Cumulative intraprocedural complexity and diffusion-weighted imaging lesions after endovascular coil embolization

Background Postprocedural diffusion-weighted imaging (DWI) lesions are common markers of microembolic injury after coil embolization of unruptured intracranial aneurysms. We evaluated associations of a thrombus-excluded cumulative procedural complexity score with DWI lesion burden and periprocedural neurologic events. Methods We retrospectively analyzed 394 patients who underwent elective coil embolization of unruptured intracranial aneurysms between 2021 and 2024. Cumulative procedural complexity was assessed using an exploratory five-domain framework that excluded thrombus-related events. Associations with postprocedural DWI lesion count and periprocedural neurologic events were evaluated using multivariable negative binomial and logistic regression analyses, respectively. Results Postprocedural DWI lesions were identified in 160 patients (40.6%), and periprocedural neurologic events occurred in 35 patients (8.9%). Each 1-point increase in the thrombus-excluded cumulative procedural complexity score was associated with a 10% increase in the expected postprocedural DWI lesion count (adjusted IRR, 1.10; 95% CI, 1.02–1.19; p = .015) and 22% higher odds of periprocedural neurologic events (adjusted OR, 1.22; 95% CI, 1.08–1.38; p = .002). Conclusions A higher thrombus-excluded cumulative procedural complexity score was associated with greater postprocedural DWI lesion burden and higher odds of periprocedural neurologic events. This exploratory, consensus-based framework should be considered hypothesis-generating and requires external validation before clinical application.