Magnitude of Benefit of Combined Endovascular Thrombectomy and Intravenous Fibrinolysis in Large Vessel Occlusion Ischemic Stroke

Abstract

Background and Purpose— Quantifying the benefit magnitude of combined endovascular thrombectomy (EVT) and intravenous thrombolysis (IVT) versus nonreperfusion care in patients with acute ischemic stroke caused by large vessel occlusion would aid organization of regional stroke care systems. Methods— NINDS rt-PA Study (National Institute for Neurological Disorders and Stroke Recombinant Tissue Plasminogen Activator) and SWIFT PRIME trial (Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment) patients were matched for prognosis (based on age and National Institutes of Health Stroke Scale) and definite/likely anterior circulation large vessel occlusion (based on National Institutes of Health Stroke Scale total score and item pattern), using optimal inverse variance matching, to determine comparative outcomes with nonreperfusion care alone, IVT alone, and IVT+EVT. Results— Matching yielded 240 patients, including 80 each treated with nonreperfusion care, IVT alone, and IVT+EVT, with, respectively, mean age 67.1, 67.1, and 66.9 and presenting deficit severity (National Institutes of Health Stroke Scale) mean 15.8, 15.9, and 15.9. Outcomes at 3 months for IVT+EVT versus nonreperfusion care included freedom from disability (modified Rankin Scale score, 0–1) 48.1% versus 21.3%, P =0.0004; functional independence (modified Rankin Scale score, 0–2) 62.9% versus 32.6, P =0.0001; and reduced disability over all 7 modified Rankin Scale levels, common odds ratio 3.34, P <0.0001. Outcomes for IVT alone versus nonreperfusion care included: freedom from disability 30.0% versus 21.3%, P =0.28 and reduced disability over all 7 modified Rankin Scale levels, common odds ratio 1.14, P =0.65. Compared with nonreperfusion care, the number needed to treat with EVT+IVT for 1 more patient to have reduced disability was 1.8. Conclusions— Matched patient analysis across randomized trials provides evidence that the strategy of combined IVT and mechanical thrombectomy is a highly beneficial treatment strategy for acute ischemic stroke caused by large vessel occlusion patients. A reasonable effect magnitude estimate is that, among every 100 patients treated, combined IVT+EVT reperfusion therapy, compared with no reperfusion therapy, reduces long-term disability in 57, including conferring functional independence upon 30.