Conventional TEE Research Articles

Automated and semi-automated 3D echocardiographic software for aortic annulus sizing in transcatheter aortic valve implantation helps bridge the gap between expert and novice operators.

3D-transesophageal echocardiography (3D-TEE) is an alternative to multidetector row computed tomography (MDCT) for aortic annulus (AoA) sizing in preparation for Transcatheter aortic valve implantation (TAVI). We aim to evaluate how the fully automated (auto) and semi-automated (SA) TEE methods perform compared to conventional manual TEE method and the gold standard MDCT for annulus sizing both in expert and novice operators. In this prospective cohort study, eighty-nine patients with severe aortic stenosis underwent multimodality imaging with 3D-TEE and MDCT. Annular measurements were collected by expert echocardiographers using 3D auto, SA and manual methods and compared to MDCT. A novice in the field of echocardiography retrospectively measured the AoA for all patients using the same methods. TEE measurements, independently of the method used, had good to very good agreement to MDCT. They significantly underestimated aortic annular area and circumference vs. MDCT with the auto method underestimating it the most and the manual method the least (6.5% and 1.3% respectively for area and circumference). For experts, the manual TEE method offered the least systematic bias while the SA method had narrower limits of agreement (LOA). For the novice operator, SA method provided the least bias and narrower LOA vs. MDCT. There is good agreement between novice and experts for all 3 TEE methods but better agreement with auto and SA methods as opposed to manual one. Our study supports the use of 3D-TEE as a complementary method to MDCT for aortic annular sizing. The newer auto and SA software, that requires minimal operator intervention, is an easy to use, reliable and reproducible tool for aortic annulus sizing for experienced operators, and especially less experienced ones.

P1360Association between left atrial appendage dysfunction and thromboembolic risk in nonvalvular atrial fibrillation

Abstract Background/Introduction: Atrial fibrillation (AF) is associated with higher risk for thromboembolism , and the discriminative ability of the widely used CHA2DS2-VASc scores for risk stratification is modest. Although the presence of thrombus in the LAA is the most powerful predictors for thromboembolic risk, they are often absent in patients with AF and prior stroke. AF may be related to myocardial fibrosis, and even though left atrial fibrosis is associated with mechanical dispersion, this phenomenon is not well studied in LAA. We hypothesized that detection of LAA dysfunction and mechanical dispersion using strain echocardiography is useful in the identification of cardiac thromboembolism. Purpose The aim of this study was to determine the association of LAA mechanics assessed using strain analysis with previous thromboembolic events in patients with nonvalvular AF and to assess the potential incremental significance of LAA mechanical dispersion over the traditional risk stratification scheme. Methods A group of 116 patients with AF referred for TEE was prospectively analyzed. LAA strain and mechanical dispersion in parallel with other conventional TEE parameters were analyzed in terms of their association with previous embolic stroke and peripheral embolization. Results Patients with embolic events had a higher mean CHA2DS2-VASc score, higher incidence of LAA dense SEC or thrombi, and other clinical data were comparable. Patients with embolic events had greater impairment in the LA standard parameters, and lower global and regional LAA longitudinal strain than those of the controls. LAA MD was significantly higher in patients with embolization than in those without it (18.91 ± 7.19 %vs 13.8 ± 5.54%; P < .001). In ROC analysis, cut-off values for LAA MD,LAEF, LAA GLS for the presence of dense SEC/ thrombus were >20.21 % (p = 0.0076), ≤31.11 % (p = 0.017), and ≤ 7.31 % (p = 0.014), respectively. LAA MD, LAEF, LAA thrombus and CHA2DS2-VASc scores were independently associated with the presence of thromboembolism in multivariate analyses, and LAA MD had additional significance over the CHA2DS2-VASc score. Conclusion LAA MD, LAA thrombi and LAEF had statistically significant meaning for the presence of prior embolism that was independent of the standard planimetric and volumetric measurements. What’s more, LAA MD had an incremental value over CHA2DS2-VASc score in risk stratification and warrants testing in a larger study. Abstract Figure. ROC curves for LAA parameters

Is transnasal TEE imaging a viable alternative to conventional TEE during structural cardiac interventions to avoid general anaesthesia? A pilot comparison study of image quality

