1-month safety results in a randomized controlled trial (COATING) evaluating a surface-modification flow diverter (p64-MW-HPC) under single antiplatelet treatment

Background Flow diversion is an effective technique for treating intracranial aneurysms (IAs), with a high rate of complete aneurysm occlusion at 1 year. As dual antiplatelet treatment (DAPT) is required, it is restricted to unruptured IA. Surface-modification (SM) flow diverters (FDs), introduced to reduce thrombogenicity, have been poorly evaluated. COATING (Coating to Optimize Aneurysm Treatment In the New Flow Diverter Generation) is the first randomized controlled trial (RCT) evaluating an SM FD (p64-MW-HPC (hydrophilic polymer coating), phenox GmbH) under single antiplatelet treatment (SAPT). Methods We compared the treatment arm, SM p64-MW-HPC under SAPT (ticagrelor or prasugrel), to the control arm, bare p64-MW under DAPT (ticagrelor or prasugrel+aspirin), for unruptured IA management. The primary endpoint (number of diffusion-weighted imaging (DWI) lesions on MRI 48 hours (±24 hours) after the index procedure) and safety data up to 1 month post-procedure were analyzed. Results From September 2021 to November 2024, 171 patients (female 84.8%, mean age 55±11 years) were included in 15 centers in Europe and Israel with 83 patients in the treatment arm and 88 in the control arm. The mean (±SD) number of DWI lesions within 48 hours (±24 hours) of the index procedure in the treated aneurysm territory was 6.0 (±13.28) in the HPC and 5.3 (±11.75) in the bare group (P non-inferiority testing <0.0001). 1-month safety data showed no statistically significant difference in thromboembolic events between study arms. Conclusion COATING is the first RCT to evaluate an SM FD (p64-MW-HPC) under SAPT and shows favorable safety at 1 month.