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Echocardiography in Acute Aortic Syndromes Chapter | 15 161
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dissection have a 30-day mortality of 10% [1,4]. However, those who develop ischemic complications or contained aortic
rupture often require urgent aortic repair.
Immediate diagnosis and prompt implementation of definite therapy are crucial for survival in AAS. The optimal diagnostic method should be noninvasive, accurate, safe, helpful in identifying patients for emergency surgery and immediately
available in both emergency room and operating theater [14].
ROLE OF ECHOCARDIOGRAPHY IN DIAGNOSIS OF ACUTE AORTIC SYNDROME
Comprehensive imaging of the aorta is critical for the accurate diagnosis of AAS [13,14]. Imaging in AAS should include
the aortic diameters, presence and extent of dissection, aortic valve functional status, evaluation of the aortic branches, and
presence of possible complications. Computed tomography (CT) is considered a gold standard in AAS diagnosis and is
strongly recommended by the guidelines [4,14,15]. However, this technique is not immediately available, impossible to be
done at the bedside manner, thus it is not ideal for hemodynamically unstable patients. Bedside echocardiography, given
its rapidity, portability, and availability, may be a good imaging alternative, especially in high-risk patients. Unlike CT
and magnetic resonance imaging (MRI), echocardiography offers Doppler flow imaging and functional assessment of the
entire heart. This technique can be also useful as a monitoring tool during surgery (TEE) and in postoperative intensive care
[transthoracic echocardiography (TTE) and TEE].
Transthoracic Echocardiography
TTE is widely available and therefore should be performed immediately in all patients with suspected AAS. TTE is not the
technique of choice for the entire visualization of the aorta. However, it is extremely useful for the assessment of proximal
aortic segments that is crucial for the decision of emergency surgical intervention, indicated in all cases of proximal aortic
involvement. Additionally, using a thorough step-by-step approach with all available standard and off-axis views allow the
full assessment of the thoracic aorta. TTE for AAS includes evaluation of the ascending aorta from the standard and high
parasternal long axis, apical three-chamber and five-chamber views. However, it should be mentioned that in apical views
the aortic walls are seen with suboptimal lateral resolution. The aortic arch is evaluated from the suprasternal notch window.
The descending aorta may be partially visualized in the long parasternal, modified two-chamber, and suprasternal views.
The abdominal aorta can be imaged from the subcostal views in most patients.
The diagnosis of aortic dissection by TTE is based on detecting intimal flap in the aorta (a linear, mobile echogenic
structure observed within an aortic lumen) (Figs. 15.1–15.4). The intimal tear (entry) is most likely to occur on the right
lateral wall of the proximal ascending aorta or in the descending aorta close to ligamentum arteriosum [4,14–16]. In the
vast majority of cases (65%), entry tear is observed within 3 cm of coronary ostia [15,16], which can be perfectly visualized
using standard TTE views (Fig. 15.1). Echocardiographic detection of a bicuspid aortic valve (Fig. 15.5), an aortic regurgitation or a dilated aortic root accompanied by pericardial effusion or lateral hypokinesia strongly supports the diagnosis of
type A aortic dissection [15,16]. TTE identifies high-risk features of proximal aortic dissection, including severe proximal
aortic dilatation, pericardial effusion, regional wall motion abnormalities (suggestive of coronary occlusion), and aortic
regurgitation [4,15,16].
TTE is very useful in the differential diagnosis of unstable patients [10]. Normal appearance of thoracic aorta significantly decreases the clinical likelihood of AAS and implies the search for other possible etiologies of chest pain, including
ACS, valvular disease, pulmonary embolism, or pericarditis. Everyday emergency practice and current clinical guidelines
confirm the importance of TTE in patients with acute chest pain. Even limited TTE that usually takes less than 5 min and
may be performed simultaneously with other procedures on admission provides relevant information and directs further
diagnostics [10]. Recently, Sobczyk et al. [17] implemented a simple, easy-to-remember A–F mnemonic that was found to
be extremely useful in suspected acute aortic dissection and other life-threatening conditions.
