What the SWIFT and TREVO II Trials Tell Us About the Role of Endovascular Therapy for Acute Stroke

The Solitaire With the Intention for Thrombectomy (SWIFT) trial1 and the TREVO II trial,2 published online in Lancet in August 2012, are important trials in the history of endovascular therapy for acute ischemic stroke for several reasons. First, both randomized trials compared a new technology, 2 versions of a stent-retriever, with a previously Food and Drug Administration-cleared technology, the Merci Retriever. The latest iteration of the Merci Retriever, which had been cleared for use since 2005, is a flexible nitinol wire with distal corkscrew-shaped coil loops with attached filaments. Stent-retriever technology is based on self-expanding stents that can be fully deployed and then retrieved about 5 minutes later, after migration of the thrombus through the stent struts.3 Retrievable stents were introduced in 2010 in experienced, high-volume comprehensive European stroke centers with increased rates of recanalization in a shorter time compared with intra-arterial thrombolysis.4 The Merci Retriever and retrievable stents are distal thrombectomy devices that require navigation of the device through and beyond the site of occlusion without image-guidance of a high-resolution biplane or 3D roadmap. In contrast, proximal thrombectomy devices allow a safe, image-guided approach to the site of occlusion and aspiration of the thrombus. These 2 randomized trials broke the trend of single-arm trials comparing a new technology with the intravenous heparin arm of the randomized PROACT II trial study, which was completed in 1998.5 The goal of past single-arm trials, used for both the Merci Retriever6,7 and Penumbra Aspiration System,8 was to obtain 510k clearance by the FDA, or regulatory approval in other countries, for thrombectomy in acute ischemic stroke. However, no randomized trial of these devices has demonstrated improved clinical outcome by a thrombectomy device compared with standard therapy, whether intravenous tissue-type plasminogen activator (tPA) within 3 and …

[1]  Michael D Hill,et al.  Endovascular therapy after intravenous t-PA versus t-PA alone for stroke. , 2013, The New England journal of medicine.

[2]  Max Wintermark,et al.  A trial of imaging selection and endovascular treatment for ischemic stroke. , 2013, The New England journal of medicine.

[3]  Elad I Levy,et al.  Solitaire flow restoration device versus the Merci Retriever in patients with acute ischaemic stroke (SWIFT): a randomised, parallel-group, non-inferiority trial , 2012, The Lancet.

[4]  Gregory W Albers,et al.  Trevo versus Merci retrievers for thrombectomy revascularisation of large vessel occlusions in acute ischaemic stroke (TREVO 2): a randomised trial , 2012, The Lancet.

[5]  Manabu Inoue,et al.  MRI profile and response to endovascular reperfusion after stroke (DEFUSE 2): a prospective cohort study , 2012, The Lancet Neurology.

[6]  G. Schroth,et al.  Impact of Retrievable Stents on Acute Ischemic Stroke Treatment , 2011, American Journal of Neuroradiology.

[7]  A. Demchuk,et al.  ASPECTS and other neuroimaging scores in the triage and prediction of outcome in acute stroke patients. , 2011, Neuroimaging clinics of North America.

[8]  G. Schroth,et al.  In Vivo Evaluation of the First Dedicated Combined Flow-Restoration and Mechanical Thrombectomy Device in a Swine Model of Acute Vessel Occlusion , 2011, American Journal of Neuroradiology.

[9]  J. Broderick,et al.  Good clinical outcome after ischemic stroke with successful revascularization is time-dependent , 2009, Neurology.

[10]  J. Serfaty,et al.  Comparison of intravenous alteplase with a combined intravenous–endovascular approach in patients with stroke and confirmed arterial occlusion (RECANALISE study): a prospective cohort study , 2009, The Lancet Neurology.

[11]  Penumbra Pivotal Stroke Trial Investigators.  The Penumbra Pivotal Stroke Trial: Safety and Effectiveness of a New Generation of Mechanical Devices for Clot Removal in Intracranial Large Vessel Occlusive Disease , 2009, Stroke.

[12]  M. Kaste,et al.  Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke. , 2008, The New England journal of medicine.

[13]  H. Lutsep,et al.  Mechanical Thrombectomy for Acute Ischemic Stroke: Final Results of the Multi MERCI Trial , 2008, Stroke.

[14]  T. Tomsick.  TIMI, TIBI, TICI: I came, I saw, I got confused. , 2007, AJNR. American journal of neuroradiology.

[15]  H. Lutsep,et al.  Safety and Efficacy of Mechanical Embolectomy in Acute Ischemic Stroke: Results of the MERCI Trial , 2005, Stroke.

[16]  P. Akins,et al.  Intra-arterial prourokinase for acute ischemic stroke. , 2000, JAMA.

[17]  R. Higashida,et al.  Intra-arterial Prourokinase for Acute Ischemic Stroke: The PROACT II Study: A Randomized Controlled Trial , 1999 .