C8: Mitral Stenosis Flashcards
define MS
incomplete opening of the MV during diastole w/ thickened MV leaflets
which valve does rheumatic fever effect first
MV
3 layers of the MV leaflets
describe them
from ventricle side to atrial side:
fibrosa: provides structural support and stiffness when valve is closed
spongiosa: provides flexibility, contains less dense tissue
atrialis: smooth layer composed of endocardial cells that line the whole atria
which MV leaflet is more complex
how
AML, one layer extends mediallu towards the AV to form the aorto-mitral curtain
do both MV leaflets cover the same area of the valve orifice
yes, approx…. AML is longer and occupies up 1/3 of the MV annulus, PML is shorter and occupies 2/3 of MV annulus
how are the MV scallops labeled
lateral to medial, 1-3
which MV leaflet is more susceptible to MAC
PML
3 functions of chordae tendinae
how many are there
anchoring the valve
maintain ventricular geometry
prevent prolapse during systole
120
main function of pap muscles
contract during systole to hold the valve closed
describe the position and structure of the PM pap muscle
on the inferior wall of the LV (seen from PSAX adjacent to the septum)
has 2 bodies that trifurcate into 3 heads
blood supply for PM pap muscle
posterior descending A
describe the position and structure of the AL pap muscle
on the anterolateral wall of the LV (seen from PSAX near LV free wall)
had 1 body that bifurcated into 2 heads
blood supply for AL pap muscle
left anterior descending A and circumflex A
which pap muscle is more susceptible to complications from ischemia or infarction
PM pap muscle because it only has 1 artery supplying it
4 etiologies on MS
- rheumatic fever
- degenerative (MAC)
- congenital
- masses
describe how rheumatic fever causes MS
inflammation causes swelling and then scarring of the leaflets, starts at the leaflet tips… will eventually lead to calcifications
how are the commissures effected w/ rheumatic MS
chordae?
- theyre thickened and fibrosed
- matted and shortened (think rheu’matted’ fever)
characteristic appearance of MV w/ rheumatic MS
fish mouth
describe how degeneration (MAC) causes MS
calcification of the MV annulus that usually starts at the posterior basal annulus and progresses inwards to the leaflets
which area of the MV is usually spared w/ MAC
leaflet tips
MAC is associated w/ which conditions
HTN diabetes hypercalcemia age Marfan's syndrome renal dialysis
describe the congenital causes of MS
usually involves subvalvular apparatus like a single pap muscle
term for a single pap muscle
parachute MV
what types of masses may cause MS
large MV vegetation from bacterial endocarditis
large LA myxoma
describe the pathophysiology of MS in the heart
reduce opening of MV leads to increased LA pressure, this increases PV, lung and PA pressure and evetually increases RVSP and RA press which leads to TR
describe the pathophysiology of MS in body
increase RH press leads to increase venous press w/ hepatomegaly, pedal edema, sometimes distended JVs
which arrhythmia is common w/ severe MS
A fib
symptoms of MS are similar to which other condition
backwards HF
w/ MS, does LV and LA pressure equalize during diastasis
why
no, you’ll lose diastasis and will see forward flow into the LV instead
theres a smaller opening for blood to pass through so press takes longer to drop
what kind of murmur is heard w/ MS
diastolic rumble at apex
3 symptoms of MS
dyspnea
reduced execise capacity (SOBOE)
fatigue
what factors can make the symptoms of MS worse
any increase in HR or CO: fever anemia preg hyperthyroidism rapid arrhythmia
complications of MS
a fib atrial enlargement blood clots and thromboembolism hempotysis endocarditis
what is hempotysis
frothy, bloody sputum in the lungs
w/ MS would you measure the thickness of the valve leaflets
how do you do this
yes
zoom on the MV, scroll until valve is at maximal opening and well seen, measure both leaflets
4 important doppler parameters to grade MS severity
mean trans-mitral press gradient (important) - trace VTI
MV area - measure PHT
pulmonary artery pressures
MR
also do continuity equation
rheumatic MS 2D appearance
commissural fusion: leads to doming of the AML and restricts the movement of the PML
restricted motion
whats the characteristic MV appearance of rheumatic MS
hockey stick
w/ the MV have the double bump w/ MS
no
norm value for MV leaflet thickness
1-2 mm
characteristic of severe MAC
posterior shadowing in and behind the LA
can the chordae be effected by MAC
yes
another term for MAC
mitral sclerosis
