Regional angiographic evaluation of collateral circulation predicts infarction during endovascular procedures for middle cerebral artery stroke

Abstract

Background and purpose. We aimed to improve patient selection by developing a regional angiographic evaluation of leptomeningeal collateral flow that can be used to predict infarction during stroke endovascular procedures. Materials and methods. We evaluated all consecutive patients treated for a middle cerebral artery occlusion between 2009 and 2013. Two readers performed a zonal collateral circulation evaluation in 5 cortical regions based on the vascular anatomy. Zonal scores were correlated with the presence of infarction in the same cortical sector on pretreatment and follow-up imaging. Results. In 49 patients with 217 cortical zones we found good correlation between the degree of zonal collateral flow and the absence of infarction in the same zone on pretreatment imaging (receiver operator characteristic (ROC) curve of 0.74, p < 0.0001). In a subgroup of 23 recanalized patients (TICI 3) with 105 cortical zones, retrograde collateral flow to the proximal M4 segment predicted the absence of infarction within the same zone on follow-up imaging (positive predictive value 89,4% , negative predictive value 80%). We found good inter-rater agreement for the presence of collateral flow to the M4 proximal segment or further – kappa 0.77 (p = 0.05, 95%CI 0.66-0.88). The number of cortical regions with collateral flow to the M2 segment predicts the absence of insular infarction on follow-up imaging (ROC curve of 0,76, p = 0,001). Conclusion. Anatomic collateral flow evaluation can provide a real-time estimation of the size and location of irreversible ischemia during stroke endovascular procedures.