How to Quantify Early Systolic Mitral Regurgitation
The importance of timing
May 7, 2022
Pages 1 – 5
Topics
- Quantification of mitral regurgitation
- Duration of regurgitation
- Left atrial reservoir function
- Color Doppler
- PISA quantification
- Pitfalls
The quantification of mitral regurgitation is based on both Qualitative and Quantitative evaluation algorithms, both utilizing a number of measurements and parameters. The Guidelines from both sides of the Atlantic suggest a comprehensive approach – which always begins with an “eyeballing” method – that integrates different measurements since echocardiography is heavily dependent on image quality and the experience of the operator (sonographer or cardiologist).
(tt2938) A 38 year-old male patient (BSA= 2.1 m2) with ischemic heart disease (apycal dyskinesis) and an aortic mechanical valve prosthesis presented with an echocardiographic diagnosis of moderate mitral valve regurgitation. Heart rate= 64 bpm.
- LV end-diastolic volume index= 59 ml/m2 (normal)
- LV ejection fraction= 44 % (moderate reduction)
- Stroke volume index= 37 ml/m2 (low normal)
- Left atrial volume index= 50 ml/m2 (moderate to severe dilatation)
- Normal LV filling pressures (see below)
- Mitral E wave peak velocity= 79 cm/s
- Pulmonary venous flow= systolic dominant
- Estimated pulmonary systolic pressure= 29 mmHg
- (Normal estimated right atrial pressure)
The apical 4-chamber view in Figure 1 shows an apparently normal mitral valve anatomy with normal thickness of both leaflets and normal systolic apposition. There is hypokinesis of the mid to distal lateral wall and dyskinesis of the apical inferior septum, confirming the diagnosis of ischemic heart disease. At biplane evaluation (this 4-chamber view is focused on the left ventricle) the left atrium is moderately dilated but with apparently normal (at “eyeballing”) reservoir function.
The reservoir function is the capacity of the atrial chamber to expand during ventricular systole by 70%-100%, proportionally to stroke volume, and is dependent on the compliance of the atrial chamber. Look in Figure 1 at the difference between the minimum atrial area at the end of atrial systole (corresponding to the Q wave on the ECG) and the maximum area just before mitral valve opening: this chamber expansion is the reservoir function. Although today it is “fancy” to measure it using speckle tracking strain technology, it can be simply evaluated with this 2D approach.
A normal reservoir function is usually related to normal left atrial pressure.
By looking more closely (higher resolution and frame rate) at the mitral leaflets (Figure 2), there are possibly minor signs of fibrosis (brighter speckles within the normal grey appearance of the valvular tissue) but valve closure is normal and below the plane of the mitral annulus (in the ventricular cavity).
Evaluation of mitral valve regurgitation: summary
(see Criteria to Grade mitral regurgitation in this website)
| Qualitative parameters | Quantitative parameters | ||
|---|---|---|---|
| 2D echocardio | – Valvular anatomy (-> mechanism of regurgitation) – Left atrial dimensions – LV hyperkinesis | Vena contracta | – Good specificity for mild / severe – Categorizes, but no EROA – Mistakes are easy (measurements in a few millimeters range) – Widely used |
| Color Doppler | – “Eyeballing” (mild / severe) – Area of regurgitation – Easy under- or over-estimation | PISA | – Quantifies EROA and regurgitant volume – Acknowledge limits |
| Color M-mode | – Duration of regurgitation | Quantitative flow Doppler | – Quantifies EROA and regurgitant volume – Is the Gold Standard for echocardiography – Requires a longer learning curve |
| Continuous-wave Doppler | – Spectral density of signal – Shape of signal | ||
| Pulsed Doppler mitral | – Height of E wave | ||
| Pulsed Doppler pulmonary veins | – Inversion of systolic flow wave | ||
| Continuous-wave tricuspid regurgitation | – Estimation of pulmonary pressure |