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

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.

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.

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).

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