1. Correct Answer: B. Maximal velocity (Vmax) across the AV in the apical five-chamber view >4 m/s

Rationale: The three basic echocardiographic parameters to evaluate the presence of AS include (level 1 recommendation):

Additional AS echocardiographic parameters can be seen in Table 24.1.

Severe AS is defined by current guidelines as calcified or thickened valve leaflets with reduced systolic opening and antegrade velocity across the valve of >4.0 m/s equivalent to a mean transvalvular pressure gradient of >40 mm Hg. Typically, AVA is <1.0 cm². The guidelines also take into account the BSA of the patient, thus severe AS is defined as AVA <0.65 cm²/m².

Beware of lower velocities (underestimation of the severity of AS) when the Doppler beam is misaligned with the direction of the blood flow. The degree of AS is also underestimated with low stroke volume (SV) (LF-LG AS). The velocity ratio (also referred to as dimensionless index) may be helpful in these circumstances where there is Doppler misalignment and in situations where one may be concerned about LF-LG AS.

Option D refers to the dimensionless index, which is the ratio of subvalvular velocity obtained by pulsed-wave Doppler and the maximum velocity obtained by continuous-wave Doppler across the AV. This dimensionless index expresses the size of the valvular effective orifice area as a proportion of the cross-sectional area (CSA) of the LVOT. In the absence of valve stenosis, the velocity ratio approaches 1, with smaller numbers indicating more severe stenosis. Severe AS is suggested when the velocity ratio is <0.25, corresponding to a valve area 25% of normal.

1. Baumgartner H, Hung J, Bermejo J, 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(4):372-392.

2. Correct Answer: A. Start epinephrine

Rationale: Both fixed lesions such as valvular AS and dynamic LVOT obstruction such as seen in HOCM present with increased LVOT velocities. However, in AS, the orifice remains fixed in systole, whereas in HOCM, the LVOT obstruction is worse in mid- to late systole.

The spectral Doppler waveforms in Figure 24.1A show an elevated LVOT velocity of 2 m/s with a “rounded” velocity profile. Figure 24.1B obtained during a Valsalva maneuver shows a higher velocity of 4 m/s with a “dagger-shaped” velocity profile along with an intracavitary gradient of approximately 80 mm Hg. This increase in velocity across the LVOT with Valsalva occurs in dynamic LVOT obstruction (aka HOCM) due to worsening obstruction with the reduced venous return from the Valsalva maneuver. Dynamic obstruction is made worse with increased inotropy (option A—use of epinephrine), reduced venous return (low preload), and reduced afterload. Hence options B, C, and D (phenylephrine to increase afterload, fluid bolus to maintain preload, and esmolol to reduce inotropy) are appropriate next steps.

1. Geske JB, Ommen SR, Gersh BJ. Hypertrophic cardiomyopathy. JACC Heart Fail. 2018;6(5):364.

2. Sherrid MV, Wever-Pinzon O, Shah A, Chaudhry FA. Reflections of inflections in hypertrophic cardiomyopathy. J Am Coll Cardiol. 2009;54(3):12-219.

3. Correct Answer: B. Coarctation of aorta

Rationale: Figure 24.2 and Videos 24.2A and B show a midesophageal aortic valve short axis view (ME AV SAX view) with a BAV. A congenital BAV occurs in approximately 1% to 2% of the general population, making it the most common congenital valvular malformation. Calcification of a congenitally bicuspid valve results in premature onset of AS and represents the most common cause of AS among patients younger than 70 years of age. Commonly associated findings in patients with BAVs include aortic disease, including aortic coarctation, aortic insufficiency, aortic root dilation, ascending/arch aneurysms, and an increased risk of aortic dissection. Coarctation of the aorta can be associated with 20% of BAV or even more.

Notably, BAV is often associated with aortopathy. Type 1 BAV (fusion of right and left coronary cusps) leads to aneurysm of the ascending aorta, while type 2 BAV (fusion of right and noncoronary cusps) leads to arch dilation. Fusion of the non- and left cusp is extremely rare.

1. Siu SC, Silversides CK. Bicuspid aortic valve disease. J Am Coll Cardiol. 2010;55(25):2789.

4. Correct Answer: B. 0.98 cm² and severe AS

Rationale: The continuity equation is based on the principle of conservation of mass, or “flow in = flow out.” In other words, SV through the LVOT must equal SV through the AV.

We can obtain three of the four components of the continuity equation by calculating the SV of the LVOT and measuring the peak AV velocity.

SV = VTI (chamber) × CSA of the chamber

SV (LVOT) = SV (AV)

Applying this:

AVA × VTI AV = CSA LVOT × VTI LVOT

CSA LVOT = cross-sectional area of LVOT (π r²); r is d/2 where d= diameter of the LVOT, which is 2.0 cm in this question.

