Susceptibility Vessel Sign and Intravenous Alteplase in Stroke Patients Treated with Thrombectomy : A Secondary Analysis of the SWIFT DIRECT Trial.

Background: The susceptibility vessel sign (SVS) on baseline MRI in acute ischemic stroke patients has been associated with better outcomes post-thrombectomy. This study aimed to investigate whether the presence of the SVS modifies the treatment effect of intravenous thrombolysis plus endovascular thrombectomy (IVT + EVT) versus thrombectomy alone (EVT alone).

Methods: In this secondary analysis of the SWIFT DIRECT trial, comparing IVT + EVT versus EVT alone, treatment effect and its heterogeneity were assessed with rates of pre-interventional reperfusion (eTICI 2a-3) and successful post-interventional reperfusion (eTICI of 2b-3) according to the SVS status using adjusted multivariable logistic regression. Secondary objectives were to analyze whether the presence of SVS or its individual characteristics (location, length, width, overestimation ratio, two-layered sign) were associated with outcomes.

Results: 197 of the initial 408 trial participants were included in this secondary analysis, of which 52% received IVT + EVT. SVS was present in 92% of the participants (n = 181). There was no evidence for treatment effect heterogeneity regarding the post-interventional radiological and clinical effects of IVT + EVT versus EVT alone with strata of SVS. In SVS+ participants, IVT favored pre-interventional reperfusion (aOR 7.95, 95% CI 1.42-44.46), whereas in SVS-patients, it did not (P for interaction = 0.02). The individual SVS characteristics showed no significant associations with outcomes.

Conclusion: Presence of SVS does not seem to modify the effect of IVT + EVT versus EVT alone. In SVS+ patients, IVT might improve pre-interventional reperfusion. There is insufficient evidence to recommend using SVS to inform IVT decisions prior to EVT.