title: Implications of limiting mechanical thrombectomy to patients with emergent large vessel occlusion meeting top tier evidence criteria.
abstract: BACKGROUND
  Recent guidelines for endovascular management of emergent large vessel occlusion (ELVO) award top tier evidence to the same selective criteria in recent trials. We aimed to understand how guideline adherence would have impacted treatment numbers and outcomes in a cohort of patients from a comprehensive stroke center.
  
  
  METHODS
  A retrospective observational study was conducted using consecutive emergent endovascular patients. Mechanical thrombectomy (MT) was performed with stent retrievers or large bore clot aspiration catheters. Procedural outcomes were compared between patients meeting, and those failing to meet, top tier evidence criteria.
  
  
  RESULTS
  126 patients receiving MT from January 2012 to June 2015 were included (age 31-89 years, National Institutes of Health Stroke Scale (NIHSS) score 2-38); 62 (49%) patients would have been excluded if top tier criteria were upheld: pretreatment NIHSS score <6 (10%), Alberta Stroke Program Early CT score <6 (6.5%), premorbid modified Rankin Scale (mRS) score ≥2 (27%), M2 occlusion (10%), posterior circulation (32%), symptom to groin puncture >360 min (58%). 26 (42%) subjects had more than one top tier exclusion. Symptomatic intracerebral hemorrhage (sICH) and systemic hemorrhage rates were similar between the groups. 3 month mortality was 45% in those lacking top tier evidence compared with 26% (p=0.044), and 3 month mRS score 0-2 was 33% versus 46%, respectively (NS). After adjusting for potential confounders, top tier treatment was not associated with neurological improvement during hospitalization (β -8.2; 95% CI -24.6 to -8.2; p=0.321), 3 month mortality (OR=0.38; 95% CI 0.08 to 1.41), or 3 month favorable mRS (OR=0.97; 95% CI 0.28 to 3.35).
  
  
  CONCLUSIONS
  Our study showed that with strict adherence to top tier evidence criteria, half of patients may not be considered for MT. Our data indicate no increased risk of sICH and a potentially higher mortality that is largely due to treatment of patients with basilar occlusions and those treated at an extended time window. Despite this, good functional recovery is possible, and consideration of MT in patients not meeting top tier evidence criteria may be warranted.
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
authors.forename: Rohini
authors.initials: R
authors.lastname: Bhole
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
authors.forename: Nitin
authors.initials: N
authors.lastname: Goyal
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Nearing
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.|Department of Neurosurgery, Semmes-Murphey Brain and Spine Institute, Memphis, Tennessee, USA.
authors.forename: Andrey
authors.initials: A
authors.lastname: Belayev
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.|Department of Neurosurgery, Semmes-Murphey Brain and Spine Institute, Memphis, Tennessee, USA.
authors.forename: Vinodh T
authors.initials: VT
authors.lastname: Doss
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.|Department of Neurosurgery, Semmes-Murphey Brain and Spine Institute, Memphis, Tennessee, USA.
authors.forename: Lucas
authors.initials: L
authors.lastname: Elijovich
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.|Department of Neurosurgery, Semmes-Murphey Brain and Spine Institute, Memphis, Tennessee, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hoit
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.|Second Department of Neurology, 'Attikon University Hospital', School of Medicine, University of Athens, Athens, Greece.|Australian Catholic University, Sydney, Australia.
authors.forename: Georgios
authors.initials: G
authors.lastname: Tsivgoulis
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Alexandrov
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.|Department of Neurosurgery, Semmes-Murphey Brain and Spine Institute, Memphis, Tennessee, USA.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Arthur
authors.affiliation: Stroke Team, Methodist University Hospital, University of Tennessee Health Science Center, Memphis, Tennessee, USA.|Australian Catholic University, Sydney, Australia.
authors.forename: Anne W
authors.initials: AW
authors.lastname: Alexandrov
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002543:Cerebral Hemorrhage / Q000175:diagnosis / Q000209:etiology; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D020127:Recovery of Function; D012189:Retrospective Studies; D015607:Stents / Q000009:adverse effects / Q000639:trends; D020521:Stroke / Q000175:diagnosis* / Q000601:surgery*; D017131:Thrombectomy / Q000009:adverse effects / Q000592:standards* / Q000639:trends; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage* / Q000009:adverse effects; D016896:Treatment Outcome
chemical_list: D010959:Tissue Plasminogen Activator
keywords: Stroke; Thrombectomy