TTE provides the additional information on aortic valve morphology and function (bicuspid aortic valve, aortic stenosis,
or severe valve calcification) that may be crucial for the operative technique choice. Detection of significant aortic valve
abnormalities precludes the implementation of valve sparing procedure. TTE in patients with AAS should also assess global
and regional left ventricular function, right ventricular function, morphology, and function of the other heart valves, and the
presence of pericardial and pleural effusion.
Previously, TTE has been considered limited in the diagnosis of acute aortic dissection, with sensitivity 77%–90% and
specificity 93%–96% for proximal aortic dissection and 70% sensitivity for distal aortic dissection [14,15]. However, these
data originate from relatively old studies and do not reflect the reality in the modern era of excellent echocardiographic
technique. Recent data from the studies of Cecconi et al. (2012) [18] and Sobczyk et al. (2015) [19] have shown high
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FIGURE 15.1 Parasternal long-axis view in three different patients showing dilated aortic root and a dissection flap in the proximal ascending aorta.
FIGURE 15.2 Apical three-chamber and five-chamber views in a patient with proximal aortic dissection. Dissection flap is seen within 3 cm of the
coronary ostia.
FIGURE 15.3 Suprasternal view showing aortic arch with dissection flap involving left carotid artery, true and false lumens are visible.
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FIGURE 15.4 Subcostal view showing the dissection flap.
FIGURE 15.5 Dilated ascending aorta in a patient with biscuspid aortic valve (long and short axis view).
sensitivity (97%–99%) and specificity (100%) of TTE in comparison to CT in proximal aortic dissection. Contrast enhancement substantially improves the accuracy of TTE in the diagnosis of aortic dissection (Evangelista et al.) [20]. The value
of TTE may be limited in patients on mechanical ventilation or in those with difficult acoustic window, i.e., with chest wall
abnormalities, narrow intercostal spaces, obesity, and pulmonary emphysema. These problems may be overcome by using
TEE.
Transesophageal Echocardiography
The relative anatomic proximity of the esophagus and aorta allows for nearly complete evaluation of the aorta with TEE.
Transesophageal images of the aorta have excellent resolution due to better ultrasound tissue penetration while using a
higher frequency transducer. TEE has a sensitivity approaching 100% and specificity of 100% for identifying an intimal
flap in proximal AD, comparable to helical CT and MRI [21].
TEE can be performed at the bedside or in the operating room, when the clinical suspicion of proximal AAS is high, to
avoid unnecessary delay in the surgical treatment. Patients with suspected AAS need continuous monitoring of heart rate,
blood pressure, and oxygen saturation during the TEE procedure. Blood pressure control is obtained using intravenous
beta-blockers or vasodilators. The deterioration of patients with acute aortic dissection during TEE has been described
in the literature, possibly as a result of blood pressure while introducing the probe [22]. TEE is minimally invasive and
complications of the procedure in patients with AAS are rare when adequate opioid analgesia or intravenous sedation is
implemented.
It is important to use a systematic approach with the standard image sequence. Aortic valve can be imaged in midesophageal aortic valve short- and long-axis views. The mid-esophageal ascending aortic short- and long-axis views are
useful in the assessment of proximal ascending aorta. One of the disadvantages of TEE is the inability to visualize the distal
ascending aorta. The upper esophageal aortic arch long- and short-axis views allow the visualization of the distal aortic
arch. The descending thoracic aorta is usually well seen in the descending aortic short- and long-axis views.
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PROLAPSE OF THE LEAFLET
ANNULAR DISSECTION
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Comprehensive Echocardiographic Management of Acute Aortic Syndrome
The most typical sign of aortic dissection is the intimal flap seen as a mobile linear echo separating two lumens. It is very
difficult to differentiate the true and false lumens. The false lumen is often larger than the true lumen. The true lumen is
often round in shape in short-axis views and expands during systole. The blood flow is usually greater in the true lumen,
with flap moving toward the false lumen. Aortic regurgitation is present in the majority of patients with type A aortic dissection (Fig. 15.6). It has multiple potential mechanisms (Fig. 15.7), including dilatation of the aortic annulus, aortic leaflet
prolapse (Fig. 15.8), prolapse of the dissection flap through the aortic valve [23] (Fig. 15.9), and preexisting valvular disease. Echocardiographic assessment of suspected AAS should also include left and right ventricular function, pericardial
and left pleural effusion.
