A Practical Approach to Transesophageal Echocardiography Chapter 1 Flashcards
Through simple manipulations, the transesophageal echocardiography (TEE) probe offers a multifaceted picture of cardiac anatomy. Progressive advancement of the probe in the midesophagus provides a cross-sectional view of the aortic valve (A) followed by a long-axis view of the cardiac chambers (B) Further advancement and anteflexion of the probe head (C) allows visualization of the left ventricle in the short-axis. Rotation of the imaging plane expands the imaging capacity of TEE. In this example, the left ventricle and its outflow tract are brought into view by rotating the imaging plane to 120°. LA, left atrium; RA, right atrium; N, noncoronary cusp; L, left coronary cusp; R, right coronary cusp; RV, right ventricle; LV, left ventricle; Ao, aorta.
Midesophageal ascending aortic short-axis view.
From the initial position following passage into the esophagus, the probe is advanced slightly until the proximal aorta is seen. The probe angle is then rotated until a true short-axis is seen, usually between 0° and 45°. The main pulmonary artery is seen bifurcating and the right pulmonary artery will lie posterior and perpendicular to the proximal aorta (Fig).
This view is useful for identifying pulmonary artery catheter placement as well as for visualizing thromboembolism in the pulmonary artery.
Midesophageal Right Pulmonary Vein View
The probe is then turned to the right to display the ME right pulmonary vein view. Small changes in depth and angle may be needed to optimize this view. The right upper pulmonary view is seen entering the left atrium from the approximate 7 o’clock position in the far field and the lower pulmonary vein is seen near field traveling left to right into the atrium. The orientation of the upper view allows for pulsed-wave spectral Doppler interrogation but the lower view is perpendicular and can rarely be interrogated with spectral Doppler. The superior vena cava is often seen in the short-axis to the right of the upper pulmonary vein (Fig).
Midesophageal ascending aortic long-axis view
The probe is then turned back to the left and the ME ascending aortic short-axis view is reacquired. From here, the probe angle is rotated to visualize the proximal aorta in the long-axis. The right pulmonary artery is seen in cross-section at the apex of the imaging sector. This view may identify the proximal extent of a dissection, may allow for visualization of saphenous vein grafts, and can also be used to interrogate the proximal suture line of an ascending aortic tube graft (Fig.
Midesophageal Aortic Valve Short-Axis View
The imaging plane is then rotated back to 45° and then advanced to obtain the ME aortic valve short-axis view. For novice examiners or when anatomy is confusing, the ME aortic valve short-axis, can be used as a reference point to start the examination. The recognizability of the aortic leaflets makes this image easy to identify. Evaluation should include the size of the aortic valve, in comparison with the atrial chambers, the mobility of the aortic leaflets and the presence of leaflet calcification.
The primary diagnostic goals of this view are to define the general morphology of the aortic valve (e.g., bicuspid vs. tricuspid) and to determine if aortic stenosis is present. The classic “Mercedes-Benz” view of the aortic valve is seen with the noncoronary cusp in the near field of the valve on the left, the left coronary cusp on the right, and the right coronary cusp in the far field of the valve. The relative sizes of the aorta and the atria should be noted.
Slight withdrawal of the probe will reveal the origins of the left and right coronary arteries at approximately 2 and 6 o’clock respectively. If the left main coronary bifurcation is seen, the circumflex coronary artery will travel upward toward the sector apex and the left anterior descending coronary artery will travel downward toward the far field of the image. T
he intra-atrial septum is observed originating near the noncoronary cusp of the aortic valve and should be inspected for openings consistent with an atrial septal defect. In addition, look for continuous deviation of the septum away from an atrium with elevated pressures (Fig. 2.11).
This view, along with the ME bicaval view, is used extensively in structural heart procedures involving atrial septal puncture
Midesophageal Right Ventricular Inflow–Outflow
After completion of the ME short-axis view of the aortic valve, the next three views are obtained at the level of the aortic valve in the longitudinal plane. The first view is the ME right ventricular inflow–outflow view. Start at the ME aortic valve short-axis and, without moving the probe, change the rotation of the imaging angle to approximately 60° to 90°. The desired imaging plane will visualize the tricuspid valve, right ventricular outflow tract (RVOT), and proximal pulmonary artery. Note that the right atrium will be at 10 o’clock, the tricuspid valve at 9 o’clock, the right ventricular cavity at 6 o’clock, and the pulmonary valve and pulmonary artery at 3 o’clock. Two leaflets of the tricuspid valve are seen in this view. The leaflet on the left is the posterior leaflet and the leaflet to the right near the aortic valve is either the anterior or septal leaflet.
