Thrombus Imaging Characteristics and Outcomes in Posterior Circulation Stroke Patients Treated With EVT

BACKGROUND Contrary to anterior circulation stroke, studies on the association between thrombus imaging characteristics and outcomes are scarce in patients with posterior circulation stroke (PCS). We aimed to investigate the association of thrombus imaging characteristics with reperfusion and functional outcome in patients with PCS who underwent endovascular treatment. METHODS In patients with PCS included in the MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in The Netherlands) Registry, thrombus imaging characteristics (thrombus density and perviousness in Hounsfield Units [HU] and thrombus length in mm) were assessed on thin‐slice imaging (<2.5 mm). Regression models were used to assess the relation between thrombus imaging characteristics, reperfusion, functional outcome (24‐hour National Institute of Health Stroke Scale [NIHSS] and 90‐day modified Rankin Scale score ), and safety outcomes. RESULTS In 118 patients with PCS, median thrombus density and perviousness were 53 HU (interquartile range [IQR], 47–61 HU) and 4 HU (IQR, −5 to 12 HU), respectively. Median thrombus length was 23 mm (IQR, 15–43 mm). IV alteplase treatment was administered to 57/118 patients with PCS (48%) before endovascular treatment. Thrombus length was associated with 24‐hour NIHSS (adjusted β coefficient 1.4%; 95% CI 0.5%–2.1% increase of NIHSS per mm increase in thrombus length; P =0.002) and reperfusion (adjusted common odds ratio 0.99; 95% CI 0.97–1.00; P =0.049). None of the other thrombus imaging characteristics were associated with 24‐hour NIHSS or reperfusion. No thrombus characteristic was associated with 90‐day modified Rankin Scale score. CONCLUSION In our population of patients with PCS who underwent endovascular treatment, only thrombus length was associated with 24‐hour NIHSS and reperfusion. None of the thrombus imaging characteristics were associated with 90‐day functional outcome. Our findings suggest that in patients with PCS, thrombus imaging characteristics are not useful predictors for functional outcome after endovascular treatment.