REVIEW ARTICLE |
https://doi.org/10.5005/jp-journals-10089-0095 |
Basic Comprehensive Transesophageal Echocardiography
1,2Department of Cardiac Anesthesia, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India
3Department of Anesthesia, PES University Institute of Medical Sciences and Research, Bengaluru, Karnataka, India
Corresponding Author: Nagaraja P Subbaiah, Department of Cardiac Anesthesia, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India, Phone: +91 9739864268, e-mail: docnag10@gmail.com
Received: 28 February 2023; Accepted: 28 March 2023; Published on: 19 February 2024
ABSTRACT
Transesophageal echocardiography (TEE) is a valuable tool for understanding cardiac anatomy and physiology. It has an advantage as a real-time dynamic monitoring tool to assess cardiac function. Due to its better spatial resolution, the cardiac structures are well delineated. It is preferred over transthoracic echocardiography (TTE) for better visualization of the posterior cardiac structures and more so in suboptimal acoustic TTE windows. The clinical utility of TEE in diagnosing and guiding therapeutic interventions in both cardiac surgical and critically ill patients has been widely reported. The knowledge of acquiring comprehensive TEE views ensures that the clinician does not miss out on any vital information. It also ensures that all the views have been acquired systematically in a limited time frame.
How to cite this article: Subbaiah NP, Singh NG, Gupta A. Basic Comprehensive Transesophageal Echocardiography. J Acute Care 2023;2(3):110–120.
Source of support: Nil
Conflict of interest: None
Keywords: Probe, Transesophageal echocardiography, Transthoracic echocardiography.
INTRODUCTION
Transesophageal echocardiography (TEE) was introduced in the 1980s and has gained popularity with major advancement over the years as it provides an opportunity to overcome many of the limitations of transthoracic echocardiography (TTE), out of which chest wall acoustic window is a significant one. Frazin et al. used M-mode echocardiography for the first time in 1976.1 The transducer with biplane was introduced in 1984, and multiplane transducers in 1992.2 Intraoperative use of TEE acts as a real-time dynamic monitoring tool for understanding cardiac anatomy and physiology. It opens up a cardiac window with great spatial resolution. The clinical usefulness of echocardiography using the esophageal route (TEE) as a tool for diagnosis and guide for therapeutic intervention in cardiac surgery and critical care medicine is widely studied and reported. The guidelines for acquiring 20 TEE standard views were published by the American Society of Echocardiography (ASE) and the Society of Cardiovascular Anesthesiologists in 1999. This was necessary to provide uniformity in educational training and reporting. With technological advances and increasing indications for TEE, eight more views have been appended to the established standard 20 TEE views.3 The sequential assessment of standard TEE views, which will be of great value in the perioperative management of cardiac, noncardiac, and critically ill patients, will be discussed in this review.
INDICATIONS OF TRANSESOPHAGEAL ECHOCARDIOGRAPHY
Cardiac Surgery and Thoracic Aortic Procedures
- An adult open heart, coronary artery bypass grafting, and aortic (thoracic) surgery to (1) confirm and further verify the established preoperative diagnosis; (2) identify any new pathology; (3) guide for anesthetic and surgical management; and (4) assess the surgical intervention.4
- In pediatric patients, the indication of TEE is based on the benefits vs the risks.
- Catheterization-guided intracardiac interventions: They are used in transcatheter intracardiac procedures.
Noncardiac Surgery
- Transesophageal echocardiography (TEE) may be indicated in noncardiac surgery in patients with moderate to severe cardiovascular disease, especially when associated with significant hemodynamic compromise.
- Transesophageal echocardiography (TEE) is indicated in patients who develop life-threatening cardiovascular instability, which is not responding to conventional management.
Critical Care
Transesophageal echocardiography (TEE) may be used in critically ill patients when the diagnostic information obtained by TTE or other modalities is inconclusive.
Appropriate indications of TEE in cardiology are5:
- Noncoronary cardiac intervention.
- Acute aortic pathology.
- Valvular structure and function with the suitability of intervention.
- Diagnose infective endocarditis.
