Modified continuity equation using left ventricular outflow tract three‐dimensional imaging for aortic valve area estimation

Teixeira, Paulo Fonseca; Ramos, Rubén; Rio, Pedro; Branco, Luísa Moura; Portugal, Guilherme; Abreu, Ana; Galrinho, Ana; Marques, Hugo; Figueiredo, Luísa; Ferreira, Rui Cruz

doi:10.1111/echo.13589

Cited by 11 publications

(8 citation statements)

References 30 publications

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“…Transesophageal echocardiography (TOE) is a well-known and valid alternative to TTE to assess AV planimetry and provides a good visualization of LVOT. It has even been suggested that TOE could guarantee not only a more accurate planimetric valve area assessment than TTE but also a more reliable LVOT area calculation; consequently, a hybrid approach with TTE-derived VTI and TOE-derived LVOT area would give a more precise estimation of true AVA by continuity equation [ 12 ]. Also, the invasive measurements of left ventricle and aortic pressures can give a functional AVA estimation by the Gorlin equation or by the Hakki’s simplified version of the formula, during left heart catheterization.…”

Section: Severity Assessmentmentioning

confidence: 99%

How to deal with low-flow low-gradient aortic stenosis and reduced left ventricle ejection fraction: from literature review to tips for clinical practice

et al. 2021

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Low-flow low-gradient aortic stenosis (LFLG AS) with reduced left ventricle ejection fraction (LVEF) is still a diagnostic and therapeutic challenge. The aim of this paper is to review the latest evidences about the assessment of the valvular disease, usually difficult because of the low-flow status, and the therapeutic options. Special emphasis is given to the available diagnostic tools for the characterization of LFLG AS without functional reserve at stress echocardiography and to the factors that clinicians should evaluate to choose between surgical aortic valve repair, transcatheter aortic valve implantation, or medical therapy.

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Section: Severity Assessmentmentioning

confidence: 99%

How to deal with low-flow low-gradient aortic stenosis and reduced left ventricle ejection fraction: from literature review to tips for clinical practice

et al. 2021

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“…This is done by obtaining the LVOT diameter (D1) from the parasternal long‐axis view as measured from the inner edge to the inner edge within 0.3–1 cm below the aortic valve annulus and then applying the formula LVOT Area = π ( D /2) 2 , assuming a circular shape of the LVOT. However, 3D imaging techniques have shown that this shape is often elliptical, and only rarely circular . This leads to underestimation of LVOT area, and hence of AVA, by the CE.…”

Section: Introductionmentioning

confidence: 99%

“…However, 3D imaging techniques have shown that this shape is often elliptical, and only rarely circular. [8][9][10][11][12][13][14][15][16][17][18][19][20][21] This leads to underestimation of LVOT area, and hence of AVA, by the CE.…”

Section: Introductionmentioning

confidence: 99%

Aortic valve area using computed tomography‐derived correction factor to improve the validity of left ventricular outflow tract measurements

2020

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Aims Given the inherent inaccuracies stemming from the assumption that the left ventricular outflow tract (LVOT) is circular, this study aimed to improve the accuracy of transthoracic echocardiography (TTE)‐based aortic valve area (AVA) calculation using continuity equation (CE) by introducing a correction factor (CF) derived from multidetector computed tomography angiography (MDCTA) images and validate it in aortic stenosis (AS) patients. Methods and Results This retrospective study used MDCTA images of 400 patients for modeling and 403 TTE dataset for validation. Echocardiographic parasternal long‐axis view was modeled using MDCTA, and LVOT diameter (D1) was measured. Direct planimetry of LVOT area was performed and subsequently converted into a theoretical circle. The assumed circle (D2) diameter was derived, and D2/D1 was calculated and termed as the CF. The CF was 1.13, and it improved the agreement between MDCTA‐ and TTE‐derived LVOT areas and correlation between AVA and peak velocity, mean pressure gradient, and velocity ratio. In discordant subgroups of severe AS, the CF reclassified patients to moderate AS in 40% in the low flow (LF), low gradient (LG), and low ejection fraction (EF) group; 53% in the LF, LG, and normal EF group; and 68% in the LF, high gradient, and normal EF group. Conclusions CF of 1.13 derived from MDCTA improved the accuracy of TTE‐derived LVOT area and AVA and improved correlation with hemodynamic variables in AS patients. Reclassification of AS patients using CF may have clinical applicability for patient selection for early intervention.

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“…It is well known that the true LVOT shape is elliptical, and the circular assumption that underlies 2D echocardiographic measurement is a major source of error in the calculation of the aortic valve area . A hybrid approach has been proposed using direct planimetry of the LVOT area and Doppler‐derived hemodynamic assessment but it lacks robust clinical validation . Another approach includes substituting Doppler‐based stroke volume calculation by the stroke volume derived from 3D volumetric analysis .…”

Section: Aortic Stenosismentioning

confidence: 99%

“…60 A hybrid approach has been proposed using direct planimetry of the LVOT area and Doppler-derived hemodynamic assessment but it lacks robust clinical validation. 61,62 Another approach includes substituting Doppler-based stroke volume calculation by the stroke volume derived from 3D volumetric analysis. 63 The most studied application of 3D echocardiography has been direct 3D-guided 2D planimetry of the aortic valve area.…”

Section: Aortic Stenosismentioning

confidence: 99%

Echocardiographic 3D‐guided 2D planimetry in quantifying left‐sided valvular heart disease

Argulian

Seetharam

2018

Echocardiography

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Echocardiographic 3D-guided 2D planimetry can improve the accuracy of valvular disease assessment. Acquisition of 3D pyramidal dataset allows subsequent multiplanar reconstruction with accurate orthogonal plane alignment to obtain the correct borders of an anatomic orifice or flow area. Studies examining the 3D-guided 2D planimetry approach in left-sided valvular heart disease were identified and reviewed. The strongest evidence exists for estimating mitral valve area in patients with rheumatic mitral valve stenosis and vena contracta area in patients with mitral regurgitation (both primary and secondary). 3D-guided approach showed excellent feasibility and reproducibility in most studies, as well as time efficiency and good correlation with reference and comparator methods. Therefore, 3D-guided 2D planimetry can be used as an important clinical tool in quantifying left-sided valvular heart disease, especially mitral valve disorders.

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Modified continuity equation using left ventricular outflow tract three‐dimensional imaging for aortic valve area estimation

Abstract: 2DTTE and 3DTEE underestimate LVOT area when compared to MDCT with significant impact on AVA estimation. Assessment through MDCT fusion AVA may be of incremental value in patients with discrepant severity criteria for AS.

Cited by 11 publications

References 30 publications

How to deal with low-flow low-gradient aortic stenosis and reduced left ventricle ejection fraction: from literature review to tips for clinical practice

How to deal with low-flow low-gradient aortic stenosis and reduced left ventricle ejection fraction: from literature review to tips for clinical practice

Aortic valve area using computed tomography‐derived correction factor to improve the validity of left ventricular outflow tract measurements

Echocardiographic 3D‐guided 2D planimetry in quantifying left‐sided valvular heart disease

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