Intraoperative 3D Transesophageal Echocardiography Research Articles

Right ventricular ejection fraction derived from intraoperative three-dimensional transesophageal echocardiography versus cardiac magnetic resonance imaging.

Right ventricle (RV) assessment is critical during cardiac surgery. Traditional assessment consists of visual estimation and measurement of validated parameters. Cardiac magnetic resonance imaging (cMRI) is the gold standard for RV analysis, and transthoracic three-dimensional (3D) echocardiography is validated against this. We aimed to show that intraoperative 3D transesophageal echocardiography (TEE) RV assessment is feasible and can produce results that correlate with cMRI. We recruited cardiac surgery patients who underwent cMRI within the preceding twelve preoperative months. An anesthetic protocol was followed pre-sternotomy and a 3D RV data set was acquired. We used TOMTEC 4D RV-Function to derive RV end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF). We compared these data with the corresponding MRI values. Twenty-five patients were included. Transesophageal echocardiography EDV and ESV differed from MRI measurements with a mean bias of -53mL (95% confidence interval [CI], -80 to 26) and -21mL (95% CI, -34 to -9). Transesophageal echocardiography EF did not differ significantly, with a mean bias of -4% (95% CI, -8 to 1). Results were unchanged after excluding MRIs older than 180days. Correlation coefficients for EDV, ESV, and EF were r = 0.85, 0.91, and 0.80, respectively. Interclass correlation coefficients for EDV, ESV, and EF were 0.86, 0.89, and 0.96, respectively. Intraoperative TEE RV, EDV, and ESV are underestimated relative to cMRI because of analysis, anesthetic, and ventilation factors. The EF showed a low mean difference, and all values showed strong correlation with MRI. Reproducibility and feasibility were excellent and increased use in clinical practice should be considered.

Impact of a one-day three-dimensional transesophageal echocardiography workshop on clinical practice at a single academic centre.

Transesophageal echocardiography (TEE) is a powerful diagnostic tool which has become an integral part in the management of cardiac surgery patients. We developed a one-day 3D TEE workshop specifically designed to meet the needs of perioperative cardiac anaesthesiologists. We hypothesized that participation in the workshop would increase the uptake of 3D TEE in routine perioperative practice. To examine the impact of one-day 3D TEE workshop on 3D TEE image acquisition and incorporation into routine perioperative practice. Tertiary care hospital. Prospective observational monocentric study. A convenience sample of 20 cardiac anesthesiologists (with an option to attend the one- day workshop midway through the study) from a single center consented to have their intraoperative TEE images collected during the course of the study reviewed for research purposes. Images acquired 6 months before, immediately after, and 6 months following the workshop and images were examined by a blinded, expert echocardiographer. Data collected for 16 participants (8 workshop attendees, 8 non-attendees) indicate that the TEE workshop increased the number of 3D TEE images, but not x images acquired immediately following the workshop (P=0.006). No difference was observed in number of 3D images at six months' post workshop. Workshop participants obtained more 3D and multi-plane images after the workshop and more 3D images at 6 months compared to those who did not attend the workshop. Our study suggests that a single day hands-on 3D TEE workshop may have had an impact on the implementation of intraoperative 3D TEE in experienced echocardiographers.

Association of Three-Dimensional Mesh-Derived Right Ventricular Strain with Short-Term Outcomes in Patients Undergoing Cardiac Surgery