- In atrial fibrillation, assess the need for anticoagulation, cardioversion, and/or radiofrequency ablation.
- Transesophageal echocardiography (TEE) is inconclusive.
- This is a follow-up of prior TEE (resolution of thrombus postanticoagulation).
- Evaluation of cardiovascular emboli with unidentified noncardiac source.
CONTRAINDICATIONS
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Probe
The TEE probes are available in various sizes to cater to all age groups—infant, pediatric, and adult probes with extended operating frequencies ranging from 3 to 7 MHz. Modern TEE probes have a flexible distal tip to allow a wide range of motion: anteriorly—anteroflexion, posteriorly—retroflexion, and laterally to the right or left. It also has a unique multiplane angle rotation from 0 to 180°. The TEE probe has the shaft, handle, cable, and pin connector. The probe shaft is flexible, containing coaxial cables carrying signals to and from the transducer. There are depth markers on the shaft to guide the clinician to various views at a particular depth. The desired depth is achieved either by advancing or withdrawing the probe. Rotation of the probe is performed by rotating the handle either to the right or left. The handle of the adult TEE probe possesses two wheels. The bigger wheel performs anteflexion and retroflexion when rotated clockwise and anti-clockwise, respectively, whereas the smaller wheel is used to flex in either the right or left direction (Fig. 1). There are two multiplane angle controller buttons housed in the handle: one button to increase and the other to decrease the multiplane angle. The connector attaches the handle to the echo machine through the cable. Leads for three-lead electrocardiography (ECG) are available along with the echo machine, and it is mandatory to attach the ECG leads before performing any TEE examination. The TEE probe should always be inserted with a bite guard, even in intubated patients. Before inserting the probe, liberal lubrication of the probe is necessary for the ease of insertion into the esophagus, and the depth markers will guide the depth of insertion. If any resistance is encountered, the TEE probe should never be inserted with force into the esophagus or the stomach. The nasogastric tube should be checked for its position and aspirated for any air or fluid before insertion of the TEE probe.
Figs 1A to E: (A) Flexible TEE probe tip in a neutral position; (B) TEE probe tip flexed to the left; (C) TEE probe tip flexed to the right; (D) TEE probe tip anteflexion; (E) TEE probe tip retroflexion
COMPREHENSIVE TRANSESOPHAGEAL ECHOCARDIOGRAPHY EXAMINATION
The ASE recommends 20 standard views and eight modified views. Two additional views have been added to the recent guidelines.7 It is important to do the TEE imaging sequentially to obtain the standard views so that it allows the clinician to compare the images pre and postintervention. It further ensures that vital information is not missed during imaging. However, it may not be possible to obtain similar images at a particular depth or multiplane angle due to the difference in anatomy or body habitus. There are four different depths at which the imaging planes are obtained. Upper esophageal view at an approximate depth of 25 cm, midesophageal view by advancing to 35 cm, transgastric (TG) and deep TG views obtained by further advancing the probe to 40 and 50 cm, respectively, from the upper incisor. Recent guidelines have added deep esophageal (DE) views, which are obtained between midesophageal and TG levels to visualize the right heart structures.7 The twenty comprehensive views will be discussed in detail in this review.
Midesophageal Views
Midesophageal four-chamber (ME4C) view: The TEE probe is inserted to a depth of 35 cm to obtain midesophageal views. When the multiplane angle is at 0–10°, the imaging plane is posterior to the left atrium. The right-sided structures are displayed on the left side of the imaging sector, and the left-sided structures are on the right of the sector. The ME4C view displays the four chambers of the heart (Fig. 2A).
Midesophageal mitral commissural (MEMC) view: This view is obtained by increasing the multiplane angle to 50–70° from the ME4C view, where the imaging plane bisects the two mitral commissures (Fig. 2B).
Midesophageal two-chamber (ME2C) view: The multiplane angle is further increased to 80–100° from the MEMC view to obtain the ME2C view where the imaging plane bisects the LV (Fig. 2C).
Midesophageal bicaval (MEBC) view: This view is obtained by rotating the probe to the right from the ME2C view and increasing the multiplane angle to 100–110° might be necessary to optimize the image, where the imaging plane bisects both the vena cava (Fig. 2D).
