Thrombus enhancement sign predicts distal embolization in anterior circulation stroke treated with endovascular thrombectomy

Abstract Background: Distal embolization (DE) is a concerning complication of endovascular treatment (EVT) that is linked to adverse clinical outcomes in acute ischemic stroke (AIS). The thrombus enhancement sign (TES) has been identified as a potential biomarker of occlusion; however, its predictive value for DE remains to be fully clarified. Methods: We retrospectively evaluated data of consecutive patients with large vessel occlusion (LVO) in anterior circulation who underwent EVT between January 2020 and December 2023. Each included patient was underwent baseline non-contrast computed tomography (CT) and CT angiography (CTA). We assessed the incidence of DE and its association with clinical and technical outcomes. The association of DE with patient characteristics, thrombus imaging, and composition features was assessed using univariable and multivariable logistic regression. Results: A total of 308 patients were included in the analysis. Distal embolization occurred in 21.1% (65/308) of patients. Patients with DE had longer recanalization time (58 min vs 46 min; p = 0.002), lower proportion achieving successful reperfusion (86% vs 95%; p = 0.022) and decreased frequency of functional independence (31% vs 45%; p = 0.041). TES was significantly more frequent in the DE group compared to the non-DE group (89% vs 70%, p = 0.001). Histopathological examination revealed that TES-positive thrombi contained a higher fibrin/platelet proportion (50.9% vs 48.2% in TES-negative thrombi, p = 0.009) and fewer erythrocytes (41.7% vs 43.5% in TES-negative thrombi, p = 0.043). In multivariable analysis, TES (OR, 2.76; 95% CI, 1.23–7.10; p = 0.022) was the only independent predictor of DE. Discussion and Conclusion: Our study demonstrates that distal embolization is a prevalent complication of EVT that hinders full recanalization and favorable outcomes. The presence of TES on baseline CT imaging could serve as a reliable radiologic predictor of distal embolization after EVT.