Comparing the utility of 3D vs 2D left atrial volumes by echocardiography to predict stroke in the general population

Abstract Background Left atrial (LA) volume dilatation is associated with stroke in the general population. Two-dimensional echocardiography (2DE) is commonly used to measure LA size but is known to underestimate LA volumes compared to three-dimensional echocardiography (3DE). It is unknown whether this difference has clinical significance. Purpose We hypothesized that LA volumes by 3DE are more closely associated with stroke risk than 2DE in the general population. Methods We included 2,085 participants from a longitudinal cohort study from the general population who underwent 3DE and 2DE assessment of maximal and minimal LA volume index (LAVimax and LAVimin, respectively). After excluding participants with poor image quality, low volume rate, atrial fibrillation at baseline and non-sinus-rhythm during examination, a total of 1,956 participants were included for this analysis. The endpoint was stroke. Multivariable Cox regression models were adjusted for the CHA2DS2-VASc stroke risk score (age, sex, heart failure, hypertension, stroke, vascular disease, and diabetes). Results Mean age was 54±17 years, 43% were male, mean CHA2DS2-VASc score was 1.6±1.3. During a median follow-up of 4.8 years (interquartile range 4.3-5.5 years), 36 participants (1.8%) developed stroke. After multivariable adjustment, 2D LA volumes were not associated with stroke, whereas both 3D-LAVimax (HR 1.03 (95% CI 1.00-1.06), p=0.046, per 1 mL/m2 increase) and 3D-LAVimin (HR 1.05 (95% CI 1.02-1.08), p=0.002, per 1 mL/m2 increase) remained significantly associated with stroke (Figure 1). In addition, 3D-LAVimin showed the highest discrimination for predicting stroke with a C-statistic of 0.70 (95% CI: 0.59-0.80), which was significantly higher than 2D-LAVimax (C-statistic: 0.58 (95% CI 0.48-0.69); p=0.02), 2D-LAVimin (C-statistic: 0.54 (95% CI 0.42-0.65); p<0.001) and 3D-LAVimax (C-statistic: 0.62 (95% CI 0.52-0.73); p=0.004). 3D-LAVimin also showed incremental prognostic information when added to the CHA2DS2-VASc risk score (continuous net reclassification index 0.28±0.17; p=0.047). Conclusion Increasing 3D-LA volumes are significantly associated with higher risk of stroke in the general population which was not the case for 2D-derived LA volumes.