Refining Residual Ischemic Stroke Risk in Anticoagulated Atrial Fibrillation Using Index Outpatient LA Diameter: The CHA2DS2-VALa Score.

Background

Atrial fibrillation (AF) increases ischemic stroke risk nearly fivefold. Although the CHA2DS2-VA score is widely used for risk stratification, its predictive performance is limited, particularly in intermediate-risk patients. Left atrial (LA) enlargement, a marker of structural remodeling, may improve risk prediction.

Aims

To evaluate whether adding LA diameter to CHA2DS2-VA (creating CHA2DS2-VALa) enhances ischemic stroke prediction in AF patients. We additionally derived a multivariable β-weighted model and benchmarked its performance against CHA2DS2-VA (and the simplified +1 LA rule).

Methods

This retrospective study included 1648 AF patients. LA diameter was measured by standardized echocardiography. A ROC-derived cut-off (> 4.7 cm) defined enlargement. Patients were followed for a mean of 4.18 ± 0.35 years. Imaging-confirmed ischemic stroke events were identified through institutional hospital records and the electronic health registry, and were validated using hospitalization documentation, neurology consultation notes, discharge summaries, and available brain CT/MRI findings. Predictors were assessed using multivariable logistic regression, and Kaplan-Meier/log-rank analyses compared CHA2DS2-VALa versus CHA2DS2-VA.

Results

Imaging-confirmed ischemic stroke events occurred more frequently in patients with LA > 4.7 cm (25 [3.8%] vs. 21 [2.1%], p < 0.001). Elevated CRP, NT-proBNP, diabetes, hypertension, CAD, and heart failure were also associated with stroke. LA > 4.7 cm independently predicted events (OR 1.97, 95% CI 1.36-2.86, p < 0.001). ROC analysis showed strong discrimination for LA diameter (AUC 0.872; sensitivity 82%, specificity 85%). Kaplan-Meier analysis demonstrated superior prediction with CHA2DS2-VALa compared to CHA2DS2-VA (log-rank p < 0.001).

Conclusion

The CHA2DS2-VALa score significantly improves stroke risk stratification in AF by integrating LA diameter into conventional scoring. As echocardiographic measurement is widely available and reproducible, this modification offers a simple, pragmatic approach to refine residual stroke-risk stratification and support closer evaluation and follow-up in anticoagulated AF patients. Prospective validation in diverse populations is warranted.