European Journal of Echocardiography Advance Access published online on October 2, 2008
European Journal of Echocardiography, doi:10.1093/ejechocard/jen254
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Accuracy and reproducibility of left ventricular outflow tract diameter measurement using transthoracic when compared with transesophageal echocardiography in systole and diastole
Department of Cardiovascular Medicine, Lady Davis Carmel Medical Center Israel, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 7 Michal Street, Haifa 34362, Israel
Received 13 March 2008; accepted after revision 10 September 2008.
* Corresponding author. Tel: +972 4 825 0507; fax: +972 4 834 3755. E-mail address: shiranad{at}012.net.il
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Abstract |
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Aims: Accurate measurement of left ventricular outflow tract diameter (LVOTd) is essential for reliable estimation of aortic valve area (AVA) using the continuity equation. Transesophageal echocardiography (TEE) can accurately delineate the LVOT. The aim of this study was to assess the accuracy and reproducibility of LVOTd measurement using transthoracic echocardiography (TTE) with harmonic imaging when compared with TEE, in both systole and diastole.
Methods and results: We prospectively studied 50 patients [20 with aortic stenosis (AS) and 30 without AS]. LVOTd was measured offline in a blinded fashion in both systole and diastole by two experienced observers using TTE in the parasternal long axis view and TEE in the mid-oesophageal aortic view (
130°). There was strong correlation between TTE and TEE (r = 0.91). LVOTd was slightly smaller by TTE when compared with TEE (2.11 ± 0.21 vs. 2.16 ± 0.22 cm, mean difference –0.05 ± 0.09 cm, P = 0.0003). Compared with TEE, 95% (2SD) of LVOTd measurements by TTE were within +0.14 and –0.24 cm. Inter- and intra-observer variability for LVOTd was 4.8 ± 4.1 and 2.8 ± 1.9% for TTE and 4.2 ± 3.1 and 2.5 ± 1.6% for TEE (P = 0.4 and 0.6). In patients with AS, estimated AVA was 0.93 ± 0.22 cm2 using TTE and 0.96 ± 0.24 cm2 using TEE, P = 0.08. Diastolic LVOTd by TEE was slightly smaller compared with systolic LVOTd by TEE (–0.03 ± 0.07 cm, P = 0.0005), and there was strong correlation between the two (r = 0.95).
Conclusion: We present the data regarding accuracy and reproducibility of LVOTd measurements by TTE when compared with TEE. LVOTd measurements at end-diastole may be helpful when systolic images are suboptimal.
Keywords: Left ventricular outflow tract; Aortic stenosis; Continuity equation; Transthoracic echocardiography; Transesophageal echocardiography