Background: Energy loss index (ELI) and valvuloarterial impedance (Z(va)) have been evaluated with a lack of three-dimensional (3D) information regarding the left ventricular outflow tract (LVOT) and sino-tubular junction (STJ). Our aim of this study is to compare the difference of ELI and Z(va) between two-dimensional (2D) and 3D echocardiography.
Methods: In 74 patients with moderate-to-severe aortic stenosis, the effective orifice area index (EOAI: EOA/body surface area) was calculated by continuity equation based on both 2D transthoracic echocardiography (2DTTE) and 3D transesophageal echocardiography (3DTEE). The areas of the LVOT and the STJ were calculated with the assumption of π × (dimension/2)(2) by 2DTTE and were measured directly by 3DTEE. Severe AS was defined as EOAI or ELI <0.6 cm(2) /m(2) or Z(va) ≥ 4.5 mmHg/mL per m(2) .
Results: Both the LVOT and STJ were elliptical, and LVOT was more elliptical than STJ. The ELI by 3DTEE (0.58 cm(2) /m(2) [median]) was larger than the other 3 values: EOAI on 2DTTE = 0.41, P < 0.01; EOAI on 3DTEE = 0.49, P < 0.01; and ELI on 2DTTE = 0.49, P < 0.01. Furthermore, Z(va) by 2DTTE, 4.7 mmHg/mL per m(2), was larger than that by 3DTEE (3.8, P < 0.01).
Conclusions: 2DTTE underestimated EOAI and ELI relative to 3DTEE and overestimated Z(va) relative to 3DTEE.
Keywords: aortic valve stenosis; diagnosis; three-dimensional echocardiography.
© 2014, Wiley Periodicals, Inc.