Abstract 346: One‐Year Outcomes of Endovascular Therapy 6 to 24 Hours After Posterior Circulation Ischemic Stroke with Tandem Lesions
Authors: Doheim M. , Li W. , Zhao Z. , Zi W. , Qiu Z. , Hu W. , Liu X. , Huang J. , Sun W. , Han Z. , Chen Z. , Chen Z. , Nogueira R. 
Published: January 2025

Background
Endovascular therapy (EVT) in posterior circulation patients with tandem lesions (PCTL) within 6‐24 hours after last seen well (LSW) remains unclear. We evaluated the clinical and safety outcomes among PCTL patients treated within 6‐24 hours.

Methods
Individual patients’ data were pooled from two Chinese multicenter observational studies: the BASILAR (EVT for Acute Basilar Artery Occlusion Study) and the PERSIST (Posterior Circulation Ischemic Stroke Registries). Patients with acute ischemic stroke due to PCTLs who were treated with endovascular therapy were included in the present cohort. Patients were divided into early (<6h) and extended (6‐24h) window groups based on LSW to puncture time. The primary efficacy outcome was the comparison of the modified Rankin Scale scores (mRS range, 0 to 6 points) at 90 days across the 2 groups assessed as a common odds ratio using ordinal logistic regression shift analysis, adjusted for prespecified prognostic factors. The secondary efficacy outcome was the rate of favorable functional outcomes defined as mRS of 0 to 3 at 90‐days and 1‐year. Safety outcomes included symptomatic intracerebral hemorrhage at 24 hours and all causes of mortality at 90 days and 1‐year.

Results
Among 1320 PCTL patients treated with EVT in the 2 registries (647 from the BASILAR registry and 673 from the PERSIST registry), 263 (19.9%) presented with tandem lesions of the posterior circulation (110 from the BASILAR registry and 153 from PERSIST registry) and 215 qualified for final analysis (124 in the early window and 91 in the extended window). As compared with the early window, extended window patients showed lower rates of intravenous thrombolysis (15.4% vs 29.8%, P=0.01), a longer procedure time (140 [IQR, 99‐191] vs 120 [IQR, 86‐160], P=0.03), and higher proportions of rescue treatments (16.5% vs 7.3%, P=0.03). After adjustment for the potential confounders, both groups were comparable regarding the shift in 1‐year mRS scores (adjusted common odds ratio, 1.59, 95% confidence interval [CI], 0.64‐3.96, P=0.31). Successful reperfusion (mTICI 2b‐3) was achieved in 112 (90.3%) early window patients versus 76 (83.5%) extended window patients (Adjusted OR 0.42, 95% CI [0.11‐1.58], P=0.20). Complete reperfusion (mTICI 3) was achieved in 70 (56.5%) early window patients versus 52 (57.1%) extended window patients (Adjusted OR 1.16, 95% CI [0.44‐3.06], P=0.76). Rates of symptomatic intracerebral hemorrhage (sICH) were 7/122 (5.7%) early window patients versus 8 (8.8%) extended window patients (Adjusted OR 1.31, 95% CI [0.17‐10.12], P=0.80). One‐year mRS 0‐2 was achieved in 48/120 (40.0%) early window patients versus 26/87 (29.9%) extended window patients (Adjusted OR 0.57, 95% CI [0.19‐1.71], P=0.31). One‐year mRS 0‐3 was achieved in 55/120 (48.8%) early window patients versus 29/87 (33.3%) extended window patients (Adjusted OR 0.54, 95% CI [0.19‐1.54], P=0.26). One‐year mortality was 48/120 (40.0%) early window patients versus 51/87 (58.6%) extended window patients (Adjusted OR 2.48, 95% CI [0.89‐6.88], P=0.08).

Conclusion
EVT for acute PCTL treated within 6‐24 hours after LSW was associated with similar rates of clinical and safety outcomes, compared to patients treated within 6 hours. More prospective studies are needed to confirm these results.