Meredith and Mansani [16] proposed the practical diagnostic algorithm for suspected acute aortic dissection with an
immediate transthoracic echocardiography as a first-line imaging technique. If TTE identifies proximal aortic dissection or
high-risk features (including dilated aortic root, aortic regurgitation, pericardial effusion, and regional wall motion abnormalities), the other imaging techniques are recommended. Given its availability and portability, TEE is usually preferred.
TEE in patients with suspected type A aortic dissection should be performed in critical care unit or operating theater with
FIGURE 15.6 Acute aortic regurgitation in patient with proximal aortic dissection; apical five-chamber view: Color Doppler, continuous wave Doppler imaging.
PROLAPSE OF INTIMAL FLAP
FIGURE 15.7 Pathophysiological mechanisms of acute aortic regurgitation in acute type A aortic dissection.
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FIGURE 15.8 Aortic leaflet prolapse in patient with type A aortic dissection secondary to infective endocarditis.
FIGURE 15.9 Prolapse of the intimal flap through the aortic valve in patient with acute proximal aortic dissection; apical five-chamber view.
cardiac surgeons and anesthetists standing by [24,25]. This approach minimizes delays and lowers preoperative mortality
[24]. In some centers, unstable patients with a certain echocardiographic diagnosis of type A dissection are transferred
directly to the operating theater, usually without any additional diagnostic tests. In patients with cardiogenic shock, immediate life-saving surgery is performed based on the limited echocardiographic data to reduce mortality related to time delay.
If immediate TTE does not report aortic dissection or high-risk features, the patient may be diagnosed without haste and
safely transferred to CT/MRI laboratory. The current joint practical guidelines [14] of the cardiac, cardiothoracic, anesthesiology, radiology, and vascular societies recommend the selection of a specific imaging modality based on an immediate
availability (class I, level of evidence C) and local expertise.
PERIOPERATIVE ECHOCARDIOGRAPHIC ASSESSMENT
Preoperative TTE and TEE provide the cardiac surgeon with invaluable information. Proximal extent of aortic dissection
remains an undoubtful indication for emergent cardiac surgery. Assessment of aortic valve is essential in planning the
operative technique. It is important to describe both the severity and underlying mechanism of aortic valve regurgitation.
If AR is a result of annular dilatation, aortic leaflet prolapse, or intimal flap prolapsing through the aortic valve of normal
morphology, it is usually possible to resuspend the native valve and restore its proper function. Valve-sparing procedure is
also performed in some cases of bicuspid aortic valves. Intraoperative TEE monitoring is important especially in high-risk
patients. TEE provides information on left ventricular function, development of pericardial effusion, distal or proximal
expansion of dissection, or involvement of the coronary ostia. Intraoperative TEE monitoring is mandatory to confirm the
aortic valve competence after valve-sparing procedures. Postoperative echocardiographic follow-up should concentrate on
native or artificial aortic valve function and integrity of anastomoses of vascular grafts. TTE/TEE allows prompt diagnosis
of early postoperative hemodynamic instability, which is usually a result of postoperative complications. Pericardial effusion/tamponade, pleural effusion, or left ventricular failure are easily detectable using limited bedside echocardiography
(Table 15.2).
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TABLE 15.2 Echocardiographic Data Important for Cardiac Surgeon
Visualization of intimal dissection flap and its proximal extent
Localization of entry and reentry tears
Identification of the true and false lumen
Aortic valve morphology (number of cusps, calcifications)
Aortic regurgitation: mechanism and grading severity
Pericardial effusion, cardiac tamponade
Left pleural effusion
Involvement of side branches
Global and regional left ventricular function
Additional cardiac pathologies
SUMMARY
l Correct and prompt diagnosis of a suspected AAS at admission determines mortality and outcome.
l Early surgical intervention is recommended for type A aortic dissection and has been shown to improve the outcome.
l TTE is recommended as a first-line imaging technique in all patients with suspected AAS. However, a negative TTE
result does not exclude AAS.
l TEE should be performed in all patients with a high-risk proximal AAS, preferably performed with the surgical team
standing by.
l Echocardiography is an excellent bedside diagnostic tool enabling immediate diagnosis of AAS and monitoring the
effectiveness of the instituted treatment.
