Role of 3D Echocardiography in Cardiac Surgery: Strengths and Limitations

Usefulness of perioperative transoesophageal echocardiography during paediatric cardiac surgery

BACKGROUND

Paediatric transoesophageal echocardiography probes allow perioperative evaluation during paediatric congenital heart disease surgery.

AIM

To assess the usefulness of perioperative transoesophageal echocardiography in evaluating the severity of residual lesions, based on the type of congenital heart disease repaired in paediatric patients.

METHODS

A retrospective analysis was conducted on paediatric patients who underwent open-heart surgery at our tertiary centre over a four-year period. Perioperative transoesophageal echocardiography studies were performed, and residual lesions were classified as mild, moderate or severe.

RESULTS

Overall, 323 procedures involving 310 patients with a median age of 13.8 (0.07-214.4) months and a median weight of 8.2 (2-96) kg at intervention were enrolled in the study. Twenty-one (6.5%) residual lesions led to immediate reintervention: severe right ventricular outflow tract obstruction (n=12); severe aortic regurgitation (n=3); superior vena cava stenosis (n=2); moderate residual ventricular septal defect (n=2); severe mitral regurgitation (n=1); and severe mitral stenosis (n=1). Three (0.9%) neonates had ventilation difficulties caused by the transoesophageal echocardiography probe having to be removed, but experienced no sequelae.

CONCLUSION

Perioperative transoesophageal echocardiography is a safe procedure, providing information on severe residual lesions, leading to the immediate revision of several paediatric congenital heart disease cases.

3D localization of vena contracta using Doppler ICE imaging in tricuspid valve interventions

Purpose

Tricuspid valve (TV) interventions face the challenge of imaging the anatomy and tools because of the ‘TEE-unfriendly’ nature of the TV. In edge-to-edge TV repair, a core step is to position the clip perpendicular to the coaptation gap. In this study, we provide a semi-automated method to localize the VC from Doppler intracardiac echo (ICE) imaging in a tracked 3D space, thus providing a pre-mapped location of the coaptation gap to assist device positioning.

Methods

A magnetically tracked ICE probe with Doppler imaging capabilities is employed in this study for imaging three patient-specific TVs placed in a pulsatile heart phantom. For each of the valves, the ICE probe is positioned to image the maximum regurgitant flow for five cardiac cycles. An algorithm then extracts the regurgitation imaging and computes the exact location of the vena contracta on the image.

Results

Across the three pathological, patient-specific valves, the average distance error between the detected VC and the ground truth model is \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$({1.22 \pm 2.00})$$\end{document}(1.22±2.00)mm. For each of the valves, one case represented the outlier where the algorithm misidentified the vena contracta to be near the annulus. In such cases, it is recommended to retake the five-second imaging data.

Conclusion

This study presented a method for ultrasound-based localization of vena contracta in 3D space. Mapping such anatomical landmarks has the potential to assist with device positioning and to simplify tricuspid valve interventions by providing more contextual information to the interventionalists, thus enhancing their spatial awareness. Additionally, ICE can be used to provide live US and Doppler imaging of the complex TV anatomy throughout the procedure.

Ruptured left ventricular subvalvar mitral aneurysm into the left atrium and left ventricle to left atrium fistula: case report of two pathological entities

Subvalvar mitral aneurysm is a rare entity that mostly occurs in the African population. We present a case of a 23-year-old male patient who presented with shortness of breath and atypical chest pain. On preoperative transthoracic echocardiography, a subvalvar mitral aneurysm was noted with severe regurgitation from the aneurysm opening into the left atrium. The surgical findings revealed a single aneurysm neck present in the posterior mitral valve annulus. In addition to and separate from the aneurysm, a left ventricular to left atrial fistula was present.

Innovations in cardiovascular imaging

Cardiovascular diseases are culpable for the majority of mortalities the world over, hence the significance of advances in preventive medicine and imaging. Cardiovascular imaging constitutes the cornerstone of not only early but also precise diagnoses. Indeed, advanced imaging enables cardiologists to make efficacious management plans for various heart conditions. The present article discusses essential innovations in cardiovascular imaging.

Three-dimensional echocardiographic acquisition and validity of left ventricular volumes and ejection fraction

Transthoracic (TTE) and transesophageal (TEE) three-dimensional echocardiography (3DE) is now used in daily clinical practice. Advancements in technology have improved image acquisition with higher frame rates and increased resolution. Different 3DE acquisition techniques can be used depending upon the structure of interest and if volumetric analysis is required. Measurements of left ventricular (LV) volumes are the most common use of 3DE clinically but are highly dependent upon image quality. Three-dimensional LV function analysis has been made easier with the development of automated software, which has been found to be highly reproducible. However, further research is needed to develop normal reference range values of LV function for both 3D TTE and TEE.

Comparing the Mutual Interchangeability of ECOM, FloTrac/Vigileo, 3D-TEE, and ITD-PAC Cardiac Output Measuring Systems in Coronary Artery Bypass Grafting

OBJECTIVE

The aim of this study was to compare the mutual interchangeability of 4 cardiac output measuring devices by comparing their accuracy, precision, and trending ability.

