Three-dimensional transesophageal echocardiography measurement of mitral valve area in patients with rheumatic mitral stenosis: multiplanar reconstruction or 3D direct planimetry?

Left atrial myopathy in rheumatic mitral stenosis; three-dimensional and speckle tracking echocardiography study

BACKGROUND

In developing countries, rheumatic mitral valve stenosis (MS) is still a problem and its progression leads to left atrial (LA) damage. Due to the complexity of the LA geometry, currently used techniques like antero-posterior dimension (LAD) and 2D echo derived LA volume (LAV) have several limitations that are corrected by 3D derived LA volumes in addition to functional evaluation.

PURPOSE

To assess the LA functions using 2D speckle tracking echocardiography and 3D transthoracic echocardiography in patients with clinically significant MS in comparison to normal healthy subjects.

RESULTS

Fifty patients and 50 healthy controls were studied. Patients' mean age was 40.2 ± 8.8 years, the majority were female 45(81.8%). 3D indexed LA maximum (LAVmaxI) and minimum (LAVminI) volumes were significantly higher in MS than in the control group, whereas 3D LA EF was significantly lower in MS than in the control group (p 0.001). LA strain reservoir, conduit, and contraction parameters were significantly lower in the MS group than in the control group (p = 0.001). However, only 3D LAEF, 2D LASr, 2D LAScd, and 2D LASct showed a correlation with the mitral valve area with a p < 0.05, but 3D LAVmaxI and 3D LAVminI did not. Additionally, in the comparison of severe and very severe mitral stenosis subgroups, 3D LAVmaxI and 3D LAVminI did not show any statistically significant differences between the two groups, although 3D LAEF, 2D LASr, 2D LAScd, and 3D LASct showed significant difference between the two groups (p < 0.05).

CONCLUSIONS

Left atrial functional and structural remodelling has been highlighted in patients with significant rheumatic MS. However, left atrial functional assessment by 3D echocardiography and 2D speckle tracking echocardiography correlate better with mitral valve area than conventional LA size measurements. Whether the functional assessment of the LA has an additive predictive value with regards to patient outcome needs to be interrogated.

Multi-modality imaging to assess rheumatic mitral stenosis severity

Multi-modality imaging is the recommended approach to assess the severity of valvular heart diseases. Rheumatic mitral stenosis (MS), however, has yet to benefit from this approach. The aim of this study is to assess the added value of cardiac MRI (CMR) and computed tomography (CT) calcium score in assessing severity of MS when compared to 3D echocardiography. Patients with MS in sinus rhythm were included. Both CMR and 3D echo assessments of the mitral valve were performed. Subsequently, three radiologists and three cardiologists independently measured mitral valve area (MVA). In addition, CT of the mitral valve was conducted. Mitral calcium score was calculated according the Agatston method. A total of 41 patients were included. CMR significantly overestimated MVA when compared to 3D echo MVA regardless of the investigator [F (1, 40) = 23.3, p < 0.001, η2 = 0.36]. The more severe the MS, the greater the overestimation by CMR compared to 3D echo. Regarding CT of the mitral valve, 25 (61%) patients had an undetectable calcium. There was no significant difference in CT calcium scores between severe and non-severe MS (74 ± 282 HU vs. 65 ± 210 HU, p = 0.9). MVA measurement by CMR is overestimated when compared to 3D echo. Additionally, mitral valve calcium score is not correlated to MS severity.

Combining 2D Planimetry and Yeo's Index Can Help Accurately Identify Patients with Severe Rheumatic Mitral Stenosis-A Perspective from a 3D Assessment Using Transoesophageal Echocardiography

BACKGROUND

Yeo's index is a novel measure of the severity of rheumatic mitral valve stenosis (MS). It is derived from the product of the mitral leaflet separation index and dimensionless index. This study aims to validate Yeo's index using a transesophageal echocardiogram (TEE) three-dimensional (3D) mitral valve area (MVA) as a comparator and to compare the concordance of existing echocardiographic measures of the MVA with TEE 3DMVA.