Midesophageal LV long axis (ME LAX) view: The multiplane angle is increased to 120–140° from the ME2C view to obtain the ME LAX view where the imaging plane bisects the mitral valve at A2 and P2 scallops (Fig. 2E).
Figs 2A to L: (A) ME 4C view; (B) MEMC view; (C) ME2C view; (D) MEBC view; (E) ME LAX view; (F) ME Ao LAX view; (G) ME RV inflow-outflow view; (H) ME Ao SAX view; (I) ME AAo SAX view; (J) ME AAo LAX view; (K) ME DAo SAX view; (L) ME DAo LAX view
Midesophageal aortic long axis (ME Ao LAX) view: This view is obtained by slightly withdrawing the probe without changing the multiplane angle from ME LAX view to obtain ME Ao LAX view where the imaging plane displays the aortic valve in the long axis. Aortic measurements (aortic annulus, diameter of sinus, sinotubular junction, ascending aorta) can be obtained in this view (Fig. 2F).
Midesophageal RV inflow outflow (ME RV outflow) view: The multiplane angle is decreased to 50–70° from the ME Ao LAX view to obtain ME RV outflow view where the imaging plane displays the RV inflow (tricuspid valve) and outflow (pulmonary valve) wrapped around the short axis of the aortic valve in the middle of the sector (Fig. 2G).
Midesophageal aortic short axis (ME Ao SAX) view: Decreasing the multiplane angle further to 20–40° from the ME RV outflow view will display the ME Ao SAX view where the imaging plane displays the Aortic valve leaflets in the center of the imaging sector. Aortic valve area can be obtained in this view using planimetry (Fig. 2H).
Midesophageal ascending aortic short axis (ME AAo SAX) view: This view is obtained by slightly withdrawing the probe from the ME Ao SAX view until the aortic valve leaflets disappear, and slight anteflexion might be necessary to visualize the ascending aorta in the short axis with main pulmonary artery to the right of the screen and SVC to the left of the screen. Ascending aortic aneurysms and dissection can be visualized in this view (Fig. 2I).
Midesophageal ascending aortic long axis (ME AAo LAX) view: The multiplane angle is increased to 80–100° from the ME AAo SAX view to obtain this view. The near field displays the right pulmonary artery in the short axis and the long axis of the ascending aorta right below it (Fig. 2J).
Midesophageal descending aortic short axis (ME DAo SAX) view: The probe is rotated to the left from the ME 4C view until the descending aorta is visualized in the near field. The sector depth may be decreased to approximately 6 cm for better visualization (Fig. 2K). The view provides information about aortic atheroma and dissections.
Midesophageal descending aortic long axis (ME DAo LAX) view: By increasing the multiplane angle to 80–100° from the DAo SAX view, this view is obtained. The image displays the descending aorta on a long axis (Fig. 2L). The proximal descending aorta and distal descending aorta are to the right and left of the screen, respectively.
Upper esophageal aortic arch long axis (UE AoArch LAX) view: This view is obtained by withdrawing the probe from the ME DAo SAX view until the circular aorta becomes oblong in shape. This would be the distal aortic arch in the long axis (Fig. 3A).
Figs 3A and B: (A) UE AoArch LAX view; (B) UE AoArch SAX view
Upper esophageal aortic arch short axis (UE AoArch SAX) view: The multiplane angle is increased to 80–100° from the UE AoArch LAX view to obtain UE AoArch SAX view to visualize aortic arch in short axis with left carotid artery visualized at 4 o’clock position (Fig. 3B). Aortic arch dissections can be visualized in this view.
Transgastric basal short axis (TG basal) view: By gently advancing the TEE probe into the stomach from the ME 4C view and on anteflexion to optimize the image, this view is obtained. The LV, along with the mitral valve and crescent-shaped RV in the short axis, are visualized. The mitral valve orifice area can be obtained by planimetry in this view (Fig. 4A). The LV segmental function can be assessed semi-quantitatively by the wall motion score index. In a seventeen-segment model,8 each segment is allotted a score from 1 to 4 (1 = normal, 2 = hypokinesia, 3 = akinesia, 4 = dyskinesia).
