Doppler transesophageal echocardiographic determination of aortic valve area in adults with aortic stenosis

Abstract

Two-dimensional transesophageal echocardiography has been shown to be an accurate method of measuring aortic valve area in patients with aortic stenosis. The accuracy of Doppler transesophageal echocardiography for this purpose is unknown. Thus 86 consecutive adult patients (mean age 68 ± 11 years) with calcific ( n = 79) or congenital bicuspid ( n = 7) AS were studied by biplane or multiplane transesophageal echocardiography. From the transgastric long-axis view, continuous wave Doppler of peak aortic valve velocity and pulsed Doppler of left ventricular outflow tract velocity were determined. Left ventricular outflow tract diameter was measured from a transesophageal echocardiography long-axis view, and cross-sectional area was calculated. Aortic valve area was calculated by the continuity equation. Two-dimensional transesophageal echocardiography was used to directly measure aortic valve area by planimetry of the minimal orifice from a short-axis view. Aortic valve area determination was less feasible by Doppler (62 of 86 patients, or 72%) versus two-dimensional transesophageal echocardiography (81 of 86 patients, or 94%; p < 0.0025) because of the inability to align the continuous wave Doppler beam with the aorta in 24 patients. The feasibility of obtaining aortic valve area by Doppler transesophageal echocardiography improved from the first 43 patients (24 of 43 patients, or 56%) to the latter 43 patients (38 of 43 patients, or 88%; p < 0.0025) and suggests a significant learning curve. In 62 patients, aortic valve area by Doppler and two-dimensional transesophageal echocardiography did not differ (1.30 ± 0.54 cm 2 vs 1.23 ± 0.46 cm 2, p = not significant) and correlated well ( r = 0.88; standard error of the estimate = 0.26 cm 2; intercept = 0.02 cm 2; slope = 1.04; p = 0.0001). Absolute and percent differences between aortic valve area measured by Doppler and two-dimensional transesophageal echocardiography were small (0.18 ± 0.20 cm 2 and 15% ± 15%, respectively). Mild, moderate, and severe aortic stenosis by two-dimensional transesophageal echocardiography was correctly identified in 93% (28 of 30), 79% (15 of 19), and 77% (10 of 13) of patients by Doppler transesophageal echocardiography, respectively. Doppler transesophageal echocardiography is an accurate method to measure aortic valve area in patients with aortic stenosis and should complement two-dimensional transesophageal echocardiography. The feasibility of Doppler transesophageal echocardiography for aortic valve area determination has a significant learning curve