How to walk the tightrope between harm and protection in selecting the optimal antiplatelet treatment strategy after transcatheter left atrial appendage occlusion

摘要

The left atrial appendage (LAA) conceals 90% of thrombi found in the left atrium in patients with atrial fibrillation (AF), and thus has been declared the main villain responsible for thromboembolic events associated with AF [1]. Systemic anticoagulation cuts the risk of stroke and peripheral embolism associated with AF by more than 60% [2, 3]. However, it is a?double-edged sword, as it carries a?substantial bleeding risk [4]. The bleedings affect tissues and organs located far from the LAA – innocent bystanders, one could say. Hence, it seems perfectly reasonable to call for a?local solution to a?local problem, without putting patients at risk of systemic complications. In response to this call the concept of mechanical closure of the LAA (LAAC) has appeared [5, 6]. The concept proved to be at least as effective as anticoagulation with vitamin K antagonists in randomised and non-randomised studies with the two CE marked left atrial appendage occluders available on the market: the WATCHMAN Device and the Amplatzer Cardiac Plug (ACP) Device [7–13]. It was suggested that LAAC would show its full potential in delivering net clinical benefit over vitamin K antagonists at longer-term follow-ups, after having left behind early hazards of the implantation procedure and with continuous accumulation of adverse events with anticoagulation. Indeed, in a?very recent landmark report with 3.8-years follow-up of patients from the initial PROTECT AF trial, the WATCHMAN device has met superiority criteria over warfarin in reducing combined outcome, including thromboembolic events. What is even more momentous, WATCHMAN proved superior in reducing cardiovascular as well as all-cause mortality [14]. Still, the body of evidence on this relatively novel technology is scarce when compared to extensive data on the efficacy and safety of oral anticoagulation, including novel drugs. Furthermore, the technology itself is still young and the procedure carries inherent risks that are partly mitigated with growing operators’ experience. The current European guidelines recommend that this procedure should be limited to AF patients at high stroke risk and with contraindications to anticoagulation [15]. The guidelines, however, do not address the issue of the scope and duration of antiplatelet treatment after successful elimination of the LAA. This issue remains unresolved, as no systematic or randomised data comparing various treatment strategies have been published... View full text...