Sex‐Stratified Outcomes in Balloon Angioplasty for Symptomatic Intracranial Artery Stenosis: The BASIS Subgroup Analysis

Background The BASIS (Balloon Angioplasty for Symptomatic Intracranial Artery Stenosis) trial demonstrated that balloon angioplasty plus aggressive medical management was superior to aggressive medical management alone for symptomatic intracranial atherosclerotic stenosis. However, whether sex modifies this treatment effect is unknown. Methods This prespecified secondary analysis of the BASIS randomized controlled trial included 501 patients with symptomatic intracranial atherosclerotic stenosis from 31 Chinese centers (November 2018 to April 2022). Baseline characteristics and outcomes were compared between sexes and across treatment arms within each sex. The primary outcome was stroke or death within 30 days, or ischemic stroke in the qualifying artery territory or revascularization beyond 30 days through 12 months. Results Among 501 patients (mean age, 58 years), 158 (31.5%) were women. No significant sex‐by‐treatment interaction was observed for primary or key secondary outcomes (all P for interaction >0.05). In sex‐stratified analyses, balloon angioplasty reduced primary outcome risk versus aggressive medical management in men (2.9% versus 11.1%; hazard ratio [HR]=0.21 [95% CI, 0.07–0.65]; P =0.01). In women, the effect favored balloon angioplasty but was not statistically significant (7.8% versus 18.5%; HR=0.37 [95% CI, 0.14–1.01]; P =0.051). Conclusions No significant interaction between sex and treatment effect was found, suggesting balloon angioplasty's benefit relative to aggressive medical management does not clearly differ by sex. Sex‐stratified results showed significant benefit in men and a nonsignificant trend in women, but the study lacked power for definitive interaction testing, so findings are exploratory. Further research is needed to confirm these findings in broader populations. Registration URL: https://www.clinicaltrials.gov ; Unique Identifier: NCT03703635.