Is it safe to stop anticoagulants after successful surgery for atrial fibrillation?

Abstract

A best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was: is it safe to stop anticoagulants after successful surgery for atrial fibrillation? Altogether, 177 papers were found using the reported search, of which 14 were selected that represented the best evidence to answer the clinical question. Selection criteria included study relevance, primary outcome, size of study population and length of follow-up. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The weight of evidence, including over 10,000 patient-years of follow-up, supports the discontinuation of warfarin following atrial fibrillation correction procedures as being safe, with an associated annual thromboembolic stroke rate of 0-3.8% off warfarin, in studies where warfarin was stopped at a mean of 3.6 months (range 0-8 months) after the procedure. However, the confidence of this conclusion suffers from a paucity of high-quality randomized controlled trials in the field, with the main body of evidence coming instead from observational non-randomized studies. The stroke rate also varies with the exact procedure performed; pulmonary vein isolation procedures are the most extensively evaluated and carry the lowest stroke rate following warfarin discontinuation (0-0.4% per annum when performed as an isolated procedure). By contrast, left atrial appendage occlusion by insertion of a transcatheter device has an associated annual stroke rate of 0-3.8% off warfarin. Thus, discontinuation of warfarin following such transcatheter procedures cannot be recommended at this time. Concomitant heart surgeries, such as mitral valve repair have been shown to increase the thromboembolic rate both unpredictably and dramatically, and this review thus identifies concomitant mitral valve surgery as a potentially substantial risk factor for late thromboembolic stroke in patients undergoing corrective surgeries for atrial fibrillation. This review finds in favour of warfarin discontinuation in selected patients at three months post-procedure, emphasizing consideration of the patient's individual risk-factor profile as paramount. This recommendation is in line with the 2010 guidelines for the management of atrial fibrillation produced by the European Society of Cardiology.