG recommended for their torque response).
The FRED delivery system includes a 185 cm pusher wire. The proximal and distal ends of the inner mesh are marked with radiopaque markers visible under fluoroscopy, allowing the operator to confirm the extent of neck coverage during deployment. The FRED can be partially resheathed for repositioning before full release, provided resheathing is performed within the permitted repositioning window specified in the instructions for use.
FRED™ vs. FRED X and Pipeline Flex: Comparing Flow Diverters
The FRED X is the current-generation successor to the original FRED, incorporating X Technology nanoscale surface treatment that reduces thrombogenicity and extends the treatable vessel diameter range down to 2.5 mm via a System 21 configuration. The original FRED remains available and clinically validated through multiple prospective registries since its CE mark in 2013, and is preferred by operators experienced with its specific deployment mechanics. For new programs adopting flow diversion for the first time, FRED X System 27 covers the same 3.5–5.5 mm range as the original FRED with improved delivery characteristics.
Against the Pipeline Flex (Medtronic), the FRED’s dual-layer design distinguishes it through independently optimised inner-mesh density and outer-scaffold support. Both devices require DAPT and have comparable published occlusion rates at 12–36 months. FRED’s lower delivery force compared to early Pipeline generations and its compatibility with Headway 27 within the MicroVention Terumo ecosystem are practical advantages for programs already using SOFIA, LVIS, and Headway.
Clinical Applications and Indications
FRED is indicated for large (10–24 mm) and giant (≥25 mm) unruptured intracranial aneurysms of the anterior circulation ICA, MCA, and ACA where coil embolization is not technically feasible due to sac size, wide neck, or fusiform morphology. Posterior circulation indications — vertebral artery, basilar artery — are also treated with FRED, though the risk profile differs and procedural expertise requirements are higher for the posterior circulation.
FRED is generally not used in the ruptured setting due to the DAPT requirement during the acute post-haemorrhage period. Adjunctive coil placement at the time of FRED deployment is performed at operator discretion in large-volume sacs to accelerate occlusion, though coils are not required for treatment success.
Ordering Through Modern Medical Solutions
Modern Medical Solutions is the authorised MicroVention Terumo distributor for Tajikistan and Afghanistan. FRED is available across the full diameter and length range for neurointerventional programmes in Tajikistan and Afghanistan.
Contact Modern Medical Solutions to discuss FRED alongside FRED X, FRED Jr, and the Headway 27 delivery microcatheter as a complete flow diversion program. The team can provide guidance on DAPT protocols, sizing algorithms, and access to MicroVention Terumo clinical training resources for flow diversion.