Three-dimensional (3D) right ventricular (RV) strain analysis is not routinely performed perioperatively. Although 3D RV strain adds incrementally to outcome prediction in various cardiac diseases, its role in the perioperative setting is not sufficiently understood. The aim of this study was to investigate the association between 3D RV strain measured on RV meshes created from 3D transesophageal echocardiographic data and short-term outcomes among patients undergoing cardiac surgery. A total of 496 patients undergoing cardiac surgery who underwent intraoperative 3D transesophageal echocardiography (under general anesthesia, before sternotomy) were retrospectively selected, and RV meshes were generated using commercially available speckle-tracking software. Custom-made software automatically quantified longitudinal and circumferential RV strains on the mesh surfaces. Echocardiographic and clinical parameters were entered into logistic regression models to determine their associations with the primary (in-hospital death or need for extracorporeal life support) and secondary (postoperative ventilation > 48hours) end points. Mesh-derived RV strain analysis was feasible in 94% of patients and revealed distinct regional patterns with basal-apical gradients for both longitudinal and circumferential strain. Thirty-seven patients (7.6%) reached the primary end point, and 118 patients (23.8%) reached the secondary end point. In a multivariable logistic regression model, serum lactate (P<.01), an emergency indication for surgery (P<.01), tricuspid regurgitation (P<.001), and mesh-derived RV global longitudinal strain (RV-GLS; P<.01) were independently associated with the primary end point, while established measures of RV function (3D RV ejection fraction, fractional area change, tricuspid annular plane systolic excursion) and left ventricular (LV) function (3D-derived LV ejection fraction and LV-GLS) were not independently associated. Hematocrit (P<.01), serum lactate (P<.001), pulmonary hypertension (P=.04), tricuspid regurgitation (P<.01), emergency procedures (P=.02), LV-GLS (P=.02), and RV-GLS (P<.001) were associated with the secondary end point. RV-GLS measured on RV meshes derived from 3D transesophageal echocardiography was independently associated with short-term outcomes in patients undergoing cardiac surgery and might be helpful for identifying patients at risk for adverse postoperative events.

Mitral Valve Cleft-like Indentations in Hypertrophic Obstructive Cardiomyopathy: Insights From Intraoperative Three-Dimensional Transesophageal Echocardiography

Cleft-like indentations (CLIs) of the mitral valve (MV) are best assessed with three-dimensional (3D) transesophageal echocardiography (TEE). The present study examined the prevalence, characteristics, and surgical effect of MV CLIs in patients with hypertrophic cardiomyopathy (HCM). Prospective, observational, case-control study. Tertiary medical center. The study comprised 90 patients with HCM undergoing myectomy and 59 patients undergoing cardiac surgery for non-MV related indications. Intraoperative 3D TEE was used to evaluate the presence and characteristics of MV CLIs compared, with a random control group of 59 patients undergoing cardiac surgery for non-MV related indications. Ninety patients with HCM (mean age 54.8 ± 13.3 y, 67.8% male) were compared with 59 control patients (mean age 67 ± 12.7 y, 79.7% male). Three-dimensional TEE images were interpreted by consensus of two experienced echocardiographers. At least one MV CLI was present in 84 patients with HCM (93.3%), compared with 23 control patients (39%; p < 0.01). Compared with control patients, patients with HCM were more likely to have deep MV CLIs (85.6% v 25.4%; p < 0.01) and ≥2 CLIs (52.2% v 26.1%; p=0.02). Six HCM patients (7%) appeared to have true congenital posterior leaflet clefts versus 0% in control patients (p=0.08). Preoperative mitral regurgitation severity and jet direction were not associated with the presence of deep or multiple MV CLIs (all p > 0.2). None of the MV CLIs in the HCM group required MV surgical intervention or second pump runs for MV regurgitation correction after myectomy. Deep and multiple MV CLIs are common in patients with HCM undergoing septal myectomy, including possible true posterior clefts, but they are not associated with the premyectomy severity of mitral regurgitation or jet direction, and do not result in surgical MV intervention.

Development of a software algorithm for comprehensive right ventricular strain analysis employing meshes derived from three-dimensional speckle-tracking echocardiography

