BACKGROUND AND AIMS:
Serum light-chain neurofilament (sNfL) is an emerging biomarker for neuroaxonal injury in inflammatory, neurodegenerative and vascular brain disease. Its role as a potential neurological outcome marker in heart disease has not been investigated. Our aim was to study if sNfL is associated with the CHA2DS2-VASc score, a validated score predicting stroke risk in patients with atrial fibrillation (AF).

METHODS:
sNfL was measured at baseline in 278 patients with AF included in the SWISS-AF cohort study (mean age 73, 75% male) 90% of whom were under oral anticoagulation. Linear regression was used to investigate associations between log-transformed sNfL and (1) CHA2DS2-VASc alone, (2) CHA2DS2-VASc adjusted for age, and (3) all components of the score (congestive heart failure, hypertension, age, diabetes, stroke and TIA history, vascular disease, sex) in a multivariable analysis. 

FINDINGS:
sNfL was significantly associated with the CHA2DS2-VASc score (figure), also after correction for age (p<0.001). On average, sNfL levels increased by 22.3 % per unit increase in CHA2DS2-VASc score. In the multivariable model including the score components, age (4.7% increase per year) and diabetes (62.5% increase) were independently associated with sNfL (p<0.001 each), as was stroke history by trend (29.4% increase; p=0.06).

CONCLUSION:
Our findings indicate increasing subclinical neuroaxonal injury with increasing CHA2DS2-VASc score among patients with AF. The mechanisms underlying this association remain to be elucidated.

SERUM LIGHT-CHAIN NEUROFILAMENT, A BRAIN LESION MARKER, IS ASSOCIATED WITH THE CHA2DS2-VASC SCORE AMONG PATIENTS WITH ATRIAL FIBRILLATION: A CROSS-SECTIONAL STUDY