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 <25%, or left ventricular ejection fraction <40%.
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. Qureshi said. The analysis demonstrated that the ischemic stroke rate was 1.1% and 0.2% for individuals with and without warfarin discontinuation, respectively, P=0.001.
Stroke risk with warfarin discontinuation was similar in men and women.
Dr. Qureshi emphasized that the risk associated with discontinuation of warfarin for procedures must be recognized and considered in the risk-benefit analysis of any surgical procedure.