Debra P is a 62-year-old African American woman who calls your office to report that she has an upcoming routine colonoscopy planned in 2 weeks. She has been taking warfarin for the past 2 years for ischemic stroke prevention secondary to atrial fibrillation (AF), and her gastroenterologist recommended that she contact her family physician (FP) to discuss periprocedural anticoagulation plans. Ms. P is currently taking warfarin 5 mg on Mondays, Wednesdays, and Fridays, and 2.5 mg all other days of the week. Her international normalized ratio (INR) was 2.3 when it was last checked 2 weeks ago, and it has been stable and within goal range for the past 6 months. Her medical history includes AF, well-controlled hypertension, and type 2 diabetes mellitus, as well as gout and stage 3 chronic kidney disease. Ms. P denies any history of stroke or transient ischemic attack (TIA). She is requesting instructions on how to manage her warfarin before and after her upcoming colonoscopy.
Jerry Q is a 68-year-old Caucasian man with longstanding osteoarthritis who is scheduled to undergo a total left knee arthroplasty in one week. His orthopedic surgeon recommended that he contact his FP for instructions regarding managing apixaban perioperatively. Jerry has been taking apixaban 5 mg bid for the past 9 months due to a history of recurrent deep vein thrombosis (DVT) and pulmonary embolism (PE) (both unprovoked). Mr. Q had been taking warfarin following his first DVT 4 years ago, but, after reporting that INR monitoring was a burden, he was started on apixaban. The patient has normal renal function and is relatively healthy otherwise. How should apixaban be managed before and after his upcoming surgery?
Each year, approximately 15% to 20% of patients taking an oral anticoagulant undergo a procedure that carries a heightened risk for bleeding.1,2 Stopping oral anticoagulation is often necessary before—and sometimes briefly after—many of these procedures in order to minimize the risk of bleeding.3 This means that countless decisions must be made by health care providers each year regarding if, when, and how to pause and resume oral anticoagulation. These decisions are not always straightforward, especially when you consider the risks for thrombosis and bleeding that are unique to the procedure and to the individual patient.
With these variables in mind, the health care provider must make decisions regarding anticoagulation during the periprocedural period based on the following 5 questions:
- Will this patient need to have his/her oral anticoagulant stopped prior to the procedure?
- If the patient’s oral anticoagulation needs to be held, when should it be stopped and for how long?
- Will periprocedural bridging with a parenteral anticoagulant be necessary prior to the procedure?
- When should the patient resume his or her oral anticoagulant after the procedure, and at what dosage?
- Will bridging with a parenteral anticoagulant be necessary after the procedure?
Before addressing these 5 questions, though, physicians must assess patients’ thrombotic and bleeding risks.4-6
Anticoagulant regimens and the risks of discontinuing them
The 2 most common indications for long-term oral anticoagulation are venous thromboembolism (VTE), which occurs in approximately one million Americans every year,7,8 and stroke prevention in the setting of AF (AF occurs in 3-6 million US adults per year).6
Warfarin is also often used in patients with mechanical heart valves for long-term stroke prevention; however, direct oral anticoagulants (DOACs) are not recommended for patients with mechanical heart valves because trials have not yet demonstrated their safety or efficacy in this population.4,5,9
Who’s at highest risk for an acute thromboembolic event?
When planning for interruptions in oral anticoagulation, it is important to identify patients at highest risk for an acute thromboembolic event. Patients with 10% or higher annual risk for VTE or ischemic stroke are generally placed into this high-risk category (TABLE 13,5,6,9-11).3 Keep in mind that the absolute risk for thromboembolism during a brief period of oral coagulation interruption is relatively low, even in those patients considered to be at high risk. Using a mathematical approach (although simplistic), a patient with a 10% annual risk for a thromboembolic event would have <0.3% chance for developing such an event in the acute phase, even if their anticoagulation was withheld for up to 10 days ([10%/365 days] × 10 days).
Patients with mechanical heart valves. Nearly all patients with a mechanical heart valve are at moderate to high risk for ischemic stroke.3
For patients with AF, the CHADS2 and CHA2DS2-VASc scoring tools can be used to estimate annual thrombosis risk based on the presence of risk factors (TABLE 210,11).6,9-11 It should be noted, however, that these scoring tools have not been validated specifically for periprocedural risk estimations. Nonetheless, the latest 2017 American College of Cardiology (ACC) guidelines recommend the use of the CHA2DS2-VASc scoring tool for making decisions regarding perioperative bridging in patients with AF.11