Updated guidance on the safe and effective use of non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation is presented today at EHRA 2021, an online scientific congress of the European Society of Cardiology (ESC), and published in EP Europace, a journal of the ESC.

The 2021 EHRA Practical Guide on the use of NOACs in patients with atrial fibrillation, now in its fourth edition, was produced by the ESC’s European Heart Rhythm Association (EHRA). Since its first version in 2013, initiated by the current edition's senior author Professor Hein Heidbüchel, its associated Key Message booklet has been distributed more than 0.5 million times worldwide. Knowledge on the use of NOACs has greatly advanced – but at the same time new frontiers and challenges have emerged.

Atrial fibrillation is the most common heart rhythm disorder, affecting more than 40 million people globally. People with the disorder have a five times greater risk of stroke. ESC guidelines recommend NOACs, also called direct oral anticoagulants (DOACs), in preference to vitamin K antagonists (e.g. warfarin) to prevent stroke in patients with atrial fibrillation.

“The NOAC practical guide complements the ESC atrial fibrillation guidelines by giving specific advice on how to handle these medications in numerous situations encountered in clinical practice,” said lead author Professor Jan Steffel of the University Heart Centre, Zurich, Switzerland. “This includes scenarios with limited data on the use of any anticoagulant drug – for example in severe renal insufficiency.”

Information on drug-drug interactions has been updated – including a new section on commonly used herbal medicines. “Many patients and healthcare professionals are not aware that herbal remedies can impact the effectiveness of NOACs,” said Professor Steffel. “St. John’s wort, for example, can reduce anticoagulant levels in the blood and increase the risk of stroke. We greatly caution against using both NOACs and St. John’s wort.”

A common area of uncertainty is when to stop NOACs around interventions and the section on perioperative management has been refined. The document clearly illustrates, for different procedures, when to take the last dose before the intervention and when to restart afterwards. Professor Steffel said: “Many healthcare professionals switch patients to heparin around the time of a procedure, but we clearly advise against that. For many minor interventions, continued NOAC use may be feasible while more invasive procedures require an interruption.”

A section is devoted to frail and older patients who are at high risk for stroke, bleeding, and undertreatment. Guidance is given on how to assess the level of frailty and which patients should, or should not, be anticoagulated. “Most patients with atrial fibrillation benefit from NOACs but in those with moderate to severe frailty the risks may outweigh the benefits,” said Professor Steffel.

Finally, the document outlines how to manage these medications during the pandemic. This includes what to do in patients on NOACs who are hospitalised for COVID-19 – when they should continue their drugs and when they should be switched to parenteral anticoagulation. Detailed instructions are provided on how patients taking these medications can be safely vaccinated against COVID-19. Professor Steffel explained: “As for any intramuscular injection, patients should just drop their morning NOAC dose on the day of vaccination, then restart the drug later that day or latest the day after. This very short interruption avoids increased risks of stroke or bleeding in the muscle.”

Since the third version of the guide was published in 2018, many regions of the world have approved the use of andexanet alfa which is an antidote for the factor Xa inhibitors. Advice is given on when to use the antidote and at what doses. Professor Steffel said: “There is a temptation to use direct antidotes at a stage where it’s not necessarily required in daily clinical care. Use should be limited to life-threatening bleeding or bleeding into critical organs or spaces – for example severe trauma or intracerebral haemorrhage – and avoided for minor bleeding like bruising or nose bleeds.”

New sections have been added on NOAC use in high and low body weights, women of reproductive age, and in Asians and other non-Caucasian ethnicities. Professor Steffel noted that the guide is used globally, and some regions have limited experience with these medications. He said: “There are differences between ethnic groups with respect to metabolism, and baseline risks of stroke and bleeding. We provide practical advice for the use of NOACs in populations around the world.”