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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3677_Библиотеки_им_академика_М_И_Перельмана
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Transesophageal Echocardiography
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(TEE) forPediatric Congenital Cardiac
Surgery andCatheter Intervention
2.1 The History andDevelopment ofPediatric TEE
Pediatric transesophageal echocardiography (TEE) has been developed since the
1990s [1, 2] (Fig.2.1) and was initially used for critical care in adults. As technology of TEE advanced and its benets became more apparent, it was extended to use
in pediatric patients. Its usefulness in improving outcomes in cardiac surgery has
been extensively documented [3, 4] (Fig.2.2), and it is now also used as a navigation tool during interventional procedures for CHDs [5, 6] (Fig.2.3). This has made
TEE an important tool in the diagnosis and treatment of CHDs. However, it is
important to understand the anatomy, techniques, indications, contraindications,
and risks associated with TEE usage in pediatric patients, since it is a semi-invasive
diagnostic modality. In children, the insertion and manipulation of the ultrasound
probe during TEE may result in esophageal or gastric trauma, respiratory impairment, or vascular compression. Therefore, comprehensive multiplane TEE examinations should be performed following guidelines and standards set from the
American Society of Echocardiography and the Society of Cardiovascular
Anesthesiologists [7, 8].
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2.1.1 The Evolutionary Development ofPediatric
TEE Transducers
The development of TEE probes for children has been a gradual process that has
taken place over several decades. The rst TEE probe was reported in 1976 by
Frazin [9], but it was primitive and consisted of a single M-mode crystal probe
attached to a rigid endoscope. As TEE became more commonly used in pediatric
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023
S.-K. Tsai et al., Transesophageal Echocardiography in Pediatric Congenital Cardiac
Surgery and Catheter Intervention, https://doi.org/10.1007/978-981-99-6582-3_2
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2 Transesophageal Echocardiography (TEE) forPediatric Congenital Cardiac Surgery…
Fig. 2.1 Depicts a baby undergoing transesophageal echocardiography (TEE) monitoring for
congenital heart disease (CHD) surgery. During this procedure, a pediatric TEE probe is inserted
into the baby’s esophagus and connected to an ultrasound machine (GE Vingmed CFM 800 ultrasound, Norway) under nasal endotracheal anesthesia. To facilitate probe insertion and minimize
interference with TEE imaging, the baby’s head is positioned in the midline and slightly exed.
Before the procedure, nasogastric or feeding tubes are removed, and lubricating jelly can be used,
although excessive force should be avoided. To minimize the risk of complications, hemodynamic
changes such as blood pressure, pulse rate, and oxygenation are closely monitored. Following the
procedure, the TEE probe should be properly cleaned with glutaraldehyde to reduce the risk of
infection
patients, there was a growing need for smaller and more exible probes. In 1988,
Omoto [10] improved TEE technology by creating a single-plane phased array with
24 elements, which was more suitable for pediatric use, with a frequency of 5Hz
and a diameter of 6.8mm. Over the years, transducers have been miniaturized, and
advancements in phased array ultrasound technology have led to the development of
smaller and more exible probes that offer higher resolution imaging. These probes
de
2.1 The History andDevelopment ofPediatric TEE
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a
b
c
Fig. 2.2 Intraoperative TEE in an infant undergoing VSD Repair. (a) An operative photograph
shows the insertion of a TEE probe into the esophagus of the infant. (b) A diagram of the TEE
probe used during the procedure, the S8-3t Philips microTEE transducer. (c) An intraoperative
photograph showing the infant undergoing heart surgery. (d) Preoperative TEE imaging in color
displays a 4mm diameter ventricular septal defect (VSD) with left-to-right shunting, as seen in the
ve-chamber view. (e) Postoperative TEE imaging in the ve-chamber view shows complete closure of the VSD using a patch
are now available in a range of sizes and shapes, including miniaturized probes for
use in neonates and infants (Figs.2.4 and 2.5b). Furthermore, with advancements in
phased array ultrasound technology and miniaturized crystals, TEE technology has
rapidly evolved. Consequently, it now offers 3D real-time imaging [11] (Fig.2.4),
enabling more accurate visualization of cardiac structures.
2.1.2 The Current TEE Transducer forInfants inPediatrics
The diameter of the esophagus in neonates, children, and adolescents varies as a
function of weight. In a 3kg child, the diameter of the esophagus ranges from 4.8
to 8.48mm, with a variation range of 1.5 to 2mm [12]. The recommended mean
maximal diameter of the esophagus based on age [13] and weight [14] is displayed
in Fig.2.5a, and the corresponding size of TEE probes is shown in Fig.2.5b. The
GE Vingmed multiplane and Philips mini-multilane transducer can be used in newborns weighing 3.5kg, while the Philips microTEE probe can be used in premature
infants weighing 2.5kg.
