Essence of this Article
Patients with indications for oral anticoagulants who are scheduled to undergo percutaneous coronary intervention with stent placement will also require standard antiplatelet therapy. Data on the optimal management of anticoagulation in these patients are currently limited. An important consideration when treating patients undergoing these procedures is to balance the benefit of thromboprophylaxis with the risk of bleeding.
Anticoagulation with primary percutaneous coronary intervention and stent placement in patients with atrial fibrillation
Percutaneous coronary intervention (PCI) with stent placement is a well-established method of reperfusing occluded cardiac vessels in patients with acute coronary syndrome (ACS).524 Between 20 and 30% of patients with atrial fibrillation (AF) have concomitant coronary artery disease and thus may have to undergo PCI with stent placement. Patients with AF and one or more risk factors for stroke require long-term oral anticoagulation.525 Moreover, patients undergoing PCI with stent implantation are recommended to receive periprocedural anticoagulation and dual antiplatelet therapy for at least 12 months after implantation to reduce the risk of stent thrombosis.524, 526 Concurrent AF, ACS and stent placement represents a serious treatment challenge527 because achieving a balance between preventing ischaemic complications and avoiding major bleeding events is difficult. Patients with AF who are hospitalized for myocardial infarction have a 32% higher risk of in-hospital death than those without AF.528 There is a paucity of studies involving patients with AF and ACS who undergo PCI, leading to uncertainty over the optimal antithrombotic treatment of these patients.529 In the absence of robust data, guidelines based on expert opinion recommend a period of triple therapy. This consists of initial oral anticoagulation (dose-adjusted vitamin K antagonist [VKA] or a novel oral anticoagulant) plus dual antiplatelet therapy (acetylsalicylic acid [ASA] and clopidogrel), followed by oral anticoagulation plus mono antiplatelet therapy, and finally, after 1 year, oral anticoagulation alone in stable patients.525, 530 A recently published guidance consensus document provides updated recommendations on the efficacy and safety of novel oral anticoagulants compared with VKA for triple therapy after coronary artery stent placement in patients with AF.531 These recommendations are based on data that have become available since the publication of the 2010 European Society of Cardiology (ESC) consensus document (Figure 1).531
Figure 1. Choice of antithrombotic therapy, including combination strategies of oral anticoagulation (O), ASA (A) and/or clopidogrel (C).
For Step 4, background colour and gradients reflect the intensity of antithrombotic therapy (i.e. dark background colour=high intensity; light background colour= low intensity). Solid boxes represent recommended drugs. Dashed boxes represent optional drugs depending on clinical judgement. New generation drug-eluting stents are generally preferable over bare-metal stents, particularly in patients at low bleeding risk (HAS-BLED score 0–2). When vitamin K antagonists are used as part of triple therapy, the INR should be targeted at a range from 2.0–2.5 and the time in the therapeutic range should be >70%. *Dual therapy with oral anticoagulation and clopidogrel may be considered in selected patients. **ASA as an alternative to clopidogrel may be considered in patients on dual therapy (i.e. oral anticoagulation plus single antiplatelet). ***Dual therapy with oral anticoagulation and an antiplatelet agent (ASA or clopidogrel) may be considered in patients at very high risk of coronary events.
ACS, acute coronary syndromes; CAD, coronary artery disease; DAPT, dual antiplatelet therapy; PCI, percutaneous coronary intervention.
Novel oral anticoagulants
The WOEST [link to WOEST article on TA.com website] randomized controlled trial followed patients with a long-term indication for oral anticoagulation and a requirement for PCI. The primary objective was to assess the safety of traditional triple therapy (dose-adjusted VKA plus dual antiplatelet therapy [ASA +clopidogrel]) versus dual therapy (VKA plus mono antiplatelet therapy [clopidogrel]). Results showed that patients receiving VKA plus mono antiplatelet therapy had similar efficacy outcomes to patients receiving VKA plus dual antiplatelet therapy, but experienced significantly fewer bleeding events and lower mortality rates.532 The implications of the WOEST trial are limited by the small number of patients enrolled, with larger studies needed to confirm the results. Despite this, WOEST suggested a potential for combining anticoagulant therapy with antiplatelet therapy (without ASA) for reducing the risk of cardiovascular events in patients undergoing PCI.
The PIONEER AF-PCI phase III randomized controlled trial (clinicaltrials.gov; NCT01830543) will evaluate the safety of rivaroxaban in patients with non-valvular AF undergoing PCI with stent placement. The trial will assess two rivaroxaban treatment strategies (rivaroxaban plus mono antiplatelet therapy [clopidogrel] and rivaroxaban plus dual antiplatelet therapy [clopidogrel + ASA]) versus dose-adjusted VKA plus dual antiplatelet therapy.
The challenge of ensuring effective anticoagulation in patients with AF who require PCI and stent placement could be helped by the combination of oral anticoagulant agents with antiplatelet therapy, with or without ASA. More results on these regimens are eagerly awaited by physicians.