Recommended Standards for the Performance of Transesophageal Echocardiographic Screening for Structural Heart Intervention: From the American Society of Echocardiography

Abstract

•Pre-interventional TEE acquired by a level II trained echocardiographer is standard practice.•The current reference guideline focuses on the acquisition of pre-interventional TEE images that would help accurately identify the mechanism, severity and anatomy of structural/valvular dysfunction.•Imaging protocols should be tailored to be comprehensive but focused on the abnormal structure identified and/or transcatheter intervention under consideration.•Appropriate image acquisition will facilitate assessment of device candidacy, procedural planning and intra-procedural imaging guidance. Attention ASE Members:Visit www.ASELearningHub.org to earn free continuing medical education credit through an online activity related to this article. Certificates are available for immediate access upon successful completion of the activity. Nonmembers will need to join the ASE to access this great member benefit!This document is endorsed by the following American Society of Echocardiography International Alliance Partners: Argentine Federation of Cardiology; Argentine Society of Cardiology; ASEAN Society of Echocardiography; Australasian Society for Ultrasound in Medicine; British Heart Valve Society; Canadian Society of Echocardiography; Chinese Society of Cardiothoracic and Vascular Anesthesiology; Chinese Society of Echocardiography; Cuban Society of Cardiology, Echocardiography Section; Indian Academy of Echocardiography; Indonesian Society of Echocardiography; Iranian Society of Echocardiography; Israel Working Group on Echocardiography; Italian Association of Cardiothoracic Anaesthesiologists; Japanese Society of Echocardiography; Korean Society of Echocardiography; Mexican Society of Echocardiography and Cardiovascular Imaging; National Association of Cardiologists of Mexico, AC; National Society of Echocardiography of Mexico, AC; Philippine Society of Echocardiography; Saudi Arabian Society of Echocardiography; Society of Cardiovascular Images of the Inter-American Society of Cardiology; Thai Society of Echocardiography; The Pan-African Society of Cardiology; Venezuelan Society of Cardiology, Echocardiography Section; and Vietnamese Society of Echocardiography. Visit www.ASELearningHub.org to earn free continuing medical education credit through an online activity related to this article. Certificates are available for immediate access upon successful completion of the activity. Nonmembers will need to join the ASE to access this great member benefit! This document is endorsed by the following American Society of Echocardiography International Alliance Partners: Argentine Federation of Cardiology; Argentine Society of Cardiology; ASEAN Society of Echocardiography; Australasian Society for Ultrasound in Medicine; British Heart Valve Society; Canadian Society of Echocardiography; Chinese Society of Cardiothoracic and Vascular Anesthesiology; Chinese Society of Echocardiography; Cuban Society of Cardiology, Echocardiography Section; Indian Academy of Echocardiography; Indonesian Society of Echocardiography; Iranian Society of Echocardiography; Israel Working Group on Echocardiography; Italian Association of Cardiothoracic Anaesthesiologists; Japanese Society of Echocardiography; Korean Society of Echocardiography; Mexican Society of Echocardiography and Cardiovascular Imaging; National Association of Cardiologists of Mexico, AC; National Society of Echocardiography of Mexico, AC; Philippine Society of Echocardiography; Saudi Arabian Society of Echocardiography; Society of Cardiovascular Images of the Inter-American Society of Cardiology; Thai Society of Echocardiography; The Pan-African Society of Cardiology; Venezuelan Society of Cardiology, Echocardiography Section; and Vietnamese Society of Echocardiography. In the American Society of Echocardiography (ASE) guidelines for performing a comprehensive transesophageal echocardiographic (TEE) examination, a standard 28-view (Table 1) imaging protocol as well as specific structural imaging assessments were introduced.1Hahn R.T. Abraham T. Adams M.S. Bruce C.J. Glas K.E. Lang R.M. et al.Guidelines for performing a comprehensive transesophageal echocardiographic examination: recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists.J Am Soc Echocardiogr. 