Abstract Body: Objective: To investigate the prevalence of no-reflow phenomenon detected on DSA-derived perfusion imaging and explore its association with functional outcome after successful recanalization in patients with acute ischemic stroke due to large vessel occlusion in the anterior circulation.

Methods:
Consecutive patients from a prospectively maintained stroke database who presented with occlusion in the internal carotid artery or middle cerebral artery (MCA) and underwent thrombectomy within 24 hours after stroke onset with final angiographic modified Treatment in Cerebral Infarction score (mTICI) of 2c to 3 were included in this study. No-reflow was operationally defined as focal hypoperfusion on post-recanalization perfusion maps, which were post-processed from the final sagittal DSA source images. Visual no-reflow was defined as any perfusion deficits visually detected in the MCA downstream territory or in the anterior cortex. Quantitative measurements of perfusion parameters (i.e., cerebral blood flow [CBF], cerebral blood volume [CBV], mean transit time [MTT] and time to maximum of the residual function [Tmax]) in MCA downstream territory were also recorded. Functional outcome was evaluated by modified Rankin Scale (mRS) and functional dependence was defined as a 90-day mRS of 3 to 6.

Results: Regions of post-recanalization perfusion deficits on DSA-derived perfusion maps were identified in 27(33.3%) of the 81 patients included. Visual no-reflow in the anterior cortex (odds ratio 3.40 [95% confidence interval 1.21-9.61]; p =0.021) was associated with functional dependence. Multivariable logistic regression analysis showed a trend (odds ratio 3.03 [95% confidence interval 0.88-10.43]; p =0.078) after adjusting for age, sex and baseline NIHSS. Among all quantitative perfusion parameters, a strong relation was found between the minimum value of regional CBF in MCA downstream territory (odds ratio 0.21 [95% confidence interval 0.07-0.62] and functional dependence after adjustment for age, sex and baseline NIHSS.

Conclusion: Tissue no-reflow can be detected by DSA-derived perfusion imaging profile in the clinical setting, and is associated with posttreatment functional outcome despite complete recanalization in patients with large vessel occlusion.