Histopathologic Analysis of Retrieved Thrombi Associated with Successful Reperfusion after Acute Stroke Thrombectomy

Background and Purpose - Histopathologic evaluation of occlusive thrombi retrieved from cerebral arteries using endovascular therapy is possible. We investigated the relationship between successful reperfusion after thrombectomy and histopathologic characteristics of retrieved thrombi. Methods - Among consecutive patients with acute ischemic stroke treated with endovascular therapy at our institute from December 2010 to July 2015, we retrospectively reviewed those with acute major arterial occlusion from which retrieved thrombi were evaluated histopathologically. Obtained thrombi were assessed for the existence of atheromatous gruel, organization, and the ratios of erythrocyte and fibrin/platelet components. Successful reperfusion was defined as the modified Treatment in Cerebral Ischemia grade of 2b to 3. Results - Of 83 patients studied, 58 (70%) underwent successful reperfusion. Atheromatous gruel was less frequently identified (3% versus 20%; P=0.024), and the proportion of erythrocyte components was higher (57±23% versus 47±24%; P=0.042) in thrombi retrieved from the reperfused than the unreperfused group. On multivariate logistic regression analysis, atheromatous gruel was inversely related (odds ratio, 0.062; 95% confidence interval, 0.002-0.864), and >64% erythrocyte components (cutoff obtained from receiver operating characteristic curve) were positively related (odds ratio, 4.352; 95% confidence interval, 1.185-19.363) to successful reperfusion. Conclusions - Successful reperfusion could be associated with the histopathology of occlusive thrombi, including the existence of atheromatous gruel and proportion of erythrocyte components. Clinical Trial Registration - URL: http://www.clinicaltrials.gov. Unique identifier: NCT02251665.