2013; 26: 921-964Abstract Full Text Full Text PDF PubMed Scopus (568) Google Scholar Interventional echocardiography is increasingly recognized as a subspecialty requiring advanced training for intraprocedural guidance.2Wiegers S.E. Ryan T. Arrighi J.A. Brown S.M. Canaday B. Damp J.B. et al.2019 ACC/AHA/ASE advanced training statement on echocardiography (revision of the 2003 ACC/AHA clinical competence statement on echocardiography): a report of the ACC Competency Management Committee.J Am Soc Echocardiogr. 2019; 32: 919-943Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar, 3Hahn R.T. Mahmood F. Kodali S. Lang R. Monaghan M. Gillam L.D. et al.Core competencies in echocardiography for imaging structural heart disease interventions: an expert consensus statement.JACC Cardiovasc Imaging. 2019; 12: 2560-2570Crossref PubMed Scopus (15) Google Scholar, 4Otto C.M. Nishimura R.A. Bonow R.O. Carabello B.A. Erwin III, J.P. Gentile F. et al.2020 ACC/AHA guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.J Am Coll Cardiol. 2021; 77: 450-500Crossref PubMed Scopus (99) Google Scholar However, acquisition of preinterventional TEE images by a level II–trained echocardiographer is accepted standard practice. The purpose of the present document is to provide a reference guideline focused on the acquisition of essential preinterventional TEE images that would help identify (1) the mechanism of structural or valvular dysfunction, (2) the hemodynamic and anatomic severity of the disease, and (3) the specific anatomic features that allow appropriate device selection or exclusion. Intraprocedural imaging, whether by transesophageal or intracardiac echocardiography, is not covered, but rather a general approach to TEE screening of the structural target (e.g., aortic valve [AV], mitral valve [MV], or tricuspid valve [TV]; left atrial appendage [LAA]; septal defect) is described. It is not our intent to suggest that complete imaging protocols specific to each structure should be performed in all patients. Rather, protocols should be tailored to be comprehensive but focused on the abnormal structure identified and/or transcatheter intervention under consideration, thus facilitating assessment of device candidacy, procedural planning, and intraprocedural imaging guidance.Table 1Comprehensive TEE examination views30 views of the comprehensive TEE examination∗For tables of the original 28 views, see Hahn et al.1 1. ME five-chamber view 2. ME four-chamber view 3. ME mitral commissural view 4. ME two-chamber view 5. ME long-axis view 6. ME AV view 7. ME ascending aorta long-axis view 8. ME ascending aorta SAX view 9. ME right pulmonary vein view 10. ME AV SAX view 11. ME right ventricular inflow-outflow view 12. ME modified bicaval TV view 13. ME bicaval view 14. ME right and left pulmonary veins view 15. ME LAA view 16. TG basal SAX view 17. TG LV midpapillary SAX view 18. TG ventricular apical SAX view 19. TG right ventricular basal view 20. TG right ventricular inflow-outflow view 21. DT five-chamber view 22. TG two-chamber view 23. TG RV inflow view 24. TG long-axis view 25. TG to ME descending aorta (SAX) 26. TG to ME descending aorta (long axis) 27. UE aortic arch SAX to long axis 28. UE aortic arch SAX viewAdditional imaging level and views 29. DE right ventricular two-chamber view 30. DE right ventricular inflow-outflow viewRV, Right ventricular.∗ For tables of the original 28 views, see Hahn et al.1Hahn R.T. Abraham T. Adams M.S. Bruce C.J. Glas K.E. Lang R.M. et al.Guidelines for performing a comprehensive transesophageal echocardiographic examination: recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists.J Am Soc Echocardiogr. 