Mass screening for atrial fibrillation using ECG plus a heart failure biomarker doesn’t prevent ischemic stroke or systemic embolism (blood clot) in older people aged 75-76 years over a 5-year follow-up period, in keeping with latest research presented during a Hot Line session at this 12 months’s ESC Congress 2024 in London, UK (August 30-September 2). Nevertheless, the biomarker may improve prediction of which individuals are at low risk of ischemic stroke and systemic embolism beyond single-lead ECG in older people undergoing mass screening for AF.
Our findings don’t support the efficacy of this method for systematic screening of atrial fibrillation in older adults, but suggest that screening efforts mustn’t be focused on individuals with low NT-proBNP levels, but this requires confirmation in further studies.
Dr. Katrin Kemp Gudmundsdottir, lead writer at Karolinska Institutet, Stockholm, Sweden
She explained: “Individuals with low biomarker levels had a lower risk of developing atrial fibrillation over the 5-year follow-up period, as did the danger of developing stroke or systemic embolism, compared with the control group and folks with higher biomarker levels.”
Atrial fibrillation (AF) – a kind of irregular heartbeat that causes blood clots to form in the guts and increases the danger of stroke, heart failure and premature death – affects at the least 40 million people worldwide.
Individuals with atrial fibrillation are five times more prone to have a stroke, which is more prone to result in everlasting disability and a lower probability of survival. Nevertheless, about 30% of individuals with atrial fibrillation don’t have any symptoms in any respect, underscoring the urgent must discover individuals with this potentially dangerous heart rhythm.
Internationally, most AF guidelines recommend opportunistic screening for AF in people aged 65 years and older and oral anticoagulation in those at high risk of stroke. The European Society of Cardiology also recommends systematic ECG screening for AF in patients aged 75 years and older or those at high risk of stroke.
Adding biomarkers can improve the accuracy of screening. Studies suggest that NT-proBNP (N-terminal pro-B-type natriuretic peptide) — a marker of cardiovascular health — is a powerful predictor of incident AF and stroke.
In 2020, screening results from the STROKESTOP II trial showed that NTproBNP could also be a useful stratification tool in atrial fibrillation screening, and individuals with elevated NTproBNP levels may profit from more intensive screening.
The STROKESTOP II study, a mass screening programme for all 75–76-year-olds within the Stockholm region of Sweden, included 28,712 people born between 1940 and 1941. The aim of the study was to check whether inviting people to screening (each adults who showed up for screening and those that didn’t) would cut back the danger of thromboembolic events compared with a control group (individuals who weren’t invited to screening).
Participants were randomly assigned 1:1 to receive an invite to AF screening (13,905) or a control group (13,884), after excluding those that died or emigrated. Of those invited to screening, 6843 (49%) accepted the invitation (53% women).
Participants without previously diagnosed AF had blood samples collected and NTproBNP levels analyzed, then were divided into high-risk (NTproBNP 125 ng/L or higher) and low-risk (lower than 125 ng/L) groups. They were then screened based on NT-proBNP levels either once (low-risk group) or more intensively (high-risk group).
The high-risk group (3743/6288; 60%) underwent home screening with a transportable single-lead ECG 4 times a day for 2 weeks, whereas the low-risk group (2545/6288) underwent one episode of single-lead ECG screening but didn’t undergo intensive two-week screening.
Latest AF was detected in 2.4% (165/6843) of all participants offered oral anticoagulation. Consequence data were collected from the Swedish national registries.
After a median follow-up of 5 years, there was no difference in the danger of stroke or thrombotic events between the intervention group (including each participants who attended screening and those that were invited but didn’t attend screening) and the control group.
Further subanalyses showed that the danger of stroke or blood clots was 41% lower amongst participants with low levels of the guts failure marker NTproBNP compared with the control group (0.61 and 1.03 events per 100 years of risk, respectively).
Within the high-risk group (with elevated NTproBNP levels), the danger of latest onset of atrial fibrillation inside 5 years was greater than twice as high, and the danger of ischemic stroke or systemic embolism was 57% higher than within the low-risk group (0.95 and 0.61 events per 100 years, respectively).
Dr Kemp Gudmundsdottir said: “Screening participation was lower than expected, which could have confounded the outcomes. Further research is required and it seems sensible to focus screening efforts on those at highest risk and potentially reduce the variety of preventable strokes.”