The primary diagnostic goals of this view are to measure the tricuspid and pulmonary annulus sizes and to evaluate the pulmonic valve. Two of the pulmonary valve leaflets are visualized with the left or right cusp seen on the left and the anterior cusp seen on the right. The RVOT diameter is best measured here for subsequent calculation of right-sided stroke volume. This view is often superior to the ME four-chamber view for spectral Doppler interrogation of the tricuspid valve. The short septal tricuspid leaflet often directs the regurgitant jet toward the atrial septum in a path parallel to the Doppler beam angle. In adults with uncorrected congenital heart disease or prior congenital heart surgery, evaluation of the RVOT and pulmonary valve may provide important diagnostic information. In addition color flow Doppler in this view can discriminate perimembranous from supracristal ventricular septal defects.
This view may be helpful in confirming the location of a pulmonary artery catheter if a diagnostic waveform is not identified. The echodense linear pulmonary artery catheter will be seen in the proximal pulmonary artery if the catheter is in the correct location
Midesophageal-Modified Bicaval Tricuspid Valve View
If a tricuspid regurgitant jet is not adequately interrogated, turn the probe to the right (clockwise) and the ME-modified bicaval tricuspid valve view is seen (Fig. 2.13). In this view spectral Doppler is usually effective for interrogation of non-eccentric TR jets. The tricuspid leaflet seen on the left side of the image is either the posterior or septal leaflet and the one on the right is the anterior leaflet.
Midesophageal Bicaval View
The ME bicaval view is then obtained by turning the probe further to the patient’s right. This image is often best with 5° to 15° less rotation than in the ME aortic valve long-axis view. The key structures in this view are the left and right atria, inferior and superior vena cavae, interatrial septum, and right atrial appendage. Minor adjustment to probe depth and multiplane angle will often bring the tricuspid valve or coronary sinus into view (Fig. 2.15).
The primary diagnostic goals of this view are to examine for atrial chamber enlargements and the presence of a patent foramen ovale or an atrial septal defect, and to detect intra-atrial air. If the integrity of the intra-atrial septum is questioned, color flow Doppler or bubble contrast should be performed.
This view may be helpful in the placement of pulmonary artery catheters in patients where entry into the right ventricle is difficult. The pulmonary artery catheter is floated to 20 cm and the balloon inflated and advanced. When the echodense inflated balloon enters the proximal superior vena cava it will be seen entering the right atrium. The catheter can be turned clockwise or counterclockwise to steer it toward the tricuspid valve at approximately 7 o’clock in the atrium rather than the inferior vena cava located at approximately 9 o’clock.
Midesophageal Right and Left Pulmonary Vein View
The pulmonary vein views are difficult to reproduce in all patients. Angles are often slightly different in each patient and the lower pulmonary veins are in the extreme near field and mostly perpendicular to the imaging beam making spectral Doppler interrogation difficult in many patients.
To visualize the right veins, turn the probe rightward (clockwise) from the ME bicaval view and withdraw slightly, the right upper vein is seen entering into the left atrium from the approximate 4 o’clock position, heading posteriorly toward the apex of the imaging sector (Fig. 2.16). Slight changes in scanning angle are required to open up a full view of the vein. Small movements inward and outward are necessary to visualize the lower veins. The angle of the upper view is usually amenable to spectral Doppler interrogation.
The ASE guidelines then state to turn the probe leftward (counterclockwise) to visualize the left-sided veins. As described before, the upper veins will enter the left atrium from the far field and the lower veins are seen in the near field in a perpendicular course to the ultrasound beam (Fig. 2.17).
Midesophageal five-chamber view
After completion of the ME right pulmonary vein view, the imaging angle is returned to 0° and the TEE probe is advanced to the mitral valve level. Depending on the patient, either the four-chamber or five-chamber view will be seen. The five-chamber view is obtained slightly cephalad to the four-chamber view.