2013; 26: 921-964Abstract Full Text Full Text PDF PubMed Scopus (568) Google Scholar Open table in a new tab RV, Right ventricular. The present document is divided as follows: section I offers a review of the comprehensive TEE examination, including basic two-dimensional (2D) and three-dimensional (3D) image acquisition. Section II presents structure-specific imaging protocols for assessment of the AV, MV, pulmonic valve (PV), TV, left atrial appendage, atrial septum, and ventricular septum. The American College of Cardiology clinical competence statement on echocardiography5Quinones M.A. Douglas P.S. Foster E. Gorcsan III, J. Lewis J.F. Pearlman A.S. et al.ACC/AHA clinical competence statement on echocardiography: a report of the American College of Cardiology/American Heart Association/American College of Physicians-American Society of Internal Medicine Task Force on Clinical Competence.J Am Soc Echocardiogr. 2003; 16: 379-402Abstract Full Text Full Text PDF PubMed Google Scholar addresses the minimum knowledge required for the performance and interpretation of transesophageal and perioperative echocardiography in adults. For structural heart intervention screening, we recommend acquiring the 28 views of the comprehensive TEE examination1Hahn R.T. Abraham T. Adams M.S. Bruce C.J. Glas K.E. Lang R.M. et al.Guidelines for performing a comprehensive transesophageal echocardiographic examination: recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists.J Am Soc Echocardiogr. 2013; 26: 921-964Abstract Full Text Full Text PDF PubMed Scopus (568) Google Scholar whenever possible (Table 1). The 2013 transesophageal echocardiography guideline defined the terminology for probe manipulation (Figure 1A), and while the 2013 guideline defines the terminology for four levels of imaging (Figure 1B) as upper esophageal (UE), midesophageal (ME), transgastric (TG) and deep TG (DT), the current guideline adds a fifth level of imaging, the deep esophageal (DE) view between the ME and TG levels, which is particularly useful for imaging right heart structures (Table 1, Figure 1B). In this document we describe the image acquisition required for valvular disease quantitation, but the reader is otherwise referred to the referenced guidelines for details of functional assessment.6Zoghbi W.A. Adams D. Bonow R.O. Enriquez-Sarano M. Foster E. Grayburn P.A. et al.Recommendations for noninvasive evaluation of native valvular regurgitation: a report from the American Society of Echocardiography developed in collaboration with the Society for Cardiovascular Magnetic Resonance.J Am Soc Echocardiogr. 2017; 30: 303-371Abstract Full Text Full Text PDF PubMed Scopus (1163) Google Scholar,7Baumgartner H. Hung J. Bermejo J. Chambers J.B. Edvardsen T. Goldstein S. et al.Recommendations on the echocardiographic assessment of aortic valve stenosis: a focused update from the European Association of Cardiovascular Imaging and the American Society of Echocardiography.J Am Soc Echocardiogr. 2017; 30: 372-392Abstract Full Text Full Text PDF PubMed Google Scholar Of note, with any structural heart pathology, an assessment of pulmonary artery (PA) systolic pressure, derived from the tricuspid regurgitant jet and an estimate of right atrial pressure, is recommended.8Lang R.M. Badano L.P. Mor-Avi V. Afilalo J. Armstrong A. Ernande L. et al.Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging.J Am Soc Echocardiogr. 2015; 28: 1-39.e14Abstract Full Text Full Text PDF PubMed Scopus (5393) Google Scholar Note that when tricuspid regurgitation (TR) is severe, this method may be less accurate.9Ozpelit E. Akdeniz B. Ozpelit E.M. Tas S. Alpaslan E. Bozkurt S. et al.Impact of severe tricuspid regurgitation on accuracy of echocardiographic pulmonary artery systolic pressure estimation.Echocardiography. 2015; 32: 1483-1490Crossref PubMed Scopus (10) Google Scholar There are a variety of methods for assessing PA mean and diastolic pressures if these measurements are required.10Rudski L.G. Lai W.W. Afilalo J. Hua L. Handschumacher M.D. Chandrasekaran K. et al.Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography.J Am Soc Echocardiogr. 