Global vasodilatation in the middle cerebral artery territory as a new imaging marker of poor outcome after endovascular thrombectomy.

BACKGROUND: Identifying new imaging markers may refine risk stratification and guide clinical management for endovascular thrombectomy (EVT). We observed a phenomenon that on a subset of patients' post-procedural TOF-MRA, the successfully recanalized vessels demonstrated marked vasodilatation in the middle cerebral artery (MCA) territory. The association between global vasodilatation in the MCA territory and clinical outcomes has not yet been investigated. OBJECTIVE: We aimed to characterize the incidence and radiological characteristics of global vasodilatation in the MCA territory, and to investigate its associated risk factors and prognostic implications. METHODS: Retrospective analysis of 494 consecutive anterior circulation large vessel occlusion stroke (LVOS) patients with successful EVT. In patients with recanalization, global vasodilatation in the MCA territory can be defined if either of the following criteria is met: displayable distal branching number exceeded the contralateral side by > 50%, or vascular visible extension length surpassed the contralateral MCA by > 50%. Univariate and multivariate logistic regression analyses were conducted to explore the association of global vasodilatation in the MCA territory with 90-day functional independence (mRS 0-2), and the independent risk factors for the occurrence of this vasodilatation. RESULTS: Our study identified global vasodilatation in the MCA territory in 6.3% (31/494) of successful recanalization patients, who had significantly worse 90-day functional outcomes (67.7% vs. 33.5%, P < 0.001). Multivariate analysis confirmed that the vasodilatation was an independent predictor of poor prognosis (OR = 2.438, 95% CI 1.012-5.876). Additionally, the incidence of the vasodilatation was associated with lower ASPECT scores (OR = 0.671, 95% CI 0.560-0.804) and worse collateral (OR = 0.370, 95% CI 0.160-0.858). CONCLUSIONS: Global vasodilatation in the MCA territory is a potentially valuable indicator for the postprocedural stratification of high-risk patients following EVT.