REFERENCES
[1] Tsai TT, Nienaber CA, Eagle KA. Acute aortic syndromes. Circulation 2005;112:3802–13.
[2] Ahmad F, Cheshire N, Hamady M. Acute aortic syndrome: pathology and therapeutic strategies. Postgrad Med J 2006;82:305–12.
[3] Nienaber CA, Powell JT. Management of acute aortic syndromes. Eur Heart J 2012;33(1):26–35.
[4] Erbel R, Aboyans V, Boileau C, et al. 2014 ESC guidelines of the diagnosis and treatment of aortic diseases. The task force for the diagnosis and
treatment of aortic diseases of the European society of cardiology. Eur Heart J 2014;35:2873–926.
[5] Hagan P, Nienaber CA, Isselbacher EM, et al. The international registry of acute aortic dissection: new insights into an old disease. JAMA
2000;283:897–903.
[6] Harris KM, Strauss CE, Eagle KA. Correlates of delayed recognition and treatment of acute type A aortic dissection: the International Registry of
acute aortic dissection (IRAD). Circulation 2011;124:1911–8.
[7] Booher AM, Isselbacher EM, nienaber CA, et al. The IRAD classification system for characterizing survival after aortic dissection. Am J Med
2013;126:19–24.
[8] Howard DP, Banerjee A, Fairhead JF, et al. Population-based study of incidence and outcome of acute aortic dissection and premorbid risk factor
control: 10-year results from the Oxford Vascular Study. Circulation 2013;127:2031–7.
[9] Shah BN, Ahmadvazir S, Pabla JS, et al. The role of urgent transthoracic echocardiography in the evaluation of patients with acute chest pain. Eur J
Emerg Med 2012;19(5):227–83.
[10] Sobczyk D, Nycz K, Andruszkiewicz P. Validity of a 5-minute focused echocardiography with A-F mnemonic performed by non-echocardiogra-
phers in the management of patients with acute chest pain. Cardiovasc Ultrasound 2015;13:16.
[11] Augostides JG, Geirsson A, Szeto WY, et al. Observational study of mortality risk stratification by ischemic presentation in patients with acute type
A aortic dissection: the Penn classification. Nat Clin Pract Cardiovasc Med 2009;6(2):140–6.
[12] Pisano C, Balistreri CR, Torretta F, et al. Penn classification in acute aortic dissection patients. Acta Cardiol 2016;71(2):235–40.
[13] Trimarchi S, Nienaber CA, Rampoldi V, et al. Contemporary results of surgery in acute type A aortic dissection: the International Registry of Acute
Aortic Dissection experience. J Thorac Cardiovasc Surg 2005;129:112–22.
[14] Goldstein SA, Evangelista A, Abbara S, et al. Multimodality imaging of diseases of the thoracic aorta in adults: from the American society of echo-
cardiography and the European association of cardiovascular imaging. J Am Soc Echocardiogr 2015;28:119–82.
[15] Nienaber C, von Kodolitsch Y, Nicolas V, et al. The diagnosis of thoracic aortic dissection by noninvasive imaging procedures. N Engl J Med
1993;328:1–9.
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[16] Meredith EL, Masani ND. Echocardiography in the emergency assessment of acute aortic syndromes. Eur J Echocardiogr 2009;10:i31–9.
[17] Sobczyk D, Andruszkiewicz P. Simple mnemonic for focused ultrasound cardiac examination in an emergency. Eur J Anesthesiol 2014;31:1–2.
[18] Cecconi M, Chirillo F, Constantini C, et al. The role of transthoracic echocardiography in the diagnosis and management of acute type A aortic
syndrome. Am Heart J 2012;163(1):112–8.
