Dissociation between two-dimensional and three-dimensional echocardiography – clinical implications

Abstract Objectives To investigate the agreement between two-dimensional (2DE) and three-dimensional echocardiography (3DE) in a general population, along with clinical impact of the differences. Background Left ventricular ejection fraction (LVEF) has prognostic value and is used to guide cardiac treatment. The preferred technique is two-dimensional (2D) echo, although three-dimensional (3D) echo is more accurate when compared to MRI. Our study evaluates the agreement between 2D and 3D LVEF and the potential clinical impact of disagreements. Methods Study population ware participants from the Copenhagen City Heart Study, who underwent 2DE and 3DE between 2011–2014. Means of difference (MD) were assessed in participant groups with a LVEF below 40%, 40–50%, and above 50%. Age-adjusted Cox proportional hazard ratios (HR) were calculated for all-cause mortality, major adverse cardiovascular event (MACE) and cardiac event of any kind. Results In total 2554 participants from the Copenhagen City Heart Study were included. Median age was 58.3 (IQR: 44.2–69.8) years and 1137 (44.5%) were male. Mean LVEF in 2D was 56.6% (95% CI: 56.4–56.9%) and 52.0% (95% CI: 51.7–52.4%) in 3D, p<0.05. MD increased the further LVEF deteriorated: −14.9% (95% CI: −16.0 to −13.9%) (LVEF <40%), −9.3% (95% CI: −9.8 to −8.9%) (LVEF 40–50%) and −1.2% (95% CI: −1.6 to −0.9%) (LVEF ≥50%). 2DE overestimated the LVEF relative to 3D in 1824 (71.4%) instances. 3D LVEF <40% was associated with a HR for all-cause mortality of 2.58 (95% CI: 1.55–4.31, p<0.05), MACE: 1.90 (95% CI: 1.22–2.98, p<0.05) and cardiovascular event: 1.61 (95% CI: 1.04–2.48, p<0.05). HR for 2D LVEF <40% 0.84 (95% CI: 0.21–3.41, p=0.80) (all-cause), 3.12 (95% CI: 1.64–5.94, p<0.05) (MACE) and 2.68 (95% CI: 1.42–5.09, p<0.05) (cardiovascular event). Conclusion With declining LVEF, 2D echo is prone to significantly overestimate LVEF and a 3D LVEF less than 40% is associated with excess all-cause mortality but less with MACE and cardiovascular events when compared to 2D LVEF. Funding Acknowledgement Type of funding sources: None.