DESIGN

A single-center prospective observational study.

DESIGN

Nonuniversity teaching hospital, single center.

PARTICIPANTS

Forty-four consecutive patients scheduled for elective, nonemergent coronary artery bypass grafting (CABG).

INTERVENTIONS

The cardiac output was measured for each participant using 4 methods: intermittent thermodilution via pulmonary artery catheter (ITD-PAC), Endotracheal Cardiac Output Monitor (ECOM), FloTrac/Vigileo System (FLOTRAC), and 3-dimensional transesophageal echocardiography (3D-TEE).

MEASUREMENTS AND MAIN RESULTS

Measurements were performed simultaneously at 5 time points: presternotomy, poststernotomy, before cardiopulmonary bypass, after cardiopulmonary bypass, and after sternal closure. A series of statistical and comparison analyses including ANOVA, Pearson correlation, Bland-Altman plots, quadrant plots, and polar plots were performed, and inherent precision for each method and percent errors for mutual interchangeability were calculated. For the 6 two-by-two comparisons of the methods, the Pearson correlation coefficients (r), the percentage errors (% error), and concordance ratios (CR) were as follows: ECOM_versus_ITD-PAC (r = 0.611, % error = 53%, CR = 75%); FLOTRAC_versus_ITD-PAC (r = 0.676, % error = 49%, CR = 77%); 3D-TEE versus ITD-PAC (r = 0.538, % error = 64%, CR = 67%); FLOTRAC_versus_ECOM (r = 0.627, % error = 51%, CR = 75%); 3D-TEE_versus ECOM (r = 0.423, % error = 70%, CR = 60%), and 3D-TEE_versus_FLOTRAC (r = 0.602, % error = 59%, CR = 61%).

CONCLUSIONS

Based on the recommended statistical measures of interchangeability, ECOM, FLOTRAC, and 3D-TEE are not interchangeable with each other or to the reference standard invasive ITD-PAC method in patients undergoing nonemergent cardiac bypass surgery. Despite the negative result in this study and the majority of previous studies, these less-invasive methods of CO have continued to be used in the hemodynamic management of patients. Each device has its own distinct technical features and inherent limitations; it is clear that no single device can be used universally for all patients. Therefore, different methods or devices should be chosen based on individual patient conditions, including the degree of invasiveness, measurement performance, and the ability to provide real-time, continuous CO readings.

Three dimensional transesophageal echocardiography: a missing link in infective endocarditis imaging?

The role of two dimensional (2D) echocardiography (ECHO) for the diagnosis and clinical decision making in infective endocarditis (IE) has been extensively studied and described in the medical literature. Some reports have demonstrated the incremental value of three dimensional (3D) transesophageal (TE) ECHO in the setting of IE. However, a systematic review focusing on the role of 3D imaging is lacking. In this manuscript, we examine the role of 3D TE ECHO in the diagnosis of IE. IE is a challenging disease in which 2D transthoracic (TT) and TE ECHO have complementary roles and are unequivocally the mainstay of diagnostic imaging. Still, 2D imaging has important limitations. Technological advances in 3D imaging allow for the reconstruction of real-time anatomical images of cardiac structure and function. 3D imaging has emerged as a diagnostic technique that overcame some of the limitations of 2D ECHO. Currently, both transthoracic and transesophageal echocardiography transducers are able to generate 3D images. However, 3D TE ECHO provides images of a higher quality in comparison to 3D TT ECHO, and is the best echocardiographic modality able to allow for a detailed anatomical imaging. 3D TE ECHO may represent the key adjunctive echocardiographic technique being able to positively impact on IE-related surgical planning and intervention and to facilitate the interaction between the surgeon and the imaging specialist. Importantly, 3D TE ECHO is not the recommended initial modality of choice for the diagnosis of IE; however, in highly specialized centers, it has become an important complementary technique when advanced surgical planning is required. Furthermore, anatomical imaging has become the link between the different techniques that play a role in IE imaging. In fact, both computed tomography and magnetic resonance allow three dimensional reconstruction. An important future goal should allow for the fusion among various imaging modalities. Our review highlights the role of 3D TE ECHO in IE imaging and emphasize where it offers incremental value.

The clot thickens: an incompletely ligated left atrial appendage

Our patient presented with known mechanical mitral valve endocarditis documented by 2D transesophageal echocardiogram (TOE) from a recent hospitalization at an outside facility. On admission to our center, there was no prior knowledge of an incompletely ligated left atrial appendage (LAA) according to patient- or family-reported history, review of outside records or the outside facility’s 2D TOE report. A 3D TOE performed at our center to assess her pathology, since a month had passed from her prior hospitalization, revealed a LAA ligation with evidence of communication to the left atrium and with clot present in the appendage. This case report highlights the common finding of incomplete closure of the LAA following surgical ligation, thus making it inadequate for stroke prevention in patients with atrial fibrillation, and that 3D TOE plays a valuable role in assessing the durability of LAA ligation.