CHoosing Triple or Double therApy in the Era of nOac for patientS Undergoing PCI: the CHAOS a Multicenter Study.

INTRODUCTION: About 6-8% of patients undergoing PCI have an indication for long-term oral anticoagulants (OACs) due to various conditions such as atrial fibrillation (AF), mechanical heart valves, or venous thromboembolism. The addition of single or double antiplatelet therapy to OACs therapy results in an increase in bleeding complications (1-4). The standard of care of management in this patients, indicated by 2017 ESC focused update on dual antiplatelet therapy in coronary artery disease (5), recommends the use of a triple therapy (Aspirin, clopidogrel and OAC) for 1-6 months (depending on the ischemic and hemorrhagic risk), then continue with double therapy only up to twelve month (Aspirin or clopidogrel and OAC) and after twelve months continue with the OAC only; the use of prasugrel or ticagrelor as part of triple therapy should be avoided (6). Only RELY study enrolled a small number of patients, less than one thousand, treated with dabigatran plus DAPT. Moreover, In the recent RCTs (WOEST(7), PIONEER AF-PCI study(8) and REDUAL-PCI(9)) only the double therapy (Aspirin or Clopidogrel/ticagrelor and DOAC) against triple therapy with warfarin was tested; and furthermore patients enrolled in RCTs represent only a small and not always representative sample of people treated in everyday clinical practice, who report a large burden of comorbidities and an older age. Randomized head to head comparison of warfarin and DOACs life-long (over 12 months from the PCI) have not been performed yet with clinical events as end points.

AIMS: Aim of the present study is to describe the contemporary management of patients who underwent a PCI and have an indication to OAC for AF evaluating the different types of combination therapies used (triple therapy with warfarin or with DOAC, single anti-platelet therapy plus warfarin or DOAC) and their management in the first year after a PCI in a "real-life" setting. Secondary we would also evaluate the safety (in term of bleedings) and the efficacy (in term of ischemic and cardioembolic events) of the use of the different combination of single or double antiplatelet with OACs, in patients with coronary artery disease.

MATERIALS AND METHODS: This is a retrospective, multicenter study including patients presenting with coronary artery disease (acute or stable setting) undergoing to PCI, in single or double antiplatelet therapy (aspirin, clopidogrel, ticagrelor, prasugrel, aspirin and clopidogrel, aspirin and ticagrelor, aspirin and prasugrel) with an indication to anticoagulant therapy (warfarin, dabigatran, rivaroxaban, edoxaban). The different groups will be compared with a propensity score analysis with matching.

Primary (efficacy) end-points:

• A composite end points including death, myocardial infarction, stent thrombosis, revascularization stroke (MACE).
• A composite end points including death, myocardial infarction, stent thrombosis, revascularization, stroke and BARC [Bleedings according to the Bleeding Academic Research Consortium] 2,3,5 (7,8): all events mutually exclusive (NACE).

Secondary end-points: Individual components of NACE; Cardiac death; Stroke; Target vessel revascularization (TVR) and non TVR and the number of the revascularization.