METHODS AND RESULTS

We studied 111 patients with rheumatic MS who underwent both transthoracic echocardiography (TTE) and a TEE assessment of MS severity. Yeo's index, the MVA determined by 2D planimetry, pressure half-time (PHT) and continuity equation (CE) measured on TTE were compared with the TEE 3DMVA. With a linear correlation, Yeo's index showed the best correlation with TEE 3DMVA (r2 = 0.775), followed by 2D planimetry (r2 = 0.687), CE (r2 = 0.598) and PHT (r2 = 0.363). Using TEE 3DMVA as comparator, Yeo's index (ρc = 0.739) demonstrated the best concordance, followed by 2D planimetry (ρc = 0.632), CE (ρc = 0.464) and PHT (ρc = 0.366). When both Yeo's index and 2D planimetry suggested significant MS, the positive predictive value was high (an AUC of 0.966 and a PPV of 100.00% for severe MS, and an AUC of 0.864 and a PPV of 85.71% for very severe MS). When both measures suggested the absence of significant MS, the negative predictive value was also high (an AUC of 0.940 and an NPV of 88.90% for severe MS, and an AUC of 0.831 and an NPV of 88.71% for very severe MS).

CONCLUSIONS

Yeo's index performed well in identifying severe MS when compared with TEE 3DMVA and may be a useful adjunct to existing methods of measuring MS severity. Combining it with 2D planimetry could further enhance its accuracy.

Three-dimensional transoesophageal echocardiography: how to use and when to use-a clinical consensus statement from the European Association of Cardiovascular Imaging of the European Society of Cardiology

Three-dimensional transoesophageal echocardiography (3D TOE) has been rapidly developed in the last 15 years. Currently, 3D TOE is particularly useful as an additional imaging modality for the cardiac echocardiographers in the echo-lab, for cardiac interventionalists as a tool to guide complex catheter-based procedures cardiac, for surgeons to plan surgical strategies, and for cardiac anaesthesiologists and/or cardiologists, to assess intra-operative results. The authors of this document believe that acquiring 3D data set should become a 'standard part' of the TOE examination. This document provides (i) a basic understanding of the physic of 3D TOE technology which enables the echocardiographer to obtain new skills necessary to acquire, manipulate, and interpret 3D data sets, (ii) a description of valvular pathologies, and (iii) a description of non-valvular pathologies in which 3D TOE has shown to be a diagnostic tool particularly valuable. This document has a new format: instead of figures randomly positioned through the text, it has been organized in tables which include figures. We believe that this arrangement makes easier the lecture by clinical cardiologists and practising echocardiographers.

Mitral valve stenosis in the current era: a changing landscape

Mitral stenosis results from haemodynamic obstruction at the mitral valve level because of structural abnormalities of the valve apparatus, leading to increased resistance to the transmitral flow. Although rheumatic fever remains the predominant cause of mitral stenosis worldwide, other causes are increasingly relevant in the developed countries with degenerative mitral stenosis (DMS) because of mitral annulus calcification (MAC) becoming growingly prevalent in industrialized countries with higher life expectancy. Rheumatic mitral stenosis (RMS) and DMS display dramatic differences in pathophysiology, prognosis, and disease progression. Furthermore, to date, robust evidence regarding the management of DMS because of MAC is lacking. Nevertheless, new diagnostic techniques and catheter-based interventions are changing this landscape and paving the way to a significant reduction in DMS-related morbidity and mortality. Here we briefly review the current knowledge on the pathophysiology, diagnosis and treatment of DMS and RMS, underscoring the current diagnostic and therapeutic pathways, as well as persisting uncertainties and perspectives.

