title: Factors associated with ischemic stroke on therapeutic anticoagulation in patients with nonvalvular atrial fibrillation.
abstract: OBJECTIVE
  In this study, we investigated the stroke mechanism and the factors associated with ischemic stroke in patients with nonvalvular atrial fibrillation (NVAF) who were on optimal oral anticoagulation with warfarin.
  
  
  METHODS
  This was a multicenter case-control study. The cases were consecutive patients with NVAF who developed cerebral infarction or transient ischemic attack (TIA) while on warfarin therapy with an international normalized ratio (INR) ≥2 between January 2007 and December 2011. The controls were patients with NVAF without ischemic stroke who were on warfarin therapy for more than 1 year with a mean INR ≥2 during the same time period. We also determined etiologic mechanisms of stroke in cases.
  
  
  RESULTS
  Among 3569 consecutive patients with cerebral infarction or TIA who had NVAF, 55 (1.5%) patients had INR ≥2 at admission. The most common stroke mechanism was cardioembolism (76.0%). Multivariate analysis demonstrated that smoking and history of previous ischemic stroke were independently associated with cases. High CHADS2 score (≥3) or CHA₂DS₂-VASc score (≥5), in particular, with previous ischemic stroke along with ≥1 point of other components of CHADS₂ score or ≥3 points of other components of CHA₂DS₂-VASc score was a significant predictor for development of ischemic stroke.
  
  
  CONCLUSIONS
  NVAF patients with high CHADS₂/CHA₂DS₂-VASc scores and a previous ischemic stroke or smoking history are at high risk of stroke despite optimal warfarin treatment. Some other measures to reduce the risk of stroke would be necessary in those specific groups of patients.
authors: Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors: Young Dae
authors: YD
authors: Kim
authors: Department of Neurology, Gangnam Severance Hospital, Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, Seoul, Korea.
authors: Kyung Yul
authors: KY
authors: Lee
authors: Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors: Hyo Suk
authors: HS
authors: Nam
authors: Department of Neurology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.
authors: Sang Won
authors: SW
authors: Han
authors: Department of Neurology, National Medical Center, Seoul, Korea.
authors: Jong Yun
authors: JY
authors: Lee
authors: Department of Neurology, Pusan National University Hospital, Pusan National University College of Medicine and Biomedical Research Institute, Busan, Korea.
authors: Han-Jin
authors: HJ
authors: Cho
authors: Department of Neurology, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea.
authors: Gyu Sik
authors: GS
authors: Kim
authors: Department of Neurology, Yonsei University Wonju College of Medicine, Wonju, Korea.
authors: Seo Hyun
authors: SH
authors: Kim
authors: Department of Neurology, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
authors: Myoung-Jin
authors: MJ
authors: Cha
authors: Department of Neurology, Chosun University School of Medicine, Gwangju, Korea.
authors: Seong Hwan
authors: SH
authors: Ahn
authors: Department of Neurology, CHA Bundang Medical Center, CHA University, Seongnam, Korea.
authors: Seung-Hun
authors: SH
authors: Oh
authors: Department of Neurology, Konyang University College of Medicine, Daejeon, Korea.
authors: Kee Ook
authors: KO
authors: Lee
authors: Department of Neurology, Changwon Fatima Hospital, Changwon, Korea.
authors: Yo Han
authors: YH
authors: Jung
authors: Department of Neurology, Kyung Hee University School of Medicine, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
authors: Hye-Yeon
authors: HY
authors: Choi
authors: Department of Neurology, School of Medicine, Konkuk University, Chungju, Korea.
authors: Sang-Don
authors: SD
authors: Han
authors: Department of Biostatistics, Yonsei University College of Medicine, Seoul, Korea.
authors: Hye Sun
authors: HS
authors: Lee
authors: Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors: Chung Mo
authors: CM
authors: Nam
authors: Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors: Eun Hye
authors: EH
authors: Kim
authors: Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors: Ki Jeong
authors: KJ
authors: Lee
authors: Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors: Dongbeom
authors: D
authors: Song
authors: Department of Cardiology, Yonsei University College of Medicine, Seoul, Korea.
authors: Hui-Nam
authors: HN
authors: Park
authors: Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea. jhheo@yuhs.ac.
authors: Ji Hoe
authors: JH
authors: Heo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications*; D002318:Cardiovascular Diseases; D016022:Case-Control Studies; D002544:Cerebral Infarction / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012307:Risk Factors; D020521:Stroke / Q000209:etiology / Q000517:prevention & control*; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: Cardiac embolism; anticoagulation; atrial fibrillation; cerebral infarction; risk factors