title: Thrombus burden is associated with clinical outcome after intra-arterial therapy for acute ischemic stroke.
abstract: OBJECTIVE
  Studies have established a relation between recanalization and improved clinical outcome in acute ischemic stroke patients; however, intra-arterial clot size has not been routinely assessed. The aim of the study was to determine the impact of intra-arterial thrombus burden on intra-arterial treatment (IAT) and clinical outcome.
  
  
  METHODS
  A retrospective review of our IAT stroke database included procedure time, recanalization, symptomatic intracranial hemorrhage, poor outcome (modified Rankin Scale score >/=4 at discharge), and mortality. The modified Thrombolysis in Myocardial Infarction thrombus grade was dichotomized into grades 0 to 3 (no clot or moderate thrombus, <2 vessel diameters) versus grade 4 (large thrombus, >2 vessel diameters).
  
  
  RESULTS
  Data were collected on 135 patients with thrombus grading. The baseline median National Institutes of Health Stroke Scale score was higher in patients of grade 4 compared with grades 0 to 3 (19 vs 17, P=0.012). Grade 4 thrombi required longer (median, range) times for IAT (113, 37 to 415 minutes vs 74, 22 to 215 minutes, respectively; P<0.001) and higher rates of mechanical clot disruption (wire, angioplasty, snare, stent, or Merci retriever) compared with grades 0 to 3 (76% vs 53%, P=0.005). There were no differences in rates of symptomatic intracranial hemorrhage (6.6% vs 4.1%, P=0.701) or recanalization (50% vs 61%, P=0.216) in grade 4 versus grades 0 to 3. Multivariate analysis adjusted for age, baseline National Institutes of Health Stroke Scale score, and artery of involvement showed that grade 4 thrombi were independently associated with poor outcome (odds ratio=2.4; 95% CI, 1.06 to 5.57; P=0.036) and mortality (odds ratio=4.0; 95% CI, 1.2 to 13.2; P=0.023).
  
  
  CONCLUSIONS
  High thrombus grade as measured by the modified Thrombolysis in Myocardial Infarction criteria may be a risk factor that contributes to poor clinical outcome.
authors.affiliation: Department of Neurology, Stroke Division, University of Texas, Houston Health Science Center, Houston, TX 77030, USA. andrew.d.barreto@uth.tmc.edu
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Barreto
authors.forename: Karen C
authors.initials: KC
authors.lastname: Albright
authors.forename: Hen
authors.initials: H
authors.lastname: Hallevi
authors.forename: James C
authors.initials: JC
authors.lastname: Grotta
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Noser
authors.forename: Aslam M
authors.initials: AM
authors.lastname: Khaja
authors.forename: Hashem M
authors.initials: HM
authors.lastname: Shaltoni
authors.forename: Nicole R
authors.initials: NR
authors.lastname: Gonzales
authors.forename: Kachi
authors.initials: K
authors.lastname: Illoh
authors.forename: Sheryl
authors.initials: S
authors.lastname: Martin-Schild
authors.forename: Morgan S
authors.initials: MS
authors.lastname: Campbell
authors.forename: Raymond U
authors.initials: RU
authors.lastname: Weir
authors.forename: Sean I
authors.initials: SI
authors.lastname: Savitz
mesh_terms: D000368:Aged; D017130:Angioplasty / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D001925:Brain Damage, Chronic / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D002545:Brain Ischemia / Q000209:etiology / Q000473:pathology*; D002533:Cerebral Angiography; D002543:Cerebral Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D003131:Combined Modality Therapy; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D007261:Infusions, Intra-Arterial; D020767:Intracranial Thrombosis / Q000150:complications / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015424:Reperfusion; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015607:Stents; D015912:Thrombolytic Therapy / Q000009:adverse effects / Q000706:statistics & numerical data; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents
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