When performing a comprehensive echocardiography exam quantification of mitral regurgitation has to rank as one of the more challenging routine questions you will be asked to answer. No single parameter can be relied upon to accurately report the severity of mitral regurgitation.
A comprehensive assessment of both qualitative and quantitative parameters is necessary to fully understand the full extent of mitral regurgitation in a patient. By utilizing a standardized approach to mitral regurgitation in your echo report you will better define mitral regurgitation and guide surgical decision making.
Checklists have been shown to improve standardization and improve patient care. Get our quantitive evaluation tips presented in an organized easy to use checklist to improve your echocardiography skills and prepare for your echo boards.
Get our free Mitral Regurgitation Assessment Checklist Here and start standardizing your mitral regurgitation evaluation.
When assessing Mitral Regurgitation look for and note the following four points
- The pathologic Process Causing the Regurgitation
- Myxomatous degeneration
- Rheumatic disease
- Ventricular dysfunction
- The mechanism of Regurgitation
- The location of the lesion / Which segments are involved
- The severity of the lesion
The Pathologic Process Causing Mitral Regurgitation:
Pattern recognition and mental models are shortcuts to help you do your job better and faster. By knowing the patient’s medical history you can begin to tailor your exam to key points related to these know pathologies.
Myxomatous Degeneration is a non-inflammatory progressive degradation of the valve structure caused by a defect in the synthesis and/or remodeling by type VI collagen. Key points include:
- the most frequent complication of myxomatous valvular disease is the mitral valve prolapse (MVP), defined as the atrial bulging of the mitral leaflets of more than 2 mm during systole beyond the annular plane, a valvular thickening of ≥3 mm and/or ruptured chordae tendineae.
- mostly involves the posterior leaflet, usually in the absence of commissural fusion and with a normal or enlarged annulus
- Characterized by the ballooning of the leaflets or “hooding” of the posterior leaflet
- affected leaflets are enlarged, thick, rubbery
Mitral Valve General Assessment:
Mitral regurgitation is a challenging valve lesion to assess in the perioperative setting. Mitral regurgitation is a dynamic valvular lesion affected by changes in preload, afterload, and ventricular function.
The clinical presentation of mitral regurgitation can be different if it is an acute lesion or if it has been a chronic problem.
Mitral regurgitation will present different as an acute lesion than it does as a chronic lesion.
There is rarely a single measure that you can rely on for quantification of mitral regurgitation Instead a series of measurements that point to the severity of the lesion. Here at EchoBoards Academy we refer to this series of measurements as the Mitral Matrix.
For our beginners, we will walk you through the matrix so you know where to begin when assessing mitral regurgitation.
There are many options for sequential analysis of the mitral regurgitation. Whichever way you choose, the goal is to be consistent and assess the mitral valve in an organized manner
Here is a view of the mitral valve in cross section. Reference this image as you get familiar with the anatomy of the six standard views to image mitral regurgitation. When you are learning the standard views for the mitral valve exam, remember that the exact angle doesn’t make the view. The angle at which the view is best obtained will change slightly depending on the rotation of the heart and associated pathology. What you see is more important than the omniplane angle.
Every mitral valve exam starts in the ME 4-Chamber View. This view gives you a good general assessment of the mitral valve, left ventricle, right ventricle and the aortic valve. All of which can effect your mitral regurgitation.
ME 4-Chamber View
Begin Your Exam by looking at the Mitral Valve without Color.
Assessment of the mitral valve without color flow Doppler helps you focus on the etiology of the mitral regurgitation before trying to quantify the severity.
When evaluating the mechanism of mitral regurgitation, it is helpful to have an understanding of what the most common diseases associated with mitral regurgitation are and how they appear on echocardiography.
Many echocardiographers will skip looking at the valve without color. After all, it is impossible to quantify mitral regurgitation without color flow doppler.
Common Causes of Mitral Regurgitation and Mechanisms:
Mitral regurgitation is caused by abnormalities in one or any combination of the three following anatomical regions:
- The Leaflets
- The Annulus
- The Subvalvular Apparatus: Cordae Tendinea/Papillary Muscles
The most common diseases that can cause one of these four leaflet abnormalities include:
- Rheumatic disease: usually with mitral stenosis
- Mitral Valve Prolapse
- Connective Tissue Disorders (Marfans, Ehlers-Danlos )
- Congenital, clefts, etc….
Abnormalities of The Leaflets
When assessing mitral regurgitation arising from a leaflet etiology, the mitral regurgitation can arise from four main leaflet abnormalities:
- motion (prolapse/flail vs restriction)
- coaptation (point high/low and length)
- perforation / cleft ( congenital/secondary absence of leaflet)
Of these four, leaflet motion receives the most attention The motion of the mitral valve leaflets are so important that an entire classification system was developed to categorize different types of mitral regurgitation based upon the motion of the leaflets. The Carpentier Classification of Mitral regurgitation.
Carpentier Type I:
thin leaflets at annulus decreased coaptation length open normally decreased global LV function
Thick leaflets Above the annulus mal-coaptation Normal opening Normal LV
Type III a : this is our rheumatic valve
Thick leaflets At annulus Normal Coaptation decreased opening Normal LV
Type IIIb normal associated with regional wall motion abnormalities (ischemic)
Thin leaflets Below annulus decreased coaptation lengthnormal opening Left ventricle with regional wall motion abnormalities.
