week 4 MR Flashcards
MR etiology
primary cause vs secondary (functional) cause
primary cause - smt wrong with MV apparatus
secondary cause - dilated LV so MV doesn’t close properly (normal MV but smt wrong with heart)
What are some primary causes of MR?
MVP
flail leaflet
trauma
endocarditis
prosthetic valve malfunction
cleft MV
MAC (mild MR)
rheumatic fever (usually causes MS, sometimes causes MR)
What are some secondary causes of MR?
tethered leaflet
LV dilation
Ischemic causes
ruptured pap muscle
SAM
MV prolapse
MVP = bowing of >2 mm above the MV annulus
Myxomatous degeneration of MV
another name for MVP
called myxomatous degeneration of MV bc weakening of CT
Barlow syndrome
another name from MVP
Named after doctor who first described MVP
usually refers to most severe form of MVP
What causes MVP?
Don’t know!
Idiopathic
genetic
associated with CT disorders
MVP murmur
mid systolic click then late systolic murmor
click bc sudden tensing of leaflet as it is pushed into LA
If there is MVP of AMVL, what does the MR jet look like?
Eccentric jet, posteriorly directed
What does the m-mode look like if have MVP?
late systolic dip
use M-mode to determine timing of MVP: mid - late systolic dip? holosystolic?
Flail MV leaflet
caused by torn chordae tendineae = acute MR
MR: how to tell the difference btw MVP and flail leaflet in 2D
MVP - tip of the leaflet point towards LV
Flail - tip of the leaflet points towards LA
If there is a flail AMVL, what does the MR jet look like?
Eccentric jet, posteriorly directed
Can trauma cause MR?
yes, if MVA, look at
Right heart bc most anterior
MV - sudden severe MR bc ruptured chordae or pap?
Endocarditis
bacterial infection of heart valves - get vegetation or bacteria eats a hole in valve
More likely to cause MR than MS
Prosthetic valve malfunction
most prosthetic valves have trivial MR = washes out valve so no clots
Shouldn’t see significant MR
especially bad if leaking through sewing ring!
cleft MV
hole in leaflet, usually AMVL
rare, congenital
Tethered leaflet
post MI, the LV changes shape and pap muscle shifts more apically
= tightens chordae
= MV can’t close properly
LV dilation
post MI, LV dilates
= MV leaflets too far apart to close properly
Ischemic causes
We used to think that damaged paps bc MI caused MR…
new research shows that revascularization of paps does not improve MR
ruptured pap muscle
causes sudden severe MR - pap muscle is attached to leaflet with chordae and swings between LA and LV
bc trauma (MVA) or post MI (rare)
SAM
Systolic Anterior Motion of MV
Associated with hypertrophic cardiomyopathy (= thick IVS)
= narrowed LVOT sucks AMVL over
- more suctioning effect in late systole = more MR
Which MV pap muscle is more likely to rupture?
PM pap muscle bc its supplied by only one coronary
PM pap - PDA
AL pap - LAD and Cx
If there is SAM, what does MR jet look like?
eccentric MR jet, posteriorly directed
Hemodynamic consequences of Acute MR? Symptoms?
sudden significant MR
Incr LA press
Incr Pulm press
Sudden severe pulm congestion, edema, SOB, cardiogenic shock
Hemodynamic consequences of chronic compensated MR (stable)? Symptoms?
Chronic significant MR
LA dilates = normal LA press and pulm press
LV dilates to accommodate excess blood = incr SV = extra blood pushed out
No symptoms, incr risk clot and may have A-fib (bc dilated LA)
Hemodynamic consequences of chronic decompensated MR? Symptoms?
severe LV dilation
decr LV contractility = decr EF
systolic failure
incr end systolic vol = incr LV filling press = diastolic failure = incr pulm press
SOB, poor exercise tolerance, fatigue, edema, A-fib
Murmur for MR
holosystolic or pansystolic
- lasts all of systole and both isovolumetric periods
Role of echo in MR
- determine etiology - if see MR, you must find the reason especially if it is an eccentric jet
- Assess for severity of MR
a) visual assessment
b) specific signs of MR:
- colour jet area
- vena contracta width
- flow convergence
- pulm vein reversal
c) supportive signs of MR:
- Mitral inflow pattern
- LA size
- CW of MR
d) quantitative params:
- PISA
- Regurg Vol
- Regurg Fraction
Assess for severity of MR:
Visual Assessment
- how would you grade an eccentric jet?
Assess MR in every view (PLAX, Ap) - go off axis to get max vel
PSAX is good for location and number of jets
*Always grade eccentric jets one higher than they look visually bc get sucked against wall which makes them seem narrower than they are
Assess for severity of MR:
Colour jet area
A specific sign of MR - not routine in BC
store clip with largest MR
trace around aliasing jet
get jet area
or divide jet area by LA size to get %
Assess for severity of MR:
Vena contacta width
A specific sign of MR
PLAX with colour
zoom in on MR
measure the width of narrowest spot of jet
- incr vena contracta width = incr MR severity
Assess for severity of MR:
Pulm vein reversal
A specific sign of MR
in severe MR, get S wave reversal bc MR jet enters pulm vein in systole
Assess for severity of MR:
Mitral Inflow pattern
A supportive sign of MR
if severe MR, get an E wave dominant pattern, bc so much blood in LA
E > 1.2 m/s
big E? MR or grade 3?
Assess for severity of MR:
LA size
A supportive sign of MR
if MR, expect big LA
big LA? MR or diastolic dysf?
Assess for severity of MR:
CW trace through MR jet
A supportive sign of MR
Looking at INTENSITY of waveform (not Vmax - vel is ~4-5 m/s for mild mod and severe MR)
Severe MR
- bright
- triangle shaped and asymmetric (bc incr LA press = decr LV/LA gradient in mid-late sys)
Mild MR
- not bright
- parabolic
- compare brightness to mitral inflow intensity
Assess for severity of MR:
PISA
Quantitative param
* only do PISA if mod or worse MR
Ap 4 ch
zoom on MV with colour
shift baseline down to ~30 cm/s
find largest PISA shell
measure PISA radius from MV leaflet to first aliasing vel
CW through MR
trace
get Vmax and VTI
EROA = 2πr^2 * Vn / Vmax
for PISA, which way do you shift the baseline?
Shift the baseline in the direction of the regurg
*careful if TEE!
PISA formula
PISA = EROA
EROA = 2πr^2 * Vn / Vmax
r is PISA radius
Vn is aliasing vel
Vmax is peak vel of MR
Should a MR trace include the valve clicks?
Yes, bc MR includes the isovolumetric periods
Assess for severity of MR:
Regurgitant volume
Quant param - not done in BC
volume of blood leaking in each beat
Regurg Vol = EROA * VTI
already have EROA from PISA calculation and VTI from the CW of MR trace
Assess for severity of MR:
Regurgitant fraction
Quant param - not done in BC
volume of regurg as % of total SV
RF = R Vol/SV
R Vol = EROA * VTI (already calculated)
SV = CSA MV * VTI MV
CSA MV - measure size of MV opening in early diastole in Ap 4 ch = NOT ACCURATE
VTI MV - PW at MV annulus and trace
Treatment for MR
Meds
Percutaneous
- Percutaneous ring = tightens annulus
- MitraClip = pins leaflets together
Surgical
- prosthetic valve
