Flow redirection endoluminal device (FRED) for treatment of intracranial aneurysms: A systematic review

Abstract

Introduction The Flow Redirection Endoluminal Device (FRED; MicroVention) is a dual-layered flow diverter used for the treatment of intracranial aneurysms. The objective of this systematic review was to compile device-related safety and effectiveness data. Methods The literature from January 1, 2013 to April 30, 2021 was searched for studies describing use of the FRED for intracranial aneurysm treatment irrespective of aneurysm location and morphology. The review included anterior and posterior circulation ruptured and unruptured saccular, fusiform or dissection, and blister aneurysms. MeSH terms related to “flow re-direction endoluminal device” and “FRED for aneurysms” were used. Data related to indication, complications, and rates of aneurysm occlusion were retrieved and analyzed. Results Twenty-two studies with 1729 intracranial aneurysms were included in this review. Overall reported morbidity was 3.9% (range 0–20%). Overall procedure-related mortality was 1.4% (range 0–6%). Complication rates fell into 5 categories: technical (3.6%), ischemic (3.8%), thrombotic or stenotic (6%), hemorrhagic (1.5%), and non-neurological (0.8%). The aneurysm occlusion rate between 0 and 3 months (reported in 11 studies) was 47.8%. The occlusion rate between 4 and 6 months (reported in 14 studies) was 73.8%. Occlusion rates continued to increase to 75.1% at 7–12 months (reported in 10 studies) and 86.6% for follow-up beyond 1 year (reported in 10 studies). Conclusion This review indicated that the FRED is a safe and effective for the treatment of intracranial aneurysms. Future studies should directly compare the FRED with other flow diverters for a better understanding of comparative safety and effectiveness among the different devices.

Derivo embolization device for intracranial aneurysms: a Spanish multicenter retrospective study

“…We found high complete occlusion rates at the latest follow-up (83%), in line with the estimated rate reported in the recent meta-analysis by Monteiro et al (81.4%) 15. This rate is also within the range of occlusion rates observed (75–90.6%) for other FD stents studied in recent publications 16–19…”

The Pennsylvania Postmarket Multicenter Experience With Flow Redirection Endoluminal Device

“…The re-treatment rate was 2.8% in our data because of technical device failure secondary to foreshortening of the inner flow-diverting stent with subsequent inadequate coverage of the aneurysmal neck, close to 3.6% from previous literature. 9 Our results further reiterate the device's safety and efficacy, in line with the overall aggregate literature documenting the favorable results of the FRED system, 3-5 albeit comparing slightly favorably with the recently published US Pivotal Trial that granted the FDA approval for the FRED device. 6 The multicenter investigational device exemption study evaluated a total of 145 patients from 23 US centers harboring intracranial aneurysms deemed of unfavorable morphology for traditional endovascular techniques.…”

“…The safety of the FRED system is reinforced in our experience, evidently by the low rate of permanent disabling stroke encountered in 1 patient (1.4%) without procedural mortality, comparable with the other major device studies, 3,4,6 and data from other literature series with average ischemic complications of 3.8%. 9…”

“…This is similar to the multicenter European SAFE (Safety and efficacy Analysis of FRED Embolic device in aneurysm treatment) study, where the 2 re-treatments during the first follow-up year were due to device foreshortening and were re-treated by coiling, 4 and to those reported in 3.6% of other series. 9 Delayed hypersensitivity to the metal components has been hypothesized as an underlying mechanism 17 ; however, the reason for this remains unknown. In this series, the foreshortening was noted on follow-up without identifiable change in the device geometry on postdeployment runs, rendering it unlikely to be anticipated in advance.…”

FRED flow diversion with LVIS protection of large posterior communicating artery aneurysm: the "FRELVIS" technique

“…Therefore, a 4.5 × 20-mm FRED flow diverter was placed across the orifice of the aneurysm as well as the posterior communicating artery through the internal carotid artery. 5,6 3:43 Final Runs and Contrast Stasis. Here is our final run demonstrating stasis of contrast within the aneurysm as well as the final construct.…”