Atrial fibrillation (AF) and coronary artery disease are both common cardiovascular diseases that share certain risk factors, such as diabetes mellitus and hypertension. In addition, certain clinical conditions in coronary artery disease, such as myocardial infarction and heart failure, are also risk factors for AF. Therefore, coronary artery disease is one of the most common complications of atrial fibrillation, and about 20% to 30% of patients with atrial fibrillation have a combination of coronary artery disease in clinical practice. Clinicians are often faced with the dilemma of dealing with the coexistence of these two diseases. Atrial fibrillation requires oral anticoagulants (mainly warfarin) to reduce ischemic stroke, whereas in patients with coexisting coronary artery disease, especially those requiring percutaneous coronary intervention (PCI) or suffering from acute coronary syndrome (ACS), long-term antiplatelet therapy is required to reduce coronary events. Therefore, balancing the risk of stroke and bleeding in such patients becomes a real topic. Previously, antithrombotic therapy for atrial fibrillation alone, or anticoagulation for ACS/PCI, had guidelines in their respective fields to guide clinical practice. None of these guidelines, however, addressed anticoagulation protocols for patients with AF combined with coronary artery disease. For this reason, the European Society of Cardiology (ESC), the European HeartRhythmAssociation (EHRA), and the European Association of Percutaneous Cardiovascular Interventions (EAPCI) have developed guidelines for anticoagulation in patients with ACS/PCI. The EuropeanAssociationofPercutaneousCardiovascularIntervention (EAPCI) has jointly developed an expert consensus on anticoagulation in patients with atrial fibrillation combined with coronary artery disease or PCI based on the published literature. The guidelines cover antithrombotic agents such as warfarin, aspirin, clopidogrel, platelet glycoprotein IIb/IIIa receptor antagonist (GPI), and bivalirudin; the risk of stroke, bleeding, and other factors such as the site of the punctured vessel, the risk of in-stent thrombosis, and the risk of stroke (Table 1). The recommendations were developed for factors such as the site of the punctured vessel, risk of in-stent thrombosis, risk of stroke, and risk of bleeding (Table 1). This recommendation is summarized in Table 2, as follows. (1) For elective PCI in patients with atrial fibrillation, bare metal stents should be used when possible. The use of drug-eluting stents is limited to certain specific conditions, such as long lesions, small vessel lesions, and combined diabetes mellitus. When using bare metal stents, triple antithrombotic therapy is required for the first 4 weeks, i.e. warfarin (maintenance INR 2.0-2.5) + aspirin (≥100 mg/d) + clopidogrel (75 mg/d). For months 2 to 12, warfarin + clopidogrel (or aspirin) was used. When using aspirin, proton pump inhibitors (PPI) may be used as appropriate to prevent gastrointestinal bleeding. (2) When using drug-eluting stents, rapamycin-eluting (sirolimus) stents, triple antithrombotic needs to be used for 3 months; in case of paclitaxel-eluting (paclitaxel) stents, it needs to be used for 6 months. Use PPI to protect the gastrointestinal tract as appropriate. (3) For patients at moderate to severe risk of thromboembolism, warfarin should not be discontinued and INR should continue to be maintained at 2.0 to 3.0. Radial artery should be chosen as the puncture vessel as much as possible. (4) For patients at high risk of thromboembolism, if warfarin needs to be discontinued for more than 48 hours, heparin replacement is required. Subcutaneous injection of low-molecular heparin (dalteparin or enoxaparin) may also be used as a substitute. However, when heparin or low-molecular heparin is administered, although warfarin is discontinued, its effect is still present (it lasts 3 to 5 days) and therefore may contribute to an increased risk of bleeding. A more feasible option is to discontinue warfarin for a short period of time and allow the INR to fall to the lower limit of the therapeutic range before PCI is safer. (5) When warfarin is used in combination with antiplatelet agents, special care should be taken to adjust the dose so that the INR is maintained at 2.0-2.5. Non-ST-segment elevation ACS (1) Dual antiplatelet therapy, i.e. aspirin + clopidogrel, is recommended for all patients with non-ST-segment elevation ACS, whether or not PCI is performed. If combined with atrial fibrillation and high risk of stroke, warfarin is added. (2) If emergency PCI is performed, aspirin + clopidogrel + heparin (either regular heparin or low molecular heparin) is often used first. Heparin can also be replaced by bivalirudin. In addition, GPI may be added as appropriate, at which point warfarin must be discontinued. Bivalirudin or GPI should also be used only if the INR does not exceed 2. It is recommended that bare metal stents be used as much as possible during PCI. Drug-eluting stents are limited to certain specific conditions, such as long lesions, small vessel lesions, and combined diabetes mellitus. However, in patients with AF at high risk of thromboembolism, it is best not to stop warfarin, even if the INR is still as high as 2.0 to 3.0, as long as the radial artery route is used, it is still safe. (3) In patients with low risk of bleeding, triple antithrombotic therapy needs to be used for 3 to 6 months. For patients at high risk of thromboembolism, a combination of warfarin + clopidogrel for 12 months is required. If clopidogrel cannot be used, aspirin 75-100 mg/d is used instead. PPI, H2 receptor antagonist or antacid can be added to protect the gastrointestinal tract. (4) If warfarin needs to be combined with clopidogrel or low-dose aspirin, adjust the dose of warfarin very carefully so that the INR is maintained at 2.0-2.5. Direct PCI for acute ST-segment elevation myocardial infarction (STEMI) (1) When patients with atrial fibrillation presenting with acute STEMI undergo direct PCI, aspirin + clopidogrel + heparin (mostly plain heparin) is usually used first. If the intracoronary thrombus load is high, GPI (commonly abciximab) may be added. If heparin and GPI are not available, bivalirudin may be used instead. Intraoperative aspiration catheters may also be used for thrombus aspiration. In this case, warfarin should be discontinued. When INR exceeds 2, GPI and bivalirudin should not be used. (2) The principle of intraoperative heparin dosage is to maintain activated clotting time (ACT) of 200-250 seconds in patients who are also using GPI and 250-300 seconds in patients who are not using GPI. (3) It is recommended that radial artery be preferred as the vascular pathway for PCI. (4) For patients with low risk of bleeding, triple antithrombotic therapy needs to be used for 3 to 6 months. For patients at high risk of thromboembolism, a combination of warfarin + clopidogrel for 12 months is required. If clopidogrel is not available, aspirin 75-100 mg/d is substituted, and a PPI may be added to protect the gastrointestinal tract. Antithrombotic strategy for patients with high bleeding risk (1) Radial artery route is preferred for PCI vascular pathway when INR is 2.0 to 3.0. For non-ST-segment elevation ACS, enoxaparin can also be replaced by fondaparinux. (2) Heparin + GPI can be replaced with bivalirudin. (3) The triple antithrombotic regimen should not be used for too long; drug-eluting stents are limited to certain specific conditions, such as long lesions, small vessel lesions, and combined diabetes mellitus. In the case of bare metal stents, triple antithrombotic use for 2 to 4 weeks is sufficient. In the case of drug-eluting stents, triple antithrombotic use is required for 3 to 6 months. This is followed by oral warfarin alone. To shorten the duration of antiplatelet agents, second- or third-generation drug-eluting stents may be considered. For some selected patients with a high risk of cardiovascular events, clopidogrel (75 mg/d) can be added to oral warfarin. Other conditions of combined coronary artery disease in patients with atrial fibrillation (1) For patients with stable vascular disease, only oral warfarin is required. It is not necessary to add antiplatelet agents to warfarin. (2) Patients younger than 65 years of age with no organic heart disease, isolated atrial fibrillation, and a CHADS2 score of 0 are at low risk of thromboembolism. For such patients, if PCI is desired, conventional antiplatelet therapy is sufficient. (3) After the development of ACS, dual antiplatelet therapy with aspirin + clopidogrel is required for 12 months, regardless of whether PCI is performed. After that, aspirin alone is sufficient. Conclusion The 2009 ESC/EHRA/EAPCI Expert Consensus on periprocedural anticoagulation in atrial fibrillation combined with ACS or PCI is the first guideline to focus on both atrial fibrillation and antithrombotic therapy for coronary artery disease. Since there are not many clinical trials for this specific population, there is certainly room for improvement of this guideline. As more relevant clinical evidence becomes available in the future, it is believed that the guideline will be improved in the course of future revisions.