Introduction Although right ventricular (RV) function assessment is important in cardiac surgical patients, dedicated software solutions to measure RV strain on three-dimensional (3D) speckle-tracking echocardiography-based (STE) meshes are lacking. Hence, a novel tool to do so was developed and tested for its feasibility in a clinical setting. Methods RV meshes were generated using dedicated 3D-STE software (4D RV-Function 2.0, Tomtec). A software algorithm was programmed in the Visualization Toolkit (www.vtk.org) to measure systolic peak strains of four regional longitudinal and circumferential contours on the mesh surface (see figure). Longitudinal strains were tracked using fixed-angle pathways (“fixed”) and compared with frame-to-frame angle definition (“variable”). The four circumferential strain layers were defined by strict long-axis segmentation in each frame (“constant”) and compared to “pinning” the planes to points along the anterior and posterior edge (“tilted”). For longitudinal strains, different strategies for the segmentation into basal and apical segments were tested. Global strain values were calculated by averaging the corresponding regional strains. Results 22 patients undergoing mitral valve surgery (MVS) received intraoperative 3D transesophageal echocardiography (TEE) before and after cardiopulmonary bypass. STE yielded 44 meshes for inclusion. 44 percutaneous mitral valve repair (PMVR) patients received 3D-TEE before and after PMVR and 88 meshes were generated. Altogether, 132 total meshes were included. Complete strain analysis was feasible in 126 meshes (95%). Visual validation of each mesh carried out by experienced investigators revealed that “fixed” longitudinal strain calculation resulted in more plausible contour tracking and shortening patterns compared to “variable” calculation, whereas peak longitudinal strain values did not differ (-0.04%, p=0.12). Baso-apical segmentation was best achieved by fixing the segment border in planes defined by neighboring mesh points in the end-diastolic frame. Regarding circumferential strains, “tilted” tracking was visually superior to “constant” segmentation in maintaining functionally matching surface units in the circumferential planes along the heart cycle. “Tilted” vs. “constant” tracking resulted in significantly different global strain values (1.5%, p Discussion RV strain analysis on meshes derived from transesophageal 3D-STE using a custom-made algorithm is feasible. In patients undergoing cardiac surgery, this approach might able be to detect subtle changes of RV function more sensitively than established parameters.

Intraoperative 2D and 3D transesophageal echocardiographic assessment of cor triatriatum with ostium secundum atrial septal defect in an adult patient

Cor triatriatum is a rare congenital cardiac anomaly. Majority of the cases present in the childhood with an incidence of 0.4%. However, we report a case of cor triatrium sinister with ostium secundum atrial septal defect (ASD) in a 39-year-old female. The intraoperative 3D transesophageal echocardiography (TEE) offers an advantage over 2D TEE in visualizing the interatrial septum and the attachments of the fibromuscular accessory membrane in the left atrium (LA), which could help in surgical decision-making in this patient.

Imaging Challenges in Secondary Mitral Regurgitation

Chronic secondary mitral regurgitation (SMR) is a complex entity that is often clinically underappreciated.1 It complicates either ischemic heart disease or dilated cardiomyopathy; its prevalence varies among series but may reach ≤50% in patients with heart failure.2 When present, SMR may exhibit a broad range of severity and confers an adverse prognosis, which is worse with increasing severity of mitral regurgitation (MR).3,4 The management of SMR poses a unique set of challenges, based partly on the complexity of the valve disorder and the still-evolving adoption of the optimal therapeutic approach.5 Noninvasive imaging and, in particular, echocardiography, plays a critical role for the initial and longitudinal assessment, for individual risk stratification and outcome prediction, and for guiding intervention in patients with chronic SMR.6 SMR develops because of a combination of mitral leaflet tethering secondary to left ventricular (LV) dilatation/deformation with papillary displacement/discoordination, annular dilatation/dysfunction, insufficient LV-generated closing forces attributable to reduction of LV contractility, and global LV/papillary muscle dyssynchrony.1,5 Tethering of the mitral leaflets is the principal lesion of SMR and results in restriction of systolic leaflet motion, namely type IIIb of Carpentier’s classification. SMR does not typically occur in global LV dysfunction without tethering. However, once tethering occurs, leaflet closure is further impaired by LV dysfunction because there is decreased force opposing tethering.6–9 The key event in the pathogenesis of SMR is the distortion of normal LV geometry—regional and global LV remodeling—with subsequent apical and lateral displacement of papillary muscles, which, in turn, draws the chordae tendineae away from the line of coaptation.7,8 The extent of LV systolic dysfunction and dilatation is weakly correlated to the degree of SMR unless accompanied by geometric distortion in the region of the papillary muscles.1,9 …

Intraoperative Three-Dimensional Versus Two-Dimensional Echocardiography for Left Ventricular Assessment