2010; 23 (quiz 86-8): 685-713Abstract Full Text Full Text PDF PubMed Scopus (4236) Google Scholar The assessment of structural heart disease abnormalities requires a full understanding of 3D technical principles as well as a systematic approach to image acquisition, analysis, and display of the various cardiac structures, including knowledge of the limitations of the different 3D techniques, described in prior ASE guidelines.11Lang R.M. Badano L.P. Tsang W. Adams D.H. Agricola E. Buck T. et al.EAE/ASE recommendations for image acquisition and display using three-dimensional echocardiography.J Am Soc Echocardiogr. 2012; 25: 3-46Abstract Full Text Full Text PDF PubMed Scopus (459) Google Scholar Advanced 3D imaging display and navigational tools may be helpful (Figure 2). Acquiring 3D volumes of the cardiac structures (i.e., valves and LAA) should be a standard part of the TEE examination, permitting immediate as well as postacquisition processing. The methods available for 3D data acquisition include (1) simultaneous multiplane or biplane imaging, (2) real-time or live 3D imaging, and (3) electrocardiographically triggered multiple-beat 3D imaging. The 3D study usually starts with real-time imaging modes such as live and narrow-angle acquisition. However, gated 3D modes, including 3D color Doppler, should also be used whenever electrocardiographic gating is possible to take advantage of the improved spatial and temporal resolution of these wide-angle acquisitions (Figure 3). Current 3D systems have different resolutions for each of the three dimensions, with axial resolution (∼0.5 mm) better than lateral or azimuthal (∼2.5 mm) and elevational resolutions (∼3 mm).12Badano L.P. Agricola E. Perez de Isla L. Gianfagna P. Zamorano J.L. Evaluation of the tricuspid valve morphology and function by transthoracic real-time three-dimensional echocardiography.Eur J Echocardiogr. 2009; 10: 477-484Crossref PubMed Scopus (95) Google Scholar These differences create “nonisotropic voxels” such that slight changes in imaging angles or levels may result in a different 3D echocardiographic appearance of the same cardiac structure. Awareness of these limitations will help determine the best imaging plane(s) for a specific abnormality. Optimization and alignment of cross-sectional 2D imaging planes within the 3D volume, or multiplanar reconstruction, allows accurate quantification of structural dimensions and areas. Measuring directly on a 3D-rendered image is discouraged because (1) the object to be measured may be off axis in the 3D volume, changing the structural appearance compared with an on-axis image (i.e., parallax), and (2) increased slice thickness of a 3D volume may accentuate structures in the near or far field, preventing a clear delineation of the structure of interest. A three-step approach, described in Figure 4, can be used to align a 2D imaging plane within the 3D volume using on-cart software. More recent advances (real-time multiplanar reconstruction) enable 2D reconstruction of real-time 3D acquisitions. A multibeat spliced image is not typically used when precise measurements (e.g., aortic annular area or perimeter) are required because undetectable splice artifacts may significantly affect the measurements. When multibeat acquisitions are required (e.g., to optimize volume rates), using this multiplane display will depict the subvolumes in the elevational plane, allowing the imager to choose multibeat volumes without obvious splice artifacts. Other 3D artifacts are listed in Table 2.13Faletra F.F. Ramamurthi A. Dequarti M.C. Leo L.A. Moccetti T. Pandian N. Artifacts in three-dimensional transesophageal echocardiography.J Am Soc Echocardiogr. 2014; 27: 453-462Abstract Full Text Full Text PDF PubMed Scopus (32) Google ScholarTable 2Artifacts of 3D imagingType of artifactMechanismImpact on images3D exampleStitchingIncorrect juxtaposition at the interface of sequential subvolumes (because of arrhythmias, breathing, probe/patient motion)Strong demarcation between subvolumes leading to a “broken” imageDropoutPoor echocardiographic signal strength due to weak echoesThese artifacts can be misdiagnosed as true holes/perforationsBlurringIndistinct edges of structures due to the assembly of nonisotropic voxels (2° to differences in axial > lateral > elevational resolution)Thin structures (i.e., sutures) appear