Acute Carotid Stenting for Tandem Lesions in Patients Randomized to Endovascular Treatment With or Without Thrombolysis: Results From the IRIS Individual Participant Data Meta-Analysis

BACKGROUND: Equipoise persists whether patients with stroke with carotid tandem lesions undergoing endovascular treatment (EVT) should undergo acute carotid stenting, and whether intravenous thrombolysis (IVT) before EVT should influence this decision. We assessed functional and safety outcomes of acute carotid stenting in patients with carotid tandem lesions randomized to IVT plus EVT or EVT alone. METHODS: Individual participant data meta-analysis of 6 randomized clinical trials conducted in Asia, Europe, and Oceania between 2017 and 2021 investigating IVT plus EVT versus EVT alone in patients with carotid tandem lesions presenting directly to EVT-capable centers. The primary outcome was the 90-day modified Rankin Scale score, assessed with mixed-effect ordinal regression models. Safety outcomes were any intracranial hemorrhage and symptomatic intracranial hemorrhage. A secondary analysis used inverse probability of treatment weighting. Treatment effect heterogeneity between IVT plus EVT and EVT alone was assessed in a 2-step meta-analysis. RESULTS: Overall, 340 of 2267 (15%) patients had carotid tandem lesions with 113 of 329 (34%) undergoing acute carotid stenting. Stenting was associated with better 90-day functional outcomes (adjusted common odds ratio, 1.60 [95% CI, 1.03–2.47]), confirmed in inverse probability of treatment weighting analysis (adjusted common odds ratio, 1.66 [95% CI, 1.08–2.54]). Patients undergoing stenting had no statistically significant higher rates of any intracranial hemorrhage (44% versus 35%; adjusted odds ratio, 1.30 [95% CI, 0.79–2.15]) and symptomatic intracranial hemorrhage (6.3% versus 3.7%; adjusted odds ratio, 2.09 [95% CI, 0.78–5.59]). No heterogeneity in treatment effect was observed in patients randomized to IVT plus EVT (adjusted common odds ratio, 2.07 [95% CI, 1.06–4.07]) or EVT alone (1.21 [95% CI, 0.59–2.50]; P interaction=0.81). CONCLUSIONS: In this international individual participant data meta-analysis of patients with carotid tandem lesions randomized to EVT alone or IVT followed by EVT, acute carotid stenting during EVT was associated with better functional outcomes, and this association was not modified by prior treatment with IVT.