Miniaturized transesophageal echocardiography in newborn infants

Intracardiac echocardiography probe via oesophageal to guide percutaneous left atrial appendage closure procedure: a case series

Background

Left atrial appendage closure (LAAC) can be an alternative to oral anticoagulant therapy in patients with non-valvular atrial fibrillation, characterized by high risk of stroke (CHA2D2VASC ≥ two for men and CHA2D2VA2SC ≥ three for women) and high risk of bleeding (HASBLED = 3).

Case summary

We describe three case reports in which an intracardiac echocardiography probe was used via the oesophageal route as an alternative to traditional transoesophageal echocardiography (TEE) or ICE methods to guide LAAC. Guiding the procedure via conventional TEE, even if feasible, could be difficult in these patients due to different causes: one patient was affected by Brugada syndrome while the other two patients reported oropharyngeal abnormalities. For these reasons, we performed an alternative use of the ICE probe to guide the entire LAAC procedure.

Discussion

Currently, LAAC is performed using intracardiac or transoesophageal echocardiography. This alternative use of ICE probe via oesophageal (ICE-TEE) is reported in previous studies that describe the feasibility of this technique both in excluding the presence of thrombus in left atrial appendage before cardioversion and in guiding percutaneous foramen ovale closure. Therefore, the ICE probe has been used as an intraoperative transoesophageal echocardiographic probe to repair congenital heart disease in infants or children with oropharyngeal abnormalities.This case series reports the first use of ICE-TEE to guide the entire LAAC procedure, guaranteeing the visualization of all echocardiographic views needed to perform it. The present case series highlights the potential of ICE-TEE to safely perform both pre-procedural and intraoperative evaluations in LAAC procedure.

Evaluation of two probes for transesophageal echocardiography in small dogs: imaging capabilities, image quality, and usability

INTRODUCTIONS

Patient size is a limiting factor for transesophageal echocardiography (TEE) in small dogs. The objective of this study was to describe imaging capabilities of two probes for TEE in small dogs.

ANIMALS, MATERIALS, AND METHODS

Prospective study in 10 client-owned dogs weighing <4 kg with congenital heart disease (CHD). Dogs had TEE performed with a microprobe (10T-D, GE Medical) and intracardiac echocardiography (ICE) catheter-based probe (AcuNav™, Biosense Webster) in the esophagus in alternating order. Ease of placement, ability to acquire images of the CHD, image quality, and probe limitations were recorded.

RESULTS

Median weight was 2.4 kg (range, 1.0-3.2). Congenital abnormalities included patent ductus arteriosus (n = 9) and pulmonary valve stenosis (n = 1). The 10T-D microprobe was easy to place (n = 8) or achievable with gentle manipulation (n = 2), and image quality of the CHD was optimal (n = 8), adequate (n = 1), or poor (n = 1). The ICE probe was difficult to place in the esophagus even with an external support system (n = 9) or could not be placed (n = 1), and image quality of the CHD was optimal (n = 2), adequate (n = 3), or poor (n = 5). Both probes provided images in a 1.0-kg dog. Probe limitations included lack of lateral motion (microprobe), the need for an external support system (ICE probe) and inability to consistently maintain contact with the esophagus (ICE probe).

CONCLUSION

The 10T-D microprobe provided high-quality TEE images more consistently than the ICE probe in the majority of dogs in this study; however, the lack of lateral motion can diminish its utility in some dogs.

Evaluation of a Second-Generation Microtransesophageal Echocardiography Transducer and Software

Background:

Transesophageal echocardiographic imaging of small infants has been limited because of equipment size. A newer miniaturized transducer has allowed for the imaging of even the smallest patients but has been limited by intermittent poor image quality because of hardware durability. A second generation of the transducer was developed to address this problem. The aim of this study was to evaluate the performance and durability of the second-generation transducer over multiple uses and to compare the image quality from the modified transducer and new software preset to the original transducer.

Methods:

Patients undergoing transesophageal echocardiography (TEE) based on clinical indications with the original or second-generation transducers were included in the study. All studies were reviewed for image quality and unacceptable image degradation, which was defined as imaging quality inadequate for clinical use. Study review was performed by two echocardiographers.

