Yonsei Med J.  2015 Mar;56(2):410-417. 10.3349/ymj.2015.56.2.410.

Factors Associated with Ischemic Stroke on Therapeutic Anticoagulation in Patients with Nonvalvular Atrial Fibrillation

• Kim YD
• Lee KY
• Nam HS
• Han SW
• Lee JY
• Cho HJ
• Kim GS
• Kim SH
• Cha MJ
• Ahn SH
• Oh SH
• Lee KO
• Jung YH
• Choi HY
• Han SD
• Lee HS
• Nam CM
• Kim EH
• Lee KJ
• Song D
• Park HN
• Heo JH

• KMID: 2070018
• DOI: http://doi.org/10.3349/ymj.2015.56.2.410

Abstract

PURPOSE
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.
MATERIALS AND 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) > or =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 > or =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 > or =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 (> or =3) or CHA2DS2-VASc score (> or =5), in particular, with previous ischemic stroke along with > or =1 point of other components of CHADS2 score or > or =3 points of other components of CHA2DS2-VASc score was a significant predictor for development of ischemic stroke.
CONCLUSION
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.

Keyword

Cardiac embolism; cerebral infarction; risk factors; atrial fibrillation; anticoagulation

MeSH Terms

Aged
Aged, 80 and over
Anticoagulants/adverse effects/*therapeutic use
Atrial Fibrillation/*complications
Cardiovascular Diseases
Case-Control Studies
Cerebral Infarction/complications
Female
Humans
Male
Middle Aged
Multivariate Analysis
Risk Factors
Stroke/etiology/*prevention & control
Warfarin/adverse effects/*therapeutic use
Anticoagulants
Warfarin

Figure

• 

  Fig. 1 Patient selection. TIA, transient ischemic attack; NVAF, nonvalvular atrial fibrillation; INR, international normalized ratio.

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