Risk of Ischemic Stroke in High Risk Atrial Fibrillation Patients during Periods of Warfarin Discontinuation for Surgical Procedures.
The risk of ischemic stroke during periods of warfarin discontinuation for surgical procedures is recognized but not well characterized.



The study aimed to quantitate the risk of ischemic stroke associated with high risk atrial fibrillation during periods of warfarin discontinuation.



A cohort of 4,060 patients (mean follow-up period of 3.5 ± 1.3 years) were randomized into the Atrial Fibrillation Follow-Up Investigation of Rhythm Management study. Patients enrolled in the study had atrial fibrillation plus at least one other risk factor for stroke or death: age ≥65 years', systemic hypertension, diabetes mellitus, congestive heart failure, transient ischemic attack, prior stroke, left atrium >50 mm, left ventricular fractional shortening <25% or left ventricular ejection fraction <40%.



Warfarin discontinuation for procedure.



The association of warfarin discontinuation with the incidence of ischemic stroke using pooled repeated measures and Cox proportional hazards analyses during follow-up after adjusting for age, gender, obesity, diabetes mellitus, hypercholesterolemia, cigarette smoking and study period.



Warfarin discontinuation for procedure occurred in 265 (0.4%) of the 71,355 person observations. Compared with those without warfarin discontinuation, the rate of ischemic stroke was higher among participants with surgery-related warfarin discontinuation (1.1% of 265 person observations vs. 0.2% of 71,090 person observations, p = 0.001). Warfarin discontinuation was associated with an increased risk for ischemic stroke (relative risk 5.8; 95% CI 1.8-18.4) after adjusting for potential confounders. The population-attributable risk associated with surgery-related warfarin discontinuation was estimated to be 23.1% (95% CI 15.2-30.9%) for ischemic stroke.



The 6-fold higher risk of ischemic stroke associated with discontinuation of warfarin for surgical procedures must be recognized in high risk atrial fibrillation patients and considered in the risk-benefit analysis of any procedure.
Zeenat Qureshi Stroke Institute (ZQSI), St. Cloud, Minn., USA.
Adnan I
AI
Qureshi
Nauman
N
Jahangir
Ahmed A
AA
Malik
Mohammad Rauf
MR
Afzal
Fayyaz
F
Orfi
M Fareed K
MF
Suri
D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D002545:Brain Ischemia / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D019990:Perioperative Care; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D013514:Surgical Procedures, Operative; D013997:Time Factors; D016896:Treatment Outcome; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects
D000925:Anticoagulants; D014859:Warfarin