title: Association of aspirin resistance with increased stroke severity and infarct size.
abstract: OBJECTIVE
  To investigate the relationship between aspirin resistance and clinical and neuroimaging measures of stroke severity in acute stroke patients.
  
  
  METHODS
  Prospective single-center survey of acute ischemic stroke patients receiving aspirin therapy.
  
  
  METHODS
  The Royal Melbourne Hospital, Parkville, Victoria, Australia.
  
  
  METHODS
  Ninety acute stroke patients who previously received aspirin therapy were enrolled.
  
  
  METHODS
  Clinical stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS) and stroke infarct size was measured using the Alberta Stroke Program Early CT Score (ASPECTS). Aspirin resistance was measured using the VerifyNow system.
  
  
  RESULTS
  The mean (SD) age was 75 (9.9) years and 64.4% were male. The median NIHSS score and ASPECTS were 4 (interquartile range [IQR], 3-10) and 9 (IQR, 6-10), respectively. Aspirin resistance was detected in 28.9% (95% CI, 0.19 to 0.38) of all patients. The median aspirin reaction unit (ARU) was 486.0 (IQR, 432.3-557.0). Every 1-point increase in ARU was associated with a 0.03-point increase in NIHSS score (95% CI, 0.01 to 0.04; P<.001) and a 0.02-point decrease in ASPECTS (95% CI, -0.03 to -0.01; P<.001). This corresponded to an approximate median increase of 1 point in NIHSS score for every 33-point increase in ARU or a decrease of 1 point in ASPECTS for every 50-point increase in ARU.
  
  
  CONCLUSIONS
  Aspirin resistance is associated with increased clinical severity and stroke infarct volume in acute stroke patients. Our results support the need for a randomized controlled study to investigate alternative antiplatelet therapy in patients with aspirin resistance.
authors.affiliation: Melbourne Brain Centre, Department of Medicine, The University of Melbourne, Australia.
authors.forename: Amy S Y
authors.initials: AS
authors.lastname: Zheng
authors.forename: Leonid
authors.initials: L
authors.lastname: Churilov
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Colley
authors.forename: Christine
authors.initials: C
authors.lastname: Goh
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Davis
authors.forename: Bernard
authors.initials: B
authors.lastname: Yan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000009:adverse effects*; D002544:Cerebral Infarction / Q000139:chemically induced / Q000473:pathology* / Q000517:prevention & control; D004351:Drug Resistance / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012720:Severity of Illness Index; D020521:Stroke / Q000139:chemically induced / Q000473:pathology* / Q000517:prevention & control; D016896:Treatment Outcome
chemical_list: D001241:Aspirin