Inappropriate Use of Oral Antiplatelet Drugs

JB is a 78-year-old man with a history of paroxysmal atrial fibrillation (AF), hypertension, hyperlipidemia, and degenerative joint disease of the spine and hips necessitating the use of a cane. He comes to you, his primary care physician, for a follow-up visit after consulting with a cardiologist in the emergency department.

JB previously was taking warfarin for stroke prevention, but he was switched to the direct oral anticoagulant (DOAC) apixaban (Eliquis) after several episodes of epistaxis associated with an elevated international normalized ratio. He was doing well until 1 month ago, when he had to go to the emergency department with multiple contusions after a fall. He did not have a head injury, and results of computed tomography of the brain were normal. He was instructed by the emergency department physician to continue the apixaban and to follow up with you.

You have a detailed shared decision-making discussion with JB, including a review of his CHA₂DS₂-VASc (congestive heart failure, hypertension, age 75 years or older, diabetes, stroke/transient ischemic attack/thromboembolism, vascular disease, age 65–74 years, sex category) score and estimated risk of embolic stroke. You decide to discontinue apixaban because the bleeding risk outweighs the benefits. JB tells you that the cardiologist who consulted in the emergency department suggested that JB could take aspirin or clopidogrel instead of apixaban. He asks you about that today.

Epidemiology

Antiplatelet use has risen substantially in the past 2 decades in response to American Heart Association/American Stroke Association guidelines that recommend antithrombotic therapy for nearly all patients without contraindications after an ischemic stroke.¹ Each year, approximately 795,000 people in the United States experience a stroke, 87% of which are ischemic.² There has been a significant reduction in stroke risk due to improved blood pressure control and use of antiplatelet therapy.¹

AF is the most common arrhythmia, affecting approximately 2.7 million Americans. Incidence increases with age, affecting up to 10% of all individuals older than 80 years.³ AF is one of many modifiable risk factors for acute stroke, with a risk between 1% to 20% annually, and it is one of the leading causes of cardiac morbidity and mortality.² Due to the aging population and increasing prevalence of risk factors, such as hypertension, obesity, and diabetes, the incidence of AF is increasing, with an estimated 160,000 new cases diagnosed each year.^2,3

Antiplatelet drugs include aspirin, oral thienopyridines (eg, clopidogrel, ticagrelor [Brilinta], prasugrel), and phosphodiesterase 3 inhibitors (eg, cilostazol, dipyridamole).⁴ Since aspirin is available over the counter, patients have often used it for prevention regardless of evidence-based indications.⁵ The use of aspirin for primary prevention of cardiovascular disease (CVD) is controversial. In individuals without CVD, aspirin has been associated with a lower risk of cardiovascular events but with an increased risk of major bleeding.^6,7 Factors associated with increased bleeding risk include advanced age, recent falls, history of bleeding, chronic anemia, chronic kidney disease, and female sex.

Antiplatelet drugs are used despite many contraindications, including a history of intracerebral hemorrhage, esophageal varices, and thrombocytopenia.⁸ Guidelines recommend baseline and ongoing assessment of bleeding risk and kidney function in patients taking antiplatelet drugs, as well as discontinuation 5 to 7 days before surgical procedures.^4,9