Aim The role of transoesophageal echocardiography in cardiac interventional structural procedures is well established and appreciated. However, the need for general anaesthesia (GA) throughout the procedure remains a controversial issue. The aim of the present study is to assess the feasibility and imaging quality of using a transnasal microrobe that allows the usage of conscious sedation in patients who undergo cardiac structural interventional procedures without missing the benefits, guidance and navigation of conventional trans-procedural TEE.Methods We analysed the trans-procedural images of 24 consecutive patients who underwent TAVI, TMVI or ASD/PFO closure, using a transnasal 2D microprobe (PHILIPS) and then we compared them with images taken by using a conventional 3D TEE probe (PHILIPS). In particular, we compared the imaging quality of the two probes regarding: (1) The anatomy, visualisation of valvular calcification and transvalvular colour Doppler of the aortic and mitral valve; (2) the imaging quality of PFO, ASD and interatrial communication colour flow; (3) the imaging of left ventricle systolic function and pericardial space and (4) transgastric imaging.Results: All images were graded with a scale from 5 to 1. The average grade of imaging quality in the mitral valve was: anatomy, 4.3; calcification, 3.8; colour Doppler, 4.2. The average grade of imaging quality in the aortic valve was: anatomy, 4.3; calcification, 3.7; colour Doppler, 4.3. The average grade of imaging quality in PFO/ASD was 4.3. The average grade of imaging quality in LV/pericardial space was 4.2. The average grade of imaging quality in transgastric imaging was 4.1.Conclusion: These results suggest that transnasal TEE can provide good anatomical image quality of relevant cardiac structures during cardiac structural interventions and this may facilitate these procedures being performed during conscious sedation without having to lose TEE guidance.

The Diagnostic Value of Contrast Enhanced Ultrasound in Acute Aortic Dissection

Acute aortic dissection is an life-threatening disease that symptoms come on abruptly and progress quickly. patients without treatment have a mortality approaching 1%-2% in the acute stage. Prompt and accurate diagnosis and timely treatment are profoundly important. CTA is first examination method selected to patents who are suspected for AD, but it has some limitations such as contrast agent allergy and radiation exposure. contrast enhanced ultrasound is convenient and safe, however the research on the AD is rare. From November 2015 to Jaunary 2017, We enrolled 41 patients (28 males and 13 females, mean age 57.8±11.1 years) with clinical suspicion of AD in Wuhan Union hospital. Conventional transthoracic echocardiography (TTE)、contrast transthoracic echocardiography (c-TEE) and multislice computed tomography angiography (MS-CTA) were performed to scan the whole aorta in sequence. Serving CTA as the reference standard, We compared conventional ultrasound with CEUS in diagnosing the characterization of AD. Of the 41 patients, 22 patients were diagnosed for AD and 20 underwent surgical repair. Using Stanford classification system, type A were detected in 40.9% (9/22) of patients, type B were seen in 59.1% (13/22). C-TEE correctly diagnosed all the patients, however Conventional TEE had 5 false-positive results because of artifacts (4 in ascending aorta and 1 in the arch). C-TEE distinguished a flap from an artifact in 5 cases, identifed the false lumen slow blood flow in 1 and defined the border of false lumen thrombosis clearly in 8. Conventional TEE visualized intmal flaps in 20 of 22 cases, with the use of contrast enhancement increased to 22 (p=0.49). Conventional TEE correctly identified the true lumen from false lumen in 19/22 (86.4%) cases, and c-TEE in 22/22 (100%) ( P = 0.23) cases. Specificity of conventional TEE increased after contrast enhancement from 73.68 to 100% (P =0.046) for the diagnosis of AD, and both two methods’ sensitivity are 100% (P=1.0). CEUS can accurately diagnose and analysis the characteristics of AD, it is superior than conventional ultrasound in discovering the details lesions of AD, and will provide important information for the diagnosis of AD.

Impact of Modified Transesophageal Echocardiography on Mortality and Stroke after Cardiac Surgery: A Large Cohort Study.

