Aspirin Still Wrongly Given to Lower Afib Stroke Risk

For your doctor.
http://www.medpagetoday.com/Cardiology/Arrhythmias/58683?

Nearly 40% of patients on aspirin instead of oral anticoagulant

• by Salynn Boyles
  Contributing Writer

• This article is a collaboration between MedPage Today® and:
  

Action Points

• About 40% of cardiac outpatients with atrial fibrillation (AF) with a moderate to high risk of stroke were treated with aspirin alone without an oral anticoagulant (OAC), according to data from the large, real-world ACC PINNACLE Registry.
• Note that there is now good evidence that aspirin is not an anticoagulant, and that it does not prevent stroke due to atrial fibrillation.

Well over one-third of atrial fibrillation patients who have a moderate to high risk for stroke are prescribed aspirin to lower this risk instead of oral anticoagulants, even though aspirin has no benefit for the prevention of Afib-related thromboembolism, researchers reported.
Their newly published analysis of data from the American College of Cardiology's PINNACLE registry involving Afib patients found that close to 40% of patients were treated with aspirin alone instead of an oral anticoagulant.
After multivariable adjustment, it was determined that patients prescribed aspirin were also more likely to have other risk factors for cardiovascular disease than those prescribed an oral anticoagulant, Jonathan C. Hsu, MD, of the University of California San Diego, and colleagues wrote in the Journal of the American College of Cardiology.
"These data indicate a gap in care, most prominent in patients with or at risk for coronary artery disease, and it should draw attention to a high rate of prescription of aspirin therapy in atrial fibrillation patients at risk for stroke, despite previous data that show aspirin to be inferior to oral anticoagulants in this population," the researchers wrote.
Cardiologist Samuel Wann, MD, of St. Mary's Hospital in Milwaukee, said the finding is especially concerning because the PINNACLE registry includes highly motivated patients and cardiologists. Wann co-wrote an editorial published with the study.
"There is good evidence now that aspirin is not an anticoagulant, and that it does not prevent stroke due to atrial fibrillation," he told MedPage Today. "We may have thought that years ago, but not anymore."
The study included two cohorts of atrial fibrillation outpatients with a moderate to high thromboembolic risk (CHADS₂ score ≥2 and CHA₂D₂-VASc ≥2) enrolled in the PINNACLE registry between 2008 and 2012.
In one cohort of close to 210,400 patients with CHADS₂ scores ≥2 on antithrombotic therapy, 38.2% were treated with aspirin alone and 61.8% were treated with warfarin or a non-vitamin K antagonist oral anticoagulant. In a second cohort of close to 300,000 patients, with CHA₂DS₂-VASc scores ≥2, 40.2% were treated with aspirin alone and 59.8% were treated with an oral anticoagulant.
After multivariable adjustment, hypertension, dyslipidemia, coronary artery disease, prior heart attack, unstable and stable angina, recent coronary artery bypass graft, and peripheral arterial disease were all associated with a higher incidence of aspirin prescriptions.
Male sex, higher body mass index, prior stroke/transient ischemic attack, embolism history, and congestive heart failure were associated with more frequent prescription of an oral anticoagulant.
"The specific patient characteristics associated with (aspirin prescribing), including those related to coronary artery disease, highlight opportunities to improve appropriate prescription of oral anticoagulants in atrial fibrillation, including identifying knowledge gaps that might be informed by future studies," the researchers wrote.
In their editorial, Wann and St. Mary's Hospital colleague Sanjay Deshpande, MD, wrote that while the American College of Cardiology/American Heart Association still "give tepid support" to the use of aspirin in patients with a low risk for stroke (CHA₂DS₂-VASc ≤1), other guidelines, including those from the European Society of Cardiology and NICE in the United Kingdom, no longer recommend aspirin for Afib-related thromboembolism prevention.
"This variance from guidelines does not appear to be related to true contraindication to anticoagulation, but may reflect a lack of appreciation that aspirin administration places a patient at significant risk for bleeding, while offering virtually no protection from stroke," they wrote.
They concluded that greater awareness of aspirin's lack of benefit for reducing Afib-related stroke risk is needed among both physicians and patients.
"'Take two aspirin and call me in the morning' is not appropriate treatment for a patient with atrial fibrillation at risk for thromboembolism," they wrote. "The clot only thickens."