All about anticoagulation with AF

It’s usually up to family physicians to prescribe and manage anticoagulation in patients with atrial fibrillation (AF) in order to reduce the risk of stroke. While guidelines make recommendations on anticoagulation, the guidance can get complicated and often changes thanks to the latest clinical research. Here are five pieces of advice on how to manage anticoagulation for patients with atrial fibrillation. Read: Pop quiz: Myocarditis/pericarditis and COVID-19 vaccines 1. Just do it Family physicians may look for reasons not to provide anticoagulation to a patient with AF because they “are never congratulated for having prevented something, but are blamed for any bleeds that occur as an adverse event,” said Dr. L. Brent Mitchell, cardiologist at the Libin Cardiovascular Institute of Alberta and professor of medicine at the University of Calgary Basically, providing anticoagulation to patients with AF is now the default option, Dr. Mitchell said. Evidence from clinical trials suggests that anticoagulation provides a significant reduction of risk of stroke for the majority of people with AF. For example, studies have shown that even frailty or a risk of falling are not reasons to avoid anticoagulation, he said. “It is something we need to do even if we don’t want to do it,” he said. The only time anticoagulation is not recommended in patients with AF is in those who are younger than 65 who have no thromboembolic risk factors as determined by the Canadian Cardiovascular Society (CCS) algorithm (CHADS-65), outlined in the 2020 CCS/Canadian Heart Rhythm Society guidelines for the management of atrial fibrillation. Read: Guidance on myocarditis/pericarditis now included in COVID-19 vaccine guidelines In order to treat AF, and initiate stroke prevention, AF has to be identified. The guidelines recommend that all patients over 65 years old should be screened for AF, simply by taking a patient’s pulse. “Not very highly technical but highly beneficial,” Dr. Mitchell said. 2. Tailor the anticoagulant to your patient’s existing medication regimen For most patients, direct oral anticoagulant (DOAC) medications are recommended over warfarin. There are four options of DOAC medications in Canada, and they are considered interchangeable in most patients given that there are no solid randomized control trials comparing the efficacy between them. When deciding what to prescribe, consider the patient’s existing medication regimen and choose a DOAC that easily fits into the patient’s daily life. Apixaban (Eliquis) and dabigatran (Pradaxa) are taken twice a day; and edoxaban (Lixiana) and rivaroxaban (Xarelto) are taken once a day. “If they’re only on a once-aday medication, prescribing a BID medication, now you’re at risk of not having very good adherence,” said Dr. Clare Atzema, scientist at the Sunnybrook Research Institute and an emergency physician at Sunnybrook Health Sciences Centre in Toronto. Read: Gout medication shows potential for secondary prevention of cardiovascular events Adherence is important with DOAC agents. While it was safe to miss a dose or two on warfarin, there are repercussions if you miss doses of DOAC medications, including thromboembolic events, Dr. Atzema said. 3. Review prescriptions coming from the emergency department Dr. Atzema published a study in 2019 that showed patients with AF who were given a prescription for anticoagulants in the emergency department were significantly more likely to fill their prescription compared to patients with AF who were told in the emergency department to consult their family physician for a prescription. While prescribing in the emergency department may help adherence, emergency physicians will only prescribe for 30 days, because they are unable to follow the patient to adjust dose and monitor side-effects. Family physicians need to provide the followup, and they may want to adjust the prescription. “Don’t just go with what the emergency doctor has started. If you know a drug or you’re more comfortable with a different DOAC, you can always switch them,” Dr. Atzema added. Read: What is the optimal dose of ASA for risk reduction in atherosclerotic CV disease? Dr. Atzema said that most family physicians will continue with the medication the emergency physician prescribed, but they should still review the medication and its dosing based on the patient’s risk of bleeding. An emergency physician doesn’t have time to do that assessment, she said. There are standardized followup tools to help with the regular assessment of bleeding risk available from Thrombosis Canada. 