Measurement of mitral valve area by direct three dimensional planimetry compared to multiplanar reconstruction in patients with rheumatic mitral stenosis

Mitral valve area (MVA) measurement by three-dimensional transesophageal echocardiography (3D-TEE) has a crucial role in the evaluation of mitral stenosis (MS) severity. Three-dimensional direct (3D-direct) planimetry has been proposed as a new technique to measure mitral valve area. This study aimed to compare the 3D-direct mitral valve planimetry to conventional three-dimensional multiplanar reconstruction (3D-MPR) in severe MS using 3D-TEE. In this cross-sectional, prospective study; 149 patients with severe MS who were referred for transesophageal echocardiography in Shahid Madani Hospital (Tabriz Iran), just before percutaneous transmitral commissurotomy (PTMC), recruited consecutively. All patients underwent 2D transthoracic echocardiography (2D-TTE) and 3D-TEE in a single session before PTMC. During 2D-TTE planimetry, pressure half time (PHT), and proximal isovelocity surface area (PISA) were applied to measure the MVA. Transmitral mean pressure gradient (MPG) was measured. During 3D-TEE, MVA planimetry was carried out with both 3D-direct and 3D-MPR methods. 3D-direct was applied from both atrial and ventricular views. The consistency of MVA measurements with 3D-direct, 3D-MPR, and 2D-TTE methods was statistically investigated. Our sample consisted of 109 (73.2%) women and 40 (26.8%) men. The mean age was 51.75 ± 9.81 years. The agreement between 3D-direct and 3D-MPR planimetry was significant and moderate (0.99 ± 0.29 cm2 vs. 1.12 ± 0.26 cm2, intraclass correlation = 0.716, p value = 0.001).The accuracy of the 3D-direct method reduced significantly compared to the MPR method at MVA > 1.5 cm2. The maximum difference between two methods was observed in cases with MVAs larger than 1.5 cm2. MVA measured with the 3D-MPR method was significantly correlated with a 2D-TTE method, with a moderate agreement (intraclass correlation = 0.644, p value = 0.001). Also, 2D-TTE and 3D-direct TEE techniques yielded significantly consistent measurements of the MVA (1.06 ± 0.026 cm2 vs. 0.99 ± 0.29 cm2, intraclass correlation = 0.787, p value = 0.001); however, with a slight overestimation of the MVA by the former with a net difference of 0.06 ± 0.013 cm2. Mitral valve pressure gradient (MPG) had no significant correlation with planimetry results. A significant inverse correlation was seen between the MVA and pulmonary arterial systolic pressure. 3D-direct planimetry has an acceptable agreement with 3D-MPR planimetry at MVA less than 1.5 cm2, but their correlation decreases significantly at MVA above 1.5 cm2. 3D-direct planimetry underestimates MVA compared to 3D-MPR, especially at MVA above 1.5 cm2. It seems that the saddle shape of mitral valve, interferes with 3D-direct measurement of commissures at moderate MS. The 2D-TTE planimetry has generally acceptable accuracy, but its correlation to the 3D-TEE methods is significantly reduced in cases with moderate to severe MS (i.e. MVA > 1.0 cm2).

[Rheumatic mitral aggression. Usefulness of 3d transesophageal echocardiography]

Rheumatic heart disease is the leading cause of cardiovascular disease in children under 25 years of age worldwide, with the highest prevalence in low-income countries. The usual and distinctive finding of rheumatic aggression is mitral stenosis, which leads to serious cardiovascular consequences. International guidelines establish transthoracic echocardiography (TTE) as the diagnostic test for rheumatic heart disease; however, it has limitations in the measurement of planimetry and those inherent to Doppler. Transesophageal 3D echocardiography (TTE-3D) is a new modality that shows realistic images of the mitral valve and has the added value of accurately locating the plane of maximum stenosis and better determining commissural involvement.

Advances in Procedural Echocardiographic Imaging in Transcatheter Edge-to-Edge Repair for Mitral Regurgitation

Transcatheter edge-to-edge repair (TEER) therapy is recommended by the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for selected patients with symptomatic severe or moderate-severe mitral regurgitation (MR). Echocardiography, in particular transesophageal echocardiography (TEE), plays a critical role in procedural planning and guidance for TEER. Recent innovations and advances in TEE techniques including three-dimensional (3D) imaging, unlimited x-plane imaging, live 3D multiplanar reconstruction, as well as transillumination imaging with color Doppler and transparency rendering have further enhanced procedural imaging for TEER, especially for complex diseases including commissural defects, clefts, and multi-segment pathologies. This review discusses the technology of these advanced procedural imaging techniques and provides a "step-by-step" guide on how to apply them during the TEER procedure with a focus on their added values in treatment of complex valve lesions.