The aim of this study was to investigate the impact of perioperative screening with modified transesophageal echocardiography (A-View method). We compared, in consecutive patients who underwent cardiac surgery between 2006 and 2014, 30-day mortality and in-hospital stroke incidence, operated either with perioperative modified TEE screening (intervention group) or only with conventional TEE screening (control group). Of the 8,605 study patients, modified TEE was applied in 1,391 patients (16.2%). Patients in the intervention group were on average older (71 versus 68 years, p < 0.001) and more often females (31.0% versus 28.0%, p < 0.001) and had a higher predicted mortality (EuroSCORE I: 5.9% versus 4.0%, p < 0.001). The observed 30-day mortality was 2.2% and 2.5% in both groups, respectively, with multivariable and propensity-score adjusted relative risks (RRs) of 0.70 (95% CI: 0.50–1.00, p = 0.05) and 0.67 (95% CI: 0.45–0.98, p = 0.04). In-hospital stroke was 2.9% and 2.1% in both groups, respectively, with adjusted RRs of 1.03 (95% CI: 0.73–1.45) and 1.01 (95% CI: 0.71–1.43). In patients undergoing cardiac surgery, use of perioperative screening for aortic atherosclerosis with modified TEE was associated with lower postoperative mortality, but not stroke, as compared to patients operated on without such screening.

Congenital Submitral Aneurysm with Rupture into the Left Atrium: Assessment by 2D and 3D Transesophageal Echocardiography

We describe two cases of congenital submitral aneurysms (SMAs) in which three-dimensional transesophageal echocardiography (3D TEE) proved useful to define the spatial extent of these aneurysms. In both cases, rupture into the left atrium was accurately delineated. 3D TEE was useful in case 1 as it depicted the precise site of rupture into the left atrium as well as pseudoprolapse of the P2 segment of the mitral valve. In case 2 it also localized the rupture into the left atrium in relation to the annulus to be adjacent to the anterolateral commissure. In addition, a cleft between the A1 and A2 scallops were identified and together with failure of the leaflets to coapt enabled the mechanisms contributing to the mitral regurgitation to be elucidated. Thus, imaging from the left atrial perspective using 3D TEE provided superior spatial anatomical delineation of the rupture and its relationship to the mitral valve, as well as accurate anatomical definition of the mitral leaflets. This information provides added benefit to the surgeon in planning a transatrial surgical repair of the SMAs. 3D TEE is superior to conventional 2D TEE in defining the spatial anatomy of SMAs as well as the mechanisms contributing to mitral regurgitation.

Real-time three-dimensional transoesophageal echocardiography during percutaneous transcatheter occlusion of mitral periprosthetic paravalvular leak

We present the case of an 86-year-old female patient with a history of mitral valve replacement due to relevant stenosis. After surgery, an increasing periprosthetic valvular leak (PVL) became obvious causing regurgitation and an increasing haemolysis. Conventional two-dimensional transoesophageal echocardiography (2D TEE) showed a defect of 15 mm length located from the lateral to the posterior circumference subdivided by two surgical sutures into three parts. The patient refused additional surgical therapy. Hence, we suggested a percutaneous transcatheter occlusion of the leakage with a 12 × 5 mm Amplatzer(®) Vascular Plug III device (AVP) (AGA Medical Corporation, Plymouth, MA, USA). The placement of the device was supported indispensably by real-time three-dimensional TEE. The device occluded the leakage nearly completely and downgraded the regurgitation from moderate to neglectable. Also haemolytic parameters improved significantly. V-wave decreased promptly from 70 to 35 mmHg after placing AVP. Percutaneous closure of PVL by AVP, a self-expandable nitinol device approved for peripheral vessel occlusion, is described in limited cases with more or less successful results. It is graded as a technically demanding procedure reserved to poor surgical candidates. The main challenge is finding and intubating the leakage and the correct placement of the device. Three-dimensional TEE seems to be superior to conventional 2D TEE as it allows an easier guidance of the device into the defect. Hence, it is strongly recommended for this intracardiac intervention.

Transnasal transoesophageal ultrasound: the end of the intracardiac echocardiography age?

This editorial refers to ‘First experience with microprobe transoesophageal echocardiography in non-sedated adults undergoing atrial fibrillation ablation: feasibility study and comparison with intracardiac echocardiography’ by S. Stec et al. , on page 51 In recent years, two major technical developments were implemented in clinical cardiac imaging allowing further developments: miniaturization and three-dimensional (3D) imaging. Clinical cardiac electrophysiology, especially catheter ablation, has benefited significantly from these methodologies. Miniaturization has allowed the development of intracardiac echocardiography (ICE) probes, whereas 3D reconstruction has recently been implemented in the most advanced electroanatomical mapping systems. Although there is still ongoing debate over the real clinical value of 3D image integration, there is growing evidence supporting the idea. Stec et al . describe the use of a novel transoesophageal ultrasound (TEE) transducer for monitoring of left atrial ablation procedures.1 This probe is an extremely miniaturized version of a conventional TEE probe which can be introduced through the nose and left in place during a prolonged period with far less discomfort to the patient than a standard TEE probe. Insertion of small TEE probes via the nose has been investigated earlier2 with much bigger devices and has been shown to have advantages in terms of patient comfort and suitability for monitoring of the procedure. Although Stec et al. report on a preliminary study of …

