Simple decision-making between a vitamin K antagonist and a non-vitamin K antagonist oral anticoagulant : using the SAMe-TT2R2score

Stroke prevention with oral anticoagulation (OAC) is central to the modern management of atrial fibrillation (AF) patients.1 For many years, vitamin K antagonists (VKAs, e.g. warfarin) have been the default class of OAC, but we now recognize that it is not simply prescribing VKA but very close attention to quality of anticoagulation control is necessary, as reflected by the individual time in therapeutic range (TTR).2 An average individual TTR of >70% is recommended to maximize efficacy and safety of the VKAs.2,3 Nonetheless, the VKAs have significant inter- and intra-patient variability, partly from diet and drug interactions, thus necessitating regular international normalised ratio (INR) monitoring.2 More recently, we have had the non-VKA oral anticoagulants (NOACs, previously referred to as new or novel OACs4) available, which offer efficacy, safety, and relative convenience compared with the VKAs, for stroke prevention in AF.