title: Protected stent retriever thrombectomy prevents iatrogenic emboli in new vascular territories.
abstract: BACKGROUND
  Diagnostic tools to show emboli reliably and protection techniques against embolization when employing stent retrievers are necessary to improve endovascular stroke therapy. The aim of the present study was to investigate iatrogenic emboli using susceptibility-weighted imaging (SWI) in an open series of patients who had been treated with stent retriever thrombectomy using emboli protection techniques.
  
  
  METHODS
  Patients with anterior circulation stroke examined with MRI before and after stent retriever thrombectomy were assessed for iatrogenic embolic events. Thrombectomy was performed in flow arrest and under aspiration using a balloon-mounted guiding catheter, a distal access catheter, or both.
  
  
  RESULTS
  In 13 of 57 patients (22.8%) post-interventional SWI sequences detected 16 microemboli. Three of them were associated with small ischemic lesions on diffusion-weighted imaging (DWI). None of the microemboli were located in a new vascular territory, none showed clinical signs, and all 13 patients have been rated as Thrombolysis in Cerebral Infarction (TICI) 2b (n = 3) or 3 (n = 10). Retrospective reevaluation of the digital subtraction angiography (DSA) detected discrete flow stagnation nearby the iatrogenic microemboli in four patients with a positive persistent collateral sign in one.
  
  
  CONCLUSIONS
  Our study demonstrates two things: First, SWI seems to be more sensitive to detect emboli than DWI and DSA and, second, proximal or distal protected stent retriever thrombectomy seems to prevent iatrogenic embolization into new vascular territories during retraction of the thrombus, but not downstream during mobilization of the thrombus. Both techniques should be investigated and refined further.
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.|Department of Radiology, University of Basel, Basel, Switzerland.
authors: Pascal P
authors: PP
authors: Klinger-Gratz
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland. gerhard.schroth@insel.ch.
authors: Gerhard
authors: G
authors: Schroth
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
authors: Jan
authors: J
authors: Gralla
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.|Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.
authors: Simon
authors: S
authors: Jung
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
authors: Christian
authors: C
authors: Weisstanner
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
authors: Rajeev K
authors: RK
authors: Verma
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
authors: Pasquale
authors: P
authors: Mordasini
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
authors: Frauke
authors: F
authors: Kellner-Weldon
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
authors: Kety
authors: K
authors: Hsieh
authors: Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.
authors: Mirjam R
authors: MR
authors: Heldner
authors: Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.
authors: Urs
authors: U
authors: Fischer
authors: Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.
authors: Marcel
authors: M
authors: Arnold
authors: Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.
authors: Heinrich P
authors: HP
authors: Mattle
authors: Department of Diagnostic and Interventional Neuroradiology, Inselspital, Freiburgstrasse 10, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
authors: Marwan
authors: M
authors: El-Koussy
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods; D020878:Device Removal / Q000295:instrumentation; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007049:Iatrogenic Disease / Q000517:prevention & control; D020766:Intracranial Embolism / Q000473:pathology / Q000517:prevention & control*; D020767:Intracranial Thrombosis / Q000473:pathology* / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D061185:Mechanical Thrombolysis / Q000295:instrumentation*; D008875:Middle Aged; D011379:Prognosis; D011474:Prosthesis Design; D015607:Stents; D016896:Treatment Outcome
keywords: Collaterals; SWI; Stent retriever; Stroke; TICI