Transgastric midpapillary (TG MID) view: The probe is gently advanced into the stomach a little further from the TG basal view, or the anteflexion could be decreased to visualize the LV, along with the two papillary muscles and crescent-shaped RV in short axis. Regional wall motion abnormalities can be assessed in this view (Fig. 4B).
Transgastric two-chamber (TG 2C) view: This view is obtained by increasing the multiplane angle to 80–100° from the TG midpapillary view to visualize the LV along with its subvalvular apparatus in the long axis (Fig. 4C). Mitral subvalvular pathology is well delineated in this view.
Figs 4A to F: (A) TG basal view, AML-anterior mitral leaflet; (B) TG MID view; (C) TG 2C view; (D) TG LAX view; (E) TG RV inflow view; (F) DTG view
Transgastric long axis (TG LAX) view: The multiplane angle is further increased to 110–130° from the TG 2C view to visualize the LV along with the aortic valve in the long axis. The gradient across the aortic valve can be obtained in this view as the Doppler can be aligned parallel to the aortic flow (Fig. 4D).
Transgastric RV inflow (TG RV inflow) view: The TEE probe is rotated towards the right from the TG LAX view to visualize the RA and RV along with the tricuspid valve and its subvalvular apparatus in the long axis (Fig. 4E).
Deep TG (DTG) view: The probe is gently advanced further into the stomach from the TG midpapillary view with the probe in a neutral position and then anteflexed to visualize the LV in the long axis. The gradient across the left ventricular outflow tract, if any, can be accurately obtained in this view (Fig. 4F).
CONCLUSION
Transesophageal echocardiography (TEE) is a semi-invasive, real-time perioperative monitoring tool, and possessing the knowledge of sequential assessment plays a vital role in the effective and optimal management of patients.
REFERENCES
1. Frazin L, Talano JV, Stephanides L, et al. Esophageal echocardiography. Circulation 1976;54(1):102–108. DOI: 10.1161/01.cir.54.1.102
2. Roelandt JR, Thomson IR, Vletter WB, et al. Multiplane transesophageal echocardiography: latest evolution in an imaging revolution. J Am Soc Echocardiogr 1992;5(4):361–367. DOI: 10.1016/s0894-7317(14)80268-x
3. Hahn RT, Abraham T, Adams MS, 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(9):921–964. DOI: 10.1016/j.echo.2013.07.009
4. American Society of Anesthesiologists and Society of Cardiovascular Anesthesiologists Task Force on Transesophageal Echocardiography. Practice guidelines for perioperative transesophageal echocardiography. An updated report by the American Society of Anesthesiologists and the Society of Cardiovascular Anesthesiologists Task Force on Transesophageal Echocardiography. Anesthesiology 2010;112(5):1084–1096. DOI: 10.1097/ALN.0b013e3181c51e90
5. American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, et al. ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 appropriate use criteria for echocardiography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance American College of Chest Physicians. J Am Soc Echocardiogr 2011;24(3):229–267. DOI: 10.1016/j.echo.2010.12.008
6. Hilberath JN, Oakes DA, Shernan SK, et al. Safety of transesophageal echocardiography. J Am Soc Echocardiogr 2010;23(11):1115–1111. DOI: 10.1016/j.echo.2010.08.013
7. Hahn RT, Saric M, Faletra FF, et al. Recommended standards for the performance of transesophageal echocardiographic screening for structural heart intervention: from the American Society of Echocardiography. J Am Soc Echocardiogr 2022;35(1):1–76. DOI: 10.1016/j.echo.2021.07.006
8. Cerqueira MD, Weissman NJ, Dilsizian V, et al. Standardized myocardial segmentation and nomenclature for tomographic imaging of the heart. A statement for healthcare professionals from the Cardiac Imaging Committee of the Council on Clinical Cardiology of the American Heart Association. Circulation 2002;105(4):539–542. DOI: 10.1161/hc0402.102975
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