[19] Sobczyk D, Nycz K. Feasibility and accuracy of bedside transthoracic echocardiography in diagnosis of acute proximal aortic dissection. Cardiovasc
Ultrasound 2015;13:15.
[20] Evangelista A, Avegliano G, Aguilar R, et al. Impact of contrast-enhanced echocardiography on the diagnostic algorithm of acute aortic dissection.
Eur Heart J 2010;31:472–9.
[21] Shiga T, Wajima Z, Apfel C, et al. Diagnostic accuracy of transesophageal echocardiography, helical computed tomography, and magnetic resonance
imaging for suspected thoracic aortic dissection: systematic review and meta-analysis. Arch Intern Med 2006;166:1350–6.
[22] Kristensen S, Ivarsen H, Egeblad H. Rupture of aortic dissection during attempted transesophageal echocardiography. Echocardiography
2007;13:405–6.
[23] Geyik B, Ozeke O, Ozbakir C, et al. Aortic dissection with diastolic prolapse of intimal flap into left ventricle. Eur J Echocardiogr 2005;6:311–2.
[24] MacKnight BM, Maldonado Y, Augostides JG, et al. Advances in imaging for the management of acute aortic syndromes: focus on transesophageal
echocardiography and type-a aortic dissection for the perioperative echocardiographer. J Cardiothorac Vasc Anesth 2016;30(4):1129–41.
[25] Thorsgard ME, Morrrissette GJ, Sun B, et al. Impact of Intraoperative transesophageal echocardiography on acute type-a aortic dissection. J
Cardiothorac Vasc Anesth 2014;28(5):1203–7.
Chapter 16
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Transesophageal Echocardiography in
the Assessment of Aortic Valve and Aortic
Root Disease
Maria-Magdalena Gurzun
1
Euroecolab, University of Medicine and Pharmacy “Carol Davila”, Bucharest, Romania; 2Army’s Center for Cardio-Vascular Disease, Bucharest,
Romania; 3Emergency Institute for Cardio-Vascular Diseases “CC Iliescu”, Bucharest, Romania
Chapter Outline
Introduction 169
Technical and Practical Considerations 169
Transesophageal Echocardiography Role in the
Morphological Assessment of Aortic Valve Disease 171
Transesophageal Echocardiography Role in Evaluation of
Aortic Stenosis 172
1,2
, Bogdan Alexandru Popescu
1,3
Transesophageal Echocardiography Role in Evaluation of
Aortic Regurgitation 173
Transesophageal Echocardiography Role in the
Morphological Assessment of Aortic Root Disease 175
Conclusions 177
References 179
INTRODUCTION
Echocardiography is the main imaging method in evaluating aortic valve morphology and function and remains a method
of choice for assessing the aortic root, together with multidetector computer tomography (MDCT) and cardiac magnetic
resonance (CMR). Although transthoracic echocardiography (TTE) is very useful in clinical practice, transesophageal
echocardiography (TEE) is indicated in the evaluation of cardiac and aortic structure and function in situations in which
the findings may alter the management, or the results of TTE are nondiagnostic [1]. Therefore, the superior image quality
offered by TEE due to probe proximity is sometimes necessary for a detailed morphological aortic valve and aortic root
examination and the diagnosis of aortic valve dysfunction.
TECHNICAL AND PRACTICAL CONSIDERATIONS
The aortic valve and aortic root analysis should be performed in a systematic fashion (Table 16.1).
The authors recommend to start the analysis from mid-esophageal long axis view (120 degrees) [1,3]. In this view,
the aortic cusps and the aortic annulus are visualized as well as the left ventricle outflow tract and the first 2–3 cm of the
ascending aorta. The right coronary cusp is at the bottom (in the far field), whereas the noncoronary cusp and sometimes
the left coronary cusp is on top (in the near filed). Clockwise rotation with TEE identifies coaptation between the right
coronary and the noncoronary cusps, whereas counterclockwise rotation permits the evaluation of coaptation between right
and left coronary cusps [4]. The measurements usually performed in this view are the level of the aortic annulus, the sinuses
of Valsalva, the sinotubular junction, and the ascending aorta (1 cm from the sinotubular junction). The aortic annulus is
usually measured in mid-systole, whereas the measurements of aortic diameter are performed at end-diastole [5] using the
leading edge technique [6]. For a better visualization of ascending aorta, the modified long axis view may be used. This
view is obtained from the previous one by withdrawing slightly the probe or by using the multiplane to 130–160 degrees.
