Left Atrial Geometry Improves Risk Prediction of Thromboembolic Events in Patients With Atrial Fibrillation

Abstract

Background: Left atrial (LA) sphericity (LASP) is a new remodeling parameter based on LA shape analysis, with independent predictive value for recurrence after atrial fibrillation (AF) ablation.

Objectives: To evaluate the association between LASP and thromboembolic events (TE) in patients with AF.

Methods: Twenty-nine AF patients and prior TE and 29 age- and gender-matched controls were included. LASP was calculated using a 3D-LA reconstruction. The LA appendage (LAA) volume and morphology were assessed. ROC curve analysis was performed for LASP, LA volume, LAA volume, and CHAD/CHA2 D-VASc scores (Stroke2 -the grouping variable-was excluded).

Results: Mean age of the study population was 61 ± 11 years (79.3% males, 53.4% hypertension, 8.6% diabetes). Patients with prior TE had higher LASP than those without (82.5 ± 3.3% vs. 80.2 ± 3.1%, P = 0.008); there were no differences in CHAD or CHA2 D-VASc scores, LA volume, LAA volume, or LAA morphology. The C-statistic was higher for LASP (0.71) than for other tested variables (CHAD score = 0.58, CHA2 D-VASc score = 0.59, LA volume = 0.50, LAA volume = 0.46; P < 0.01 for all vs. LASP). The best cutoff value for LASP was 83.6% (sensitivity 0.52, specificity 0.90). Logistic regression analysis showed predictive value for LASP (OR 1.26 per each 1% increase [1.85-52.20], P = 0.013), but not for clinical risk scores. The addition of LASP to the CHAD and CHA2 D-VASc scores increased the predictive value over the risk scores alone (P = 0.004), and reclassified 45.5% of patients with CHAD = 0 (no anticoagulation indicated) to moderate-risk (anticoagulation indicated).

Conclusion: LA sphericity is associated with prior TE in AF patients and improves the performance of the CHAD and CHA2 D-VASc scores alone.

Keywords: atrial fibrillation; catheter ablation; left atrial remodeling; sphericity; stroke; thromboembolism.