Predictors of left atrial appendage emptying velocity: Derivation and validation of CHIRP³(M_-1) score

Background: Atrial fibrillation (AF) leads to impaired left atrial appendage contractility, increasing the risk of thromboembolic stroke. The left atrial appendage emptying velocity (LAAev) measured on transesophageal echocardiogram (TEE) is a marker of increased thromboembolic risk.

Objectives: The purpose of this study was to evaluate predictors of reduced LAAev for identifying individuals at increased risk for cardioembolic stroke.

Methods: This was a single-center retrospective review of TEEs and clinical charts. Predictors of LAAev <30 cm/s were identified using logistic regression. A risk prediction model was created using stepwise selection in a derivation set (n = 695) and separately tested in a validated set (n = 300).

Results: We included TEEs on 995 patients (age 71.3±12.7 years; female 38.1%; history of AF 82.1%; in AF at evaluation 27.7%; CHA₂DS₂-VASc score 4.1 ± 1.9; LAAev 41.6 ± 21.0 cm/s). Significant multivariable predictors of LAAev <30 cm/s in derivation set were used to create the CHIRP³M_-1 score containing 8 variables: Coronary artery disease (1), congestive Heart failure (1), Increased left atrial volume index ≥42 mL/m² (1), current Rhythm AF (1), Paroxysmal AF (2), Persistent AF (3), longstanding Persistent/permanent AF (4), and greater than moderate Mitral regurgitation (-1). In the validation set, as compared to intermediate scores (3-4), those with low scores (≤2) and high scores (≥5) had odds ratios for LAAev <30 cm/s of 0.41 (0.21, 0.78, P = .007) and 2.58 (95% confidence interval 1.45-4.61, P = .001), respectively.

Conclusion: We developed and validated a novel risk stratification system to predict reduced LAAev using clinical and echocardiographic variables. This may help refine the stratification of cardioembolic stroke risk.