Postprocedural Residual Stenosis and 30-Day Outcomes After Angioplasty and Stenting for Symptomatic Intracranial Atherosclerotic Stenosis in Perforator-Rich Arteries.

OBJECTIVE: To investigate the association between postprocedural residual stenosis and 30-day outcomes after angioplasty and stenting for symptomatic M1 middle cerebral artery or basilar artery atherosclerotic stenosis. METHODS: This single-center retrospective cohort study included consecutive patients who underwent angioplasty and stenting for symptomatic atherosclerotic stenosis involving the M1 segment of the middle cerebral artery or the basilar artery. The primary outcome was the 30-day composite end point of stroke or death. Postprocedural residual stenosis was modeled continuously using restricted cubic splines and secondarily as prespecified categories. Adjusted analyses accounted for lesion location, lesion length, lesion calcification and preprocedural stenosis severity using Firth penalized logistic regression. RESULTS: Among 219 included patients, the 30-day composite end point occurred in 23 (11%). In the primary analysis, postprocedural residual stenosis showed evidence of a nonlinear association with the 30-day composite end point (P overall = 0.0024; P for nonlinearity = 0.0006), with the lowest estimated risk observed at intermediate residual stenosis levels. Categorical analysis revealed that event rates across residual stenosis categories of 0% to <10%, 10% to <20%, and ≥20% were 13%, 6.3%, and 18%, respectively, although adjusted between-group comparisons were not statistically significant. CONCLUSIONS: Postprocedural residual stenosis may be nonlinearly associated with 30-day outcomes after angioplasty and stenting for symptomatic stenosis of the M1 segment of the middle cerebral artery or basilar artery stenosis. These exploratory findings suggest that lower postprocedural residual stenosis is not uniformly associated with lower early risk but does not establish an optimal residual stenosis target.