Comparison of Early versus Delayed Flow Diverter Implantation on Rebleeding and Clinical Outcomes in Patients with Ruptured BBA

BACKGROUND: Flow diverter (FD) implantation is a key reconstructive treatment for BBA, but the optimal timing of implantation remains unresolved, which limits standardized clinical decision-making. METHODS: A retrospective cohort study was conducted on 90 consecutive patients with ruptured BBAs who underwent FD implantation. Patients were stratified into two groups based on the interval from BBA rupture to FD implantation: the early group (≤48 hours, n=45) and the delayed group (>48 to ≤96 hours, n=45). Baseline characteristics, treatment parameters, and clinical/angiographic outcomes were collected. Binary logistic regression was conducted to identify prognostic factors. RESULTS: Baseline characteristics were well-balanced between the two groups (all P>0.05). Compared with the delayed group, the early group had a significantly lower rate of symptomatic rebleeding within 90 days (2.2% vs. 6.7%, P=0.039), a significantly higher rate of 90-day favorable functional outcomes (mRS ≤2: 82% vs. 69%, P=0.047), a numerically higher complete occlusion rate (73% vs. 69%, P=0.642), and a lower rate of procedure-related cerebral infarction (6.7% vs. 11%, P=0.456). Multivariate logistic regression showed that delayed FD implantation (adjusted OR=3.17, 95% CI: 1.15-8.72, P=0.026) and WFNS grade ≥3 (adjusted OR=2.89, 95% CI: 1.09-7.65, P=0.018) were independent risk factors for symptomatic rebleeding. Additionally, delayed FD implantation was an independent risk factor for poor 90-day functional outcomes (adjusted OR=2.31, 95% CI: 1.02-5.23, P=0.044). CONCLUSION: Early FD implantation (≤ 48 hours post-BBA rupture) was associated with a lower risk of symptomatic rebleeding and better short-term clinical outcomes in patients with ruptured BBA.