Introduction
Mitral valve (MV) pathologies are very common and represent approximately one-third (35%) of all valvulopathies in the Euro Heart Survey (1). Echocardiography is the gold standard imaging method for MV assessment, and all patients in need for a precise mitral valve analysis, undergo a transesophageal examination (TOE) for detailed assessment of the leaflets and the mitral annulus. Precise quantification of mitral regurgitation (MR), localization of the prolapsing scallops and accurate MV area assessment are of paramount importance for the management of this subgroup of patients (2). However, considering the semi-invasive nature of the method; repeated, routine TOE examinations cannot be the common practical approach during the follow up visits of these patients. In daily practice, echocardiographers use TTE, with standard two-dimensional (2D) protocols that rarely include information about mitral annular dimensions. Three-dimensional (3D) TTE protocols are also seldomly used and depend on the performer’s training and level of expertise. Technical advancements in echocardiography, offered the option for MV and annulus reconstruction and assessment through new, dedicated, post-processing softwares that provide measurements of all mitral annular and leaflet dimensions. Until recently, TOE was the only method for correct measurements. However, TTE probes have evolved and they can achieve higher spatial and temporal resolution and allow echocardiographers to assess the mitral annulus accurately without the need of the TOE probe. This remains as the main advantage of TTE, as we do not have to sedate the patient and perform this semi-invasive transesophageal method.
3D TOE and CT are essential for planning transcatheter (TCT) interventions of the MV (3,4) and 3D TOE is the standard method used to evaluate the MV anatomy. The mitral annulus size is one of the key parameters necessary to predict outcomes in transcatheter edge-to-edge repair (TEER), and to decide about the sizing of the valve during transcatheter mitral valve replacement (TMVR) (3,4). Cardiac CT with ECG gating is the gold standard method for anatomy assessment and annulus measurements prior to TCT. However, when contrast CT is contraindicated, 2D/3D TOE may be an alternative, accurate option for MV quantitation. Insertion of TOE probe is feasible in more than 99% of the patients that undergo this examination. However, TOE with the common adult probe may not be possible in patients with esophageal disorders (5-10) and as pediatric TOE probes do not provide a sufficient image quality, we should not rely on them for accurate results. In such conditions, 3D TTE may offer the option for annulus assessment with a non-invasive way.
A direct comparison of 3D TTE and 3D TOE for mitral annulus assessment has never been previously described. The aim of this study is to demonstrate the feasibility of MVQ analysis using both methods and to evaluate the level of agreement for assessing the mitral annular geometry.