In the five-chamber view, portions of the left ventricular outflow tract (LVOT) and aortic valve will be seen and the TV is often obscured or not seen in its entirety. General chamber morphology and sizes can be interpreted in this view but the four-chamber view is more consistently obtained
Midesophageal Four-Chamber Views
From the five-chamber view advance the probe slightly to obtain the ME four-chamber view (Fig. 2.19A). See Video 2.1 at 00:14. This view allows visualization of all the chambers of the heart. The image rotation is approximately 0° to 10° with some retroflexion of the probe. Optimal position is achieved when the tricuspid annulus is at its maximal diameter.
The key structures to observe are the left atrium, left ventricle, right atrium, right ventricle, the mitral and tricuspid valves, and the inferoseptal and anterolateral walls of the myocardium. If a portion of the LVOT and aortic valve is seen, you are viewing the five-chamber view. Retroflexion of the probe and slight advancement or rotation of the imaging plane to 5° to 10° should produce the ME four-chamber view. Remember that the aortic valve and LVOT are anterior structures, and these maneuvers will produce a true cross-section of the more posteriorly located ME four-chamber view.
he ME four-chamber view is one of the most diagnostically valuable views in TEE. The diagnostic goals of this view include evaluation of chamber size and function, valvular function (both mitral and tricuspid), and regional motion of the septal and lateral walls of the left ventricle. When evaluating the mitral valve, the anterior leaflet is seen on the left and the posterior leaflet is seen on the right. The tricuspid leaflet seen on the left is either the anterior or posterior leaflet and the one on the right adjacent to the interventricular septum is the septal leaflet.
An additional important use of this view is to look for intraventricular air following cardiopulmonary bypass. Air will appear as echodense small bubbles at the junction of the septum and apex. After 2D interrogation of this view, color flow Doppler should be placed on the mitral and tricuspid valves to detect valvular insufficiency and stenosis.
Strong retroflexion and slight advancement will often allow visualization of the origin and proximal course of the coronary sinus (Fig. 2.19B). This will allow for confirmation of retrograde coronary perfusion catheter placement and measurement of the size of the coronary sinus and screening for a possible left-sided superior vena cava. The tricuspid valve leaflet adjacent to the coronary sinus is usually the septal leaflet but can be the posterior leaflet. The anterior leaflet will never be adjacent to the coronary sinus.
Midesophageal Mitral Commissural View
From the ME four-chamber view, the imaging array is rotated to approximately 60° to display the mitral valve in a characteristic P1-A2-P3 appearance. See Video 2.1 at 00:38. In this view, both the posteromedial and anterolateral papillary muscles will be visible with chordae seen going to the anterior and posterior leaflets.
Small turns clockwise and counterclockwise as well as small amounts of ante- and retroflexion will optimize the image and provide a broader perspective of the mitral valve anatomy.
Midesophageal Two-Chamber View
From the ME commissural view, rotate the imaging angle to approximately 60° to 90° to obtain the ME two-chamber view. See Video 2.1 at 00:45. This view is identified by the appearance of the left atrial appendage and the absence of right-sided heart structures, and it allows visualization of the anterior and inferior walls of the left ventricle.
Occasionally, turning the probe shaft to the right will improve chamber alignment and this is the best TEE view for visualization of the true left ventricular apex. The apex is less mechanically active compared to the mid-cavity anterior and inferior segments which contract inward. The resulting contraction pattern will mimic the narrowing and widening of a “V”. If the apex rises with contraction, you are viewing a foreshortened left ventricle and not seeing the true apex, and the probe position should be adjusted. Ventricular thrombus or hypokinesis at the apex is often best appreciated in this view.
Midesophageal Left Pulmonary Vein View
From either the two-chamber or LAA view, withdraw the probe slightly to better visualize the left upper pulmonary vein entering the left atrium. As on the right side, small manipulation of the probe is necessary to open up the course of the upper vein. As on the right side, the upper veins are most easily seen and interrogated with spectral Doppler. The lower vein is again in the near field and perpendicular to the imaging beam (Fig. 2.23). Spectral pulsed-wave Doppler interrogation of pulmonary venous flow patterns is easily performed in this view.
Transgastric Apical Short-Axis View
he probe is then slightly advanced and anteflexed (if necessary) to visualize the apical left ventricular cavity in short-axis. The anterior, septal, inferior, and lateral apical wall segments are seen in this view (Fig. 2.27).