thicker than they areBloomingMetallic structures when intersected by ultrasound produce fringes extending beyond the borders of the metallic devices/cathetersMetallic structures appear with irregular, thick edgesRailroad-shapedIn large catheters with wide lumens, two surfaces are perpendicular to the ultrasound beam, producing strong echoes, while the other two are tangential, producing very weak echoesSingle catheter appears as two linear structuresReverberationsMultiple reflection of metallic component of cathetersDepending on the perspective and the position of catheter, reverberations may appear to lengthen the catheterShadowingInability of ultrasound to pass through strong reflecting catheters/devicesLack of tissue posterior to catheters/devices that may appear as a “tear” of cardiac structuresGainVariation of gain may produce significant variation in the size of structuresOrifices may appear larger or smaller according to gain variationModified with permission from Faletra et al.13Faletra F.F. Ramamurthi A. Dequarti M.C. Leo L.A. Moccetti T. Pandian N. Artifacts in three-dimensional transesophageal echocardiography.J Am Soc Echocardiogr. 2014; 27: 453-462Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar Open table in a new tab Modified with permission from Faletra et al.13Faletra F.F. Ramamurthi A. Dequarti M.C. Leo L.A. Moccetti T. Pandian N. Artifacts in three-dimensional transesophageal echocardiography.J Am Soc Echocardiogr. 2014; 27: 453-462Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar Transcatheter AV implantation (TAVI) has become standard therapy for many patients with severe aortic stenosis (AS).4Otto C.M. Nishimura R.A. Bonow R.O. Carabello B.A. Erwin III, J.P. Gentile F. et al.2020 ACC/AHA guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.J Am Coll Cardiol. 2021; 77: 450-500Crossref PubMed Scopus (99) Google Scholar In addition, commercially available14Yoon S.H. Schmidt T. Bleiziffer S. Schofer N. Fiorina C. Munoz-Garcia A.J. et al.Transcatheter aortic valve replacement in pure native aortic valve regurgitation.J Am Coll Cardiol. 2017; 70: 2752-2763Crossref PubMed Scopus (101) Google Scholar and investigational15Hensey M. Murdoch D.J. Sathananthan J. Alenezi A. Sathananthan G. Moss R. et al.First-in-human experience of a new-generation transfemoral transcatheter aortic valve for the treatment of severe aortic regurgitation: the J-Valve transfemoral system.EuroIntervention. 2019; 14: e1553-e1555Crossref PubMed Scopus (10) Google Scholar,16Seiffert M. Bader R. Kappert U. Rastan A. Krapf S. Bleiziffer S. et al.Initial German experience with transapical implantation of a second-generation transcatheter heart valve for the treatment of aortic regurgitation.JACC Cardiovasc Interv. 2014; 7: 1168-1174Crossref PubMed Scopus (102) Google Scholar devices have been used to treat native aortic regurgitation (AR). Although its role has evolved, echocardiography continues to be essential before, during, and after TAVI.17Hahn R.T. Nicoara A. Kapadia S. Svensson L. Martin R. Echocardiographic imaging for transcatheter aortic valve replacement.J Am Soc Echocardiogr. 2018; 31: 405-433Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar Preprocedural TEE imaging to evaluate the AV and aortic root complex may be appropriate, particularly when contrast-enhanced computed tomography (CT) is contraindicated or unavailable or when anatomic features seen by transthoracic echocardiography (TTE) raise concern for TAVI feasibility or suggest a high risk for complications. Physicians involved in the care of TAVI patients should be familiar with the acquisition and interpretation of relevant TEE images and be able to use them for shared decision-making before interventions.3Hahn R.T. Mahmood F. Kodali S. Lang R. Monaghan M. Gillam L.D. et al.Core competencies in echocardiography for imaging structural heart disease interventions: an expert consensus statement.JACC Cardiovasc Imaging. 2019; 12: 2560-2570Crossref PubMed Scopus (15) Google Scholar The AV is composed of three cusps attached in a semilunar fashion along the entire length of the aortic root, with the highest point of attachment at the level of the sinotubular junction and the cusp nadirs defining the “virtual annulus”18Ho S.Y. Structure and anatomy of the aortic root.Eur J Echocardiogr. 