Atrial Fibrillation Studies from ESC 2022
In recognition of Atrial Fibrillation Awareness month, we wanted to highlight a few of the AF-related studies presented at the European Society of Cardiology Congress 2022 in Barcelona, Spain.
eBRAVE-AF: Smartphone App More Than Doubles the Odds of Detection and Treatment of AF
In the eBRAVE-AF trial in older adults at risk of stroke, the use of ordinary smartphones equipped to detect atrial fibrillation (AF) that was then treated with oral anticoagulation more than doubled the detection of AF when compared to standard real-world screening.
The potential to use smart devices for large-scale screening of AF has been demonstrated, but the utility of this approach among older individuals and its direct comparison with standard screening strategies has not been investigated.
This siteless, open-label trial included 5,551 participants aged 50 to 90 years who owned a smartphone, had no known AF, no prescription of oral anticoagulants, and had a CHA2DS2-VASc score of ≥1 for men or ≥2 for women. These subjects were randomly assigned to 6 months of either digital screening or standard real-world screening, including, for example, use of symptoms and routine ECG screening.
Digital screening involved repetitive phone-based one-minute photoplethysmographic (PPG) pulse wave self-measurements twice a day for 14 days, then twice a week thereafter. In the event of abnormal results, participants received a patch to record a 14-day ECG, which was then evaluated by researchers.
The primary efficacy endpoint, assessed at 6 months, was newly diagnosed AF leading to oral anticoagulation initiation by the treating physician.
Digital screening doubled the detection of treatment-relevant AF, with rates of 1.33% and 0.63% in the digital and standard screening arms, respectively (odds ratio, 2.12; 95% CI 1.19 to 3.76; p=0.010).
While more studies are needed to demonstrate improved clinical outcomes with smartphone-based AF detection technology, these study findings are potentially impactful for an older population with undiagnosed AF. According to investigator Axel Bauer, MD (Innsbruck Medical University, Austria), “Screening using common smartphones significantly increased the detection rate of therapy-relevant AF. Digital screening was well received by older participants, who tended to perform even more PPG measurements than younger participants in the study.”
INVICTUS: VKAs Remain Standard of Care for AF in Rheumatic Heart Disease
The findings of the INVICTUS trial, which compared the direct oral anticoagulant (DOAC) rivaroxaban with vitamin K antagonists (VKA) for the prevention of cardiovascular events in patients with rheumatic heart disease (RHD) and atrial fibrillation, indicate that adjusted-dose VKA should remain the standard of care for this patient population.
Guidelines recommend VKAs for stroke prevention in patients with RHD and AF. However, regular international normalized ratio (INR) monitoring may be difficult in low- and low-middle-income countries, where RHD remains an important cause of AF. Less than 20% of eligible patients are prescribed VKAs and only about one-third achieve an INR in the therapeutic range. It was hypothesized that direct oral anticoagulants could provide a better option.
INVICTUS was an open-label, parallel-group, non-inferiority trial that included 4,531 patients from 24 countries in Africa, Asia and South America. Participants with echocardiographically-documented RHD and AF were eligible if they had an elevated risk of stroke (mitral stenosis with valve area ≤2.0 cm², left atrial spontaneous echo contrast or thrombus, or a CHA2DS2-VASc score ≥2). Patients were randomized to receive adjusted-dose VKA with goal INR of 2.0-3.0 or rivaroxaban 20 mg once daily.
The primary efficacy outcome was a composite of all-cause stroke, systemic embolism, myocardial infarction or death from vascular or unknown causes.
At a median follow-up of 3.1 years, primary efficacy outcome events occurred at a rate of 8.26% per year for rivaroxaban and 6.46% per year for VKA, yielding a hazard ratio of 1.25 favoring VKA. Proportional hazard assumptions were not met.
The difference was driven by more deaths and ischemic strokes in the rivaroxaban-treated patients, but there were no differences in the risk of major bleeding between the two treatments.
Investigators and others commenting on the trial expressed surprise at the findings. In patients with atrial fibrillation not related to RHD, treatment with rivaroxaban or other factor Xa inhibitors has been shown to be non-inferior to warfarin therapy for stroke prevention, with large reductions seen in the risk of hemorrhagic stroke.
“The results of this trial support current guidelines, which recommend vitamin K antagonist therapy for the prevention of stroke in patients with rheumatic heart disease in whom atrial fibrillation develops,” wrote the INVICTUS investigators in their simultaneous publication of the findings in the New England Journal of Medicine.
Commenting on the trial, K2P CurrentMD Cardiology Arrhythmias and EP section editor, Dr. Nishant Verma, said: “I feel like this was a particular patient population that we were unclear on because AF fro rheumatic heart disease is probably more thrombogenic than other forms of atrial fibrillation or AFib from rheumatic heart disease. That said, this is a patient population where we would like to have other tools available for CVA prophylaxis other than warfarin. However, we were concerned that the original DOAC trials did not include patients that had rheumatic AFib, so this was a very important study to answer whether warfarin is a better option for this patient population. There are other patient populations where we have also seen that DOAC are not acceptable, like patients with mechanical heart valves. So, I think we still have a lot of learning to do, even though these drugs have been on the market for quite some time now, but this was a very important trial to help guide our management.”