Midesophageal Left Atrial Appendage View
From the ME two-chamber view, focus on the anteriorly positioned left atrial appendage and perform slight probe manipulations to maximize the appearance of the opening of the appendage. The author finds this a much simpler way to view the appendage than the method described in the comprehensive guidelines. Anatomy of the left atrial appendage is quite varied but often consists of an anterior and posterior lobe separated by a ridge of tissue. Extensive imaging of the LAA is required in left atrial appendage closure procedures such as Watchman. The circumflex coronary artery is often seen in the ridge of tissue between the mitral valve and the left atrial appendage. Flow can be confirmed in the vessel with color-flow Doppler after mitral valve surgery in this view.
Midesophageal Long-Axis View
After evaluation of the left-sided pulmonary veins, the probe is further rotated to approximately 120° or until the LVOT is seen. Small amounts of rotation and flexion will allow for maximizing the diameter of the outflow tract. This view often appears similar to the ME aortic valve long-axis; however, the ventricular inflow and outflow tracts are seen as well as a majority of the ventricular cavity.
The mitral valve and LVOT can be evaluated in this view. In addition, assessment of regional wall motion and global function of the anteroseptal and inferolateral walls of the ventricle is possible in this view (Fig. 2.24; Video 2.1). This view allows for identification of mitral valve prolapse, systolic anterior motion of the mitral valve, and localization of the A2 and P2 scallops of the mitral valve (all covered extensively in subsequent chapters).
Transgastric Basal Short-Axis View
From the ME long-axis, the probe is rotated back to 0°, advanced and anteflexed, and then withdrawn to obtain the TG basal short-axis view of the left ventricle. This view is often difficult to obtain. If the “fish mouth” view of the mitral valve is not obtained advancing to the TG midpapillary short-axis, then withdrawing the anteflexed probe may allow visualization of the TG basal short-axis (Fig. 2.25). The subvalvular mitral chords are seen in this view. Anterior leaflet chords are seen on the left and posterior chords on the right. All six basal left ventricular wall segments are seen in this view.
Transgastric Midpapillary Short-Axis View
The probe is then advanced, anteflexed, and withdrawn until contact is made with the wall of the stomach and the TG midpapillary short-axis view is obtained. See Video 2.2 at 00:10. The key structures to visualize are the left ventricular walls and cavity in addition to the posteromedial and anterolateral papillary muscles. A true short-axis cross-section of the left ventricle is confirmed when the two papillary muscles are approximately of equal size.
Fine-tuning this image may be challenging and is done in two phases. In the first phase, the depth of the probe is altered, and in the second phase, the degree of flexion is adjusted. The proper depth of the probe is obtained by focusing on the posteromedial papillary muscle, which is the papillary muscle closest to the apex of the scan. If chordae tendinae are visible, the probe is too high and should be advanced. If no papillary muscle is visible, most often the probe is too low and should be withdrawn.
Once the depth of the probe is appropriate, the flexion is adjusted to bring the anterolateral papillary muscle into the correct position. If any of the anterolateral chordae tendineae are visible, the probe is excessively anteflexed, and relaxation of the large wheel on the probe handle should bring the papillary muscle into the correct position.
Transgastric Two-Chamber View
After completion of the TG apical short-axis view is completed, the probe is withdrawn to the midpapillary short-axis view and the imaging angle is rotated to approximately 90° and the TG two-chamber view is obtained. See Video 2.2 at 00:29. This provides a view of the left ventricle, with the apex to the left of the display (often cut off and outside the image sector) and the mitral valve to the right. The primary diagnostic goal of this view is analysis of regional wall motion.
This is the preferred view for evaluation of the support structures of the mitral valve because they lie perpendicular to the ultrasound beam (Fig. 2.28).
Transgastric Long-Axis View
From the TG two-chamber view, the probe is rotated to approximately 120°. Acquisition of the TG long-axis view is seen in Video 2.2 at 00:45. The LVOT and aortic valve should come into view at 4 o’clock. This view is especially helpful in the spectral Doppler interrogation of the aortic valve and LVOT (Fig. 2.29).
Transgastric Right Ventricular Inflow View
From the TG long-axis view, the probe angle is rotated back to 90° and then turned toward the patient’s right (clockwise) until the TG right ventricular inflow view is seen. This view is helpful in evaluating right ventricular wall thickening and tricuspid valve pathology (Fig. 2.30). The Doppler interrogation angle for tricuspid annular plane systolic excursion (TAPSE) measurements is often optimal in this view.
