1. Answer: A. The right coronary artery is located anteriorly within the sinuses of Valsalva, which is the highest portion of the aorta (farthest off the ground) with the patient in the supine position for a midsternal thoracotomy. Therefore, air that enters the heart during open-heart surgery is pushed by pressure into this coronary preferentially. This occurs more commonly in mitral repair than in other types of heart surgery, because of insufflation of the left ventricle (filling it with fluid under pressure) done to examine leaflet coaptation. Most cases of coronary air embolization can be treated conservatively. Sometimes, it is necessary to put the patient back on cardiopulmonary bypass (CPB) or to treat ventricular arrhythmias with medicines.

2. Answer: C. Epicardial echo is an alternative imaging modality. The need for intraoperative echo still exists for those who have a contraindication to blind TEE passage, and these can readily be accomplished by epicardial echo. A standard transthoracic echo transducer is placed within a sterile sleeve with ultrasound gel inside the sleeve for elimination of air.

3. Answer: C. Recording aortic valve gradients is less reliable. Sometimes, continuous-wave Doppler velocities through the aortic valve can be recorded from the deep transgastric transducer position, but the results are sometimes underestimates of the true values. This can occur due to difficulties obtaining the maximal jet or optimizing the angle of flow. Pulsed-wave Doppler recordings of subaortic flow using TEE can accurately be recorded. All gradients are affected by loading conditions, but such changes can be corrected for, by understanding hemodynamics, especially altered cardiac output and preload. Electrocautery does interfere with ultrasound recordings, but most TEE can be performed in between those interruptions.

4. Answer: C. Intraoperative TEE is an important monitoring tool for patients undergoing implantation of a LVAD. The presence of aortic regurgitation makes an LVAD ineffective because the aortic regurgitation (AR) would return blood back to the left ventricular (LV) cannula without providing systemic arterial perfusion. The presence of LV enlargement and mitral regurgitation (MR) is irrelevant to the placement of the device. Placement of the inflow LVAD cannula into the left ventricle does not require TEE guidance. The presence and severity of tricuspid regurgitation (TR) are less important objectives of TEE.

5. Answer: E. Like the apical transthoracic view of the same name, the midesophageal TEE long-axis view usually cuts through the inferolateral (also called the posterior wall) and anteroseptal walls. This imaging plane is usually obtained at a multiplane angle of about 130 degrees (range, 110-150 degrees).

6. Answer: B. The most specific criterion for severe MR is a maximum ROA of ≥0.4 cm², or a vena contracta of ≥7-mm diameter. The V_max of the MR jet is irrelevant to MR severity and is reflective only of the LV to left atrial pressure difference. Systolic reversal of pulmonary venous flow not systolic blunting is specific for severe MR.

7. Answer: B. The hypovolemic patient usually has a small LV end-systolic size with increased ejection fraction (EF). The increased EF probably results from sympathetic stimulation, an attempt to maintain stroke volume despite the reduced end-diastolic volume. The small end-systolic LV size is probably the most reliable visual guide to the presence of hypovolemia (underfilling).

8. Answer: A. It is common to see one or more small color jets of periprosthetic regurgitation early after cessation of CPB. When small, many of these resolve progressively after protamine administration or within a few hours.

9. Answer: C. A TEE probe may occasionally become looped, with its tip turned superiorly within the esophagus, up toward the patient’s head. Traction of the probe to pull it out may cause the esophageal wall to tear. However, if the probe is advanced further, the loop comes out after it gains more room within the stomach, and the entire probe can then be extracted.

10. Answer: C. SAM is a common (a few percent) complication of mitral valve repair, particularly when the LV cavity is small and hyperdynamic, catecholamine medications are being administered, and the posterior leaflet is redundant. Mitral SAM has also been reported after aortic valve replacement (AVR), probably because of the LV hypertrophy and the reduction in LV cavity size from relief of increased afterload. Initial treatment should consist of intravascular volume replacement, cessation of catecholamines (beta₁-agonists), appropriate diagnosis by transthoracic echo or TEE, and sometimes blood pressure support with phenylephrine. Hypovolemia, blood loss, and a protamine reaction would lower pulmonary capillary wedge pressure. Massive myocardial infarction would not have hyperdynamic LV function.

11. Answer: C. Often, the heart is underfilled on the CPB, with lower cavity size in systole and diastole than in the ambulatory state, and therefore a higher EF. However, on CPB, the patient may have metabolic abnormalities, transient ischemia, or persistent effects of the cardioplegia, making the EF lower than it will be later when the patient has been weaned from pump.

