Angiographic tapering sign as a surrogate marker for large vessel occlusion due to intracranial atherosclerotic stenosis and its clinical implication: a retrospective matched case-control study

Background The purpose of this study was to investigate whether the initial DSA appearance of the occlusion during mechanical thrombectomy (MT) can help distinguish the nature of the underlying lesion and predict radiological and clinical outcomes. Methods We retrospectively reviewed cases of patients with acute ischemic stroke who underwent MT for anterior circulation occlusion between March 2017 and February 2020. Underlying intracranial atherosclerotic stenosis (ICAS) was determined based on the presence of fixed stenosis after endovascular treatment. Patients were categorized based on the appearance of the occlusion observed in the initial DSA as tapering sign (+) or (-) groups. We performed 1:2 propensity score matching to establish a proper control group among the tapering sign (-) group. We analyzed and compared baseline characteristics and clinical outcomes between the two groups. Results A total of 293 patients (tapering sign (+), n=47; tapering sign (-), n=246) were included in the analysis. The procedure time of MT was significantly longer for the tapering sign (+) group, and the successful recanalization rate after MT was significantly lower in the tapering sign (+) group than in the tapering sign (-) group. Logistic regression showed that ICAS-related occlusion was strongly associated with a positive angiographic tapering sign, and the angiographic tapering sign was a negative factor for the first-pass effect during MT. However, a 3-month good functional outcome was not significantly associated with the angiographic tapering sign. Conclusions The tapering sign on the initial DSA could be a surrogate marker for ICAS-related occlusion and procedural difficulty. However, its clinical significance remains unclear.