The aortic valve is not properly visualized in this view, but the first 6–7 cm of the ascending aorta can be analyzed until the
level of the “blind spot” [5,7]. The “blind spot” represents the distal part of the ascending aorta and proximal arch, including the origin of brachiocephalic trunk that cannot be visualized by TEE due to the interposition of the trachea and left
New Approaches to Aortic Diseases from Valve to Abdominal Bifurcation. http://dx.doi.org/10.1016/B978-0-12-809979-7.00016-X
Copyright © 2018 Elsevier Inc. All rights reserved.
169
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TABLE 16.1 Transesophageal Echocardiographic (TEE) Visualization and Normal Dimensions of the Aortic Valve and
Aortic Root
Analyzed Segment View Normal Value TEE Appearance
Aortic annulus Long axis view 20–31 mm
13±1 mm/m2 [2]
Aortic valve Long axis view
Short axis view
Deep transgastric view
Long axis transgastric view
Three-dimensional (3D) aortic valve view Fig. 16.3
Aorta at the level of the left main trunk Modified short axis view Fig. 16.4
Aorta at the Valsalva sinuses level Long axis view 29–45 mm
19± mm/m2 [2]
Aorta at the sinotubular junction Long axis view 22–36 mm
15±2 mm/m2 [2]
Ascending aorta Modified long axis view 22–36 mm
15±2 mm/m
<21 mm/m2 [2]
Short axis view of ascending aorta Modified short axis view Fig. 16.8
3D ascending aorta view Fig. 16.9
3D mathematical model of ascending aorta and
aortic valve
2
Fig. 16.1
Fig. 16.2
Fig. 16.5
Fig. 16.6
Fig. 16.7
Fig. 16.10
main bronchus between the aorta and the TEE probe [8]. This blind zone can be eliminated by using a saline-filled latex
balloon inserted into the trachea through the tracheal tube [9], but this method may be used just for patients under general
anesthesia.
The short axis view of the aortic valve is obtained from the long axis view, keeping the aortic valve in the middle of
the view and using the multiplane to 40–70 degrees. In this view, the noncoronary cusp is located in the upper left third,
the right coronary cusp in the lower third. The two-dimensional (2D) planimetric area of the aortic valve is measured
mid-systole in this view. By slightly withdrawing the probe from the aortic valve in a short axis view, the coronary ostia
can be identified: left coronary ostium (at 2 o’clock of the circumference of the aortic root) and right coronary ostium
(at 6 o’clock of the circumference of the aortic root) [3]. Generally, the right coronary ostium is better visualized from
the long axis view. By withdrawing the probe further, a short axis view of the ascending aorta at different levels can be
obtained.
The aortic valve can be visualized from the transgastric views as well. The main disadvantage of this view is the fact
that the aortic valve is located in the far field, but a very important advantage is the fact that a continuous wave Doppler for
the aortic valve can be properly used due to the correct alignment. The two transgastric views used for the aortic valve are
long axis transgastric view (obtained from left ventricle short axis view by using the multiplane to 120 degrees) and deep
transgastric long axis view or five-chamber view [1,3].
Three-dimensional (3D) TEE is a very useful imaging choice, especially in some specific clinical scenarios. The
biplane imaging obtained using 3D TEE probe offers the possibility to have in the same image and the same time the
long and the short axis view of the aortic valve or aortic root. This method allows a more precise measurement of the
aortic valve area opening, exactly at the level of aortic cusps tips. The real-time or full volume 3D aortic valve images
are generally obtained from long or short axis view of the aortic valve [10,11]. This method is crucial for the precise
measurement of aortic annular diameter, as the left ventricle (LV) outflow tract is more oval than circular [12]. If 2D
echocardiography in long axis view allows the measurement of antero-posterior aortic annulus diameter (the shorter
one), 3D echocardiography allows the measurement of both diameters and the aortic annulus perimeter and area [13].
