Proposal for a Vascular Computed Tomography-Based Grading System in Posterior Circulation Stroke: A Single-Center Experience

Objective The aim of this study is to investigate the role of a computed tomography angiography (CTA)-based approach in patients undergoing mechanical thrombectomy for vertebrobasilar stroke treatment. Methods A CTA and digital subtraction angiography (DSA) retrospective analysis of patients with acute vertebrobasilar stroke treated with thrombectomy was performed. A modified Rankin Scale score of 3 or lower at 3 months was considered as favorable outcome. The posterior circulation ASPECTS (pc-ASPECTS) was evaluated on CTA and vertebrobasilar segments involved in the occlusion were assessed using a 6-point posterior circulation computed tomography angiography (pc-CTA) vascular score aimed at evaluating the posterior circulation vascular pattern including collaterals. The primary end point was the correlation between pc-CTA and outcome; secondary end points included the concordance between CTA-DSA images and the correlation between pc-ASPECTS and outcome. Results Fifteen patients with vertebrobasilar stroke were retrospectively analyzed. All patients in coma showed a bad outcome (P =.01) and all patients with an alert state showed a good outcome (P =.004). An excellent interobserver agreement for pc-CTA (P =.001) was observed with poor interobserver agreement for pc-ASPECTS (P =.21). No significant correlations between pc-ASPECTS and clinical outcome were observed. Patients with good outcome had a lower pc-CTA (P =.02). The patency of the distal third of the basilar artery and both posterior cerebral arteries was related with good outcome. Conclusion The pc-CTA seems to have prognostic value in patients with vertebrobasilar stroke undergoing mechanical thrombectomy. It may be used as an additional prognostic triage technique in this subgroup of stroke patients.