Abstract WP31: Asymmetrical Internal Veins Sign In Acute Ischemic Stroke: A New Marker For Poor Collateral Circulation.

Abstract

INTRODUCTION: Changes in venous drainage imaging have been directly related to parenchymal damage in acute ischemic stroke during endovascular treatment. Venous asymmetry assessed by CT prior to treatment may be directly related to delayed flow in the hypoperfused territory. We investigated the prevalence of asymmetry in internal cerebral vein (AIV) drainage and its correlation with collateral flow in patients with acute ischemic stroke by a multimodal CT protocol. Subjects and methods: We retrospectively evaluated clinical and radiological data of 29 consecutive patients with acute anterior circulation ischemic stroke within 6 hours from symptoms onset. Collateral status was graded as good or poor depending on the extent of contrast visualized distal to the occlusion on CT angiography (CTA). Presence and AIV (analyzed by density units, time to peak and volume) and arterial collateral score were blinded assessed on CT perfusion (PCT), CTA source images (CTASI) and MIP reconstructions. Results: We included 29 patients, with a median age of 77 ± 15 y, and 31% of them were men. Median baseline NIHSS was 11 ± 7. Mean infarct ASPECTS was 9.3 ± 1 and size 2 cm3 ± 4. Asymmetrical veins were present in 33% of patients. This sign was more prevalent in patients with proximal occlusions than in distal occlusions (67% versus 33%) and in patients with poor collaterals compared to those with good collaterals (62% versus 29%). AIV was significantly associated with increasing age (p= 0.03), increasing baseline NIHSS (p= 0.02) and poor collaterals (p=0.01). Presence of AIV reached high specificity (93%) and good sensitivity (66%) for poor arterial collaterals prediction (p=0.001). Conclusion: Impairment of venous circulation, assessed by means of AIV, is present in one third of the patients and was associated with stroke severity and low effectiveness of collateral flow. Presence of internal veins asymmetry is highly specific in detecting poor collateral circulation in acute stroke and may be a predictor of clinical and radiological severity, possibly useful for patients selection in planning reperfusion therapy strategies.