From the Guidelines
The qualitative parameters used to assess diastolic function with transthoracic echocardiography (TTE) include mitral inflow patterns, tissue Doppler imaging of the mitral annulus, pulmonary vein flow patterns, left atrial size, and left ventricular hypertrophy, as outlined in the 2016 recommendations from the American Society of Echocardiography and the European Association of Cardiovascular Imaging 1.
Key Parameters
- Mitral inflow patterns, including E/A ratio, are crucial for assessing diastolic function, with an E/A ratio ≤ 0.8 indicating grade I diastolic dysfunction and an E/A ratio ≥ 2 indicating grade III diastolic dysfunction 1.
- Tissue Doppler imaging of the mitral annulus, specifically the e' velocity, helps estimate left ventricular filling pressures, with reduced values indicating impaired relaxation 1.
- Pulmonary vein flow patterns can help differentiate normal from pseudonormal patterns and estimate left ventricular filling pressures 1.
- Left atrial size and left ventricular hypertrophy are also important parameters, as left atrial enlargement often indicates chronic elevation of left atrial pressure due to diastolic dysfunction, and left ventricular hypertrophy suggests increased wall stiffness that impairs relaxation 1.
Assessment of Diastolic Dysfunction
- In patients with reduced LVEFs, transmitral inflow pattern is usually sufficient to identify patients with increased LAP, and DT of mitral E velocity is an important predictor of outcome 1.
- In patients with preserved LVEFs, several parameters, including 2D variables, are often needed to estimate LAP, and a comprehensive assessment improves diagnostic accuracy in determining both the presence and severity of diastolic dysfunction 1.
- The E/e' ratio helps estimate left ventricular filling pressures, with values >14 suggesting elevated pressures, and peak TR velocity, E/e' ratio, and LA maximum volume index can be used to assess LAP and grade of diastolic dysfunction 1.
From the Research
Qualitative Parameters for Diastolic Function Assessment
The following qualitative parameters are used to assess the presence and severity of diastolic function with Transthoracic Echocardiography (TTE):
- Mitral inflow pulsed-wave Doppler
- Isovolumetric relaxation time
- Pulmonary venous flow Doppler
- Color M-mode velocity propagation
- Tissue Doppler imaging
- Speckle tracking 2
- Mitral valve inflow velocities
- Early deceleration time
- Pulmonary vein flow velocities 3
Parameters for Diastolic Dysfunction Evaluation
Parameters such as E velocity, E/A, pulmonary vein systolic and diastolic, and systo-diastolic ratios are significantly and independently correlated with both left ventricular end-diastolic pressure and mitral regurgitant volume 4. The difference between the duration of pulmonary vein and mitral A waves (A'-A) shows a strong correlation with left ventricular end-diastolic pressure 4.
Comparison with Other Imaging Modalities
Cardiovascular magnetic resonance (CMR) has been compared to TTE for diagnosing diastolic dysfunction, with similar results in small patient groups 2, 3. CMR can evaluate diastolic function, with overall strong agreement to TTE 5. CMR-derived parameters such as E, A, E/A, e', and E/e' correlate moderately to strongly with TTE measurements 5.
Clinical Application
TTE is the first-line and most useful imaging modality for evaluating diastolic dysfunction 5. CMR can provide clinically relevant data regarding the underlying cause of diastolic dysfunction and offers promise to gain mechanistic insights for therapeutic strategy development and clinical trial planning 2.