Intravenous Thrombolysis before Thrombectomy Improves Functional Outcome after Stroke Independent of Reperfusion Grade

Background We studied the effect of bridging intravenous thrombolysis (IVT) before thrombectomy for anterior circulation large vessel occlusion (acLVO) on functional outcome and scrutinized its dependence on grade of reperfusion and distal thrombus migration. Methods We included consecutive acLVO patients from our prospective registry of thrombectomy-eligible patients treated from 01/01/2017 to 01/01/2023 at a tertiary stroke center in Germany into a retrospective cohort study. We evaluated the effects of bridging IVT on functional outcome quantified via modified Rankin scale (mRS) at 90 days applying multivariable logistic and lasso regression including interaction terms with grade of reperfusion quantified via modified Thrombolysis in Cerebral Infarction (mTICI) scale and distal thrombus migration adjusted for demographic and cardiovascular risk profiles, clinical and imaging stroke characteristics, onset-to-recanalization time and distal thrombus migration. We performed sensitivity analysis using propensity score matching. Results In our study population of 1000 thrombectomy-eligible patients (513 females, median age 77 [67-84, interquartile range]) IVT emerged as predictor of favorable functional outcome (mRS 0-2) independent of mTICI (adjusted OR 0.49; 95% CI [0.32;0.75]; p=0.001). In those who underwent thrombectomy (n=812) the association of IVT and favorable functional outcome was reproduced (adjusted OR 0.49; 95% CI [0.31;0.74]; p=0.001) and was further confirmed on propensity score analysis where IVT led to a 0.35-point decrease in 90-day mRS score [ß=-0.35; 95CI% [-0.68;-0.01]; p=0.04]. The additive benefit of IVT remained independent of mTICI (ß=-1.79; 95% CI [-3.43;-0.15]; p=0.03) and distal thrombus migration (ß=-0.41; 95% CI [-0.69;-0.13]; p=0.004) on interaction analysis. Consequently, IVT showed an additive effect on functional outcome in the subpopulation of thrombectomy patients who achieved successful reperfusion (TICI≥2b; ß=-0.46; 95% CI [-0.74;-0.17]; p=0.002) and remained beneficial in those with unsuccessful reperfusion (TICI≤2a; ß=-0.47; 95% CI [-0.96;-0.01]; p=0.05). Conclusions In thrombectomy-eligible acLVO patients IVT improves functional outcome independent of grade of reperfusion and distal thrombus migration.