Results:

Using the original transducer, 37 studies were performed with a mean patient weight of 3.46 ± 0.89 kg (range 2.1-5.7). Using the second-generation transducer, 65 studies were performed with a mean patient weight of 4.87 ± 2.05 kg (range 2.2-13.8). Image quality was clinically inadequate in 8 of the 35 studies with the original transducer and in zero with the second generation ( P < .0001).

Conclusions:

The second-generation transducer allows for effective use of TEE even in the smallest infants and avoids the mechanical failures associated with the first-generation release.

Preliminary evaluation of a microtransesophageal probe in neonates and young infants undergoing surgery for congenital heart disease

Background:

The larger size of the currently available transesophageal echocardiography (TEE) probes limits their use to relatively older infants undergoing cardiac surgery. In very young neonates and infants, epicardial echocardiogram is used to assess postoperative residual defects. Recently, a miniaturized microTEE probe compatible in neonates has been introduced for clinical use. We evaluated the use of this probe in small infants undergoing cardiac surgery.

Materials and Methods:

Thirty-three consecutive neonates and infants undergoing cardiac surgery at our institution were included in the study. Intraoperative echocardiography with Philips s8-3t microTEE probe done using IE33 platform was utilized to study the preoperative anatomy and assess postoperative results.

Results:

Thirty-three patients aged 3 days-2 years (mean 5.1 months) and weighing 2.5-11 kg (mean 4.4 kg) underwent perioperative evaluation using the microTEE probe. Good quality two-dimensional and color Doppler images were obtained in all patients. There were no complications related to the probe insertion or manipulation. The findings on microTEE led to revision of surgery in five patients. Certain echocardiographic parameters that could never be recorded with epicardial echocardiogram could be easily seen in microTEE.

Conclusion:

On preliminary evaluation, the microTEE probe provided good quality images in very small infants who were not amenable for transesophageal echocardiographic evaluation so far. The probe could be used safely in small infants without complications. It appears to be a promising imaging modality in the perioperative assessment of young infants undergoing cardiac surgery, in whom intraoperative epicardial echocardiography is currently the only tool.

Intraoperative transesophageal echocardiogram using an intracardiac ultrasound catheter in a congenital heart surgery: a case report

Transesophageal echocardiography (TEE) during cardiac surgery is a routine procedure. The use of pediatric TEE probes is limited in small infants weighing less than 5 kg. Recent reports have shown the safety of monoplane intravascular ultrasound catheters in transesophageal echocardiograms. This report describes the case of a newborn with total anomalous pulmonary venous return who underwent cardiac surgery. A pre- and postbypass TEE examination was performed, with successful visualization of the cardiac anatomy and function and no complications.

The use of echocardiography in congenital heart surgery and intervention

Echocardiography has revolutionized the management of pediatric and adult heart disease, especially in the diagnosis of congenital heart defects. Although the early methods of echocardiography (M-mode and Doppler imaging) were limited in their ability to define the defect in question, the advent of 2D, and now 3D, imaging have clearly equaled or surpassed traditional methods of diagnosis (e.g., noninvasively obtained plain chest radiographs and electrocardiograms) and invasive tests (e.g., cardiac catheterization and angiography). Confidence in the images obtained using echocardiography has continued to increase, with many patients referred for corrective or palliative surgery on the basis of echocardiographic imaging alone. Echocardiography has eliminated the need, decreased the frequency, or improved the timing or performance of invasive studies in other patients. Specifically, it is used to definitively diagnose a cardiac defect and any associated lesions. It will also provide quantitative information for the assessment of the hemodynamic severity of the lesion. This review outlines the manner in which echocardiography is used to plan and guide congenital heart surgery or intervention, along with some of the advantages and disadvantages (pitfalls) of which to be aware. The use of echocardiography within the cardiac catheterization or surgical theater, as well as in the intensive care unit, is discussed, as is the use of echocardiography as a means of monitoring recovery and follow-up following cardiac surgery. Finally, the authors discuss who is best qualified or suited to perform these tests.