Three-dimensional (3D) transesophageal echocardiography (TEE) technology is now widely used intraoperatively in cardiac surgery. Left ventricular (LV) measurements with 3D transthoracic echocardiography correlate better with cardiac magnetic resonance measurements compared with traditional two-dimensional (2D) transthoracic echocardiography. In this study, we compared intraoperative 3D TEE against 2D TEE regarding quantitative indices of LV function. We performed 2D TEE and 3D TEE examinations on 156 patients scheduled for elective cardiac surgery. Two-dimensional TEE images of midesophageal 4-, 2-chamber, and long-axis views were acquired. LV volumes and ejection fraction (EF) were calculated by Simpson's method. Three-dimensional full-volume images were recorded to calculate by a semiautomated procedure LV volumes (indexed to body surface area) and EF. 3D and 2D LV dimensions and function, image quality, time for acquisition/analyses, and reproducibility were compared by the Wilcoxon matched-pairs signed-ranks test. Pairwise differences between 3D and 2D data were compared using 95% prediction intervals (PIs) and Bland-Altman methodology. 3D volumes were also plotted against 2D volumes in scatter plots using a 3-zone error grid. There was no significant difference between 3D and 2D in the estimation of EF (P = 0.227; median pairwise difference, -0.4% [95% PIs, -8.6% to 8.8%]). 3D LV indexed end-diastolic volumes (iEDVs) and end-systolic volumes (iESVs) were larger than 2D iEDVs (P < 0.001; median pairwise difference, 3.3 mL/m [95% PIs, -9.4 to 14.1 mL/m] and iESV: P < 0.001; median pairwise difference, 1.4 mL/m [95% PIs, -5.2 to 10.1 mL/m]). In the vast majority of cases (98.8% of cases for iEDV and 92.8% of cases for iESV), the difference between 2D and 3D TEE indexed volumes did not alter classification into normal, mildly to moderately dilated, or severely dilated volumes, as demonstrated by the 3-zone error grid analysis. Acquisition of 3D TEE image and analysis were not feasible in 4 patients (2.5%) for whom a quantitative 2D assessment of the LV was also impossible. 3D and 2D quality image was similar (P = 0.206). There was no difference in 3D versus 2D acquisition time (P = 0.805; pairwise difference = 2 seconds [95% PIs, -20 to 35 seconds]), but 3D analysis required more time (P < 0.001; pairwise difference = 117 seconds [95% PIs, 66 to 197 seconds]). Differences in repeated 3D versus 2D indexed volumes were not statistically significant, both considering interobserver reproducibility (iEDV: P = 0.125; pairwise difference, 0.26 ± 1.76 mL [95% PIs, -3.58 to 3.73 mL] and iESV: P = 0.126; pairwise difference, -0.16 ± 1.67 mL [95% PIs, -3.96 to 3.69 mL]) and intraobserver reproducibility (iEDV: P = 0.975; pairwise difference, -0.02 ± 1.20 mL [95% PIs, -2.32 to 2.08 mL] and iESV: P = 0.228; pairwise difference, -0.19 ± 1.13 mL [95% PIs, -2.47 to 2.53 mL]). Intraoperative 3D TEE quantification of LV global function, image acquisition time, and reproducibility was not statistically different when compared with 2D TEE. It was however associated with calculation of larger LV volumes and a longer analysis time. Nevertheless, the 3-zone error grid analysis of the LV indexed volumes showed that the difference between 3D and 2D measurements does not affect the LV classification as normal, mildly to moderately dilated, or severely dilated.

Relocation of Papillary Muscles for Ischemic Mitral Valve Regurgitation

The assessment of the mitral valve apparatus (MVA) and its modifications during ischemic mitral regurgitation (IMR) is better performed by three-dimensional (3D) transesophageal echocardiography (TEE). The aim of our study was to carry out nonrestrictive mitral annuloplasty in addition to relocation of papillary muscles (PPMs) oriented by preoperative real-time 3D TEE through the mitral valve quantification dedicated software. Since January 2008, a total of 70 patients with severe IMR were examined both before and after mitral valve repair. The mean (SD) coaptation depth and the mean (SD) tenting area were 1.4 (0.4) cm and 3.2 (0.5) cm2, respectively. Intraoperative 3D TEE was performed, followed by a 3D offline reconstruction of the MVA. A schematic MVA model was obtained, and a geometric model as a "truncated cone" was traced according to preoperative data. The expected truncated cone after annuloplasty was retraced. A conventional normal coaptation depth of approximately 6 mm was used to detect the new position of the PPMs tips. Perioperative offline reconstruction of the MVA and the respective truncated cone was feasible in all patients. The expected position of the PPMs tips, desirable to reach a normal tenting area with a coaptation depth of 6 mm or more, was obtained in all patients. After surgery, all parameters were calculated, and no statistically significant difference was found compared with the expected data. Relocation of PPMs plus ring annuloplasty reduce mitral valve tenting and may improve mitral valve repair results in patients with severe IMR. This technique may be easily and precisely guided by preoperative offline 3D echocardiographic mitral valve reconstruction.

