As a primary care physician (PCP), you’re often the first healthcare professional that will identify cardiac issues, including atrial fibrillation (AF).
Individuals with AF face a fivefold risk for stroke. Therefore, these patients are often prescribed blood-thinning medications (anticoagulants) to slow blood clotting, according to the American Society of Hematology (ASH).
Up to six million Americans have AF, the risk for which increases with age. The ASH says there are 450,000 hospitalizations each year because of AF.
It’s very important to check on your patient’s response within the first few months of taking blood thinners. In fact, patients with AF who took low doses of oral anticoagulants experienced a higher incidence of bleeding episodes during the first 3 months of treatment, according to a study published in Blood Advances.
When Should PCPs Prescribe Anticoagulants?
PCPs should consider prescribing oral anticoagulants when they are the principal caregivers for patients with AF, acute deep venous thrombosis, or acute pulmonary embolism, according to R. Michael Benitez, MD, a cardiologist at the University of Maryland Medical Center and a professor of medicine in the Division of Cardiovascular Medicine at the University of Maryland School of Medicine in Baltimore.
The decision to prescribe an oral anticoagulant must be based upon the patient’s risk without anticoagulation weighed in context with the patient’s risk for significant bleeding, he said.
How Can Physicians Best Communicate the Rationale for Anticoagulant Therapy?
When describing AF, PCPs can explain to patients that the upper chamber of heart is “wiggling” and not effectively contracting and when blood is not being effectively moved forward, it tends to clot, said Benitez.
Physicians can also share that a clot as small as 2 mm is large enough to cause a major stroke if it were to break loose from the inside of the top chamber and be pumped with the blood to the brain, suggested the cardiologist.
“The oral anticoagulant greatly reduces the risk of the formation of these blood clots and subsequent stroke,” Benitez said. “Stroke is a terrible event that, if survived, often changes a patient’s life permanently and significantly. In the setting of atrial fibrillation, anticoagulation greatly reduces the patient’s risk of stroke.”
Regarding deep venous thrombosis, physicians can explain that a blood clot in the leg veins could break loose and be pumped through the right side of the heart to the lungs. “This event, pulmonary embolism, can cause critical illness or even death; the risk can be greatly reduced through the use of oral anticoagulants,” said Benitez.
What Are Important Directives Regarding Usage?
PCPs should stress that daily use is critical to the success of the drug in preventing stroke. “In the case of the new direct oral anticoagulants, such as apixaban or rivaroxaban, the drugs both work very quickly but also wear off very quickly,” said Benitez. “This means that even missing just 2-3 days is enough for the blood to again clot normally. It is essential that the drugs be taken daily to prevent stroke.”
In the case of warfarin, the effect of the drug is more prolonged. While missing a single dose is unlikely to markedly change the degree of anticoagulation, it’s still best to remind patients not to miss doses and take this daily as prescribed, according to Benitez.
What Side Effects Should Be Discussed?
It is extremely important with warfarin — and to a lesser degree with direct oral anticoagulants — to always make certain that there is no drug-drug interaction that might affect the degree of anticoagulation when new medications are introduced, such as antibiotics, said Benitez.
Other side effects to bring to a patients’ attention are minor bleeding (such as gum bleeding with dental flossing) or nose bleeds that stop easily, which don’t require immediate medical attention. However, your patients should self-monitor bleeding episodes and know a course of action if injured.
“If bleeding will not readily stop then medical attention is needed, and patients who incur major injury or trauma are likely to be taken to an emergency facility where it is important for the staff caring for them to know what anticoagulant they are taking, the dose, and when they last took it,” Benitez said. “Reversal agents are now available to normalize blood clotting.”
Your patients may be concerned with food that could interact with these medications. Benitez said there are no significant food interactions or dietary restrictions. But when prescribing warfarin, some nutritional guidance is warranted.
“With warfarin, which is a vitamin K antagonist, it is essential that the patient limit their intake of food containing vitamin K, as it is essentially an antidote or reversal agent for the anticoagulant,” he said.
Some sources of vitamin K are well-known, such as leafy vegetables like spinach, kale, and other greens. However, there are many other dietary sources rich in vitamin K that may not be as obvious, such as cauliflower and soy products, Benitez said.
“It is important for the patient to familiarize themselves with vitamin K-containing foods and to keep the intake of them low and steady from day to day if they are taking warfarin,” he said.