Real-time 3-dimensional echocardiography in the operating room

Differences in Two- and Three-Dimensional Assessment of the Mitral Valve by Novices and Experts, Illustrated Using Anterior Mitral Valve Leaflet Length

OBJECTIVES

In this measurement validation study, the authors evaluated agreement between 2-dimensional (2D) and three-dimensional (3D) transesophageal echocardiography (TEE), measuring anterior mitral valve leaflet length by both novice and experienced echocardiographers.

DESIGN

This was a retrospective, observational study.

SETTING

Single university hospital.

PARTICIPANTS

Analyses on datasets from 44 patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Fifty datasets from 44 patients with mitral regurgitation were analyzed by 4 observers (2 novices, 2 experts). All observers measured the anterior mitral valve leaflet length from end-systolic 2D TEE images from the midesophageal longitudinal axis view and 3D software-augmented TEE images. The overall mean anterior mitral valve leaflet length was significantly shorter with 3D versus 2D TEE measurements (24.6 ± 4.5 mm v 26.2 ± 5.3 mm; p < 0.001), with novices measuring shorter leaflets than experts for both techniques (p < 0.001 and p = 0.005, respectively). Bland-Altman plots of 3D and 2D TEE measurements showed mean biases (95% limits of agreement) of -1.6 mm (-9.0 to 5.9 mm), -1.8 mm (-9.6 to 6.0 mm), and -1.3 mm (-8.4 to 5.7 mm) for all observers, novices, and experts, respectively. For 2D measurements, interobserver reliability was very strong among experts and strong among novices (Pearson's r = 0.83 v 0.66; p = 0.055). For 3D measurements, interobserver reliability was strong in experts and moderate in novices (Pearson's r = 0.69 v 0.51; p = 0.168).

CONCLUSION

For both novices and experts, 3D TEE measurements of the anterior mitral valve leaflet were significantly shorter than 2D measurements. Interobserver reliability was lowest for novices making 3D TEE measurements, indicating that reliable, quantitative evaluation of 3D TEE may require a greater amount of practice.

Geometric comparison of the mitral and tricuspid valve annulus: Insights from three dimensional transesophageal echocardiography

AIM

To apply real time three-dimensional transesophageal echocardiography (RT3D TEE) for quantitative and qualitative assessment of the mitral valve annulus (MVA) and tricuspid valve annulus (TVA) in the same patient.

METHODS

Our retrospective cohort study examined the MVA and TVA in 49 patients by RT3D TEE. MVA and TVA shape were examined by TEE. The MVA and TVA volume data set images were acquired in the mid esophageal 4-chamber view. The MVA and TVA were acquired separately, with optimization of each for the highest frame rate and image quality. The 3D shape of the annuli was reconstructed using the Philips^® Q lab, MVQ ver. 6.0 MVA model software. The end-systolic frame was used. The parameters measured and compared were annular area, circumference, high-low distances (height), anterolateral-posterolateral (ALPM), and anteroposterior (AP) axes.

RESULTS

A total of 49 patients (mean age 61 ± 14 years, 45% males) were studied. The ALPM and the AP axes of the MVA and TVA are not significantly different. The ALPM axis of the MVA was 37.9 ± 6.4 mm and 38.0 ± 5.6 mm for the TVA (P = 0.70). The AP axis of the MVA was 34.8 ± 5.7 mm and 34.9 ± 6.2 mm for the TVA (P = 0.90). The MVA and the TVA had similar circumference and area. The circumference of the MVA was 127.9 ± 16.8 mm and 125.92 ± 16.12 mm for the TVA (P = 0.23). The area of the MVA was 1103.7 ± 307.8 mm² and 1131.7 ± 302.0 mm² for the TVA (P = 0.41). The MVA and TVA are similar oval structures, but with significantly different heights. The ALPM/AP ratio for the MVA was 1.08 ± 0.33 and 1.09 ± 0.28 for the TVA (P < 0.001). The height for the MVA and TVA was 9.23 ± 2.11 mm and 4.37 ± 1.48 mm, respectively (P < 0.0001).

CONCLUSION

RT3D TEE plays an unprecedented role in the management of valvular heart disease. The specific and exclusive shape of the MVA and TVA was revealed in our study of patients studied. Moreover, the intricate codependence of the MVA and the TVA depends on their distinctive shapes. This realization seen from our study will allow us to better understand the role valvular disease plays in disease states such as hypertrophic cardiomyopathy and pulmonary hypertension.

Three-dimensional transesophageal echocardiographic study of aortic-mitral valve coupling after coronary artery bypass grafting

AIMS

To observe the geometric changes in aortic-mitral valve coupling (AMC) on three-dimensional transesophageal echocardiography and the factors leading to decreased mitral regurgitation (MR) after coronary artery bypass grafting (CABG).

