Does the susceptibility vessel sign influence the effectiveness of intravenous thrombolysis before endovascular thrombectomy in acute ischaemic stroke?

INTRODUCTION: The benefit of intravenous thrombolysis (IVT) prior to EVT in acute ischaemic stroke (AIS) remains debated. We evaluated the association of the susceptibility vessel sign (SVS) with clinical and angiographic outcomes and assessed whether its presence modified the effect of IVT. PATIENTS AND METHODS: We retrospectively analysed patients with anterior circulation large vessel occlusion from the multicentre ETIS registry who underwent EVT. Susceptibility vessel sign presence and extent were assessed on MRI and categorised as binary (SVS- vs SVS+) and 3-class (SVS-, SVS+, SVS++) variables. Multivariable regression was used to evaluate associations and interactions between SVS and IVT for the primary (90-day mRS 0-2) and secondary (90-day ordinal mRS and mortality, first-pass expanded thrombolysis in cerebral infarction [eTICI] 2c-3 and final eTICI 2b-3) outcomes. RESULTS: Among the 1250 patients analysed, 909 were included. Susceptibility vessel sign was present in 84.5% of patients and associated with improved 90-day mRS 0-2: adjusted odds ratio (aOR) 2.03; 95% CI, 1.18-3.46. No interaction between SVS and IVT was observed for clinical outcomes. However, SVS modified the effect of IVT on final TICI 2b-3 (Pinteraction = .03): IVT + EVT was associated with higher odds of successful reperfusion in SVS+ patients (aOR 2.00; 95% CI, 1.28-3.52) but not in SVS- patients (aOR 0.60; 95% CI, 0.16-1.97). In a secondary analysis using 3-class SVS, only SVS++ (larger hyposignal) was significantly associated with better outcomes and showed interaction with IVT for final eTICI 2b-3. CONCLUSION: Susceptibility vessel sign, particularly SVS++, was associated with improved clinical outcomes and enhanced the effect of IVT on reperfusion success in EVT-treated AIS.