4. Seek help when managing patients with multiple conditions Between 20% and 30% of patients with AF have coronary artery disease (CAD). Others may have other medical conditions, such as renal failure, diabetes or cancer. Keeping the dosing of anticoagulation agents straight with so many factors involved can be complicated. “You can’t know everything about everything, and I think we all need to recognize our limitations in that way,” Dr. Atzema said. “I tell my colleagues, just tell cardiology if you’re not sure.” Dr. Atzema also advises physicians to encourage patients to go to one regular pharmacist. “They know all the drugs you’re taking and they can check for any interactions,” she said. “It’s nice if we can do that as well but we’re not pharmacists.” Read: Be ready to recognize and manage ACEI-induced angioedema Dr. Atzema often encounters patients with AF who take a baby Aspirin (81 mg acetylsalicylic acid [ASA]) as primary prevention for CAD. “Those patients can stop the Aspirin because if you do Aspirin plus a DOAC that’s dual antiplatelets, and there’s a big increase in the risk of bleeding,” she said. For patients with AF and existing CAD, the recommendations differ depending on the seriousness of the disease. Dr. Mitchell said, “The vast majority of people with CAD are stable and we recommend that anticoagulation alone is OK.” People with AF and unstable CAD, or people who have had a percutaneous coronary intervention (PCI), benefit from dual therapy (i.e., DOAC plus clopidogrel). Dual therapy is only recommended for a short time (e.g., from one month to a year), Dr. Mitchell said. If a person continues to have unstable CAD, then triple therapy (i.e., OAC plus clopidogrel plus ASA) is recommended, but for only about a month, Dr. Mitchell said. He suggested a consult with an interventional cardiologist about switching from triple to dual therapy. People with AF and other cardiac complications also often benefit from anticoagulation, Dr. Mitchell said. This includes people with hypertrophic cardiomyopathy or congenital heart disease. The 2020 CCS guidelines have new recommendations for anticoagulation in patients with AF and chronic kidney disease and renal failure. While the CCS guidelines have a table with dosing recommendations for these patients, consulting a specialist may be best. Read: Untreated chronic diseases escalate in Canada during COVID-19 pandemic “My advice for family doctors and to emergency physicians is that if you have someone with significant renal failure, refer them to someone else to manage or at least set up a schedule,” Dr. Atzema said. “It gets very difficult to follow. It’s complex, and family doctors and emergency physicians have a multitude of other health issues to deal with and stay on top of,” she said. 5. Be aware of changing guidelines It is up to the family physician to follow new recommendations and the changing condition of their patient. The cardiologist isn’t paying attention to the day-to-day management of anticoagulation, Dr. Mitchell said. “It’s the longitudinal bits that we rely on family doctors for,” he said. Some Canadian-led studies are underway that could answer how best to prevent stroke in certain populations of patients with AF. Their results may change current guidelines. The OCEAN (Optimal Anticoagulation for Higher Risk Patients Post-Catheter Ablation for Atrial Fibrillation Trial) will shed light on whether patients have to stay on anticoagulants following successful ablation therapy. It compares antiplatelet therapy (ASA 75 to 160 mg) to a DOAC (rivaroxaban 15 mg) for preventing cerebral embolic events following successful catheter ablation for AF. Currently, patients have to stay on anticoagulants indefinitely. Results are expected in 2024. ARTESiA (Apixaban for the Reduction of Thrombo-Embolism in Patients with Device-Detected SubClinical Atrial Fibrillation) will help determine if anticoagulation is needed to prevent stroke in patients with mild AF. It compares treatment of ASA (81 mg) or apixaban (2.5 mg to 5 mg twice a day) in patients where AF was detected using a device (i.e., sub-clinical). More than 4,000 patients have been recruited and results are expected next year. A smaller study is investigating warfarin versus apixaban in patients with AF receiving dialysis. The results of SAFE-D (Strategies for the Management of Atrial Fibrillation in Patients Receiving Dialysis) are expected in 2022 or 2023. Read: Ginkgo biloba suspected to increase risk of cardiac arrhythmias

All about anticoagulation with AF

Register for free access or login.

Related Topics