3D Echocardiography in Cardiac Surgery

Herein, we present a patient who underwent successful repair of failed mitral valve repair in whom intraoperative 3D transesophageal echocardiography provided accurate assessment of the mechanism of mitral regurgitation. In addition, we review the potential advantages and limitations of 3D echocardiography and its role in cardiac surgery.

Patient-Specific Mitral Valve Closure Prediction Using 3D Echocardiography

This article presents an approach to modeling the closure of the mitral valve using patient-specific anatomical information derived from 3D transesophageal echocardiography (TEE). Our approach uses physics-based modeling to solve for the stationary configuration of the closed valve structure from the patient-specific open valve structure, which is recovered using a user-in-the-loop, thin-tissue detector segmentation. The method uses a tensile shape-finding approach based on energy minimization. This method is employed to predict the aptitude of the mitral valve leaflets to coapt. We tested the method using 10 intraoperative 3D TEE sequences by comparing the closed valve configuration predicted from the segmented open valve with the segmented closed valve, taken as ground truth. Experiments show promising results, with prediction errors on par with 3D TEE resolution and with good potential for applications in pre-operative planning.

Three-dimensional transesophageal echocardiography in Ebstein's anomaly

Three-dimensional (3D) transthoracic echocardiography has advantages over traditional two-dimensional (2D) echocardiography in visualizing tricuspid valve morphology in Ebstein's anomaly. We describe the application of intra-operative 3D transesophageal echocardiography during a tricuspid valve repair procedure in a patient with Ebstein's anomaly. Intra-operatively three-dimensional transesophageal echocardiographic (3D TEE) data sets revealed morphology and function of the tricuspid valve, right ventricle outflow tract (RVOT) and pulmonary valve before and after repair. Tricuspid valve leaflet morphology and coaptation as visualized with 3D TEE proved to be consistent with intra-operative findings. Analysis of the tricuspid valve, RVOT and pulmonary valve in the multi-planar review (MPR) mode revealed a bicuspid pulmonary valve, which had not been noticed on the preoperative 2D echocardiographic work-up. In this patient with Ebstein's anomaly, 3D TEE provided additional information on morphology and function of tricuspid valve, RVOT and pulmonary valve.

Usefulness of transesophageal three-dimensional echocardiography in the identification of individual segment/scallop prolapse of the mitral valve.

We evaluated the potential usefulness of three-dimensional (3D) transesophageal echocardiography (TEE) in assessing individual scallop/segment prolapse in 36 adult patients with mitral valve prolapse (MVP) undergoing surgical correction. Intraoperative 3D TEE correctly identified the location of scallop/segment prolapse in 34 of 36 patients (94%). However, in 6 of these patients 3D TEE images revealed more scallops or segments with prolapse than the surgeon noted intraoperatively. Prolapse of these areas was less prominent and this could possibly explain the lack of correlation with the surgical findings in these patients. In another 2 patients areas of prolapse seen by the surgeon were missed by 3D TEE because some of those scallops/segments could not be well imaged due to image "drop out" and artifacts. Thus, perfect correlation between 3D TEE and surgery was noted in 28 of 36 (78%) patients. Noncoaptation of the MV was also identified in 2 patients. The prolapsed area of posterior (n = 28 observations) and anterior (n = 9 observations) MV leaflets ranged from 1 cm2 to 9 cm2 (mean 3.50 cm2+/- 2.14) and 1.20 cm2 to 5.99 cm2 (mean 3.21 cm2+/- 1.33), respectively. Interobserver and intraobserver agreement for location and area of MVP was excellent (r = 0.97 and r = 0.99, respectively; all P values are <0.0001). In conclusion, 3D TEE is useful in identifying the location of MVP. It may also be potentially useful in assessing the extent of individual scallop/segment prolapse and identifying sites of MV noncoaptation. This information could aid the surgeon in deciding the extent of MV resection.