2D transthoracic echo (TTE) is the imaging tool recommended by EACVI as first-line choice for evaluation of valvular disease. 2D echo is often sufficient for valve disease diagnosis and quantification. 2D echo allows also making a comprehensive evaluation of the other valves and of the consequences of valve disease in size and function of cardiac chambers.
2D transoesophageal echo (TOE) is indicated when transthoracic echo evaluation is insufficient or when further diagnostic refinement is required. TOE is not indicated in patients with a good quality TTE except in the operating room when a valve surgery is performed. TOE is also useful in the evaluation of endocarditis, specially when prosthetic material in the heart is involved or when thrombosis or prosthetic dysfunction is suspected.
3D TOE can provide additional information in patients with complex valve lesions. 3D TOE is also useful for monitoring surgery or transcatheter interventions.
The basic workflow for valve disease evaluation should cover the following important steps:
Usually the evaluation of valvular disease starts with 2D TTE which leads to a valvular disease in the presence of anatomic valvular abnormalities. Then a careful assessment of flow pattern by colour Doppler using multiple views allows the detection of abnormal flows through valves. The basic tools are the demonstration of the turbulence pattern (a swirling colour mix of the red and blue colors that reflect high velocity flows inside the heart) or a flow which does not follow the logical pattern of cardiac cycle. After abnormal flow detection, a careful study with spectral Doppler is the logical next step to evaluate timing and velocity that reflects the pressure gradient driving the abnormal flow. All four valves flow should be studied in any conventional TTE.
The evaluation of the mechanism of the disease is a very important step in the study of regurgitant diseases because it is strongly linked to the chance to repair instead to replace the valve by a prosthesis in the surgical room. The functional evaluation of valve disease was described by Carpentier for mitral regurgitation, but the basic schema has been adapted for other valvular diseases. Following Carpentier's classification valve diseases are categorized as:
In stenotic lesions, pressure gradients (peak and mean) and effective valvular area (either measured by planimetry or computed by PISA or continuity equation) are the basic tools. However regurgitant lesions evaluation is quite more complex. The color flow area of the regurgitant jet can be sufficient to diagnose minimal regurgitation (as stated by EACVI recommendations) but is NOT reliable to evaluate the severity of valvular regurgitation. In all other cases, the use of a more quantitative method (vena contracta or proximal isovelocity surface area - PISA) is strongly recommended when feasible.
Symptoms and consequences of valvular disease are the main criteria to guide treatment and therefore should be carefully studied. Qualitative assessment of size and function of cardiac chambers is discouraged. Full quantitative assessment is mandatory. For left ventricular volumes and ejection fraction study the recommended approach is the 2-D based biplane summation of discs method. 3D echo could be also useful as it provides more accurate and reproducible data. Contrast echo is indicated in patients with poor acoustic windows. Left atrial volume is the recommended parameter to assess its size
Exercise testing can be useful to unmask the objective occurrence of symptoms in asymptomatic patients or having doubtful symptoms. Quantitative stress echo may provide additional information in left side valve disease in some complex patients who have discordance between clinical status and the apparent degree of disease. Exercise echo could help identify what might otherwise be considered as a moderate valve lesion and to unmask the consequences (pulmonary pressure rising, ventricular dysfunction) of valvular disease.
Myocardial deformation evaluation has a potential role in the detection of early impairment of left ventricle function. There are evidences suggesting a role of strain in the evaluation of severe stenosis asymptomatic patients. However technique still lacks validation of its prognostic value and is not included in current guidelines for patient management.
Cardiac CT can be considered as an alternative and non invasive tool for coronary anatomy evaluation that is a step included in the preoperative evaluation of patients. Cardiac CT can give useful information in left-side valve stenosis because it makes the measurement of effective valvular area possible by planimetry. However, clinical experience is still very limited. CT is widely used to assess and to measure pathology of ascending aorta and plays also an important role in the work-up of patients considered for TAVI procedure
Cardiac MRI should be used in patients with inadequate echocardiographic quality or discrepant results to assess the severity of valvular lesions (especially regurgitant lesions) and to assess ventricular volumes and systolic function as CMR has higher reproducibility than echocardiography. CMR is the reference method for evaluation of right ventricular volumes and function and is therefore used to evaluate the consequences of right side heart valves disease.
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