The question of when and how to interrupt anticoagulation for patients with nonvalvular atrial fibrillation (AF) who will undergo elective surgery has long vexed physicians. There is a high degree of variability between hospitals and private groups with most of the current practice based on historical patterns rather than on a body of clinical evidence.
In an attempt to guide clinicians and standardize practice patterns, the American College of Cardiology just released a 2017 consensus document with a decision pathway. The lengthy document entails an in-depth discussion of many factors related to indications for anticoagulation, timing of interruption, and whether bridging therapy is indicated. These guidelines were formulated for warfarin/VKA but their application to novel oral anticoagulants (NOACs) is included in the document.
Based on the consensus recommendations, we've created 5 straightforward questions to ask and answer in making the decision about interruption of anticoagulation in a periprocedural setting:
Who is the patient? Know the patient’s underlying bleeding and stroke risks; complete a careful review of medical history, medication list (including over-the-counter medications and any supplements and herbal preparations); and assess laboratory test results to identify factors that may increase risk of bleeing. This is particularly relevant for patients on antiplatelet agents as well as those with a history of gastrointestinal bleed, chronic kidney disease, or diabetes. These guidelines do not formally endorse the use of the HAS-BLED bleeding risk score.
What is the procedure? These guidelines are only for elective (not urgent/emergent) procedures. However, the bleeding risk associated with the procedure and location of bleeding risk (eg, skin biopsy vs intraocular procedure) must be considered carefully. If there are patient-related factors that increase bleeding risk and the procedure carries an uncertain bleeding risk, anticoagulation should be interrupted.
When to interrupt VKA? The document guides clinicians to check INR 5-7 days before the procedure:
• Supratherapeutic: discontinue VKA >5 days before procedure
• Therapeutic: discontinue VKA 5 days before procedure
• Subtherapeutic: discontinue VKA 3-4 days before procedure
Guidance is also offered for timing of discontinuation of NOACs with the caution that only dabigatran has a clinically-approved reversal agent. All currently available NOACs carry a black box warning regarding their use in the setting of neuraxial anesthesia (epidural and spinal anesthesia).
4. How to interrupt?
How to interrupt therapy and whether or not to bridge? NOACs, by virtue of their short half life, do not need bridging therapy. However, one must consider whether to bridge when a VKA is being used. These guidelines recommend the use of the CHA2DS2-Vasc score in the perioperative setting to assess the thrombotic risk. It is recommended to consider bridging as an individual’s thrombotic risk increases (CHA2DS2-Vasc >4) and if there is a history of prior ischemic stroke, TIA, or peripheral arterial embolism (≥3 months previously), unless there is a substantial risk of bleeding. Heparin-based parenteral agents are the first choice, unless there is a history of heparin-induced thrombocytopenia. LMWH should be discontinued >24 h prior to procedure and UFH can be discontinued >4 hours prior to procedure.
5. How to resume?
How to resume anticoagulation? The decision to restart anticoagulation should combine answers to all the previous questions: patient and procedural bleeding and thrombotic risk, timing of resumption of anticoagulation and consideration of whether bridging should be used while the INR is out of the therapeutic range.
Special mention is made of procedures that affect the pharmacokinetics of warfarin and the NOACs (eg, ileus after abdominal surgery) that should be considered when a decision about parenteral anticoagulation is made.
Source: Doherty JU, Gluckman TJ, Hucker WJ, et al for the Periprocedural Management of Anticoagulation Writing Committee. 2017 ACC Expert Consensus Decision Pathway for Periprocedural Management of Anticoagulation in Patients With Nonvalvular Atrial Fibrillation. J Am Coll Cardiol. 2017, 23217; DOI: 10.1016/j.jacc.2016.11.024.