A novel scoring system for stroke risk stratification in Japanese patients with low CHADS2 scores: Study using a transesophageal‐echocardiogram endpoint

BACKGROUND: Catheter ablation is an effective treatment for atrial fibrillation (AF), but it carries risk of perioperative thromboembolism even in cases with low CHADS2 scores. Here, we examined whether a combination of clinical variables can predict stroke risk factors that are assessed by transesophageal echocardiography (TEE). METHODS: The study population consisted of 209 consecutive AF patients with a CHADS2 score of 0 or 1 (58.7 ± 10.6 years old; persistent AF, 33.0%). All patients underwent TEE, and TEE‐determined stroke risk (TEE risk) was defined as cardiac thrombus/sludge, dense spontaneous echo contrast (SEC), and/or peak left atrial appendage (LAA) flow velocity <0.25 m/s. RESULTS: Transesophageal echocardiography risk was observed in 10.5% of the patients. In multivariate logistic analysis, persistent AF [odds ratio (OR): 11.5, CI: 3.14‐42.1, P = .0002], left atrial diameter (LAD) (OR: 1.10, CI: 1.01‐1.20, P = .0293), contrast medium defect (CMD) in the LAA detected by computed tomography (OR: 20.2, CI: 6.3‐65.0, P < .0001), and serum brain natriuretic peptide (BNP) level (OR: 1.00, CI: 1.00‐1.01, P = .0056) were independent predictors of TEE risk. A new scoring system comprising LAD > 41 mm (1 point), BNP > 47 pg/mL (1 point), CMD (2 points), and persistent AF (2 points) was constructed and defined as TEE‐risk score. The area under the curve (AUC) for prediction of TEE risk was 0.631 in modified CHADS2 score and it was 0.852 in TEE‐risk score. CONCLUSION: Transesophageal echocardiography risk is predictable by TEE‐risk score, and its combination with CHADS2 score may improve the stroke risk stratification in AF patients with a low CHADS2 score.