Cause-specific mortality after endovascular treatment for anterior vs. posterior circulation large vessel occlusion: a multicenter cohort study

Background Acute ischemic stroke due to large vessel occlusion (AIS-LVO) carries substantial mortality despite endovascular treatment (EVT). Whether causes of death differ between anterior (AVO) and posterior (PVO) circulation occlusions is poorly characterized. We compared cause-specific 90-day mortality between patients with AVO and PVO treated with EVT. Methods In this multicenter retrospective cohort, consecutive patients with AIS-LVO who underwent EVT at 111 hospitals in China (ANGEL-ACT registry [Endovascular Treatment Key Technique and Emergency Workflow Improvement of acute ischemic stroke]) were included, and adjudicated causes of death were grouped into prespecified categories. Cause-specific mortality was assessed in the complete analytic cohort using the Fine-Gray subdistribution hazard model, with survivors censored at 90 days and deaths from other causes treated as competing events. Cumulative incidence functions were estimated with the Aalen-Johansen estimator. Results Among 1,671 eligible patients (1,300 AVO, 371 PVO), 228 deaths (13.6%) occurred within 90 days. All-cause mortality was higher in PVO than AVO (19.4% vs. 12.0%). Cerebral edema-related death was significantly more frequent in PVO than AVO (90-day cumulative incidence 9.16% vs. 4.15%; adjusted subdistribution hazard ratio [sHR] 0.47, 95% CI 0.30–0.73, p = 0.001; Gray’s test p < 0.001). Fatal hemorrhagic transformation was numerically more frequent in AVO but did not reach statistical significance in the complete cohort (3.77% vs. 1.89%; adjusted sHR 1.76, 95% CI 0.78–3.98, p = 0.17; Gray’s test p = 0.076), consistent across all sensitivity analyses. Pneumonia-related (adjusted sHR 0.34, 95% CI 0.17–0.68, p = 0.003) and recurrent stroke-related (adjusted sHR 0.29, 95% CI 0.10–0.86, p = 0.026) deaths were also more frequent in PVO; the pneumonia association remained significant after Bonferroni correction, whereas the recurrent stroke association did not. Conclusion Fatal complications after EVT differ by occlusion territory. Posterior circulation occlusion is independently associated with a higher risk of death from cerebral edema, pneumonia, and recurrent stroke, although the recurrent stroke association did not survive Bonferroni correction. Hemorrhagic transformation accounted for a larger share of anterior circulation deaths, but this did not correspond to a statistically significant increase in risk in the complete cohort.