Apixaban Is Safe During Catheter Ablation
Apixaban and warfarin are equally safe during catheter ablation of atrial fibrillation, according to results of the AXAFA-AFNET 5 trial. The drugs have similar rates of stroke and bleeding, and an improvement in cognitive function was shown for the first time.
Nearly one-third of all strokes are caused by atrial fibrillation. Oral anticoagulation is the cornerstone of stroke prevention in patients with atrial fibrillation. European Society of Cardiology (ESC) guidelines recommend non-vitamin K antagonist oral anticoagulants (NOACs) in preference over vitamin K antagonists (VKAs) such as warfarin, except in patients with a mechanical heart valve or rheumatic mitral valve stenosis. Unlike VKAs, NOACs do not require frequent monitoring and dose adjustment, and NOACs reduce long-term rates of stroke and death, compared with VKAs.
Catheter ablation is used in patients with atrial fibrillation to restore and maintain the heart’s normal rhythm, but the procedure entails risks of stroke, bleeding, acute brain lesions, and cognitive impairment. ESC guidelines recommend that patients continue taking their prescribed NOAC or VKA during the procedure. The results of this study confirm that the NOAC apixaban is as safe as a VKA in this situation.
The AXAFA-AFNET 5 trial was the first randomized trial to examine whether continuous apixaban was a safe alternative to a VKA during catheter ablation of atrial fibrillation. In all, 633 patients with atrial fibrillation and additional stroke risk factors scheduled to undergo atrial fibrillation ablation in Europe and the United States were randomized to receive either continuous apixaban or the locally used VKA (ie, warfarin, phenprocoumon, acenocoumarol, or fluindione).
The primary outcome was a composite of all-cause death, stroke, and major bleeding up to three months after ablation. It occurred in 22 patients randomized to apixaban and 23 randomized to VKA. “The results show that apixaban is a safe alternative to warfarin during catheter ablation of atrial fibrillation in patients at risk of stroke,” said Professor Paulus Kirchhof, MD, Chair in Cardiovascular Medicine at the University of Birmingham in the United Kingdom.
The researchers assessed cognitive function at the beginning and end of the trial and found that it improved equally in both treatment groups. “This is the first randomized trial to show that cognitive function is improving after atrial fibrillation ablation,” said Professor Kirchhof. “It is possible that this is due to continuous anticoagulation, although we did not test this specifically.” An MRI substudy in 335 patients showed a similar rate of silent strokes in the apixaban (27%) and VKA (25%) groups.
Patients in the trial were four years older than participants of previous studies with the NOACs rivaroxaban and dabigatran, said Professor Kirchhof. Local investigators chose the VKA and catheter ablation procedure, which led to the use of various drugs and techniques. “These characteristics of the trial mean that the results apply to older patients and in different clinical settings,” said Professor Kirchhof.
European Society of Cardiology Publishes Guidelines on Syncope
European Society of Cardiology guidelines on syncope were presented at the conference and published online ahead of print March 19 in the European Heart Journal.
Syncope is a transient loss of consciousness caused by reduced blood flow to the brain. Approximately 50% of people have one syncopal event during their lifetime. The most common type is vasovagal syncope, commonly known as fainting, triggered by fear, seeing blood, or prolonged standing, for example.
The challenge for doctors is to identify the minority of patients whose syncope is caused by a potentially deadly heart problem. The guidelines recommend a new algorithm for emergency departments to stratify patients and discharge those at low risk. Patients at intermediate or high risk should receive diagnostic tests in the emergency department or an outpatient syncope clinic.
“The new pathway avoids costly hospitalizations while ensuring the patient is properly diagnosed and treated,” said Professor Michele Brignole, MD, a cardiologist at Ospedali del Tigullio in Lavagna, Italy.
Most syncope does not increase the risk of death, but it can cause injury due to falls or be dangerous in certain occupations, such as airline pilots. The guidelines provide recommendations on how to prevent syncope, which include keeping hydrated; avoiding hot, crowded environments; tensing the muscles; and lying down. The document gives advice on driving for patients with syncope, although the risk of accidents is low.
The document emphasizes the value of video recording in the hospital or at home to improve diagnosis. It recommends that friends and relatives use their smartphones to film the attack and recovery. Clinical clues, such as the duration of the loss of consciousness, whether the patient’s eyes are open or closed, and jerky movements, can distinguish between syncope, epilepsy, and other conditions.
Another diagnostic tool is the implantable loop recorder, a small device inserted underneath the skin of the chest that records the heart’s electrical signals. The guidelines recommend extending its use for diagnosis in patients with unexplained falls, suspected epilepsy, or recurrent episodes of unexplained syncope and a low risk of sudden cardiac death.
The guidelines include an addendum with practical instructions for doctors about how to perform and interpret diagnostic tests.
“The Task Force that prepared the guidelines was truly multidisciplinary,” said Professor Brignole. “A minority of cardiologists was joined by experts in emergency medicine, internal medicine and physiology, neurology and autonomic diseases, geriatric medicine, and nursing.”