Pharmacological therapy following acute coronary syndromes in patients with atrial fibrillation: how do we balance ischaemic risk with bleeding risk?

BACKGROUND: Dual anti-platelet therapy (DAPT) with aspirin and a P2Y12receptor antagonist is standard of care following an acute coronary syndrome (ACS), as it has been shown to reduce recurrent myocardial infarction (MI) and death. In atrial fibrillation (AF) patients, the use of oral anticoagulants (OACs) is the standard of care as these agents have been shown to reduce the risk of stroke and death. Current guidelines suggest that decisions around antithrombotic therapy should be made by assessing ischaemic and bleeding risks. The aim of this study was to examine current pharmacotherapy of AF inpatients with ACS.

METHODS: We prospectively enrolled ACS patients being managed invasively with a medical history of AF, or those in AF during admission ECG, from the pre-existing Wellington ACS registry. Enrolment criteria included pre-treatment on DAPT. Demographics, clinical characteristics, management, in-hospital outcomes and discharge medications were recorded.

RESULTS: At discharge, only 11.8% of AF patients were prescribed an OAC and this was not related to risk of stroke (CHA2DS2-VASc score), bleeding (CRUSADE score) or any other clinical characteristics. However, discharge OAC use was associated with whether the patient was treated with an OAC at admission (OR 14, CI 3.4-58, p=0.001). DAPT was the default discharge treatment and occurred in 72% of AF patients. A moderate correlation between stroke risk and bleeding risk was identified (rs=0.68, p=0.01). A group of 44 (47%) patients were identified who were at high risk of stroke (CHA2DS2-VASc ≥2) and low risk of bleeding (CRUSADE score ≤30).

CONCLUSION: At discharge we observed a very low rate of OAC prescription. Despite most AF patients being high risk for stroke, DAPT was the preferred treatment option. Our data suggests there is a group of patients with high stroke risk and relatively low bleeding risk, in who OAC use may be appropriate. Developing a guideline to assist clinicians in targeting this group of patients may help improve outcomes in AF patients following MI.