Ischemic Core Volume Combined with the Relative Perfusion Ratio for Stroke Outcome Prediction after Endovascular Thrombectomy.

BACKGROUND AND PURPOSE

Imaging-based selection of stroke patients for endovascular thrombectomy (EVT) remains an ongoing challenge. Our aim was to determine the value of a combined parameter of ischemic core volume (ICV) and the relative degree of cerebral blood flow in the penumbra for morphologic and clinical outcome prediction.

METHODS

In this Institutional Review Board (IRB)-approved prospective observational study, 221 consecutive patients with large vessel occlusion anterior circulation stroke within 6 hours of symptom onset and subsequent EVT were included between June 2015 and August 2017. Admission computed tomography perfusion was analyzed using automated threshold-based algorithms. Perfusion-weighted ICV (pw-ICV) was calculated by multiplying ICV with the relative cerebral blood flow reduction within the penumbra. Functional outcome was assessed by standardized assessment of the modified Rankin scale (mRS) after 3 months.

RESULTS

In multivariate analyses, pw-ICV was significantly associated with final infarction volume (FIV) (β = .38, P < .001) after adjustment for penumbra volume, age, sex and time from symptom onset. In separate multivariate analysis with either pw-ICV or ICV, pw-ICV outperformed ICV for the prediction of FIV (Akaike's information criterion: 1,072 vs. 1,089; conditional variable importance: 1,494 vs. 955). There was also a highly significant association between FIV and clinical outcome as measured by an mRS score of 2 or less (odds ratio per 10 mL = .78, P < .001). Both pw-ICV and ICV were significantly associated with NIHSS improvement (both P<.05).

CONCLUSION

In EVT-treated stroke patients, pw-ICV outperforms the more commonly used ICV in the prediction of morphological and functional outcome.