Trends in pediatric imaging: ultrasound

For the last three decades, two-dimensional (2D) echocardiography and Doppler echocardiography have been the primary imaging modalities for the diagnosis and management of heart disease in infants, children, and adolescents. These methods are non-invasive, highly sensitive, and cost-effective, and widely available, making them very useful in clinical work. During this period, the anatomic and hemodynamic abnormalities associated with different congenital and acquired pediatric heart diseases have been well outlined by echocardiography. Recent advances in computer technology, signal processing, and transducer design have allowed the capabilities of pediatric echocardiography to be expanded beyond qualitative 2D imaging and blood flow Doppler analysis. New modalities such as three-dimensional echocardiography, tissue Doppler imaging and speckle tracking echocardiography have been used to evaluate parameters such as ventricular volume, myocardial velocity, regional strain, and strain rate, providing new insight into cardiovascular morphology and ventricular systolic and diastolic function. Accordingly, a comprehensive and sophisticated quantification of ventricular function is now part of most echocardiography protocols. Use of measurements adjusted for body size and age is common practice today. These developments have further strengthened the position of echocardiography in pediatric cardiology.

Transesophageal echocardiography in critically ill acute postoperative infants: comparison of AcuNav intracardiac echocardiographic and microTEE miniaturized transducers

BACKGROUND

Multiple barriers to transthoracic echocardiography are present in critically ill infants immediately after surgery. Transesophageal echocardiography (TEE) is sometimes needed to obtain specific important information that transthoracic echocardiography fails to demonstrate. Formerly, the investigators used the AcuNav intracardiac echocardiographic (ICE) intravascular ultrasound transducer (8 Fr, 2.5 mm, 64-element crystal array, multifrequency [5.5-10 MHz], single longitudinal plane, linear phased array [Siemens Medical Solutions USA, Inc., Mountain View, CA]). Recently, the investigators have also used the microTEE transducer (8-mm transducer tip, 5.2-mm shaft, multifrequency [3-8 MHz], multiplane phased array, 32-element probe [Philips Medical Systems, Andover, MA]). Both transducers have two-dimensional, M-mode, color Doppler, and pulsed-wave and continuous-wave Doppler capabilities. The aim of this study was to compare the efficacy, safety, ease of insertion, capabilities, utilization, and cost of the AcuNav ICE transducer versus those of the microTEE transducer.

METHODS

A retrospective review of all 50 postoperative critically ill infants who underwent TEE using the AcuNav and microTEE in the past 5 years was conducted. TEE was performed as ordered by the attending physician to answer a specific question not answered by transthoracic echocardiography.

RESULTS

In all cases, the clinical information sought was obtained. The AcuNav ICE transducer was safe, easy to insert through the transnasal route, and did not require paralysis; however, it had a limited number of echocardiographic views and had greater sterilization cost. The microTEE transducer had greater echocardiographic capabilities and lower sterilization cost; however, it was slightly more difficult to insert, had a few manageable complications, and required more sedation and paralysis.

CONCLUSIONS

TEE in this setting has increased because of demonstrated efficacy and safety. Both the AcuNav ICE and microTEE transducers are useful and effective in this critical clinical scenario.

Transesophageal Echocardiography in Tetralogy of Fallot

Transesophageal echocardiography (TEE) plays an important role in the anatomical, functional, and hemodynamic assessment of patients with congenital heart disease (CHD). This imaging approach has been applied to both children and adults with a wide range of cardiovascular malformations. Extensive clinical experience documents significant contributions, particularly in the perioperative setting. In fact, in the current medical era, many consider this technology to be an essential adjunct to surgical and anesthetic management in CHD. This review focuses on the applications of TEE in patients with tetralogy of Fallot (TOF), the most common form of cyanotic heart disease. Emphasis is given to the perioperative use of this imaging modality and benefits derived during the prebypass and postbypass periods. Limitations and pitfalls relevant to the TEE assessment in patients with this anomaly are also addressed.

