Stroke risk stratification by coronary artery disease extent in patients with atrial fibrillation

Introduction Atrial fibrillation (AF) is closely associated with ischemic stroke events, and the CHA2DS2-VASc score is the most widely used tool for stroke risk prediction. The vascular component of the CHA2DS2-VASc score includes significant coronary artery disease (CAD) on angiography or cardiac imaging. However, the supporting evidence is weak for the definition or extent of CAD, only derived from a Danish population. Purpose we aimed to validate the association between ischemic stroke risk and the extent of CAD in patients with AF, and without the history of CAD. Methods Among 27,964 patients who underwent cardiac computed tomography or invasive coronary angiography between 2006 and 2025, a total of 2,898 patients were selected who have AF without history of myocardial infarction, angina and previous percutaneous coronary intervention. The primary endpoint was the incidence of ischemic stroke within 3 years after the baseline stratified by coronary artery stenosis severity: None (0%), mild (1–49%), moderate (50–69%), and severe (≥70%). To reduce confounding, inverse probability weighting was applied, and the risks were estimated using Cox hazards models. Results The 3-year ischemic stroke incidence demonstrated a significant increasing trend across stenosis grades: None 5.8%, mild 4.6%, moderate 6.3%, severe 7.3% (trend p = 0.007). Survival curves were similar among the none to moderate groups (minimum log-rank p = 0.216), but diverged significantly for the severe group (moderate vs. severe: log-rank p = 0.003). Adjusted hazard ratios (HRs) for the primary end-point by age were: age 65–74 years, HR 1.75 (95% CI, 1.36–2.26; p < 0.001); age ≥75 years, HR 2.84 (95% CI, 2.22–3.63; p < 0.001). Adjusted HRs for the primary end-point by coronary stenosis severity were: mild 0.90 (95% CI, 0.68–1.18; p = 0.435); moderate 1.22 (95% CI, 0.94–1.59; p = 0.138); Severe 1.52 (95% CI, 1.15–2.01; p = 0.003). Only severe coronary stenosis (≥70%) remained an independent predictor of stroke among patient with AF. Conclusion These findings suggest that coronary stenosis less than 70% may have limited value for stroke risk prediction in patients with AF, although external validation is warranted.