A Design of Magic Tee with Coplanar Arms

Magic tee is a widely used component in microwave systems; the four arms of conventional magic tee direct at four different directions, which give inconveniences to the assemblage of a system. In this paper, a broad-wall slot directional coupler and an E-plane dielectric loaded waveguide phase shifter is used to form a magic tee with four arms in the same E-plane. The magic tee is analyzed exactly with mode match method; and the simulated annealing method is used to optimize the performance of the magic tee. Simulation results are presented, which show good performance.

Narrow sample channel injectors for capillary electrophoresis on microchips.

In microchip CE, sample injection is generally achieved through cross, double-tee, or tee injector structures. In these reported approaches, channel width and depth are uniform at the injection intersection. Here, we present cross and tee injectors having narrow sample channels. Using a cross injector with reduced sample channel width, resolution, column efficiency, and sensitivity are remarkably improved. Furthermore, no leakage control is required in both injection and separation phases, making the microchip CE system more user-friendly. Good resolution can also be obtained using tee injectors with narrow sample channels, which would otherwise be impossible using conventional tee injectors. Using the narrow sample channel tee injector instead of conventional cross and double-tee injectors, the number of reservoirs in multiplexed systems can be reduced to N + 2 (N, the number of paralleled CE systems), the real theoretical limit. The virtues of the novel injectors were demonstrated with poly(dimethylsiloxane)-glass chips incorporating eight parallel CE channels.

Intraoperative transesophageal echocardiography using high-resolution biplane 7.5 MHz probes with continuous-wave Doppler capability in infants and children with tetralogy of Fallot

Our study indicates that (1) the biplane TEE probe provides an accurate assessment of the surgical repair of ToF in infants and children; (2) the longitudinal plane especially offers important information showing right ventricular outflow tract anatomy that cannot be fully defined using conventional transverse plane TEE; and (3) implementation of steerable CW Doppier aids quantification of residual right ventricular outflow tract obstruction, especially when implemented from transgastric views.

Three-dimensional transesophageal echocardiography in the diagnosis of mitral valve prolapse

Because the anulus of the mitral valve is nonplanar in systole, false-positive diagnosis of mitral valve prolapse may result from two-dimensional transthoracic echocardiography. Because of the superior image quality of TEE, we used the three-dimensional TEE technique to evaluate the mitral valve in both normal subjects and patients with mitral valve prolapse and with ruptured chordae tendineae. After a conventional TEE examination, sequential images of longitudinal views were obtained by probe rotation. The images at 5-degree intervals were stored in machine cine memory loop; the special temporal images were selected with ECG gating and videorecorded. During the examination, 6 to 8 images of the left heart were recorded for later off-line, three-dimensional reconstruction. A total of 42 subjects were studied: 32 normal, 9 with mitral valve prolapse, and 1 with ruptured chordae tendineae. In normal subjects, three-dimensional TEE showed nonplanarity of the entire mitral valve, which assumes a saddle shape. In mitral valve prolapse, either the anterior or posterior leaflet protruded into the left atrium like a spoon; when both leaflets are involved, they prolapse like two spoons. The anterior and posterior leaflets coapted poorly, and there was a seam between them. In ruptured chordae tendineae the tip of the mitral leaflet protruded during systole into the left atrium far from the coaptation point and was perpendicular to the body of the mitral valve and parallel to the anterior and posterior walls of the left atrium. Three-dimensional TEE study gives a clear stereoscopic view of the mitral valve and provides accurate anatomic data for the mitral valve apparatus in both normal subjects and patients with mitral valve prolapse and with ruptured chordae tendineae. It helps define spatial location and extent of the vulvular deformities. Thus three-dimensional imaging in TEE provides a new perspective that will refine the diagnosis of mitral valve prolapse.

An Efficient State Variable Transmission Line Model

Lumped models of distributed systems (power transmission lines) are considered. It is shown that models derived by a finite Fourier cosine transform are quite efficient, when compared to conventional pi and tee section models, in that the number of state variables is minimized. This paper is an introduction to the use of distributed system "modes of response" in developing these lumped models for single and multiconductor transmission lines including ground conduction and skin effect.