CT-based Higher Thrombus Density is associated with Secondary Embolism during Mechanical Thrombectomy: A Preliminary Observation

Abstract

Background: Secondary embolism (SE) during mechanical thrombectomy (MT) for acute ischemic stroke (AIS) is the main reason for incomplete recanalization, while its risk factors are largely unknown. This study addresses a potential relationship between thrombus density on preinterventional computed tomography (CT) and the occurrence of SE. Methods: We reviewed anterior circulation AIS patients who underwent MT from July 2015 to January 2019 in our center. Thrombus density was measured in Hounsfield Units (HU) on 1-mm and 5-mm preinterventional nonenhanced CT (NECT). Thrombus density, baseline characteristics, procedural, and clinical outcomes were compared between patients with SE and those without SE. Logistic regression was conducted to identified potential risk factors of SE. Results: Sixty-four consecutively patients were included, of whom SE was identified in 16 (25.0%) patients. Compared with those without SE, patients with SE showed a higher thrombus density on both 1-mm (72.85 versus 64.28, P = .005) and 5-mm NECT (60.31 versus 49.71, P < .001), a higher proportion of atrial fibrillation (75.0% versus 45.8%, P = .043), a lower clot burden score (.5 versus 6.0, P = .029), and a higher proportion of front-line contact aspiration strategy (50.0% versus 16.7%, P = .020). Multivariate regression analysis showed that only thrombus density was the independent predictor of SE (for the model including HU values on 1-mm NECT, OR 1.11, 95%CI 1.01-1.23, P = .029; for the model including HU values on 5-mm NECT, OR 1.09, 95%CI 1.02-1.17, P = .018). Conclusions: Higher thrombus density was the independent predictor for SE. Further studies are needed to investigate its role in the optimization of thrombectomy strategy.