2009; 10: i3-i10Crossref PubMed Scopus (104) Google Scholar (Figure 5). Short-axis (SAX) images from the aortic side at the level of the cusps (Figures 5A and 5B) are the most useful for determining cusp morphology and pathology. Imaging from the left ventricular (LV) side (Figures 5C and 5D) may uncover subvalvular pathologies. The majority of the annulus is composed of the base of the interleaflet triangles, or trigones (Figures 5E and 5F). The ventricular-arterial junction between the ventricular myocardium and fibroelastic wall of the aortic root has muscular and fibrous elements and includes the mitral-aortic curtain and membranous septum and adjacent conduction system.19Anderson R.H. Clinical anatomy of the aortic root.Heart. 2000; 84: 670-673Crossref PubMed Google Scholar The length of the membranous septum may be an important anatomic predictor of heart block following TAVI.20Maeno Y. Abramowitz Y. Kawamori H. Kazuno Y. Kubo S. Takahashi N. et al.A highly predictive risk model for pacemaker implantation after TAVR.JACC Cardiovasc Imaging. 2017; 10: 1139-1147Crossref PubMed Scopus (108) Google Scholar ME SAX (40°–60° mechanical rotation), long-axis (110°–140° mechanical rotation), or biplane imaging of the AV (Figure 6) is integral for assessing valve morphology: a tricuspid AV (Figures 6A and 6B) or bicuspid AV (Figures 6C and 6D) can be distinguished by visualizing cusp opening and closing with 2D (Figures 6A and 6C) or color Doppler (Figures 6B and 6D) imaging. The long-axis view of the AV is essential for analyzing leaflet pathology (Figures 6E and 6F), the basal LV septum, and subaortic pathology. Aortic measurements are performed from the ME long-axis view at end-diastole, using the leading edge–to–leading edge technique (Figures 7A and 7B).21Goldstein S.A. Evangelista A. Abbara S. Arai A. Asch F.M. Badano L.P. et al.Multimodality imaging of diseases of the thoracic aorta in adults: from the American Society of Echocardiography and the European Association of Cardiovascular Imaging: endorsed by the Society of Cardiovascular Computed Tomography and Society for Cardiovascular Magnetic Resonance.J Am Soc Echocardiogr. 2015; 28: 119-182Abstract Full Text Full Text PDF PubMed Google Scholar The aortic annular diameter is measured in the sagittal plane, from a high-resolution, zoomed ME long-axis view of the AV with the LV outflow tract (LVOT) aligned with the aortic root, perpendicular to the ultrasound beam (Figure 7C). From this view, the interleaflet trigone between the noncoronary and left coronary cusps is typically seen posteriorly, while the image should bisect the right coronary cusp anteriorly with the leaflet nadir identifying the level of the annulus (Figure 7D). The LVOT or annular measurement in systole should use the right cusp hinge as the anterior point of measurement and the posterior aortic root at the base of the interleaflet trigone (perpendicular to the aortic root) as the posterior point. Although guidelines suggest that the LVOT measurement should be made 0.5 to 1.0 cm from the annulus, studies indicate that calculating AV area using the LVOT measured at the annulus is more reproducible and accurate.22Clavel M.A. Malouf J. Messika-Zeitoun D. Araoz P.A. Michelena H.I. Enriquez-Sarano M. Aortic valve area calculation in aortic stenosis by CT and Doppler echocardiography.JACC Cardiovasc Imaging. 