Temporal progression of functional independence after mechanical thrombectomy in acute vertebrobasilar artery occlusions

Background Neurological recovery after endovascular treatment (EVT) for large vessel occlusion stroke often has diverse timelines. Understanding the temporal progression of functional independence after EVT, especially delayed functional independence (DFI) and highly delayed functional independence (HDFI), in patients who do not improve early is essential for prognostication and rehabilitation. We aimed to analyze the prevalence and predictors of DFI and HDFI after EVT in acute vertebrobasilar artery occlusions (VBAO).Methods Patients with VBAO who received EVT in China were retrospectively enrolled. Early functional independence (EFI) was defined as a modified Rankin Scale (mRS) score of 0-2 at discharge. The incidence and predictors of DFI (mRS score 0-2 at 90 days in non-EFI patients) and HDFI (mRS score 0-2 at 1 year in non-DFI patients) were analyzed.Results 2422 patients met the study criteria. EFI was observed in 20% (483) of patients. Among non-EFI patients, DFI was observed in 21% (395/1880). HDFI was observed in 13% (191/1439) of non-DFI patients. Younger age (P=0.006), lower pre-EVT National Institutes of Health Stroke Scale (NIHSS) score (P<0.001), higher posterior circulation-Alberta Stroke Program Early CT Score (PC-ASPECTS) (P=0.012), and absence of symptomatic intracranial hemorrhage (sICH) (P<0.001) were predictors of DFI. Predictors of HDFI were younger age (P<0.001) and lower pre-EVT NIHSS score (P<0.001).Conclusion A considerable proportion of patients have DFI and HDFI. The independent predictors of DFI were younger age, lower pre-EVT NIHSS score, higher PC-ASPECTS, and absence of sICH. Predictors of HDFI included younger age and lower pre-EVT NIHSS score.