Solving for AVA:

VTI LVOT is 29.5 cm and the VTI AV is 94.1 cm. Entering these numbers into the equation yields a value of 0.98 cm², which suggests severe AS, as shown in Table 24.2.

1. Baumgartner H, Hung J, Bermejo J, 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(4):372-392.

5. Correct Answer: C. Consider afterload reduction and discuss the echocardiographic findings with the proceduralist

Rationale: Figure 24.5 and Videos 24.3A and B demonstrate AV paravalvular leak (PVL). The diagnosis is made based on echocardiographic appearance and quantification, root aortography, and hemodynamics (aortic and LV waveforms). The presence of PVL causes acute aortic regurgitation with increased LV end-diastolic pressure, which may result in pulmonary edema. Giving a fluid bolus would not be recommended. There are certain treatment options if significant postdeployment PVL is noticed on an echocardiographic examination. It can be corrected with repeat dilation of the valve to minimize residual regurgitation or using valve-in-valve technique, in which a second valve is deployed over the first percutaneous valve, or with other percutaneous closure devices. Moderate-to-severe PVL after surgical or transcatheter AV replacement is associated with increased mortality and should be corrected.

Given that patients with at least moderate paravalvular leak (PVL) at 30 days harbor a 2.4-fold increase in 1-year mortality, it is essential to make every effort to avoid more than mild PVL at the time of TAVR. The updated Valve Academic Research Consortium (VARC-2) criteria used in the PARTNER I trial recommended the following with respect to the circumferential extent of PVL in SAX: trace (pinpoint jet), mild (<10% of the valve circumference), moderate (10%-30%), and severe (>30%).

1. Ionescu A, Fraser AG, Butchart EG. Prevalence and clinical significance of incidental paraprosthetic valvar regurgitation: a prospective study using transoesophageal echocardiography. Heart. 2003;89(11):1316.

2. Steinvil A, Leshem-Rubinow E, Halkin A, et al. Vascular complications after transcatheter AV implantation and their association with mortality reevaluated by the valve academic research consortium definitions. Am J Cardiol. 2015;115(1):100-106.

6. Correct Answer: D. Mitral regurgitation

Rationale/Critique: Figure 24.6 and Video 24.4 depict an ascending aortic dissection (Stanford type A). The dissected intimal (flap) is visualized to originate near the right sinus of Valsalva (most common origin). If the dissection involves the ostia of the coronary arteries, it may result in myocardial ischemia/infarction. Also, the impingement of the flap during diastole can result in malcoaptation of the AV cusps resulting in aortic regurgitation. In case of rupture, a life-threatening tamponade may occur. This leads to abrupt hemodynamic collapse and requires emergent surgery with institution of cardiopulmonary bypass to establish control of the bleeding and provide cardiopulmonary support.

Complications associated with dissections are aortic regurgitation (50%-70% of the cases), coronary dissections with myocardial ischemia (10%-20%), pleural and pericardial effusions, and global LV dysfunction. TEE midesophageal long-axis view is most helpful to assess the presence and severity of aortic regurgitation in the presence of dissection. LV dysfunction may be secondary to ischemia following coronary dissection and acute aortic regurgitation.

1. Patil T, Nierich A. Transesophageal echocardiography evaluation of the thoracic aorta. Ann Card Anaesth. 2016;19(5):44-55.

7. Correct Answer: B. Mobile echogenic mass on the right coronary cusp

Rationale: Figure 24.7 and Videos 24.5A and B TEE images depict a midesophageal AV SAX view. The valve is tricuspid. The leaflet close to the right ventricular outflow tract (6 o’ clock position) is the right coronary cusp. The leaflet abutting the interatrial septum is the noncoronary cusp, and the leaflet close to the left atrial appendage is the left coronary cusp.

1. 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.

8. Correct Answer: C. Consult cardiac surgery for evaluation

Rationale: The patient has an aortic root abscess, a serious complication of infective endocarditis that is most commonly seen after an aortic valve replacement and aortic root repair. Aortic root abscesses appear as heterogenous hyperechoic lesions and perivalvular thickening. The video shows the presence of a false aneurysm, or pseudoaneurysm, which is a collection of blood that communicates with the aortic lumen as demonstrated by color Doppler flow but is not essentially enclosed by the normal vessel wall; it is contained only by the adventitia or surrounding soft tissue. Pseudoaneurysms can arise from a defect in the aortic wall or a leaking anastomosis after aortic aneurysm repair. The blood flow through the defect of the aortic wall can be observed using Doppler modalities, such as color and pulsed-wave Doppler. Pseudoaneurysms complicate aortic grafting in 1% to 6% of cases. It is an indication for emergent aortic replacement surgery. Uncorrected, it carries 100% mortality from rupture.

