Characteristics and antithrombotic treatment patterns of patients with concomitant coronary artery disease and atrial fibrillation from Thailand’s COOL-AF registry

Concomitant coronary artery disease (CAD) and atrial fibrillation (AF) are common in clinical practice. The aim of this study was to investigate the characteristics and antithrombotic treatment patterns of patients with concomitant CAD and AF from the COhort of antithrombotic use and Optimal INR Level in patients with non-valvular atrial fibrillation in Thailand (COOL-AF Thailand) registry.

Registry enrollment criteria included patients aged ≥ 18 years who were diagnosed with AF for any duration at any of 27 public hospitals located across Thailand during 2014–2017. The That Clinical Trials Registry study registration number is TCTR20160113002. Statistical comparisons of characteristics and treatment strategies were performed between patients with and without CAD.

Of a total of 3461 AF patients, 557 had concomitant CAD (16.1%). Patients with concomitant CAD and AF were significantly older, more likely to be male, had more comorbidities, and had more cardiovascular implantable electronic devices. History of stroke/transient ischemic attack and prior bleeding was not significantly different between groups. CHA₂DS₂-VASc score and HAS-BLED score were both higher in patients with CAD than in patients without CAD (4.17 vs. 2.78, p < 0.001, and 2.01 vs. 1.45, p < 0.001, respectively). Utilization of oral anticoagulant was less in patients with CAD (76.0% vs. 84.3%, p < 0.001). Concomitant use of antiplatelet was found to be a major cause of oral anticoagulant (OAC) underutilization. Specifically, the rate of OAC prescription was 95.9% in patients without antiplatelet, and 43.7% in patients with antiplatelet. Among patients with CAD who were on OAC, the rate of concomitant antiplatelet prescription was still high. In this group, 63% of patients were on triple therapy when percutaneous coronary intervention (PCI) with drug eluting stent was performed within 1 year, and 32.2% of patients without prior PCI or acute coronary syndrome were taking at least one antiplatelet with OAC.

Among patients with concomitant CAD and AF, physicians were reluctant to discontinue antiplatelet. The use of antiplatelet discourages physicians from prescribing OAC. Underutilization of OAC may increase the risk of ischemic stroke, and an inappropriate combination of OAC and antiplatelet may increase the risk of bleeding.