title: Comparison of left ventricular outflow geometry and aortic valve area in patients with aortic stenosis by 2-dimensional versus 3-dimensional echocardiography.
abstract: The present study sought to elucidate the geometry of the left ventricular outflow tract (LVOT) in patients with aortic stenosis and its effect on the accuracy of the continuity equation-based aortic valve area (AVA) estimation. Real-time 3-dimensional transesophageal echocardiography (RT3D-TEE) provides high-resolution images of LVOT in patients with aortic stenosis. Thus, AVA is derived reliably with the continuity equation. Forty patients with aortic stenosis who underwent 2-dimensional transthoracic echocardiography (2D-TTE), 2-dimensional transesophageal echocardiography (2D-TEE), and RT3D-TEE were studied. In 2D-TTE and 2D-TEE, the LVOT areas were calculated as π × (LVOT dimension/2)(2). In RT3D-TEE, the LVOT areas and ellipticity ([diameter of the anteroposterior axis]/[diameter of the medial-lateral axis]) were evaluated by planimetry. The AVA is then determined using planimetry and the continuity equation method. LVOT shape was found to be elliptical (ellipticity of 0.80 ± 0.08). Accordingly, the LVOT areas measured by 2D-TTE (median 3.7 cm(2), interquartile range 3.1 to 4.1) and 2D-TEE (median 3.7 cm(2), interquartile range 3.1 to 4.0) were smaller than those by 3D-TEE (median 4.6 cm(2), interquartile range 3.9 to 5.3; p <0.05 vs both 2D-TTE and 2D-TEE). RT3D-TEE yielded a larger continuity equation-based AVA (median 1.0 cm(2), interquartile range 0.79 to 1.3, p <0.05 vs both 2D-TTE and 2D-TEE) than 2D-TTE (median 0.77 cm(2), interquartile range 0.64 to 0.94) and 2D-TEE (median 0.76 cm(2), interquartile range 0.62 to 0.95). Additionally, the continuity equation-based AVA by RT3D-TEE was consistent with the planimetry method. In conclusion, RT3D-TEE might allow more accurate evaluation of the elliptical LVOT geometry and continuity equation-based AVA in patients with aortic stenosis than 2D-TTE and 2D-TEE.
authors.affiliation: Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, and UCLA, Los Angeles, California, USA. shiotat@cshs.org
authors.forename: Takeji
authors.initials: T
authors.lastname: Saitoh
authors.forename: Maiko
authors.initials: M
authors.lastname: Shiota
authors.forename: Masaki
authors.initials: M
authors.lastname: Izumo
authors.forename: Swaminatha V
authors.initials: SV
authors.lastname: Gurudevan
authors.forename: Kirsten
authors.initials: K
authors.lastname: Tolstrup
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Siegel
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shiota
mesh_terms: D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging*; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging*; D019560:Echocardiography, Three-Dimensional; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012720:Severity of Illness Index