Mitral Valve Flashcards
What is the most common cause of MS in adults?
Rheumatic fever
Which papillary muscle is more likely to rupture?
The posteromedial papillary muscle (receives blood supply from only RCA in 70% of patients)
What is the short axis of the mitral valve and where is it best measured? What is its normal value?
The anterior-posterior axis; best measured in the ME LAX view.
It is the highest point in the annulus (the “high axis”).
Normal <3.6cm
What is the commissural axis of the mitral valve and where is it best measured?
What is the normal size?
The long axis; best measured in the ME commissural view.
It is the lowest point in the annulus (the “low axis”).
Normal <46mm
Which TEE view shows the high axis of the mitral valve?
ME LAX (gives us the AP diameter)
Which view is best for looking at the subvalvular apparatus?
TG 2C
Shows the posteromedial papillary muscle (closest to probe)
What is billowing, prolapse, and flail?
Billowing: body of leaflet above annular plane, tip below annular plane
Prolapse: leaflet tip above annular plane
Flail: ruptured chord, entire leaflet above annular plane
What is Carpentier’s classification of MR?
Type I: normal leaflet motion (annular dilation or perforation)
Type II: excessive leaflet motion (prolapse or flail)
Type IIIa: restricted in both systole and diastole (Rheumatic heart disease)
Type IIIb: restricted in systole (LV/LA dilation)
What are possible etiologies of MR?
- Myxomatous degeneration (most common in developed countries)
- Rheumatic disease (most common in developing nations)
- Ischemia (PM dysfunction/rupture)
- Cardiomyopathy (dilated, IHSS)
- Endocarditis
- Congenital
- Connective tissue disease
What is the cutoff for mild, moderate and severe MR by vena contracta?
Mild: <0.3cm
Moderate: 0.3-0.7cm
Severe: >0.7cm
What is the cutoff for severe MR by MR jet area?
> 10cm2
What is the cutoff for severe MR by EROA?
> /= 0.4cm2
What echo sign is seen in rheumatic mitral stenosis?
Diastolic doming of the anterior mitral valve leaflet forming a “hockey stick” appearance and immobile posterior leaflet
Risk factors for SAM after MVr
Small:
- Mitral-aortic angle <120 degrees
- C-sept <2.5cm
- AL/PL ratio <1.3
- Small, non-dilated LV (LVIDd <4.5cm)
- Small annuloplasty ring
Big:
- AMVL length >20mm
- PMVL length >15mm
- Basal septal thickness >1.5cm
When will the MR jet will be directed away from a restricted leaflet?
SAM
Causes of mitral stenosis
- Rheumatic heart disease (most common in developed and undeveloped countries both)
- Left atrial myxoma
- Severe MAC
- Thrombus
- Parachute MV
- Congenital MS
- Subvalvular mitral ring
- Cortriatriatum sinister
How does severe AR or decreased LV compliance affect mitral valve area by pressure half time?
Will cause the degree of MS to be underestimated because of a rapid rise in LV diastolic pressure leading to more rapid equilibration of pressures between the LA and LV
Factors that can cause the mitral valve mean gradient to be over- or underestimated
- Severe MR: overestimate
- Angle of incidence is off: underestimate
- Decreased LV compliance: overestimate
- Impaired LV active relaxation: underestimate
- Increased HR: increases mean gradient
- Increased stroke volume: increases mean gradient
How does severe MR affect the MV mean gradient?
Increases the LAP leading to higher gradient across the mitral valve (more volume through the same area = higher pressure)
How does decreased LV compliance affect the MV mean gradient?
Causes restrictive inflow pattern on transmitral doppler inflow velocities = overestimation of the mean graident
How does impaired LV active relaxation affect the MV mean gradient?
Impaired active relaxation leads to decreased LV filling = less volume through the same area = lower pressure (underestimation)
How does HR affect the MV mean gradient?
Higher HR = higher MG
Lower HR = lower MG
How do changes in stroke volume affect the MV mean gradient?
Larger SV = higher MG
Smaller SV = lower MG
Due to changes in diastolic inflow across the MV
What general equation is PISA based on?
The continuity equation!
When doing a PISA radius measurement, how do you want to change the baseline for MS vs MR?
Move the baseline towards the lesion
For MS, move the baseline down (flow is away from probe)
For MR, move the baseline up (flow is towards the probe)
What is the equation for MVA based on PISA?
MVA = A_PISA * Aliasing velocity / Peak transmitral velocity
What is the equation for A_PISA?
A_PISA = 2π r^2 * α/180
How is stroke volume calculated?
Area * VTI through that area
What are the ways for calculating MVA?
- 220/PHT
- 760/DT
- PISA
- Continuity equation
What is the equation for calculating regurgitant volume?
Reg vol = SV_MV - SV_LVOT
Remember, SV = A*VTI
What are the regurgitant volume cutoffs for mild, moderate and severe MR?
Mild: <30cc
Moderate: 30-59cc
Severe: >/= 60cc
How do you calculate stroke volume going through the mitral valve?
CWD through the mitral valve –> measure VTI of diastolic inflow –> multiply by MVA (need to also calculate MVA)
What is the equation for calculating regurgitant fraction?
RF = backwards flow / total flow
RF = regurgitant volume / SV_MV inflow
What are the cutoffs for mild, moderate and severe MR by regurgitant fraction?
Mild: <30%
Moderate: 30-49%
Severe: >/= 50%
What is the equation for regurgitant orifice area?
Area = volume / distance
ROA = regurgitant volume / VTI_MR
What are the cutoffs for mild, moderate and severe MR by EROA?
Mild: <0.2 cm2
Moderate: 0.2-0.39 cm2
Severe: >/=0.4 cm2
What two echo images are needed to calculate PISA?
CFD with Nyquist optimized to measure shell radius
CWD to measure peak velocity
What are the cutoffs for mild, moderate and severe MR by vena contracta?
Mild: <3mm
Moderate: 3-7mm
Severe: >7mm
What are the cutoffs for mild, moderate and severe rheumatic MS by mitral valve area?
Mild: >2.5 cm3
Moderate: 2.5-1.6 cm3
Severe: </= 1.5 cm3
What are the cutoffs for mild, moderate and severe MS by PHT?
Mild: <100 msec
Moderate: 100-140 msec
Severe: >/= 150msec
What are the cutoffs for mild, moderate and severe MS by mean gradient?
Mild: <5 mmHg
Moderate: 5-10 mmHg
Severe: >10 mmHg
On 3D imaging of the MV (oriented to surgeon’s view), what structure is seen to the left of the mitral valve annulus?
The LAA
What are the four ways you can calculate the mitral valve area?
- 220/PHT
- 760/DT
- PISA
- Continuity equation