1. Spencer KT, Kaji E, Drucker D. Transesophageal echocardiographic diagnosis of a mycotic ascending aortic pseudoaneurysm as a source of embolism. J Am Soc Echocardiogra. 1998;11(12):1155-1157.

9. Correct Answer: B. Paradoxical LF-LG AS

Rationale: Severe AS is defined by an AVA ≤1.0 cm² (<0.65 cm²/m²) and a mean transvalvular gradient ≥40 mm Hg. Occasionally, there is discordance between AVA <1 cm² and <0.6 cm²/m² (consistent with severe AS) and the mean gradient <40 mm Hg (consistent with nonsevere AS) called area-gradient mismatch. Classifying the severity of AS in the presence of area-gradient mismatch is challenging, and they largely fall under two scenarios.

LF-LG AS is found in about 5%-10% of the patients with severe AS and is characterized by area-gradient mismatch, a reduced LVEF (<50%), and SVI <35 mL/m². The reduced flow across the AV due to low EF results in insufficient gradient, even in the presence of severe AS. To investigate for the presence of severe AS, further evaluation with dobutamine echocardiography is recommended. Dobutamine administration causes an increase in SV (SVI >35) and EF. In patients with truly severe AS (LF-LG AS), echocardiographic measurements obtained at this SV will satisfy all criteria for severe AS and resolve the area-gradient mismatch. If the mean gradient does not increase to >40 mm Hg despite a SVI > 35, the patient likely does not have severe AS.

Paradoxical LF-LG AS occurs in 5%-15% of patients with AS and it is characterized by area-gradient mismatch, normal LVEF (>50%), and SVI < 35. This is typically seen in the elderly and women with small/hypertrophied LV cavities resulting in low LV end-diastolic volumes. This low LV end-diastolic volume results in a low SV (despite normal LVEF), creating insufficient gradient across the AV, despite presence of severe AS. These patients are further evaluated either by increasing their SVI with dobutamine administration or by complementary imaging to assess AV calcification with cardiac CT.

1. Baumgartner H, Hung J, Bermejo J, 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(4):372-392.

2. Pibarot P, Dumesnil JG. Low-flow, low-gradient aortic stenosis with normal and depressed left ventricular ejection fraction. J Am Coll Cardiol. 2012;60:1845-1853.

10. Correct Answer: B. LV dilation

Rationale: Aortic regurgitation can be caused by primary disease of the AV and/or abnormalities of the aortic root and ascending aortic geometry. Degenerative tricuspid and bicuspid aortic regurgitation are the most common etiologies of aortic regurgitation in developed countries. Other causes include congenital variants (BAV), infective endocarditis, aortic dissection, and rheumatic heart disease. This patient had a BAV with severe aortic regurgitation in the setting of systemic infection, which is very suspicious for endocarditis and associated aortic regurgitation.

Infectious endocarditis causes destruction of the leaflets of the AV, and/or invasion into the aortic annulus and the adjacent structures. Thus, it results in acute aortic regurgitation. The physiology is very different from chronic aortic regurgitation developing over time. Acute aortic regurgitation is poorly tolerated, because the ventricle lacks the adaptive mechanisms—LV dilation and eccentric hypertrophy. Thus, there is an abrupt increase in the LV diastolic pressure, which may lead to pulmonary edema and acutely reduced contractility. Chronic aortic regurgitation can lead to significant LV dilation and a reduced EF, which are indications for surgery in the setting of asymptomatic severe aortic regurgitation. In chronic aortic regurgitation, a high LV end-diastolic pressure and high pulse pressure (with low diastolic blood pressure) may be present.

1. Baumgartner H, Falk V, Bax JJ, et al. 2017 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J. 2017;38(36):2739-2791.

11. Correct Answer: A. Aortic stenosis

Rationale: Figure 24.10 shows flow turbulence distal from the AV in systole as evidenced by the mosaic-like appearance of the color flow Doppler. This is explained by the increased blood flow velocities across the calcified and stenotic AV orifice. As velocities exceed the Nyquist limit, flow turbulence appears on the color flow Doppler image.

Epidemiologic studies have determined that more than one in eight people aged 75 and older have moderate or severe AS due to degeneration of the AV. Symptom onset is a late sign of the disease and usually develops in the seventh to ninth decade, manifested by reduced exercise tolerance. Late symptoms include angina (35%), syncope (15%), and heart failure (50%) and are important predictors of mortality within 2 years of symptom onset.

1. Nkomo VT, Gardin JM, Skelton TN, et al. Burden of valvular heart diseases: a population-based study. Lancet. 2006;368(9540): 1005-1011, https://doi.org/10.1016/S0140-6736(06)69208-8.