METHODS AND RESULTS

This study included 23 patients undergoing CABG for coronary artery disease. Fifteen patients with moderate to severe MR were separately analyzed to determine whether the severity of MR influences the geometric change in AMC. Echocardiographic examinations were performed pre- and post-CABG, and the studied parameters were obtained using Siemens Auto Valve Analysis software. The effective mitral regurgitant orifice area, left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV) were measured pre- and post-CABG using Philips QLAB software. Ischemic MR, EDV, and ESV significantly decreased (all P < 0.05) and LVEF significantly improved (P < 0.05) after CABG. There were no significant differences between the pre- and post-CABG mitral valve (MV) parameters, aortic valve parameters, aortic-mitral annular angle, or centroid distance (all P > 0.05). Patients with moderate to severe MR exhibited the same results.

CONCLUSION

The results of this study show that CABG does not cause an acute change in the geometry of AMC. Improved left ventricular function might increase the closing force of the MV, leading to decreased MR after CABG alone. MR significantly improved after CABG alone without MV treatment in the present study. This result may help to guide surgeons in choosing the optimal surgical methods for individual patients.

Live/real time three-dimensional transesophageal echocardiographic assessment of ventricular septal volume and mass before and after myectomy in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetically transmitted cardiomyopathy. In patients resistant to medical management, myectomy is the surgical procedure of choice to reduce the symptoms of left ventricular outflow obstruction. Two-dimensional transesophageal echocardiography (2DTEE) has become part of the operative procedure by decreasing the incidence of postoperative complications. However, because of the three-dimensional geometry of left ventricular outflow tract, it is unable to comprehensively assess the location and severity of the obstruction and to provide accurate guidance during myectomy. In this study, 10 patients with HCM underwent live/real time three-dimensional transesophageal echocardiography (3DTEE) intra-operatively to measure the volume of the resected septum. This volume correlated well with the volume of the resected septal muscle directly obtained using a graduating cylinder containing water (r = 0.9, P < 0.000). 3DTEE may be potentially used as an adjunct to guide the surgeon in performing an adequate myectomy with a lower incidence of residual obstruction and complications such as an iatrogenic ventricular septal defect.

Can simulation help to answer the demand for echocardiography education?

There has been a recent explosion of education and training in echocardiography in the specialties of anesthesiology and critical care. These devices, by their impact on clinical management, are changing the way surgery is performed and critical care is delivered. A number of international bodies have made recommendations for training and developed examinations and accreditations.The challenge to medical educators in this area is to deliver the training needed to achieve competence into already over-stretched curricula.The authors found an apparent increase in the use of simulators, with proven efficacy in improving technical skills and knowledge. There is still an absence of evidence on how it should be included in training programs and in the accreditation of certain levels.There is a conviction that this form of simulation can enhance and accelerate the understanding and practice of echocardiography by the anesthesiologist and intensivists, particularly at the beginning of the learning curve.

Regional changes in coaptation geometry after reduction annuloplasty for functional mitral regurgitation

BACKGROUND

While it is known that band annuloplasty for functional mitral regurgitation (FMR) improves leaflet coaptation, the effect on regional coaptation geometry has not previously been well defined. We used three-dimensional transesophageal echocardiography (3D-TEE) to analyze the regional effects of semirigid band annuloplasty on annular geometry and leaflet coaptation zones of patients with FMR.

METHODS

Sixteen patients with severe FMR underwent a semirigid band annuloplasty. Intraoperative full volume 3D-TEE datasets were acquired pre valve and post valve repair. Offline analysis assessed annular dimensions and regional coaptation zone geometry. The regions were defined as R1 (A1-P1), R2 (A2-P2), and R3 (A3-P3); coaptation distance, coaptation depth, and coaptation length were measured in each region. Differences were analyzed with repeated measures within a general linear model.

RESULTS

Band annuloplasty decreased mitral regurgitation grade from 3.7 to 0.1 (scale 0 to 4). Annular septolateral dimension (p<0.01) and coaptation distance (p<0.01) decreased significantly in all regions. Likewise, anterior and posterior leaflet coaptation lengths increased in all regions (p<0.01 and p=0.05, respectively), with region 2 showing the greatest increase (p=0.01). Changes in coaptation depth were not significant.

CONCLUSIONS

Semirigid band annuloplasty for FMR produces significant regional remodeling of leaflet coaptation zones, with region 2 showing the greatest increase in leaflet coaptation length. This regional analysis of annular geometry and leaflet coaptation creates a framework to better understand the mechanisms of surgical success or failure of annuloplasty for FMR.

Cardiac axis-oriented full-volume data acquisition in real-time three-dimensional transesophageal echocardiography to facilitate on-cart analysis

We propose a useful method to acquire a full-volume dataset that allows for efficient assessment of cardiac structures by real-time 3-dimensional transesophageal echocardiography (3DTEE). In our method, bicommissural full-volume acquisition, the dataset is acquired with the X-Y-Z axes aligned along the lines connecting the mitral commissures, the mitral annular center to the left ventricular apex, and the mitral anterior-posterior ends, respectively. The image dataset obtained using this method not only allows for visualization of en face images of the cardiac structures, but box cropping of the dataset also provides useful sectional images that are the analogues of the standard 2DTEE views. Our method can potentially standardize 3D image orientation of the cardiac structures and facilitate intraoperative on-cart analysis in real-time 3DTEE.