Association of critical hypoperfusion biomarkers on CT with futile recanalization and poor outcome after mechanical thrombectomy in acute ischemic stroke

Background and purpose: We aimed to investigate the association between critical perfusion delay and poor outcome among recanalized stroke patients with anterior large-vessel occlusion, and to use pretreatment hypoperfusion biomarkers on CT to predict futile recanalization even after successful thrombectomy.

Methods: An ischemic region with time-to-maximum (Tmax) > 12s-10s was defined as critical hypoperfusion, Tmax > 8s as moderate hypoperfusion, and hypoperfusion intensity ratio (HIR, volumetric ratio of Tmax > 10s / Tmax > 6s) represented for severity of critical hypoperfusion and rCBF < 30% for ischemic core. The associations between these CT perfusion characteristics and favorable or unfavorable outcome (mRS 0-2 versus 3-6) were analyzed in univariable regression, and a multivariable model was then used to predict futile recanalization.

Results: Seventy-nine stroke patients were included and had good grades of instant recanalization. Forty-two patients (53%) had poor outcomes, and they had a significantly larger volume of critical hypoperfusion as seen with Tmax > 10s and > 12s (P = 0.032 and 0.008, respectively), a larger volume of ischemic core (P = 0.011) and a higher HIR (P = 0.002) than those patients achieving good outcomes. In the univariable analysis, a lower HIR (OR, 0.008; 95%CI, 0.001-0.254, P = 0.006) was associated with favorable outcome. The volume size of Tmax > 12s was significantly and positively correlated with the size of ischemic core. A HIR value higher than 0.491 might predict a futile recanalization and poor outcome (AUC = 0.701).

Conclusions: The critical hypoperfusion biomarkers on CTP could be useful in triaging endovascular treatment and identifying stroke patients at risk of futile recanalization.