Mass screening for atrial fibrillation (AF) using electrocardiography (ECG) combined with a heart failure biomarker has shown no significant reduction in ischaemic stroke or systemic embolism among older adults aged 75–76 years over a five-year period. However, the biomarker may enhance the prediction of individuals at low risk for these events, beyond what single-lead ECG can offer.
These findings were shared at the recent European Society of Cardiology (ESC) congress held from August 30 to September 2 in London.
Lead author Katrin Kemp Gudmundsdottir from the Karolinska Institute in Stockholm stated, “Our findings do not support systematic screening for AF in older adults, but they suggest it may be safe to avoid concentrating screening efforts on individuals with low levels of NT-proBNP [N-terminal pro-B-type natriuretic peptide], although further validation is needed.” She noted that individuals with lower biomarker levels had a reduced risk of developing AF and experiencing stroke or systemic embolism compared to both the control group and those with higher biomarker levels.
Currently, many AF guidelines worldwide recommend opportunistic screening for individuals aged 65 and older, along with oral anticoagulant treatment for those at high risk of stroke. The ESC advises systematic ECG screening for patients aged 75 and older or those deemed at high risk. It is believed that the inclusion of biomarkers could improve screening accuracy, with NT-proBNP emerging as a strong predictor of future AF and stroke.
The baseline screening results of the STROKESTOP II trial in 2020 highlighted NT-proBNP’s utility in stratifying AF screening, indicating that individuals with elevated levels could benefit from more thorough screening.
The STROKESTOP II initiative involved mass screening for all 75–76-year-olds in the Stockholm region of Sweden, enrolling 28,712 individuals born between 1940 and 1941. The study aimed to assess whether screening invitations could lower the risk of thromboembolic events compared to a control group not invited for screening. Participants were randomized in a 1:1 ratio to receive either an invitation for AF screening (13,905 patients) or serve as controls (13,884), excluding those who died or moved away.
Out of those invited, 6,843 (49%) accepted the screening invitation, with 53% of participants being women. Participants who previously had no known AF had blood samples taken to analyze NT-proBNP levels and were categorized into high-risk (≥125 ng/L NT-proBNP) or low-risk (<125 ng/L) groups. Screening protocols differed based on risk level, with home-based handheld ECG monitoring for the high-risk group and a one-time screening for the low-risk group. New cases of AF were identified in 2.4% (165 out of 6,843) of the participants, all of whom were offered oral anticoagulant treatment based on national data. After a median follow-up of five years, overall, there was no notable difference in stroke or clotting event risk between the screening and control groups. Further analysis revealed that participants with low NT-proBNP levels had a 41% lower risk of stroke or blood clots compared to the control group. In contrast, the high-risk group with elevated NT-proBNP faced more than double the likelihood of developing AF and a 57% increased risk of ischaemic stroke or systemic embolism compared to their low-risk counterparts. Kemp Gudmundsdottir concluded by noting that the lower than expected participation rate in the study could have negatively impacted the results. She emphasized the need for more research and suggested targeting screening efforts toward individuals at the highest risk to potentially reduce avoidable strokes.