Speaking today at the AF Symposium (23–25 January, Washington, DC, USA), Francis Marchlinski (Hospital of the University of Pennsylvania, Philadelphia, USA) reported that selected atrial fibrillation (AF) patients could safely and effectively take non-vitamin K antagonist oral anticoagulants (NOACs) “pro re nata” (PRN) without increasing their risk of stroke.
Marchlinski commented that, after successful catheter ablation, some AF patients are “reluctant to continue anticoagulants in the absence of symptoms” and express “legitimate concerns” about the risk of bleeding with these drugs. He added that some of these patients may not actually need continuous anticoagulation, noting that ablation is associated with a “dramatic reduction” in AF burden and that “duration of AF seems to be a critical factor in putting a patient at increased risk of stroke”. Therefore, for selected patients, a strategy of using NOACs PRN (i.e. as needed) may be feasible as long as there was ongoing pulse assessment to monitor for uncommon AF recurrence.
He reported that he and his colleagues are currently evaluating the safety and efficacy of such a strategy in eligible patients ( increased risk of stroke based on CHA2DS2VASC ≥1 (≥2 in women) and no AF on extended monitoring after AF ablation) in an ongoing study. In the study, patients only take NOACs [for a limited time] if they have a documented or suspected episode (detected by pulse assessment) of atrial fibrillation. “We tell patients to start taking NOACs if they have an irregular pulse for more than five minutes, with the direction to take them for two weeks if the pulse irregularity was for less than 24 hours and to take them for one month if the pulse irregularity was for more than 24 hours (and there was no additional AF detected on ECG monitoring),” Marchlinski explained. We initially had the duration of the arrhythmia that triggered NOAC treatment at more than one hour but decreased it to more than five minutes to be extra cautious.
Pulse assessment is used, he said, because “we know that this type of pulse assessment has a high negative predictive value; ‘slow and steady’ means that they are in sinus rhythm”. Therefore, to be included in the study, patients have to be able to take their pulse (which they have to do at least twice a day and if they develop any suspicious symptoms). Marchlinski stated: “If they can’t, they are excluded [from the study]. A large proportion of AF patients are also excluded because of shared decision making after reviewing standard treatment guidelines, the presence of an atriopathy based on increased LA size or LA scarring on voltage map or a history of having asymptomatic AF episodes. ” Furthermore, at least once a year, extended ECG monitoring is used to ensure patients do not have any episodes of asymptomatic AF. “Routine monitoring is important because while asymptomatic AF is rare, it does occur,” he said.
Initial results from the study were published in the Journal of Cardiovascular Electrophysiology last year. Of 99 patients for whom follow-up data (30 ± 14 months; a total of 244 patient-years) were available, 22% went back to continuous NOAC use. Some patients, Marchlinski reported, went back to continuous use because of non-compliance with pulse assessment while others chose to go back because they did not want the pressure of having to repeatedly take their pulse. However, 16% returned to continuous NOAC use because of suspected or documented AF episode(s). According to the Journal of Cardiovascular Electrophysiology data, a further 14% did use NOACs but did not transition back to daily use. Only one patient had a cerebrovascular accident felt to be due to a atheromatous emboli on brain magnetic resonance imaging for an overall stroke rate of 0.4% per year of follow-up.
Since this initial report, data for 190 patients have become available followed for a total of 576 patient-years. According to Marchlinski, these findings show that about “again, 25% restart continuous NOACs and 60% still not initiate NOACs”. He added no further cerebrovascular accidents and no episodes of major bleeding have occurred.
Marchlinski concluded: “In a selected group of motivated patients with no AF on extended ECG monitoring and CHA2DS2VASC ≥1 (≥2 in women) after ablation, monitoring for AF with pulse assessment coupled with PRN use of NOAC when AF is detected is a safe and effective strategy to maintain a low risk of stroke and low risk of major bleeding”. He added that he looked forward to randomised controlled trials to confirm these findings but such a strategy of constant vigilance was needed to best “protect patients” from bleeding and stroke after stopping anticoagulants.