Mitral Stenosis Flashcards
The MV leaflets are composed of what three layers?
Fibrosa, spongiosa, atrialis
What is the purpose of the MV fibrosa layer?
Provides structural support and stiffness
What is the purpose of the MV spongiosa layer?
Provides flexibility to the valve
What is the MV atrialis layer?
Smooth layer composed of endocardium cells that line the atria
The posterior mitral leaflet is what size compared to the anterior mitral leaflet?
Half the length of the AML
MV scallops are labelled in which direction anatomically?
Lateral to medial
Which mitral leaflet is more susceptible to MAC (Mitral annular calcification)
Posterior mitral leaflet
What three things are the chordae tendinae responsible for?
- Anchoring the valve
- Maintaining ventricular geometry
- Preventing prolapse during systole
What pap muscle is more susceptible to complications from Ischemia or infarction?
Posteromedial papillary muscle
Which vessel supplies the posteromedial papillary muscle?
Posterior descending artery
Where does the posteromedial papillary muscle lay?
Along the inferior wall seen in PSAX adjacent to the septum
Which vessel supplies the anterolateral papillary muscle?
Left anterior descending artery and the circumflex artery
Where does the anterolateral papillary muscle lay?
Along the anterolateral wall seen in PSAX
Where does MV stenosis occur with rheumatic etiology?
Leaflet tips due to inflammation followed by scarring
Where does MV stenosis occur with degenerative etiology?
Basal annulus (usually PMAC) and progresses towards the leaflets
Where does MV stenosis occur with congenital etiology?
Subvalvular (single pap muscle with parachute valve or ASD/VSD defects)
Rheumatic MV stenosis can lead to what appearance of the orifice?
Fish mouth
What does doming of the anterior leaflet (hockey stick appearance) and thick chordae indicate?
Commissural (leaflet) fusion from rheumatic AS.
What is the normal thickness of a mitral leaflet?
1-2 mm
What are the most common primary benign tumors of the heart?
Myxoma
What is Parachute MV?
MV stenosis caused by one papillary muscle instead of two.
Parachute MV is associated with what?
Shone’s syndrome
If someone has A-Fib how many beats should be captured to calculate mean PG?
3-5
What is pressure half time?
The time taken for the early diastolic pressure gradient to fall to half of its original value.
What kind of relationship does mitral valve area (MVA) have with pressure half time?
Inverse
How is MVA derived?
220 ÷ pressure half time = MVA in cm squared
What are sources of error for any valve?
Diameter and angle
Which echo study is more sensitive to LA clots due to LAE?
TEE
MS causes increased pulmonary venous pressure which leads to what?
Pulmonary arterial hypertension
Longstanding pulmonary arterial hypertension causes irreversible what?
Pulmonary vascular resistance
What are pharmacologic options to treat mitral valve stenosis?
Beta blockers, diuretics, anticoagulants, antiarrhythmics
What do beta blockers do?
Slows HR and enhances filling time
What are surgical treatments for mitral valve stenosis?
Valve repair and replacement
What things are associated with degenerative MS (MAC)? (3)
- Usual risk factors for atherosclerosis
- Barlow’s disease
- Marfan’s syndrome
What type of pressure gradient is used for the MV and why?
Mean pressure gradient
The mean is used because MV inflow is not a single peak but the E and A, the result is an average pressure over diastole
What are the values for MV mean gradient?
Mild = <
Mod = 5-10
Sev = >
How does MS affect the decel slope and why?
The decel slope will be less steep than normal due to prolonged decline of early diastolic PG between LV and LA since the atria cannot empty as quickly through the stenosis.
How is the MVA related to pressure half time?
Inversely
If MVA is decreased, pressure half time is increased.
How do you calculate MVA area from decel time?
- Find pressure half time
(P1/2t = 0.29/DT) - Find MVA with P1/2t
(MVA = 220/Phalftime)
What happens to the a-wave in severe MS?
It disappears, atria cannot contract against high pressures.
How can MVA be calculated using the continuity method?
By calculating the SV through another valve (usually AV)
What is the equation for MVA continuity?
MVA = VTI(lvot) x CSA(lvot) / VTI(mv)
When should MVA continuity NOT be used?
AR, MR, ASD or other significant shunt
What are the values for MS using MVA?
Mild MS = >1.5 cm
Mod MS = 1 - 1.5 cm
Severe MS = < 1.0 cm