Time to move beyond a functional classification to an echo classification;
Mitral regurgitation due to primary leaflet abnormalities is most commonly attributed to rheumatic heart disease leading to deformity and shortening of the mitral apparatus and is usually associated with mitral stenosis. This is the Carpentier Class IIIa Valve.
Mitral Regurgitation is not limited to just abnormalities of the leaflets. There are often other coexisting diseases of the heart leading to Mitral Regurgitation. These include:
Abnormalities of The Annulus
- Size (measure in ____- )
- Displacement ( into the LV ??)
- Dilation due to LV dysfunction / dilated cardiomyopathy
- annular calcification : idopathic, age associated, other conditions.
Degenerative mitral annular calcifications (MAC) are often seen with aging and associated with other mitral regurgitation etiologies. Often the mitral annulus has dilated causing coaptation problems for the leaflets.
Abnormalities of Subvalvular Apparatus:
The Cordea : increased or decreased length
- more commonly rupture of the posterior leaflet
- idiopathic, endocarditis, rheumatic heart disease, mitral valve prolapse
Abnormalities of The Papillary Muscles :Abnormalities of the papillary muscles most commonly involve ischemic events from coronary artery disease causing ventricular wall changes.
- dysfunction / displacement with LV size/function
- ischemia / infarction
- LV dilation
- rheumatic heart disease
- infiltration – sarcoid / amyloid
Once you have assessed the structure and function of the valve without color.
After you have looked at the valve without color, place color flow Doppler on the valve and look at the valve with color.
When you first put color doppler on the valve, you will find the mitral regurgitation jet can take on a characteristic pattern.
Mitral Regurgitation Measure Limitations:
KEY POINT: MR is particularly sensitive to the loading conditions of the left ventricle and the receiving chamber pressure. Sometimes severe MR is only recognized under stress echocardiography. 70% of patients have trace / mild
Technical Limitations: Color Doppler has a limit with Nyquist Limit, using an inappropriate nyquist Spectral Doppler has a limit with the alignment of the doppler Type of Jets, eccentric jets and multiple/complex jets Time consuming
Hemodynamic Limitations: Pressure differences depend on loading conditions and provocative testing. We all know about this with regards to mitral regurgitation. Dynamic jet changes changes in systole, not all MR is Pan systolic. Duration of MR Acute vs Chronic
IN reality we are interested in only two main aspects of quantification of regurgitation. The regurgitant Volume and the regurgitant orifice area. Or How bad does this leak and how big is the hole ?
Method #1 Jet Area
Jet Area Limitations
Jet area is useful for screening for MR. JA does not reflect regurgitation volume.
Hemodynamics (SBP) are important, proactive testing, pressure differences, hypo/er-tensive Left atrium LAP compliance and Enlarged LA Eccentric jets will be under estimated due to the Coanda effect.
Limitations of Vena contracta: often the only measure used in the OR. Linear measure of area, you are making an assumption using a single frame. Different Jets will have different shapes. Primary MR is circular, secondary MR is elongated. Vena Contracta is Dynamic and load dependent. It can be very useful in eccentric jets It is not useful in multiple jets
If its primary MR it will be circular if its secondary it will be eliptical.
GEt the blue mushroom. It allows you to more accurately measure the radius. often best obtained using a Zoomed view.
MR Spectral Doppler Peak velocity will be high, density can help you a little bit, Severe MR is a truncated truncated early peaking trace.
Most important to obtain to use in later measurements.
Pulmonary Vein Doppler Blunding is non-specific for MR. Reversal can be specific particularly if it is in more than one vein and in the presence of an eccentric jet.
If its posterior it involves the right pulmonary veins If its anterior it involves the left pulmonary veins. this helps you know the direction.
it can be used as an absolute value when you adjust your nyquist to 25-40cm/s if its greater than 1cm then it suggest its severe. measure radius (r) in Mid-systole many times you are using pisa radius to calculate EROA volume
Pisa Radius is not static, There is some variation in etiology, there are early and late peaks.
some variation in the etiology. if its functional it has early and late peaks. MVP shows a late peak.
If you have an eccentric jet and you want to quantify it. You have an orientation problem from the mid esophgeal views. Its hard to get a good CW in the mid esophageal views.
The baseline is shifted up in the direction of the Jet.
IN the TG view you shift your baseline in the direction of the jet (downwards) and you get a shell and calculate EROA
This doppler trace is filled in and better than you would get in a ME view. The velocity should be 4-6 m/s for a MR jet.
the low velocity will overestimate your EROA, just be cautious when you dont’ have great data.
Regurgitant Volume :
Your CW trace is important because it is used to calculate different aspects of severity.
You can measure regurgitation volume through three different techniques.
Case Summary: Eccentric jet, difficult to assess.
Whats the difference between type I and type III b . Type IIIb will have leaflet tethering. We rarely see type I, simple annular dilation. So why is this not type I. If your posterior leaflet is teathered you should have an eccentric jet but here we had a central jet.
Where to measure the mitral annulus. You should measure it in diastole and you should measure it in two views. Your LAX view and your commisural view. These are your “D” or diameter measurements.
SAM after mitral valve repair:
posterior directed jet. one of the only times that you can have a restricted posterior leaflet and the jet does not go towards the leaflet.