Identification of Markers Associated With Development of Stroke in "Clinically Low-Risk" Atrial Fibrillation Patients

Area of Science:

• Cardiology
• Neurology
• Internal Medicine

Background:

• Atrial fibrillation (AF) patients with low CHA2DS2-VASc scores are considered clinically low-risk for stroke.
• However, thromboembolic events can still occur in this population.
• Risk stratification in low-risk AF patients requires further refinement.

Purpose of the Study:

• To determine the proportion of AF-associated stroke patients with a CHA2DS2-VA score of 0-1.
• To identify clinical markers associated with stroke in "clinically low-risk" AF patients.
• To develop a refined risk assessment tool for stroke in AF.

Main Methods:

• Retrospective analysis of nonvalvular AF patients who experienced embolic stroke between 2013-2016 across 9 Korean institutes.
• Analysis of AF patients with CHA2DS2-VA score of 0-1 at the time of stroke.
• Comparison with clinically low-risk AF patients without stroke.

Main Results:

• Out of 3033 AF-associated stroke patients, 583 (19.2%) had a CHA2DS2-VA score of 0-1.
• Multivariate analysis identified age (≥60 years), N-terminal pro B-type natriuretic peptide (≥300 pg/mL), creatinine clearance (<50 mL/min), and left atrial dimension (≥45 mm) as independent stroke predictors.
• The combined ABCD score using these four factors demonstrated a high predictive value (c-index=0.858) in low-risk patients.

Conclusions:

• A significant proportion of AF patients experiencing stroke are initially classified as "clinically low-risk" based on CHA2DS2-VA score.
• The ABCD score, incorporating age, NT-proBNP, creatinine clearance, and left atrial dimension, effectively refines stroke risk stratification in low-risk AF patients.
• This approach offers improved identification of patients who may benefit from anticoagulation therapy.