what is a cor triatriatum sinister
a perforate LA membrane that impedes flow of blood from LA to LV and causes a gradient b/w the LA and LV
are there any symptoms unique to cor triatriatum sinister
no, same as other types of MS
is the MV usually norm w/ cor triatriatum sinister
yes
what does the severity of the cor triatriatum sinister depend on
the size of the perforation(s) in the membrane, eg. how easily blood can get through
describe a LA myxoma
most common primary tumor in the heart, most are benign… often attached to the fossa ovalis w/ a peduncle/foot
US appearance of a LA myxoma
globular, fine speckld appearance
what can happen if a LA myxoma is large
prolapse into the MV during diastole and cause functional MS
what is a parachute MV
associated w/ which syndrome
a single pap muscle that often placed too far superior in the LV
shone’s syndrome
5 anomalies of shone’s syndrome
supravalvular ring parachute MV subAO stenosis bucuspid AV Ao coarctation
how do you do MV planimetry
is it accurate
zoom on the MV in PSAX and trace around the blood tissue interface
can be the most accurate method to quantify MS if done properly
what does the accurate on MV planimetry depend on
ability to clearly see the orifice
tracing orifice directly at leaflet tips
gain settings
operator skill
if you transect the MV above the leaflet tips, how will that effect MV planimetry
will underestimate its severity
MS on M-mode
reduced excursion on MV, loss of double bump and diastasis, tracing will be brighter
when is the only time we do colour on the MV in PSAX
if theres MR
is you have MS, would your MV inflow PW be accurate for assessing diastolic dysfunction
what should you do
no, MS will cause the flow to be high velocity
reply on TDI tracing instead
PW will alias over what velocity
2m/s
how do we get MV mean press gradient
how does the machine calculate it
use CW through the MV inflow and trace the waveform…
machine will give you the mean PG by applying 4(v^2) to each point on the trace and avg the values… this is done b/w the waveform is not parabolic and the PG varies throughout diastole
how can HR effect the MV mean press gradient value
what about preload
Lower HR will result in a smaller waveform for mean PG is underestimated
can be over or underestimated w/ changes in preload
MV mean press gradient value for mild MS
severe
mild: < 5 mmHg
severe: >10 mmHg
how does MS effect PHT
the rate of atrial emptying in slowed due to a narrowed orifice which prolongs the decline on early diastolic PG b/w the LA and LV… PHT will be prolonged
how are MV area and PHT related
inversely… press fall slower w/ a more stenotic valve b/c the PG is maintained for longer
formula for MV area
MV Area = 220 / PHT
how is DT effected w/ MS
prolonged, press fall slower w/ a more stenotic valve b/c the PG is maintained for longer
as MS gets more severe, how can the MV inflow A wave change
gets merged w/ the e wave
how do we measure MV area w/ the continuity method
calculate SV through the AV/a control valve using the LVOT and LVOT VTI, then we can measure the VTI of the MV inflow and extrapolate and MV area from that
can you use to continuity method to measure MS if you have mod-severe MR or AR
no, use PHT instead, or PISA, or use a different valve for the control valve
continuity equation formula for MV area
MVA = (pie (r^2) x VTI) of LVOT / VTI of MV
you need LVOT diameter
LVOT PW trace
MV CW trace
2 sources of error when calculating MV area w/ continuity equation
incorrect measurement of LVOT area
incorrect doppler angle
continuity equation to measure MV area is less accurate in which conditions
when would you not use this meathod
significant MR, AR
ASD or other intracardiac shunt
which method for measuring MV area is the quickest
PHT
does TTE or TEE have better sensitivity for blood clots
TEE. TTE has high specificity but low sensitivity
why is it important to measure RVSP w/ MS
it tells you how the heart in handling the MS
can MS cause pulmonary hypertension
is it reversible
yes
at first, longstanding PHT causes irreversible increases and wont resolve even w/ MV surgery
what does timing of MV surgery depend on
LV/LA and Rv function
pharmacologic treatment for MS
beta blockers
diuretics
anticoagulation
anti-arrhythmics
you would try these before surgery
surgical treatment for MS
valve repair - cant be done if the cause is calcific
balloon valvuloplasty
commissurotomy (causes regurg)
valve replacement
bioprosthetic
mechanical
percutaneous
norm MV area
4-6 cm^2
MV area for mild MS
severe
mild: >1.5 cm^2
severe: < 1 cm^2
same as mild/severe AS
