Clinically Silent Microinfarct Incidence and Risk Factors After Treatment of Unruptured Intracranial Aneurysms with Hydrophilic Polymer-Coated Flow Diverters

Purpose Although flow diverters (FDs) revolutionized the treatment of unruptured intracranial aneurysms (UIAs), clinically silent microinfarcts (SMs) are consistently detected in postprocedural diffusion-weighted imaging (DWI), and their clinical consequences remain unknown. This study examined the incidence of, and factors associated with, SM development after the use of two surface-modified FDs: the p48MW-HPC and p64MW-HPC. Methods A non-concurrent cohort study was conducted in 404 consecutive patients with UIAs treated with these two FDs between January 2020 and July 2023. The primary endpoint was the number of asymptomatic DWI lesions within 72 h after the procedure. Results SMs were detected in 58.2% of the cases, and >= 20 lesions were identified in 7.2% of cases. Multivariate analysis revealed that the use of two specific types of microcatheters-Prowler Select Plus (P < 0.001; IRR, 3.2) and RapidTransit (P = 0.001; IRR, 2.2)-and difficulty in microcatheter navigation to the target vessel (P = 0.039; IRR, 1.8) were significantly associated with greater numbers of lesions. After exclusion of outlier cases, these devices remained associated with a significant 2- to 3-fold increase in SMs. Diabetes was associated with fewer SMs (P = 0.024; IRR, 0.5), although this association disappeared after exclusion of outlier cases. Conclusion The postprocedural incidence of SMs associated with hydrophilic polymer-coated FDs was similar to that previously reported. Interestingly, the main factor contributing to this phenomenon was the use of certain microcatheters. Careful device selection is crucial, and further research is needed to improve the safety of neurovascular interventions.