The risk of ischemic stroke in patients with atrial fibrillation and heart failure decreased over time, particularly among those without a history of myocardial infarction, according to findings from a nationwide Finnish cohort of 229,565 patients.
From 2007 to 2010, patients with heart failure and no prior myocardial infarction had a 32% higher risk of stroke compared with those without heart failure. By 2015 to 2018, that excess risk declined to 8%. Stroke risk among patients with both heart failure and prior myocardial infarction remained elevated and unchanged throughout the study period.
The overall stroke rate declined in all groups, but it remained consistently higher in those with heart failure. In the first year of follow-up with oral anticoagulant therapy, the stroke rate was 42.3 per 1,000 patient-years in patients with heart failure, compared with 27.4 per 1,000 patient-years in those without. Among patients who were not treated with oral anticoagulants, stroke rates were 76.5 and 37.7 per 1,000 patient-years, respectively.
Researchers used the FinACAF registry, which includes all patients diagnosed with atrial fibrillation in Finland between 2007 and 2018. Patients were followed for up to 1 year following diagnosis. Of the cohort, 17.4% had heart failure at baseline. These patients were older, more often female, and had a higher burden of comorbidities, including diabetes, vascular disease, and prior stroke. The mean CHA₂DS₂-VA score was 4.4 in the heart failure group and 2.6 in the group without heart failure.
Use of oral anticoagulants increased during the study. Among patients with heart failure, treatment initiation within 1 year of diagnosis rose from 53.3% to 68.9%. In patients without heart failure, oral anticoagulant use increased from 44.3% to 71.6%. The prevalence of heart failure in the atrial fibrillation population declined slightly, from 18.0% in 2007 to 2010 to 16.7% in 2015 to 2018, although the absolute number of patients with heart failure increased.
The study had several limitations. Data on left ventricular ejection fraction and stroke subtypes were not available. Heart failure was identified using administrative coding, which may have introduced misclassification. The analysis did not adjust for rhythm control strategies or other postdiagnosis treatments that may influence stroke risk. Despite multivariable adjustments, residual confounding remains possible.
Researchers concluded that stroke risk in patients with atrial fibrillation and heart failure is not static and has declined in some subgroups. However, heart failure continues to pose a notable stroke risk, particularly among patients with a history of myocardial infarction. These findings support the importance of ongoing risk reassessment and individualized stroke prevention strategies as treatment practices and patient profiles continue to evolve.
Full disclosures can be found in the published study.
Source: JAHA
