Predicting Value of DWI Total Posterior-circulation Infarct Volume for Endovascular Treatment Outcomes of Acute Basilar Artery Occlusion

Acute basilar artery occlusion (ABAO) is a rare and devastating type of stroke. Endovascular treatment (EVT) is routinely performed in real-world practice, encouraged by the recent result of the basilar artery international cooperation study (BASICS), a randomized controlled study.

ABAO may result in infarcts in the brainstem, cerebellar lobes, thalamus and subthalamic area, or occipitotemporal lobes. Previously, studies using the DWI Posterior-circulation Alberta Stroke Program Early CT (Pc-ASPECT) Score or brainstem score, for predicting outcome in patients with ABAO, showed that the initial infarct extend can affect outcome. Some of these studies included patients tretaed by EVT. But, results showed conflicting findings.

To date, evidence regarding the association between pre-ETVT DWI lesion volume and outcomes is relatively weak and has not yet be determined. Predictors of the outcomes of EVT for anterior circulation include infarcts volume. More recently, authors reported a predictive model of good outcome combining initial DWI infarct volume of less than 10 ml, onset-to-puncture time less than 8 hours and embolic origin in 71 Korean patients undergoing EVT for vertebrobasilar occlusion. Nevertheless, up now, there is not sufficient evidence to reach a consensus.

Using data of our prospective registry, the investigators analyzed consecutive MRI selected, endovascularly treated ABAO patients within the first 24h after symptom-onset. Using the initial Magnetic Resonance Imaging (MRI), baseline total posterior-Circulation infarct volume (TPCIV) was calculated in mL, on an apparent diffusion-coefficient map reconstruction (Olea sphere software).

TPCIV was analyzed in univariate and multivariable models as a predictor of 90-day functional independence (modified Rankin Scale [mRS] 0-2) and mortality. According to received operating characteristic (ROC) analysis, the optimal cut-off was determined by maximizing the Youden index, to evaluate the prognostic value of TPCIV.