12. Answer: D. The transgastric short axis of the left ventricle does not cut through the apex. The midesophageal 4-chamber view often foreshortens the left ventricle and passes anterior and superior to the apex; what is seen is a pseudoapex, which is really the anterior wall near but not at the apex. The midesophageal long-axis view is not as likely to be foreshortened; but it is still difficult to get a view of the true LV apex in many patients. Therefore, the transgastric long-axis of the left ventricle is the preferred view.

13. Answer: C. The trachea is between the aorta and the esophagus. Because air provides a relatively poor propagation of ultrasound, the trachea does not transmit the reflected images from the mid ascending aorta.

14. Answer: B. Similar to, and sometimes called, the “intercommissural view,” the midesophageal 2-chamber plane is often parallel to a line connecting the medial and lateral commissures of the mitral valve. In some patients, this view is rotationally midway between the 4- and 2-chamber views (Fig. 7-12). Structural or colorflow imaging can be obtained using this view to make a determination of which portion of the anterior or posterior leaflet is abnormal. Arranged in the normal way with the inferior LV wall to the left of the screen, the medial scallop (P3) is located to the left on the upper portion of the screen and the lateral scallop (P1) to the upper right.

15. Answer: E. The three-dimensional echocardiogram shows a flail P2, ruptured chordae to the middle scallop of the posterior leaflet. In patients with prolapse or flail, the MR jet is deflected to the opposite side of the valve.

16. Answer: A. The midesophageal transverse images in Figure 7-2 show severe MR, which is a systolic image exemplified by the orange color in the LV outflow tract. There is a hole (perforation) in the anterior leaflet that was caused by the jet of aortic regurgitation in the setting of aortic valve endocarditis prior to the surgery.

17. Answer: B. The MR was likely caused by the jet of aortic regurgitation that was presumably present prior to the AVR. Such a “jet lesion” causes endocardial abrasion of the LV surface at the base of the anterior mitral leaflet. This allowed for infection to set up in this region, which caused a perforation leading to the MR, which is seen in the systolic color-flow image.

18. Answer: C. The patient has a partially dehisced tricuspid prosthesis, with a periprosthetic leak of TR, located medial to the valve. The key in this case is to understand the imaging plane, which is stated in the question given. Note that the right atrium is very large and that the interatrial septum bows toward the left atrium due to right atrial hypertension. The anterior mitral leaflet is shown in the image, while the aortic prosthesis is not shown.

19. Answer: A. The IVC size is more reliable than RA size to tell the current RA pressure, because RA size reflects the chronicity of RA hypertension. The pulmonary regurgitation velocity reflects the diastolic difference in pressure between the PA and the right ventricle and could be used to determine pulmonary artery pressure and not RA pressure.

20. Answer: E. Figure 7-4A shows a 3D echo image of a mass, likely a thrombus, that obliterates the entire upper half of the atrial side of the prosthesis. Figure 7-4B shows high velocity, diastolic antegrade mitral flow, with a long pressure half-time, indicating severe prosthetic stenosis. There is also a systolic flow; shown above the baseline, with a moderate signal density, likely moderate mitral regurgitation. The upper color Doppler portion of Figure 7-4B shows antegrade mitral flow only in the rightward portion of the prosthetic ring; with an immobile posterior leaflet due to thrombotic obstruction. A mass like this, presenting acutely after stopping warfarin, is more likely thrombus than tumor or vegetation.

21. Answer: D. Figure 7-5A shows a positive contrast effect with bubbles in the left atrium that have passed from the right atrium. Figure 7-5B shows a negative contrast effect with a streak of blood without bubbles that has passed into the right atrium from the left atrium. So there is a bidirectional shunt.

22. Answer: B. There is a 64 mm Hg difference between LV systolic pressure and aortic pressure. This is a patient with aortic valve stenosis in addition to MR. The deep transgastric views are the usual and best ones with which to record LV outflow velocities using TEE. Figure 7-6 shows the continuous-wave recording of AS. It is distinguishable from MR by the blank period, lasting about 80 ms, during isovolumic relaxation. This blank period starts immediately at the cessation of the AS signal, at the time of aortic valve closure, and ends at mitral valve opening, the beginning of the mitral valve antegrade flow signal. This clear-cut separation of these two events in time confirms the systolic jet to be AS, not MR or TR.

23. Answer: D. This is a patient without fever or any signs of infection. He has a congenital bicuspid aortic valve of the horizontal type, with fusion of what would have been the right and left coronary cusps. In patients like this, the conjoined cusp has a longer length of its free edge, causing it to prolapse (small arrow) back into the outflow tract, causing aortic regurgitation.