Management of Anticoagulation for AF | Ten Points to Remember
- Kovacs RJ, Flaker GC, Saxonhouse SJ, et al.
- Practical Management of Anticoagulation in Patients With Atrial Fibrillation. J Am Coll Cardiol 2015;65:1340-1360.
The following are 10 key points from this expert recommendation for practical management of anticoagulation patients with atrial fibrillation (AF):
- Oral anticoagulation therapy is recommended for all patients with nonvalvular AF, with or without symptoms, to reduce the risk of stroke. The 2014 American College of Cardiology/American Heart Association AF guidelines recommended the use of the CHA2DS2-VASc scoring system to risk stratify patients. The HAS-BLED and ATRIA bleeding risk scores can be used to predict bleeding risk, but should not preclude patients from receiving anticoagulant therapy.
- Direct oral anticoagulants (DOACs) include Factor Xa inhibitors (e.g., rivaroxaban, apixaban, and edoxaban) as well as direct thrombin inhibitors (e.g., dabigatran). DOACs consistently demonstrated similar or reduced risk of ischemic stroke and intracranial hemorrhage with an increased risk of gastrointestinal bleeding (rivaroxaban, dabigatran, and edoxaban 60 mg). Appropriate drug selection depends on individual patient characteristics, including cost, renal function, age, and weight. Patients on DOACs still require periodic laboratory monitoring, including renal function testing (using Cockcroft-Gault equation).
- Drug-drug interactions must be considered for all oral anticoagulants. While there are numerous warfarin-drug interactions, there are important DOAC-drug interactions as well, including CYP3A4 inhibitors/inducers and P-glycoprotein inducers such as rifampin, quinidine, dronedarone, verapamil, and antiretroviral medications.
- Use of anticoagulation management services can improve patient outcomes and reduce overall costs. These services can be used to support patients on DOACs, including evaluation for drug-drug interactions, assuring periodic laboratory monitoring and continued patient education.
- Laboratory monitoring is not recommended for routine use with DOAC patients. In select cases, a prolonged activated partial thromboplastin time (aPTT) might indicate an anticoagulant effect of dabigatran, whereas a prolonged PT might indicate an anticoagulant effect of the Factor Xa inhibitors. However, normal aPTT and PT levels can be found in patients taking DOACs, limiting the utility of these tests. The dilute thrombin time (Hemoclot) is a reliable measure of dabigatran’s drug concentration, but has limited availability.
- Anticoagulant reversal can be achieved with vitamin K, fresh frozen plasma (FFP), or prothrombin complex concentrate (PCC) for warfarin-treated patients. However, these therapies have limited action in the reversal of DOAC medications.
- Anticoagulated patients experiencing major bleeding require standard measures (fluid and blood resuscitation, control of bleeding source, avoidance of further anticoagulants). Vitamin K, FFP, and PCCs can be used in warfarin-treated patients with life-threatening major bleeding. DOAC-treated patients with life-threatening major bleeding can be considered for gastric lavage (if recent ingestion) or dialysis (only for dabigatran). Reversal agents specific to DOACs are in development, but not currently available. All nonmajor bleeding should be managed conservatively as long as the patient is stable and the bleeding source can be controlled.
- In patients who require anticoagulation and antiplatelet therapy (e.g., recent coronary stenting), use of low-dose aspirin and clopidogrel is preferred to newer antiplatelet medications. After an initial period (1-6 months), continued clopidogrel plus an anticoagulant without aspirin can be considered.
- Only warfarin should be used in patients with AF and a mechanical heart valve. Food and Drug Administration (FDA) prescribing recommends avoidance of DOACs with all prosthetic heart values, despite use of several DOACs in patients with bioprosthetic valves in the major randomized trials.
- In patients undergoing cardioversion or radiofrequency ablation for AF, use of warfarin or a DOAC is reasonable. Therapy should be given at least 3 weeks prior and 4 weeks following any cardioversion procedure. For patients undergoing radiofrequency ablation, continued use of warfarin, temporary interruption of dabigatran (24 hours pre- and post-procedure), and temporary interruption of rivaroxaban (held on day of procedure) are all safe.
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