title: Aspirin resistance in the acute stages of acute ischemic stroke is associated with the development of new ischemic lesions.
abstract: BACKGROUND
  Aspirin is a primary antiplatelet agent for the secondary prevention of ischemic stroke. However, if aspirin fails to inhibit platelet function, as is expected in acute ischemic stroke (AIS), it may increase the rate of early clinical events. Therefore, we sought to determine whether aspirin resistance in the acute stage was associated with early radiological events, including new ischemic lesions (NILs).
  
  
  METHODS
  This study was a single-center, prospective, observational study conducted between April 2012 and May 2013. Aspirin 300 mg was initially administered followed by maintenance doses of 100 mg daily. The acute aspirin reaction unit (aARU) was consistently measured after 3 hours of aspirin loading. An aARU value ≥550 IU was defined as biological aspirin resistance (BAR). NILs on follow-up diffusion-weighted imaging (DWI) were defined as lesions separate from index lesions, which were not detected on the initial DWI.
  
  
  RESULTS
  A total of 367 patients were analyzed in this study. BAR in aARU was detected in 60 patients (16.3%). On follow-up DWI, 81 patients (22.1%) had NILs, which were frequently in the same territory as the index lesions (79%), pial infarcts (61.7%), and located within the cortex (59.3%). BAR was independently associated with NILs on follow-up DWI (adjusted OR 2.00, 95% CIs 1.01-3.96; p = 0.047).
  
  
  CONCLUSIONS
  In conclusion, BAR in aARU could be associated with NILs on follow-up DWI in AIS. Therefore, a further prospective study with a longer follow-up period is necessary to evaluate the clinical implications of aARU in AIS.
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Joon-Tae
authors: JT
authors: Kim
authors: Department of Radiology, Chonnam National University Hwasun Hospital, Hwasun, Jeonnam, Korea.
authors: Suk-Hee
authors: SH
authors: Heo
authors: Clinical Trial Center, Asan Medical Center, Seoul, Korea.
authors: Ji Sung
authors: JS
authors: Lee
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Min-Ji
authors: MJ
authors: Choi
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Kang-Ho
authors: KH
authors: Choi
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Tai-Seung
authors: TS
authors: Nam
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Seung-Han
authors: SH
authors: Lee
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Man-Seok
authors: MS
authors: Park
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Byeong C
authors: BC
authors: Kim
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Myeong-Kyu
authors: MK
authors: Kim
authors: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors: Ki-Hyun
authors: KH
authors: Cho
mesh_terms: D000208:Acute Disease; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects; D001241:Aspirin / Q000009:adverse effects*; D002545:Brain Ischemia / Q000150:complications* / Q000188:drug therapy / Q000473:pathology*; D004351:Drug Resistance; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D020521:Stroke / Q000150:complications* / Q000188:drug therapy / Q000473:pathology*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin