Effect on Successful Recanalization of Thrombus Length in Susceptibility- weighted Imaging in Mechanical Thrombectomy with Stentretrieval

Introduction: Susceptibility-Eeighted Imaging (SWI) enables visualization of thrombotic material in acute ischemic stroke. We analyzed the association between thrombus length on SWI and the success rate of recanalization in stent-retriever mechanical thrombectomy. Methods: A retrospective study was performed on 128 patients with Middle Cerebral Artery (MCA) thrombus on pretreatment SWI. The patients were divided into 2 groups, the successful recanalization and the failed recanalization group. Thrombus visibility and location on SWI were compared to those on Maximum Intensity Projection (MIP) in Computed Tomography (CT) angiography. A comparative analysis was performed in terms of clinical and radiologic outcomes as well as complications with respect to multiple categories. Results: No significant differences were noted in terms of baseline characteristics and clinical outcomes between the 2 groups. However, compared with the successful recanalization group, the failed recanalization group had a larger number of stent-retriever passages and a longer thrombus length (p = 0.027 and 0.014, respectively). Multivariate analyses revealed that a larger mean number of stent-retriever passages was a predictive factor for failure of recanalization (odds ratio [OR] 1.60; 95% confidence Interval [CI] 1.12-2.08; p = 0.04). Thrombus length (OR 9.91; 95% CI 3.89-13.87; p < 0.001) and atrial fibrillation (OR 5.38; 95% CI 1.51-9.58; p = 0.008) were separately associated with more than 3 stent-retriever passages. Conclusions: Thrombus length has been identified as a predictor of recanalization failure in mechanical thrombectomy. A significant decline in the success rate of recanalization was associated with longer thrombus length.