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a
b
c
d
Fig. 2.3 TEE during pediatric interventional procedure (detailed discussion to follow in Part II).
(a) During transcatheter closure under an endotracheal general anesthesia, a TEE probe, with a bite
guard in place, is inserted into the esophagus of a child with an atrial septal defect (ASD). (b)
Preprocedural color TEE imaging shows a large ASD between the left and right atria with a leftto- right shunting. (c) “Postprocedural color TEE imaging displays successful deployment of the
Amplatzer Septal Occluder device, without residual shunting, as seen in the bicaval view. (d) A
photograph captures the multichannel monitoring during the interventional procedure, including
TEE imaging, uoroscopy imaging, and hemodynamic data”
2.1 The History andDevelopment ofPediatric TEE
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Fig. 2.4 Displays the various commercially available transesophageal echocardiography (TEE)
probes that have been developed over time. The probes include: (1) Monoplane (single plane) TEE
probe with a linear array transducer, which provides a single image of the heart (2). Biplane TEE
probe with separate transducer arrays, which combines transverse and longitudinal axis images to
provide a more comprehensive view of the heart. (3) Multiplane TEE probe, which comprises a
linear phased array of 64–128 piezoelectric crystals arranged in a circular pattern to provide continuous visualization of the cardiac anatomy. This probe can be electronically or manually steered
to produce images from various angles. (4) Live 3D TEE probe (matrix array probe), which consists of 2500 piezoelectric crystals that allow for volume scanning and acquisition of raw 3D data
for processing and image display. The 3D TEE probe provides accurate evaluation of the cardiac
anatomy and ventricular function. (5) Until recently, the smallest pediatric TEE probe with multiplane imaging was 7.5–10.8mm in diameter, making it suitable for use in small babies
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Fig. 2.5 (a) The upper
diagram shows the basic
principle of pediatric
transesophageal echocardiography (TEE). This technique
uses ultrasound waves to scan
the heart, creating images
that are displayed on a
monitoring screen for
children. The lower diagram
displays the mean diameter of
the esophagus at the cranial
point of measurement, based
on age and weight, respectively [13, 14]. (b) The safety
and efcacy of using
pediatric transesophageal
echocardiography (TEE)
probes, with a diameter
ranging from 7.5 to 10.8mm,
have been extensively studied
and proven for use in infants,
including premature babies
weighing as little as 2.5kg.
Clinical utilization of these
probes, as shown in the upper
right diagram, provides a
valuable tool for evaluating
various congenital heart
conditions
a
b
2.2 Indication ofTEE
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2.2 Indication ofTEE
TEE is considered as the most sensitive method for evaluating cardiac structures
and function. The most common indications for TEE include the evaluation of cardiac emboli or masses, endocarditis, valvular dysfunction, and aortic aneurysms.
Furthermore, TEE is not only used as a diagnostic tool, but also as a monitoring tool
during cardiac surgery or percutaneous procedures. In this chapter, our focus is
specically on the use of intraoperative TEE for monitoring congenital heart disease
surgeries and guiding intervention procedures.
2.2.1 Indication ofthePediatric TEE Monitoring ofCongenital
Heart Surgery
The use of Intraoperative TEE helps conrm the preoperative diagnosis and can
alter the surgical plan if hidden or additional ndings are uncovered during the procedures. These changes may occur inside the operating room. Intraoperative TEE is
used to ensure that the heart is de-aired before separation from cardiopulmonary
bypass (CPB) and to identify any new or residual surgical lesions after CPB, which
may require a second run or early surgical revision (Fig.2.2).
2.2.2 Pediatric TEE Guidance ofCardiac Catheter Intervention
Up to 40% of congenital heart diseases (CHD) can be treated with transcatheter
procedures. TEE can facilitate these procedures by combining with uoroscopy and
reduce radiation exposure for both patients and personnel in the catheter room. The
use of TEE in CHD interventions is aimed at enhancing the safety and efcacy of
the treatment. TEE serves several important functions, including:
1. Patient Selection by Providing Imaging Information to Determine Suitability for
the Procedure
2. Assessment of the Morphology and Characteristics of the Defects, Including the
Size, Number, and Relationship to Valves and Surrounding Vessels
3. Guiding Device Positioning, Deployment, and Successful Anchoring to Tissue
4. Monitoring Residual Effects and Assessing the Impact on Valvular Function and
Surrounding Vessels
5. Early Detection of Complications Related to Catheter Procedures (Fig.2.3)
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2.3 Fundamental Aspect ofPediatric TEE
The fundamentals of pediatric TEE involve inserting a probe with a transducer into
the esophagus to create a computerized image of the heart in motion. This is
achieved by using ultrasound or high-frequency sound waves, which reect off the
heart to produce real-time images on the monitoring screen. The TEE also provides
a means of monitoring the heart’s function. TEE provides a clearer image of the
heart compared to a transthoracic echocardiogram (TTE) as it avoids interference
from the chest wall, ribs, and lungs, allowing for more accurate imaging (Figs.2.5a
and 2.6). According to the ACE Guidelines and standards [7, 8, 15], pediatric TEE
probes are limited to anteexion and retroexion, without the ability to ex right
or left.
