Adults with myocardial infarction (MI) who also have atrial fibrillation (AFib) are at risk of a recurrent ischemic event, but a minority of these patients receive antiplatelet and anticoagulant therapy for the guideline-recommended duration, according to a study published Dec. 21 in Circulation: Cardiovascular Interventions.

Using data from ACC’s Chest Pain – MI Registry, Alexander C. Fanaroff, MD, MHS, et al., looked at the incidence of recurrent ischemic events over a median of seven years among patients ages 65 years and older with MI and AFib to identify factors associated with recurrent MI or PCI and the need for extended antiplatelet/anticoagulant therapy. The researchers also looked at patterns of long-term antithrombotic therapy following recurrent ischemic events. Outcomes included all-cause mortality; readmission for MI, stroke or bleeding; and repeat inpatient or outpatient PCI. Pharmacy data were used to determine the percentage of patients who filled prescriptions for oral anticoagulants (OACs) and P2Y12 inhibitors for at least 50% of the recommended duration following MI or PCI.

The study population included 187,622 patients with MI treated at 854 hospitals between 2008 and 2017. Of these, 50,539 (26.9%) had AFib and 49,889 (98.7%) had an AFib diagnosis before the MI admission, while 650 patients (1.3%) developed AFib during hospitalization. Patients with AFib were older than those without (median age, 78 vs. 74 years) and were more likely to have prior MI or heart failure, hypertension, hyperlipidemia, diabetes, cerebrovascular and peripheral artery disease, and end-stage renal disease requiring dialysis.

Among AFib patients, cumulative incidence was 68.8% for all-cause mortality, 14.5% for recurrent MI, 12.1% for PCI, 7.9% for stroke and 9.5% for hospitalization for major bleeding. Patients with AFib had higher mortality and a greater risk of stroke and bleeding-related rehospitalization vs. those without AFib. Factors at discharge associated with recurrent MI or PCI included three-vessel coronary artery disease, prior CABG and diabetes.

Pharmacy data were available for 30,221 patients with AFib (59.8%). Only 1% of these patients filled prescriptions for OACs and P2Y12 inhibitors for the entire guideline-recommended duration, while 10.3% filled prescriptions for at least half of the recommended duration. Among the remaining patients, 88.8% received antiplatelet/anticoagulant therapy for a shorter duration or received only an OAC or a P2Y12 inhibitor. In addition, 76.4% did not receive both an OAC and a P2Y12 inhibitor during the timeframe both medications are recommended.

According to the researchers, “only a minority of patients with MI with AF[ib] are treated with antiplatelet and anticoagulant therapy for the duration recommended by practice guidelines” despite the greater risk of recurrent ischemic events requiring antiplatelet/anticoagulant therapy. The findings “highlight the need for better strategies to improve outcomes in this high-risk group of patients,” they conclude.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Cardiac Surgery, Cardiovascular Care Team, Invasive Cardiovascular Angiography and Intervention, Prevention, Atherosclerotic Disease (CAD/PAD), Anticoagulation Management and Atrial Fibrillation, Atrial Fibrillation/Supraventricular Arrhythmias, Aortic Surgery, Cardiac Surgery and Arrhythmias, Interventions and Coronary Artery Disease, Hypertension

Keywords: Chest Pain MI Registry, National Cardiovascular Data Registries, Platelet Aggregation Inhibitors, Coronary Artery Bypass, Diabetes Mellitus, Chest Pain, Hypertension, Prescriptions, Registries, Myocardial Infarction, Stroke, Anticoagulants, Patient Readmission, Patient Discharge, Coronary Artery Disease, Percutaneous Coronary Intervention, Fibrinolytic Agents, Atrial Fibrillation

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