Impact of Three-Dimensional Imaging and Pressure Recovery on Echocardiographic Evaluation of Severe Aortic Stenosis: A Pilot Study

Abstract

AIMS: In patients with aortic stenosis (AS), echocardiographic grading of stenosis severity is important, in particular for transcatheter aortic valve implantation (TAVI). Three-dimensional (3D) echocardiography and correction for pressure recovery (PR) by energy loss index (ELI) may improve aortic valve area (AVA) calculation.

METHODS AND RESULTS: Thirty-nine patients with severe AS evaluated for TAVI were included. Left ventricular outflow tract (LVOT) and ascending aorta (AA) cross-sectional area were determined in transthoracic two-dimensional echocardiography (2DTTE), 2D transesophageal echocardiography (TEE), 3DTEE, and multislice computed tomography (MSCT). AVA was calculated by the continuity equation and corrected for PR. ELI was determined as [(AVA × AA)/(AA - AVA)]/body surface area. LVOT area was 2.41 ± 0.17 cm(2) calculated using 2DTTE, 2.82 ± 0.16 cm(2) calculated using 2DTEE, 3.96 ± 0.14 cm(2) planimetered in 3DTEE, and 4.47 ± 0.18 cm(2) planimetered in MSCT (P < 0.001). AA area was 4.62 ± 0.23 cm(2) calculated using 2DTTE, 4.64 ± 0.23 cm(2) calculated using 2DTEE, 5.35 ± 0.25 cm(2) planimetered in 3DTEE, and 6.56 ± 0.31 cm(2) planimetered in MSCT (P < 0.001). Indexed aortic valve area (AVAI) calculated by 2DTTE and 2DTEE was smaller (0.27 ± 0.02 cm(2) /m(2) and 0.32 ± 0.02 cm(2) /m(2) ) compared to 3DTEE (0.45 ± 0.02 cm(2) /m(2) ; P < 0.001). When AVAI determined by 3DTEE was corrected for PR by calculation of ELI, there was a further increase (0.52 ± 0.03 cm(2) /m(2) ; P < 0.001), and 10/36 (27.8%) patients were reclassified to moderate AS.

CONCLUSION: Three-dimensional TEE is more accurate than 2DTTE and 2DTEE for determining LVOT and AA dimensions. When AS severity is determined by 3DTEE and corrected for PR using the 3D values, it needs to be reclassified from severe to moderate in almost a third of patients.