2.3.1 Key Views inPediatric TEE Imaging
The basic TEE imaging examination can be performed at three key perspectives: the
mid-esophageal (ME) view (Fig.2.7), the upper-esophageal (UE) view (Fig.2.8),
and the transgastric view (Fig.2.9).
Fig. 2.6 Illustrates the application of transesophageal echocardiography (TEE). The TEE probe
(T) is inserted into the esophagus (E) (left diagram) and sends ultrasound waves that reect off the
heart. These waves produce real-time images of the cardiac structure and provide a clear and
detailed image of the heart’s anatomy and function, which can be viewed on the monitor (right
diagram). Therefore, variations in the images of cardiac structures are anticipated when the TEE
probe is positioned in different regions of the esophagus
2.3 Fundamental Aspect ofPediatric TEE
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ab
Fig. 2.7 The middle-esophageal (ME) transesophageal echocardiography (TEE) view is obtained
by positioning the TEE probe in the middle part of the esophagus, which is located just behind the
heart and aorta. The ME view is used to obtain detailed images of the aorta and its surrounding
structures, including the atria, ventricles, and great vessels. The ME TEE view is often used to
diagnose and monitor a variety of cardiac conditions, including valvular heart disease, endocarditis, and congenital heart diseases. (a) TEE examination in the mid-esophageal (ME) four-chamber
view, with the transducer angled at 0° degrees, provides a clear visualization of the following
structures: the right atrium (RA), left atrium (LA), right ventricle (RV), left ventricle (LV), interatrial septum (IAS), interventricular septum (IVS), and mitral valve (MV) scallops (A2 and A3, P2
and P1). The function of this view is to provide a detailed and accurate evaluation of the heart’s
four chambers, enabling the detection and assessment of any abnormalities or issues that may
affect their function. (b) The ve-chamber view with the transducer angled at 0° degrees provides
a clear visualization of the following structures: the aortic valve (AV), left ventricular outow tract
(LVOT), RA, LA, RV, LV, interatrial septum (IAS), IVS, and MV scallops (A2 and A1, P1 and P2).
(c) The aortic valve short-axis (AV SAX) view, with the transducer angled between 0° and 45°
degrees, provides a clear visualization of the following structures: the aortic valve (right coronary
cusp (RCC), left coronary cusp (LCC), noncoronary cusp (NCC)), right ventricular outow tract
(RVOT), pulmonary artery (PA), RA, LA, RV, IAS, and IVS.The MEAV SAX view provides a
clear and detailed view of the AV, enabling the evaluation of its structure and function, including
the presence and severity of aortic stenosis, aortic regurgitation, atrial and ventricular septal
defects, or other abnormalities. (d) The two-chamber view, also known as the bicommissural view,
with the transducer angled between 80° and 90° degrees, provides a clear visualization of the following structures: the LA, LV, left atrial appendage (LAA), and MV scallops (P3, A2, and P1).
This view is particularly important in guiding procedures related to the MV. (A indicates anterior,
B indicates posterior). (e) The aortic valve long-axis (AV LAX) view, with the transducer angled
between 90° and 120° degrees, provides a clear visualization of the following structures: the LA,
left ventricular outow tract (LVOT), AV, proximal ascending aorta (AAo), RV, and MV scallops
(P2 and A2). This view is useful for evaluating the anatomy and function of the aortic valve, mitral
valve, and the left side of the heart. (f) The bicaval view, with the transducer angled between 90°
and 120° degrees, provides a clear visualization of the following structures: the RA, LA, superior
vena cava (SVC), inferior vena cava (IVC), and IAS.This view is useful for evaluating the anatomy and function of the right-side heart chambers and the major veins that drain blood into the
RA. (For the abbreviations, please refer to Part IV Appendix)
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c
d
ef
Fig. 2.7 (continued)
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