Deep Transgastric Five-Chamber View
The probe is then rotated back to 0°, advanced toward the left ventricular apex, then maximally anteflexed and slightly withdrawn to obtain the DG long-axis view. Leftward flexion of the probe is often required. This view allows spectral Doppler interrogation of the outflow tract and aortic valves. Probe rotation may be necessary to optimize the Doppler interrogation angle (Fig. 2.31).
TG Right Ventricular Basal View
From the deep TG five-chamber view, the probe is anteflexed, withdrawn slightly and turned rightward (clockwise) to obtain the TG right ventricular basal view. Small manipulations will be required to optimize this view. All three leaflets of the tricuspid valve should be seen with the septal leaflet on the right, the posterior leaflet in the near field, and anterior leaflet in the far field. The RVOT and pulmonic valve are seen progressing toward the image far field (Fig. 2.32).
TG Right Ventricular Inflow–Outflow View
As described in the Comprehensive Guidelines (1), the probe is then rightward flexed (small wheel) to obtain the TG right ventricular inflow–outflow view. In this author’s experience, this method to obtain the view is extremely difficult to obtain. The view is much easier to obtain by turning the probe rightward from the TG left ventricular long-axis view. If obtained this way the image is in a different orientation but all the structures are present. This view allows general inspection of the tricuspid inflow and pulmonic outflow of the right ventricle. TAPSE measurements as well as spectral Doppler of the pulmonic valve can be made in this view (Fig. 2.33).
Descending Aorta Short-Axis View
After completion of the evaluation of the ventricles, the probe is rotated to 0° and the probe shaft is turned to the patient’s left and slightly withdrawn until a transverse view of the descending aorta is obtained (the descending aorta short-axis view). Key factors in imaging the aorta are its small size and its proximity to the TEE probe head in the esophagus.
Consequently, the following maneuvers are necessary to optimize aortic imaging. First, the image depth is reduced to enlarge the displayed aortic image. Second, the time gain compensation in the near field may have to be increased because it is often set at low levels during the cardiac examination.
Finally, the frequency of the transducer can be increased to enhance resolution. In the author’s experience, these changes in the settings have allowed the visualization of aortic atheromas that were not evident before the adjustments were made. The aorta is then examined along its course as the probe is slowly withdrawn. On newer machines the biplane image setting is often helpful when evaluating the aorta. This feature allow for simultaneous viewing of the short and long-axis of the aorta. When the aorta begins to appear elongated, the probe has reached the level of the aortic arch (Fig. 2.34).
Upper Esophageal Aortic Arch Long-Axis View
At the level of the arch, the probe is turned rightward to visualize the distal ascending aorta and arch in long-axis. This view is often useful in evaluating the distal ascending aorta, especially for the presence of calcification and/or atheroma at the cannulation site (Fig. 2.35).
Upper Esophageal Aortic Arch Short-Axis View
The imaging angle is then turned to 90° to obtain the upper esophageal aortic arch short-axis view. Small left and right turns of the probe shaft will allow you to interrogate the arch for calcification, enlargement, and foreign bodies.
You may see the origins of the great vessels at approximately 3 o’clock in the short-axis of the aortic arch. The innominate vein and the origin of the left subclavian artery are visualized in this view. The pulmonary artery lies parallel to the imaging beam affording excellent Doppler interrogation (Fig. 2.36).
Descending Aorta Long-Axis View
After completion of the aortic arch views, the probe is slowly advanced to obtain the longitudinal view of the descending aorta (the descending aorta long-axis view). As the probe is advanced, small left and right turns of the probe permit better interrogation of the aortic walls (Fig. 2.37).
Preferred Basic TEE rapid Exam
The author’s recommended basic transesophageal echocardiography cardiac examination. ME, midesophageal; AV, aortic valve; CFD, color Doppler flow; TV, tricuspid valve; RV, right ventricular; I-O, inflow–outflow; PV, pulmonary valve; TG, transgastric; SAX, short-axis; LAX, long-axis; Desc, descending; 2C, two-chamber; 4C, four-chamber. (Modified from Miller JP, Lambert SA, Shapiro WA, et al. The adequacy of basic intraoperative transesophageal echocardiography performed by experienced anesthesiologists. Anesth Analg 2001;92:1103–1110, with permission.)
