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Continuous apixaban safe in patients undergoing catheter ablation for AF
Among patients with atrial fibrillation who continued their anticoagulant during catheter ablation, those assigned apixaban had similar outcomes to those assigned a vitamin K antagonist, according the results of the AXAFA-AFNET 5 study.
The investigator-initiated, prospective, multicenter study was the first randomized controlled trial to determine whether continuous apixaban (Eliquis, Bristol-Myers Squibb/Pfizer) is a safe alternative to continuous vitamin K antagonist use during catheter ablation, Paulus Kirchhof, MD, deputy director of the Institute of Cardiovascular Sciences and chair in cardiovascular medicine at the University of Birmingham, United Kingdom, told Cardiology Today.
“Catheter ablation is an increasingly used treatment for symptomatic AF,” he said. “Continuous anticoagulation is recommended. One small trial of rivaroxaban (Xarelto, Janssen) and one medium-sized trial with dabigatran (Pradaxa, Boehringer Ingelheim) found similar risks in those scenarios between those randomized to rivaroxaban or dabigatran and those randomized to a vitamin K antagonist. There are no such data on apixaban.”
The findings were presented at EHRA 2018 and published in the European Heart Journal.
The researchers randomly assigned 674 patients (median age, 64 years; 33% women) with AF and at least one stroke risk factor scheduled for catheter ablation to apixaban 5 mg twice daily or a vitamin K antagonist: warfarin in the United States and the United Kingdom, phenprocoumon in Germany, acenocoumarol in Spain and fluindione in France, Kirchhof said.
Among the cohort, 633 patients received their study drug and underwent ablation, and 335 underwent an MRI for a substudy of acute brain lesions.
“There were data showing cognitive function was reduced after atrial fibrillation ablation but not after other types of ablation,” Kirchhof said in an interview.
The primary outcome was a composite of death, stroke or Bleeding Academic Research Consortium grade 2 to 5 bleeding at 3 months.
According to the researchers, the primary outcome occurred in 6.9% of the apixaban group and 7.3% of the vitamin K antagonist group (difference, –0.38%; 90% CI, –4 to 3.3; P for noninferiority = .0002). Most of the events were major bleeds.
“This offers important reassurance that continuous non-vitamin K antagonist oral anticoagulant therapy can be used in patients undergoing AF ablation, and it’s equally effective at preventing strokes and avoiding bleeding as vitamin K antagonists,” Kirchhof told Cardiology Today. “What we did not expect was to have such a low event rate. For example, we had numerically a lower rate of ISTH major bleeds than RE-CIRCUIT (3.8% vs. 4.3%), despite the fact that our population was on average 4 years older.”
Also, he said, in RE-CIRCUIT, those assigned vitamin K antagonists had a higher rate of bleeding than those assigned dabigatran, whereas in the present study, apixaban was not associated with less bleeding than vitamin K antagonists. That could have been random chance, but another possible explanation is that in AXAFA-AFNET 5, “our investigators achieved a median time in therapeutic range of 84% in patients randomized to vitamin K antagonist therapy. That is much better than in other published trials,” Kirchhof said.
Among those in the MRI substudy, 27.2% of those assigned apixaban had acute brain lesions vs. 24.8% of those assigned a vitamin K antagonist (P = .64). “This is a signal that we need to do more research on how we can reduce acute brain lesions during AF ablation,” Kirchhof told Cardiology Today.
Cognitive function at the end of follow-up did not differ between the groups (P = .91), but increased in both groups compared with baseline (P = .0005), Kirchhof and colleagues found.
“This was an effect observed in both arms. We cannot say with certainty that cognitive function is really better, but we can say there was a significant difference,” Kirchhof said. “That reassures everybody that it is unlikely that catheter ablation on continuous anticoagulation done in the way we have done it in AXAFA leads to cognitive decline. Some of the people in the ablation world believe that restoring sinus rhythm by improving perfusion of the brain can improve cognitive function, although I would say the change is small, so we can’t state that with certainty.” – by Erik Swain
References:
Kirchhoff P, et al. Late-Breaking Trials. Presented at: EHRA: The Annual Congress of the European Heart Rhythm Association; March 18-20, 2018; Barcelona, Spain.
Kirchhof P, et al. Eur Heart J. 2018;doi:10.1093/eurheartj/ehy176.
Disclosure: The study was sponsored by AFNET with funding from Bristol-Myers Squibb/Pfizer, the German Centre for Cardiovascular Research and the German Ministry of Education and Research. Kirchhof reports he receives research support and honoraria from several drug and device companies active in AF and is listed as an inventor on two patents held by the University of Birmingham.
Perspective
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This study shows that apixaban can be continued safely periprocedurally during AF ablations without stopping, and that the results were comparable to those with continuous vitamin K antagonist use. This study exemplifies that the use of direct oral anticoagulants in AF ablations is safe and effective. Interestingly, many electrophysiologists have already adopted this into clinical practices.
The MRI substudy raises significant concerns regarding the continued high incidence of asymptomatic cerebral emboli in approximately one quarter of the patients in both arms. Although this was not associated with any adverse effects on cognitive function, the long-term impact of this remains unclear and warrants further research. Strategies beyond conventional measures to reduce the incidence of these acute cerebral emboli must become high priority for the electrophysiology community.