What is the Optimal Antithrombotic Strategy in Patients With Atrial Fibrillation Undergoing PCI?

The optimal antithrombotic management in patients with coronary artery disease (CAD) and concomitant atrial fibrillation (AF) is unknown. AF patients are treated with oral anticoagulation (OAC) to prevent ischemic stroke and systemic embolism and patients undergoing percutaneous coronary intervention (PCI) are treated with dual antiplatelet therapy (DAPT), i.e. aspirin plus P2Y12 inhibitor, to prevent stent thrombosis (ST) and myocardial infarction (MI). Patients with AF undergoing PCI were traditionally treated with triple antithrombotic therapy (TAT, i.e. OAC plus aspirin and P2Y12 inhibitor) to prevent ischemic complications. However, TAT doubles or even triples the risk of major bleeding complications. More recently, several clinical studies demonstrated that omitting aspirin, a strategy known as dual antithrombotic therapy (DAT) is safer compared to TAT with comparable efficacy.

However, pooled evidence from recent meta-analyses suggests that patients treated with DAT are at increased risk of MI and ST. Insights from the AUGUSTUS trial showed that aspirin added to OAC and clopidogrel for 30 days, but not thereafter, resulted in fewer severe ischemic events. This finding emphasizes the relevance of early aspirin administration on ischemic benefit, also reflected in the current ESC guideline. However, because we consider the bleeding risk of TAT unacceptably high, we propose to use a short course of DAPT (omitting OAC for 1 month). There is evidence from the BRIDGE study that a short period of omitting OAC is safe in patients with AF. In this study, these patients are treated with DAPT, which also prevents stroke, albeit not as effective as OAC. This temporary interruption of OAC will allow aspirin treatment in the first month post-PCI where the risk of both bleeding and stent thrombosis is greatest.

The WOEST 3 trial is a multicentre, open-label, randomised controlled trial investigating the safety and efficacy of one month DAPT compared to guideline-directed therapy consisting of OAC and P2Y12 inhibitor combined with aspirin up to 30 days. We hypothesise that the use of short course DAPT is superior in bleeding and non-inferior in preventing ischemic events. The primary safety endpoint is major or clinically relevant non-major bleeding as defined by the ISTH at 6 weeks after PCI. The primary efficacy endpoint is a composite of all-cause death, myocardial infarction, stroke, systemic embolism, or stent thrombosis at 6 weeks after PCI.