Introduction/Purpose The most recent development in the field of devices dedicated to aneurysm treatment is surface-modified flow diverters (FD). Surface modification has different roles including facilitating navigation, increasing endothelialization of the flow diverters, and decreasing platelet aggregation, so reducing thromboembolic complications. Hydrophilic Polymer Coating (HPC), a glycocalyx-like surface modification, is, according to laboratory and animal experiments decreasing platelet aggregation and can potentially lead to the reduction of antiplatelet treatment (APT) when using flow diverters with HPC. COATING is, for the time being, the unique randomized controlled trial dedicated to the assessment of a surface-modified FD (p64-MW-HPC; phenox GmbH, Bochum, Germany).

Materials & Methods The subjects are randomized 1:1 in 2 arms: p64-MW (bare) and dual APT (DAPT; prasugrel or ticagrelor + aspirin), and p64-MW-HPC (surface-modified) under single APT (SAPT; prasugrel or ticagrelor). The primary endpoint is the rate of thromboembolic complications as assessed by an independent core lab on DWI-MRI 48 hours after the procedure. Secondary endpoints are evaluating safety, performance and efficacy. Maximum enrollment is 200 subjects and an intermediate analysis will be conducted after inclusion of 85 patients.

Results Eleven European centers are currently active. First inclusion occurred in September 2021. As of now (March 2023), 70 patients have been included out of 85 to run the interim assessment (adaptive design of the study).

Conclusion Surface-modified flow diverters will potentially change the treatment strategy for intracranial aneurysms. COATING is the first RCT to evaluate a surface-modified FD under SAPT. Reference: Pierot L, Lamin S, Barreau X, et al. COATING (Coating to Optimize Aneurysm Treatment In the New Flow diverter Generation) Study. The first randomized controlled trial evaluating a coated flow diverter (p64-MW-HPC): Study design. J Neurointerv Surg 2022.

Disclosures L. Pierot: 2; C; Phenox. O. Eker: None. L. Spelle: None. X. Barreau: None. V. Hellstern: None. M. Psychogios: None. S. Lamin: None. P. Keston: None. C. Cognard: None. V. Costalat: None. A. Berlis: None.