Abstract W P426: Vascular Filling Defect Shape and Density Of Thrombus In CT/CT-Angiography Predict Results Of Thrombectomy

Abstract

BACKGROUND: In acute thromboembolic stroke, mechanical recanalization with retrieval stents may result in immediate flow restoration and improve prognosis of patients. However, in up to 20% of cases, mechanical thrombectomy with stent retrievers results in poor angiographic outcomes (TICI 0-2a). Radiological findings on baseline CT scan and CT-angiography could predict recanalization rate and clinical outcome after thrombectomy. METHODS: We performed a retrospective analysis of patients with acute MCA or TICA occlusion treated with thrombectomy using retrievable stents between July 2010 to May 2014. We analyzed thrombus attenuations (Hounsfield Units, HU) in baseline noncontrast CT (NCCT), and shape of vascular filling defect in CT-angiography (CTA) that we correlate with arteriography study. Successful recanalization was considered with TICI 2b-3. RESULTS: A total of 183 patients were analyzed (142 had a M1 segment occluded, 25 a M2 and 16 a TICA occlusion on the admission CTA). Fifty-three percent of patients had received previously rtPA. The mean age was 64.5 years+/-12 (46% women).The median NIHSS at presentation was 17 (range 6-26). Recanalization TICI 2b-3 was achieved in 78% of patients. Symptomatic hemorrhage occurred in 8% and good 90-day functional outcome (mRS ≤2) was achieved by 54%. Eighty percent of patients had a hyperdense thrombus evident on the baseline NCCT (mean 61+/-26 HU). In receiver operating characteristic (ROC) analysis attenuations of the clots was associated with higher rate of recanalization TICI 2b-3 ( AUC=0.782; p:0.001). The shape of vascular filling defect contacting the thrombus by CTA (hook, sharp and abrupt shapes) correlates exactly in 98.5% with angiography series. Recanalization rates (TICI2b-3) were significant different in hook shape compared with sharp and abrupt shape group (85% vs 25%; p:0.001). Patients with hook shaped defect were associated with better clinical outcome compared with other shapes of filling defects (90 days mRS 0-2: 71% vs 38%, p:0.001). CONCLUSIONS: We found a significant association between characteristics of thrombus by NCCT/CTA and successful recanalization (TICI 2b-3). Shape and attenuation of thrombus could be predictive of technical success of thrombectomy.