Role of transesophageal echocardiography in the management of pediatric patients with congenital heart disease

Transesophageal echocardiography (TEE) has become a critical diagnostic and perioperative management tool for patients with congenital heart disease (CHD) undergoing cardiac and noncardiac surgical procedures. This review highlights the role of TEE in routine management of pediatric cardiac patient population with focus on indications, views, applications and technological advances.

Initial experience with a miniaturized multiplane transesophageal probe in small infants undergoing cardiac operations

PURPOSE

There has been reluctance to use intraoperative transesophageal echocardiography (TEE) in small infants. We assessed the utility and safety of a new miniaturized multiplane micro-TEE probe in small infants undergoing cardiac operations.

DESCRIPTION

Hemodynamic and ventilation variables were prospectively recorded before and after micro-TEE insertion and removal in infants weighing 5 kg or less undergoing cardiac operations.

EVALUATION

The study included 42 patients with a mean weight of 3.6 +/- 0.9 kg (range, 1.7 to 5 kg). All probe insertions were successful. There were no complications or clinically significant changes in hemodynamic or ventilation variables. Information provided by TEE resulted in surgical revision in 6 of the 42 patients.

CONCLUSIONS

The micro-TEE provides high quality, useful diagnostic images without hemodynamic or ventilation compromise in small infants undergoing cardiac operations. This advance is important with the growing trend towards complete repair of complex structural heart disease in small infants.

A new transesophageal probe for newborns

Current transesophageal probes are designed for adults and are used both in the operating theatre for monitoring as well as in the outpatient clinic for patients with specific indications, like obesity, artificial valves, etc. For newborns (<5 kg), transesophageal echocardiography (TEE) is not possible because the current probes are too big for introducing them into the esophagus. There is a clear need for a small probe in newborns that are scheduled for complicated cardiac surgery and catheterization. We present the design and realization of a small TEE phased array probe with a tube diameter of 5.2mm and head size of only 8.2-7 mm. The number of elements is 48 and the center frequency of the probe is 7.5 MHz. A separate clinical evaluation study was carried out in 42 patients (Scohy et al. 2007).

Intracardiac echocardiography in congenital heart disease

The use of intracardiac echocardiography (ICE) in congenital heart disease has become well established over the past 7 years since its introduction into clinical imaging. The greatest experience has been to guide percutaneous device closures of secundum atrial septal defects and patent foramen ovale, with excellent safety and clinical results. However, ICE has also been used for the evaluation and management of many other congenital heart defects given its unique blood/transducer interface and close proximity to relevant cardiac anatomy. Clinical application of ICE is expanding, with the current ICE catheters being used as micro-transesophageal echo probes, and three-dimensional prototypes already developed and tested in animal models. It is expected that ICE will further increase in use with refinements in technology and greater operator experience, aiding the management of complex congenital heart disease.

Use of the monoplane intracardiac imaging probe in high-risk infants during congenital heart surgery

Imaging options are limited in high-risk infants with small or abnormal oropharyngeal anatomy during congenital heart surgery.

METHODS

All cases in which the monoplane intracardiac echo probe was used for transesophageal intraoperative imaging over a 15-month period at a single institution were reviewed.

RESULTS

Eleven patients underwent intraoperative imaging using the intracardiac probe. Patient weight ranged from 1.96 kg to 4 kg. Adequate images of the anatomy relevant to the surgical repair were obtained in all cases. No adverse events related to probe use occurred.

CONCLUSION

Transesophageal echocardiography using the monoplane intracardiac echo probe provides safe and effective imaging in patients who are not candidates for standard transesophageal echocardiography.

What is new in pediatric cardiac imaging?

Cardiac imaging has had significant influence on the science and practice of pediatric cardiology. Especially the development and improvements made in non-invasive imaging techniques, like echocardiography and cardiac magnetic resonance imaging (MRI), have been extremely important. Technical advancements in the field of medical imaging are quickly being made. This review will focus on some of the important evolutions in pediatric cardiac imaging. Techniques such as intracardiac echocardiography, 3D echocardiography, and tissue Doppler imaging are relatively new echocardiographic techniques, which further optimize the anatomical and functional aspects of congenital heart disease. Also, the current standing of cardiac MRI and cardiac computerized tomography will be discussed. Finally, the recent European efforts to organize training and accreditation in pediatric echocardiography are highlighted.

