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Screening for AF in older adults may reduce mortality, stroke
Screening for atrial fibrillation in adults aged at least 65 years and treating with anticoagulants may reduce risk for stroke and death, according to a white paper from the AF-SCREEN International Collaboration.
“Although many patients with AF develop symptoms leading to appropriate diagnosis and management, the first manifestation may be a debilitating stroke or death,” Ben Freedman, MBBS, PhD, professor of cardiology at Concord Hospital, Sydney, and researcher at the Heart Research Institute, Charles Perkins Centre, University of Sydney, and colleagues wrote. “Finding AF before symptoms are manifested could lead to initiation of appropriate effective therapy, including oral anticoagulants to reduce stroke and death and potentially initiation of risk-factor modifications to reduce complications from AF progression.”
Freedman and colleagues from the AF-SCREEN International Collaboration recommended implementing single time-point screening, which could be an affordable and effective method for screening for AF. This method detected AF in 1.4% of older adults, according to one study. Using a handheld ECG during a 2-week, twice-daily screening program, AF was detected in 3% (0.5% on initial ECG) of adults aged 75 to 76 years, and in those with at least one additional stroke risk factor, AF was detected in 7.4%.
Opportunistic screening for AF
Pulse palpitations or handheld ECGs are methods labeled as screen-detected AF and they do not include atrial high-rate episodes detected by a cardiac implanted electronic device, the researchers wrote.
There are currently no studies on the risk for stroke and death in individuals with untreated screen-detected AF, according to the researchers. In one study of individuals with asymptomatic clinical AF detected incidentally (n = 5,555), untreated individuals (n = 1,460) had a stroke risk of 4% and all-cause mortality risk of 7% vs. 1% and 2.5%, respectively, in matched controls during 1.5 years of follow-up.
“Screen-detected AF as found on single time-point screening or intermittent 30-second recordings over 2 weeks is not a benign condition and, with additional stroke risk factors, carries sufficient risk of stroke to justify consideration of screening and therapy to prevent stroke,” the researchers wrote.
Currently, no studies have been conducted on whether screen-detected AF should prompt oral anticoagulant treatment. Additionally, there may be ethical concerns in conducting a randomized controlled trial, according to Freedman and colleagues.
In the cohort study of patients detected incidentally through general practice (n = 5,555), anticoagulant therapy (n = 2,492) was associated with a reduced risk for stroke (1%) and death (4%) vs. no antithrombotic therapy (n = 1,460; 4% risk for stroke; 7% risk for death) in 1.5 years of follow-up.
“Screen-detected AF (single time-point screening or patient-initiated recording) is likely to have the same response to (oral anticoagulant) therapy as incidentally detected AF and symptomatic AF, with significant reduction in stroke and death,” the researchers wrote.
In the Swedish Riks-Stroke register (> 94,000 ischemic strokes), about 9% of incidents were associated with previously unknown AF and 20% had known but untreated AF.
The researchers suggest that it is likely both unknown and undertreated AF contribute to a substantial portion of strokes and that screening and subsequent treatment could decrease risk for stroke and death.
Who and how to screen
The researchers recommend an age-based screening cutoff of at least 65 years if the screening procedure is inexpensive and easy to use such as pulse-palpitation or single time-point hand-held devices.
Pulse palpitation as a screening method is accessible and has proved to be effective from the Screening for AF in the Elderly (SAFE) study. This method is beneficial for community-based screening and can be used in both high- and low-income countries, although it has some limitations, the researchers wrote.
Oscillometric BP monitors with AF detection are another affordable option and offer superior AF detection vs. pulse palpitations (92% to 100% sensitivity; 90% to 97% specificity), they wrote. Mobile phones and fitness trackers may be another way to detect AF, although an ECG would be required to confirm AF.
Handheld ECG devices showed sensitivity of 94% to 99% and specificity of 92% to 97% and can be used for single time-point AF screening. For accuracy equivalent to standard event recorders, repeat hand-held ECG screening for 2 to 3 weeks has proved effective, according to the report.
“Because ECG confirmation is mandated by guidelines for the diagnosis of AF, hand-held ECG devices have the advantage of providing a verifiable ECG trace and would, therefore, be the preferred screening tool. Prolonged continuous ECG monitoring with external or subcutaneous recorders will diagnose more paroxysmal AF but requires further evaluation: Cost-effectiveness will be limited by expense and detection of AF with lower absolute stroke risk,” the researchers wrote.
The screenings could take place at pharmacies, community events or primary care offices. The appropriate location will vary based on country and available resources.
Population screenings may be an effective method to screen for undertreated patients with identified AF, according to the researchers.
Additionally, several studies have reported cost-effectiveness of different methods of opportunistic screening, but savings will depend on the country and population.
Advocacy moving forward
The researchers highlighted the importance of patients and patient-led groups in leading the change in policy to improve AF outcomes. Public awareness and education for health care professionals are both supported by these advocacy groups.
Currently, the European Society of Cardiology guidelines recommend opportunistic pulse-taking in individuals aged at least 65 years. The American College of Cardiology/American Heart Association/Heart Rhythm Society guidelines do not currently make recommendations on AF screening.
“There is a need to perform large randomized controlled studies using hard endpoints (including stroke, systemic embolism and death), of strategies for screening, to strengthen the evidence base to inform guidelines and national systematic screening strategies,” the researchers wrote. – by Cassie Homer
Disclosure: Freedman reports receiving speakers’ fees and advisory board honoraria from Bayer Pharma AG, Boehringer Ingelheim and Bristol-Myers Squibb/Pfizer.