Comparing the prognostic efficacy of 2D and 3D left atrial emptying fraction for the prediction of heart failure in the general population

Abstract Background The left atrial (LA) emptying fraction (LAEF) has previously been found to be associated with heart failure (HF). Three-dimensional (3D) echocardiography) has several advantages over 2-dimensional (2D) echocardiography, but the value of 3D- derived LAEF compared to 2D-derived LAEF remains uncertain. In this study, we hypothesized that 3D-derived LAEF is superior to LAEF by 2D. Purpose Our aim was to compare the prognostic value of 2D and 3D LAEF for predicting heart failure in the general population. Methods A total of 1,978 participants without HF from a general population study underwent comprehensive transthoracic echocardiographic that included LAEF assessment by both 2D (2D-LAEF) and 3D (3D-LAEF) echocardiography. The endpoint was incident HF. Cox proportional hazards regression was applied. Multivariable adjustments were made for the ARIC-HF risk score (age, gender, heart rate, systolic blood pressure, antihypertensive medication, diabetes, ischemic heart disease, smoking, and body mass index). Incremental information was evaluated using the continuous net reclassification index (NRI). Reduced LAEF was defined as values below the 5th centile (2D-LAEF23% and 3D-LAEF47%). Results Overall, the mean age was 54±17 years and 43% were men. During a median follow-up time of 4.8 years (IQR 4.3-5.5 years), 35 participants (1.8%) developed HF. At baseline, mean 2D-LAEF was 42.2±14.2%, and 3D-LAEF was 59.3±7.0. There was a statistically significant but low correlation between 2D-LAEF and 3D-LAEF (Spearman’s rho = 0.14;p0.001) In univariable analysis, both 2D-LAEF and 3D-LAEF were significantly associated with HF (2D-LAEF: HR 1.04 (95% CI 1.02-1.07); p=0.002, per 1% decrease; 3D-LAEF: HR 1.12 (95% CI 1.08-1.16), p0.001, per 1% decrease). After multivariable adjustments, only 3D-LAEF remained significantly associated with HF ((HR 1.06 (95% CI 1.02-1.09), p=0.003, per 1% decrease), whereas 2D-LAEF was not (HR 1.02 (95% CI 0.99-1.05), p=0.12, per 1% decrease). These findings remained unchanged after adjusting for atrial fibrillation at baseline. 3D-LAEF added incremental prognostic information when added to the ARIC-HF risk score (continuous NRI 0.32±0.17, p=0.03). Participants with reduced 3D-LAEF had a higher risk of HF (HR 3.86 (95% CI 1.88-7.91); p0.001). Contrary, participants with reduced 2D-LAEF did not have an increased risk of HF (HR1.34 (95% CI 0.51-3.55);p=0.56) Conclusion LAEF measured using 3DE is independently associated with HF and provides incremental prognostic information, which LAEF measured by 2DE does not.