3D echocardiography allows also the measurement of the distance between aortic annulus and coronary ostia and the
distance between the annulus and leaflet tips, essential data for the optimal percutaneous placement of aortic valve
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prosthesis [14,15]. Moreover, some data necessary for aortic root repair can be obtained by 3D echocardiography: intercommissural distance and free leaflet edge lengths [16,17].
TRANSESOPHAGEAL ECHOCARDIOGRAPHY ROLE IN THE MORPHOLOGICAL
ASSESSMENT OF AORTIC VALVE DISEASE
The TEE high-spatial and temporal resolution makes it a perfect tool for morphological examination of the aortic valve cusps.
The number of cusps may be easily appreciated by 2D short axis view or 3D TEE: normal tricuspid aortic valve or congenital
abnormal unicuspid aortic valve [18], bicuspid aortic valve [19], or quadricuspid aortic valve [20] (Fig. 16.1). The bicuspid
aortic valve is classified in a purely bicuspid aortic valve, formed by two equal cusps (anterior and posterior or left and right
aortic cusps) or potentially tricuspid formed by two nonequal cusps and a raphe [21,22]. This situation is frequently the result
of fusion of the right and left coronary cusps determining a larger anterior and a smaller posterior cusp with both coronary
arteries having the origin at the level of anterior sinus (80% of cases). In 20% of cases, the fusion is between right and noncoronary cusp resulting in a larger right and a smaller left cusp, with one coronary artery arising from each sinus [23].
The morphological appearance of the cusps (cusps thickness, cusps and annulus calcification, cusps fenestration
or prolapse/flail, structures attached to aortic cusps) or commissures (fusion, splaying, attachment site, and alignment) [24] may also be appreciated by TEE. The opening and closure movement of aortic cusps must be carefully
noticed: restricted opening may suggest aortic stenosis, whereas incomplete closure may suggest aortic regurgitation. Aortic valve prolapse is defined as the downward displacement of cuspal material below the annulus plane in a
properly oriented long axis view [25]. The appearance of commissural fusion can suggest the etiology of aortic valve
disease: in rheumatic disease commissural fusion with consecutive triangular systolic thickening is usual, whereas in
degenerative disease commissural fusion is absent with consecutive stellate-shaped systolic opening [26]. The TEE
examination allows the visualization of the cusps coaptation point and measuring the coaptation high (the distance
between coaptation point and aortic annulus) [4] (Fig. 16.2). In the case of aortic regurgitation with morphologically
normal aortic valve, a coaptation leaflet height more than 8–10 mm and a ratio between sinotubular junction and
annulus more than 1.6 suggest functional aortic regurgitation [5]. In this case, the surgical treatment may consist of
aortic valve sparing procedures [27].
Based on morphological and functional characteristics of aortic cusps assessed by echocardiography, the mechanism of
aortic valve dysfunction is classified into three types [28,29]:
l Type I: normal cusp morphology and motion: Ia (dilatation of sinotubular junction and ascending aorta), Ib
(dilatation of sinotubular junction and sinuses of Valsalva), Ic (isolated dilatation of aortic annulus), and Id (leaflet
perforation);
l Type II: IIa—cusp prolapse: cusps flail (complete eversion of cusp into the left ventricle outflow tract), partial cusp pro-
lapses (distal part of a cusp prolapsing into the left ventricle outflow tract), whole cusp prolapses (free edge and entire
cusp billowing into the left ventricle outflow tract) (Fig. 16.3).
(A) (B) (C)
FIGURE 16.1 Three-dimensional transesophageal echocardiography appearance of aortic valve for a patient with normal tricuspid aortic valve (A),
for a patient with bicuspid aortic valve with left and right cusp and commissures at 2 and 8 o’clock (B), and for a patient with quadricuspid aortic
valve (C).
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