RECOAT study - Retrospective evaluation of surface-modified and coated flow diverters for the treatment of unruptured intracranial aneurysms

PURPOSE: Surface modifications may improve procedural safety of flow diverter (FD) treatment, but larger studies are rare. This multicenter study aims to evaluate the safety and efficacy of unruptured aneurysm treatment with surface-modified and coated FDs. METHODS: Patients treated with the following FDs at 8 neurovascular centers were retrospectively reviewed: Pipeline Vantage Embolization Device, Pipeline Flex with Shield Technology, FRED X, p48/64 HPC, Derivo Embolization Device (DED), and DED 2heal. Aneurysm characteristics, procedural details, and angiographic results were evaluated in detail. RESULTS: A total of 511 patients with 545 aneurysms were included (mean aneurysm size: 8.2 ± 5.5 mm, 12% posterior circulation, 14% non-saccular morphology). Multiple FDs were used in 26/515 (5%) procedures and adjunctive coiling in 76 (15%). Thromboembolic events occurred in 40 (7.8%) cases, including 9 (1.7%) major ischemic events, 20 (3.9%) minor ischemic events and 11 (2.1%) asymptomatic/technical events. Non-saccular aneurysm morphology (p = 0.014) and use of multiple FDs (p = 0.025) favored thromboembolic events. Hemorrhagic events occurred in 5 (1.0%) cases, of which 3 were symptomatic. The combined morbidity and mortality rate was 11/515 (2.1%). Complete and adequate occlusion rates were 66% (196/297) and 80% (238/297) at 6 months, respectively, and 70% (64/92) and 85% (78/92) at 12 months, respectively. CONCLUSION: The present study demonstrates high safety and efficacy for coated or surface-modified FDs. Whether the surface modifications confer a clinical benefit needs to be addressed in comparative studies.