Researchers have quantified the risk of ischemic stroke in patients with atrial fibrillation when warfarin is discontinued for surgical procedures.

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Before the present study, the risk of ischemic stroke during periods of warfarin discontinuation for surgical procedures had long been acknowledged but not well characterized.

Dr. Adnan I. Qureshi, with Zeenat Qureshi Stroke Institute in St. Cloud, Minnesota, and colleagues evaluated the association of warfarin discontinuation for surgical procedures with the incidence of ischemic stroke in a cohort of patients with nonvalvular atrial fibrillation.

All subjects had been randomized into the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) study.

After controlling for potential confounders including age, gender, obesity, diabetes mellitus, hypercholesterolemia and cigarette smoking, warfarin cessation was associated with an increased risk for ischemic stroke (relative risk: 5.6, 95% CI, 1.8 to 17.8 p=0.003) in 4,060 patients who were followed for a mean of 3.5 years.

Dr. Qureshi reported the findings at the 67th Annual Meeting of the American Academy of Neurology.

Subjects included in the analysis had atrial fibrillation plus at least one additional risk factor for stroke or death: age >65 years, systemic hypertension, diabetes, congestive heart failure, transient ischemic attack, prior stroke, left atrium diameter 50+ mm, left ventricular fractional shortening