NSTEMI - Non-ST-Segment Elevation Myocardial Infarction

The aim of the study is to compare clinical outcomes between direct oral anticoagulant (DOAC) monotherapy versus dual antithrombotic therapy (DOAC plus clopidogrel) in patients with atrial fibrillation and acute myocardial infarction after percutaneous coronary intervention (PCI).

Acute coronary syndromes (ACS) are frequently associated with multivessel coronary artery disease (CAD), and current guidelines recommend complete revascularization beyond the culprit lesion. Angiography-guided PCI is the standard approach, but anatomical assessment does not always reflect the functional significance of intermediate lesions, while FFR-guided strategies are limited by the need for pressure wires and hyperemia. Murray-law-based quantitative flow ratio (μFR) is a wire-free angiography-derived physiological index that may improve decision-making for revascularization in ACS patients. The Core-μFR is an investigator-driven, multicenter, randomized, open-label and prospective trial designed to evaluate whether μFR can act as a gatekeeper for complete revascularization in patients with ACS and multivessel disease by identifying non-culprit lesions that truly require PCI. Patients with ACS (either STEMI or NSTE-ACS) undergoing primary PCI will be considered eligible if they present multivessel CAD on visual assessment with the intention to treat the non-culprit vessel in a staged procedure within the same hospitalization. After the pPCI, eligible patients will be randomized to either group A or group B and μFR will be performed in a blinded fashion with the operator unaware of the functional result. Patients in group A will undergo a staged PCI of all NCVs guided by coronary angiography, as per standard of care. In group B, μFR will be used as a gatekeeper for staged revascularization. Operators will only be informed whether at least one non-culprit vessel is μFR-positive, without disclosure of the specific vessel involved or the μFR values. If at least one non-culprit vessel has μFR ≤0.80, patients will undergo angiography-guided PCI of all non-culprit vessels previously deemed suitable for treatment by visual assessment. If μFR is \>0.80 in all non-culprit vessels, staged PCI will be deferred and the patient will be discharged without further revascularization. Finally, to test the functional reproducibility, a blinded post-hoc μFR assessment will be performed on the baseline angiograms of the staged procedures in all the patients undergoing complete revascularization. Clinical follow-up will be performed at 30 days and 1 year from randomization.