Mechanisms of ST-segment elevation myocardial infarction in patients with atrial fibrillation, prior stenting and long-standing chronic coronary syndrome.

BACKGROUND: The optimal antithrombotic regimen for patients with atrial fibrillation (AF) and chronic coronary syndromes beyond 1 year after percutaneous coronary intervention (PCI) is a matter of debate. For these patients, guidelines recommend oral anticoagulation (OAC) alone, but the risk of thrombotic complications remains a concern. The aim of this study was to characterize the incidence, presentation and use of antithrombotic therapy in patients with AF, prior stenting > 12 months and new ST-segment elevation myocardial infarction (STEMI). METHODS: Consecutive patients were selected from an institutional registry over a 3-year period if they matched the following criteria: 1) STEMI undergoing primary PCI; 2) AF; 3) chronic coronary syndrome with prior stenting > 12 months. RESULTS: Among 852 consecutive STEMI patients undergoing primary PCI, the prevalence of AF was 4.1%, and 6 (0.9%) patients met all the inclusion criteria. Substantial heterogeneity in antithrombotic treatment for these patients was noted (e.g., OAC alone, OAC plus a single antiplatelet agent, no antithrombotic therapy). In 50% of patients, the STEMI episode was linked to a previously stented lesion or documented plaque. CONCLUSIONS: This case review illustrates the wide heterogeneity in antithrombotic pharmacotherapy among AF patients presenting with STEMI > 12 months after PCI. The underlying reason for STEMI is only partly related to disease progression or stent-related events. This finding suggests that multiple mechanisms of recurrence may be advocated, and are not only limited to antithrombotic therapy but may be explained by the natural history of coronary artery disease in remote vessels.