2015; 8: 248-257Crossref PubMed Scopus (111) Google Scholar,23Malouf J. Le Tourneau T. Pellikka P. Sundt T.M. Scott C. Schaff H.V. et al.Aortic valve stenosis in community medical practice: determinants of outcome and implications for aortic valve replacement.J Thorac Cardiovasc Surg. 2012; 144: 1421-1427Abstract Full Text Full Text PDF PubMed Scopus (68) Google Scholar Other aortic anatomy, such as the coronary height above the annular plane and length of the AV cusps, can be measured from 2D reconstructed images using a 3D zoomed volume (Figure 7E). This information is used to determine the risk for coronary artery occlusion during valve deployment or balloon valvuloplasty. Three-dimensional rendered or multiplanar imaging can also be used to define morphology and quantify valve area or regurgitation severity (Figure 8). Ao, Aorta, EOA, effective orifice area; EROA, effective regurgitant orifice area; LA, left atrium; LCC, left coronary cusp; LV, left ventricle; LVOT, left ventricular outflow tract; NCC, noncoronary cusp; PW, pulsed wave; RCC, right coronary cusp; RA, right atrium; RV, right ventricle; RVol, regurgitant volume; VC, vena contracta; VCA, vena contracta area; VTI, velocity-time integral. DT views are essential for assessing AV function. The DT five-chamber view (Figure 9A) is important for comprehensive Doppler assessment of AV function. With AS, the pulsed-wave Doppler sample volume is positioned just proximal to the flow convergence in systole (Figure 9B), whereas for AR, the sample volume should be at the level of annulus in systole. The stroke volume is calculated using the systolic LVOT diameter from ME views (Figure 7A,C). Continuous-wave (CW) Doppler across the AV is used (Figure 9C) to calculate AV area. A TG long-axis view at 80° to 120° should be attempted (Figure 9D), as this imaging plane typically will allow ultrasound beam alignment with jets that are directed more anteriorly or toward the right. Studies have suggested that up to 50% of patients with AS will have the maximum velocity recorded from the right parasternal window on TTE,24Thaden J.J. Nkomo V.T. Lee K.J. Oh J.K. Doppler imaging in aortic stenosis: the importance of the nonapical imaging windows to determine severity in a contemporary cohort.J Am Soc Echocardiogr. 2015; 28: 780-785Abstract Full Text Full Text PDF PubMed Google Scholar and the TG view at 80° to 120° is a close approximation of this imaging window. If a forward stroke volume is required for calculation of AR volume, then the right ventricular outflow tract (RVOT) stroke volume should be acquired (Figure 9E–9H). For accurate assessment of stroke volume, we recommend obtaining PW Doppler from the TG or DT view for both the LVOT and RVOT calculations. Alternatively, the UE view can be used for RVOT stroke volume if the TG views are not feasible and this alternative view is aligned with the ultrasound beam. The severity of AS is accurately determined by transthoracic 2D and Doppler echocardiography.7Baumgartner H. Hung J. Bermejo J. Chambers J.B. Edvardsen T. Goldstein S. et al.Recommendations on the echocardiographic assessment of aortic valve stenosis: a focused update from the European Association of Cardiovascular Imaging and the American Society of Echocardiography.J Am Soc Echocardiogr. 2017; 30: 372-392Abstract Full Text Full Text PDF PubMed Google Scholar In the setting of nondiagnostic TTE, TEE imaging can be used to determine the morphology of the AV and aortic root. Whereas prior studies had questioned the accuracy of 2D and 3D planimetry of the AV area,25Bernard Y. Meneveau N. Vuillemenot A. Magnin D. Anguenot T. Schiele F. et al.Planimetry of aortic valve area using multiplane transoesophageal echocardiography is not a reliable method for assessing severity of aortic stenosis.Heart. 1997; 78: 68-73Crossref PubMed Google Scholar more recent studies have suggested that 2D planimetry of the AV area with TEE imaging is accurate compared with 3D ex vivo scanned valves26Shirazi S. Golmohammadi F. Tavoosi A. Salehi M. Larti F. Sardari A. et al.Quantification of aortic valve area: comparison of different methods of echocardiography with 3-D scan of the excised valve.Int J Cardiovasc Imaging. 2021; 37: 529-538Crossref PubMed Scopus (0) Google Scholar as well as CT.27Anger T. Bauer V. Plachtzik C. Geisler T. Gawaz M.P. Oberhoff M. et al.Non-invasive and invasive evaluation of aortic valve area in 100 patients with severe aortic valve stenosis: comparison of cardiac computed tomography with echo (transesophageal/transthoracic) and catheter examination.J Cardiol. 2014; 63: 189-197Abstract Full Text Full Text PDF PubMed Google Scholar,28Klass O. Walker M.J. Olszewski M.E. Bahner J. Feuerlein S. Hoffmann M.H. et al.Quantification of aorti