Transesophageal assessment of left atrial thrombus using a 3.3-mm monoplane probe

OBJECTIVES

Our study was designed to demonstrate that transesophageal echocardiography using a 3.3-mm monoplane probe can accurately evaluate the left atrium for patients with arrhythmias before cardioversion.

BACKGROUND

Standard probes cause discomfort during intubation requiring sedation, but miniature probes do not.

METHODS

With topical anesthesia alone, a 3.3-mm probe was used for transesophageal echocardiography in 60 patients. After intravenous sedation, standard transesophageal echocardiography was then performed.

RESULTS

In 51 of 60 patients, the left atrium was visualized with the 3.3-mm probe. In 43 of 51 patients the appendage was clear. A thrombus was seen in 7 patients on both studies. In one patient spontaneous echocontrast was seen only with the 3.3-mm probe (sensitivity 100%, specificity 97%). In 9 of 60 patients, the appendage could not be assessed.

CONCLUSIONS

In many patients the 3.3-mm probe can visualize the appendage and obviate the need for sedation. Technical advances will improve image quality with miniature probes.

Radiofrequency perforation and cutting balloon septoplasty of intact atrial septum in a newborn with hypoplastic left heart syndrome using transesophageal ICE probe guidance

Newborns with hypoplastic left heart syndrome and intact atrial septum present an emergent and unique challenge to a children's heart center. This case report describes new transcatheter techniques (use of radiofrequency energy to perforate the atrial septum followed by cutting balloon and static balloon septoplasty) and novel use of a transesophageal ICE probe.

Innovations in Transesophageal Echocardiographic Imaging

Over the last three decades, the continuing development of transesophageal echocardiography (TEE) has represented a major advance in our ability to visualize cardiovascular structures with ultrasound. TEE serves as a valuable complement to transthoracic echocardiography (TTE) by allowing: images to be obtained with less attenuation from structures such as the lung, muscle, bone, and soft tissue; high resolution visualization of structures not well seen by TTE, such as left atrial appendage, descending thoracic aorta, and prosthetic heart valves; and assessment of hemodynamics and flow disorders in greater detail. This article provides a brief overview of current as well as emerging clinical applications of transesophageal echocardiography.

Feasibility of transesophageal echocardiography with a ten-French monoplane probe

OBJECTIVES

We examined the feasibility of transesophageal echocardiography (TEE) using a 10F monoplane probe developed for intracardiac ultrasound (AcuNav, Acuson/Siemens, Mountain View, Calif).

BACKGROUND

Traditional TEE uses a 10- to 12-mm-diameter probe, and conscious sedation is customary to minimize patient discomfort. Because of its small size (3.2-mm diameter), the 10F monoplane probe can be inserted into the esophagus using only topical anesthesia. This provides the potential for a more easily tolerated examination.

METHODS

A total of 20 patients underwent a comprehensive TEE using an adult multiplane probe. Immediately afterward, the 10F monoplane probe was inserted into the esophagus and a targeted examination completed. The 10F monoplane studies were blindly reviewed by 3 observers for the study indication and for 16 diagnostic elements. These were graded against an expert's review of standard TEE.

RESULTS

The 10F monoplane probe was well tolerated in all patients. Observers A, B, and C answered the clinical question in 80%, 85%, and 100%, respectively, with the 10F probe. The percentage of clinical elements deemed evaluable was 71%, 78%, and 80%, respectively. Limitations included incomplete visualization of the mitral valve and a systematic underestimation of the severity of valve regurgitation.

CONCLUSIONS

The 10F monoplane probe is safe, well-tolerated, and capable of evaluating many clinical questions. Because of its small size, conscious sedation may not be necessary. It may be useful for targeted evaluations, for monitoring invasive procedures, or for intermediate or long-term monitoring in an intensive care department.