title: Optimizing endovascular stroke treatment: removing the microcatheter before clot retrieval with stent-retrievers increases aspiration flow.
abstract: BACKGROUND
  Flow control during endovascular stroke treatment with stent-retrievers is crucial for successful revascularization. The standard technique recommended by stent-retriever manufacturers implies obstruction of the respective access catheter by the microcatheter, through which the stent-retriever is delivered. This, in turn, results in reduced aspiration during thrombectomy. In order to maximize aspiration, we fully retract the microcatheter out of the access catheter before thrombectomy-an approach we term the 'bare wire thrombectomy' (BWT) technique. We verified the improved throughput with systematic in vitro studies and assessed the clinical effectiveness and safety of this method.
  
  
  METHODS
  We compared aspiration flow of water through various access catheters (5-8 F) with a Rebar microcatheter (0.18 inch and 0.27 inch) and a Trevo stent-retriever using the standard technique and the BWT technique in vitro. We also retrospectively analyzed 302 retrieval maneuvers in 117 patients who received endovascular treatment with a stent-retriever between February 2010 and April 2015.
  
  
  RESULTS
  In the in vitro experiment, removal of the microcatheter in all tested settings resulted in significantly increased aspiration flow through the access catheter (p<0.001). This effect was particularly pronounced in access catheters with a diameter of ≤7 F. In the clinical study, the revascularization rate (Thrombolysis In Cerebral Infarction ≥2b) was 91%. There were no complications associated with the BWT technique in 302 retrieval maneuvers.
  
  
  CONCLUSIONS
  The BWT technique results in improved aspiration flow rates compared with the standard deployment technique. Our clinical data show that the BWT technique is effective and safe.
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, RWTH University Hospital Aachen, Aachen, Germany.|Department of Radiology, RWTH University Hospital Aachen, Aachen, Germany.
authors.forename: Omid
authors.identifier: http://orcid.org/0000-0002-2055-4217
authors.initials: O
authors.lastname: Nikoubashman
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, RWTH University Hospital Aachen, Aachen, Germany.
authors.forename: Jan Patrick
authors.identifier: http://orcid.org/0000-0002-7697-021X
authors.initials: JP
authors.lastname: Alt
authors.affiliation: Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany.
authors.forename: Arash
authors.identifier: http://orcid.org/0000-0003-0563-825X
authors.initials: A
authors.lastname: Nikoubashman
authors.affiliation: Institute of Applied Medical Engineering, RWTH University, Aachen, Germany.
authors.forename: Martin
authors.identifier: http://orcid.org/0000-0001-9758-2892
authors.initials: M
authors.lastname: Büsen
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, RWTH University Hospital Aachen, Aachen, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Heringer
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, RWTH University Hospital Aachen, Aachen, Germany.
authors.forename: Carolin
authors.initials: C
authors.lastname: Brockmann
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, RWTH University Hospital Aachen, Aachen, Germany.
authors.forename: Marc-Alexander
authors.initials: MA
authors.lastname: Brockmann
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, RWTH University Hospital Aachen, Aachen, Germany.
authors.forename: Marguerite
authors.initials: M
authors.lastname: Müller
authors.affiliation: Department of Neurology, RWTH University Hospital Aachen, Aachen, Germany.
authors.forename: Arno
authors.initials: A
authors.lastname: Reich
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, RWTH University Hospital Aachen, Aachen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wiesmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057785:Catheters; D002648:Child; D057510:Endovascular Procedures / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D015607:Stents; D020521:Stroke / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D017131:Thrombectomy / Q000295:instrumentation* / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Balloon; Catheter; Intervention; Stent; Stroke